| Author | Title | Year | Journal/Proceedings | Reftype | DOI/URL |
|---|---|---|---|---|---|
| Aalto, T., Hatakka, J., Kouznetsov, R. and Stanislawska, K. | Background and anthropogenic influences on atmospheric CO2 concentrations measured at Pallas: comparison of two models for tracing air mass history | {2015} | BOREAL ENVIRONMENT RESEARCH Vol. {20}({2}), pp. 213-226 |
article | |
| Abstract: The FLEXTRA and SILAM models were utilized in estimating the influence regions (TR) for the measured CO2 concentration ([CO2]) at Pallas together with tracers for anthropogenic emissions. The models produced similar synoptic features and associated background [CO2] with marine IR and elevated [CO2] with continental IR, but there were also differences which affected the interpretation of measurements. The background, i.e. marine boundary layer (MBL) signal, was compared to the NOAA MBL reference. Both models performed well, with monthly mean deviations from the reference usually inside 1 ppm. The FLEXTRA MBL signal had some seasonality in the difference, however, only very few cases were associated with anthropogenic emissions. We used [CO] and fossil fuel [CO2] simulations by the TM5 (CarbonTracker CT2011_oi) model as emission tracers. The model and [CO] captured well the timing of high [CO2] in measurements. The anthropogenic influence was more pronounced in winter than in summer, and it had a large inter-annual variation. |
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BibTeX:
@article{aalto15a,
author = {Aalto, Tuula and Hatakka, Juha and Kouznetsov, Rostislav and Stanislawska, Karolina},
title = {Background and anthropogenic influences on atmospheric CO2 concentrations measured at Pallas: comparison of two models for tracing air mass history},
journal = {BOREAL ENVIRONMENT RESEARCH},
year = {2015},
volume = {20},
number = {2},
pages = {213--226}
}
|
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| Agol, E., Jansen, T., Lacy, B., Robinson, T.D. and Meadows, V. | THE CENTER OF LIGHT: SPECTROASTROMETRIC DETECTION OF EXOMOONS | {2015} | ASTROPHYSICAL JOURNAL Vol. {812}({1}) |
article | DOI |
| Abstract: Direct imaging of extrasolar planets with future space-based coronagraphic telescopes may provide a means of detecting companion moons at wavelengths where the moon outshines the planet. We propose a detection strategy based on the positional variation of the center of light with wavelength, ``spectroastrometry.'' This new application of this technique could be used to detect an exomoon, to determine the exomoon's orbit and the mass of the host exoplanet, and to disentangle the spectra of the planet and moon. We consider two model systems, for which we discuss the requirements for detection of exomoons around nearby stars. We simulate the characterization of an Earth-Moon analog system with spectroastrometry, showing that the orbit, the planet mass, and the spectra of both bodies can be recovered. To enable the detection and characterization of exomoons we recommend that coronagraphic telescopes should extend in wavelength coverage to 3 mu m, and should be designed with spectroastrometric requirements in mind. |
|||||
BibTeX:
@article{agol15a,
author = {Agol, Eric and Jansen, Tiffany and Lacy, Brianna and Robinson, Tyler D. and Meadows, Victoria},
title = {THE CENTER OF LIGHT: SPECTROASTROMETRIC DETECTION OF EXOMOONS},
journal = {ASTROPHYSICAL JOURNAL},
year = {2015},
volume = {812},
number = {1},
doi = {https://doi.org/10.1088/0004-637X/812/1/5}
}
|
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| Agusti-Panareda, A., Massart, S., Chevallier, F., Balsamo, G., Boussetta, S., Dutra, E. and Beljaars, A. | A biogenic CO2 flux adjustment scheme for the mitigation of large-scale biases in global atmospheric CO2 analyses and forecasts | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({16}), pp. 10399-10418 |
article | DOI |
| Abstract: Forecasting atmospheric CO2 daily at the global scale with a good accuracy like it is done for the weather is a challenging task. However, it is also one of the key areas of development to bridge the gaps between weather, air quality and climate models. The challenge stems from the fact that atmospheric CO2 is largely controlled by the CO2 fluxes at the surface, which are difficult to constrain with observations. In particular, the biogenic fluxes simulated by land surface models show skill in detecting synoptic and regional-scale disturbances up to sub-seasonal time-scales, but they are subject to large seasonal and annual budget errors at global scale, usually requiring a posteriori adjustment. This paper presents a scheme to diagnose and mitigate model errors associated with biogenic fluxes within an atmospheric CO2 forecasting system. The scheme is an adaptive scaling procedure referred to as a biogenic flux adjustment scheme (BFAS), and it can be applied automatically in real time throughout the forecast. The BFAS method generally improves the continental budget of CO2 fluxes in the model by combining information from three sources: (1) retrospective fluxes estimated by a global flux inversion system, (2) land-use information, (3) simulated fluxes from the model. The method is shown to produce enhanced skill in the daily CO2 10-day forecasts without requiring continuous manual intervention. Therefore, it is particularly suitable for near-real-time CO2 analysis and forecasting systems. |
|||||
BibTeX:
@article{agusti-panareda16a,
author = {Agusti-Panareda, Anna and Massart, Sebastien and Chevallier, Frederic and Balsamo, Gianpaolo and Boussetta, Souhail and Dutra, Emanuel and Beljaars, Anton},
title = {A biogenic CO2 flux adjustment scheme for the mitigation of large-scale biases in global atmospheric CO2 analyses and forecasts},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {16},
pages = {10399--10418},
doi = {https://doi.org/10.5194/acp-16-10399-2016}
}
|
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| Ahlstrom, A., Miller, P.A. and Smith, B. | Too early to infer a global NPP decline since 2000 | {2012} | GEOPHYSICAL RESEARCH LETTERS Vol. {39} |
article | DOI |
| Abstract: The global terrestrial carbon cycle plays a pivotal role in regulating the atmospheric composition of greenhouse gases. It has recently been suggested that the upward trend in net primary production (NPP) seen during the 1980's and 90's has been replaced by a negative trend since 2000 induced by severe droughts mainly on the southern hemisphere. Here we compare results from an individual-based global vegetation model to satellite-based estimates of NPP and top-down reconstructions of net biome production (NBP) based on inverse modelling of observed CO2 concentrations and CO2 growth rates. We find that simulated NBP exhibits considerable covariation on a global scale with interannual fluctuations in atmospheric CO2. Our simulations also suggest that droughts in the southern hemisphere may have been a major driver of NPP variations during the past decade. The results, however, do not support conjecture that global terrestrial NPP has entered a period of drought-induced decline. Citation: Ahlstrom, A., P. A. Miller, and B. Smith (2012), Too early to infer a global NPP decline since 2000, Geophys. Res. Lett., 39, L15403, doi:10.1029/2012GL052336. |
|||||
BibTeX:
@article{ahlstrom12a,
author = {Ahlstrom, Anders and Miller, Paul A. and Smith, Benjamin},
title = {Too early to infer a global NPP decline since 2000},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2012},
volume = {39},
doi = {https://doi.org/10.1029/2012GL052336}
}
|
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| Ahn, D.Y., Hansford, J.R., Howe, S.T., Ren, X.R., Salawitch, R.J., Zeng, N., Cohen, M.D., Stunder, B., Salmon, O.E., Shepson, P.B., Gurney, K.R., Oda, T., Lopez-Coto, I., Whetstone, J. and Dickerson, R.R. | Fluxes of Atmospheric Greenhouse-Gases in Maryland (FLAGG-MD): Emissions of Carbon Dioxide in the Baltimore, MD-Washington, DC Area | {2020} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {125}({9}) |
article | DOI URL |
| Abstract: To study emissions of CO2 in the Baltimore, MD-Washington, D.C. (Balt-Wash) area, an aircraft campaign was conducted in February 2015, as part of the Fluxes of Atmospheric Greenhouse-Gases in Maryland (FLAGG-MD) project. During the campaign, elevated mole fractions of CO2 were observed downwind of the urban center and local power plants. Upwind flight data and Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model analyses help account for the impact of emissions outside the Balt-Wash area. The accuracy, precision, and sensitivity of CO2 emissions estimates based on the mass balance approach were assessed for both power plants and cities. Our estimates of CO2 emissions from two local power plants agree well with their Continuous Emissions Monitoring Systems (CEMS) records. For the 16 power plant plumes captured by the aircraft, the mean percentage difference of CO2 emissions was -0.3%. For the Balt-Wash area as a whole, the 1 & x1d70e;& xdf0e; CO2 emission rate uncertainty for any individual aircraft-based mass balance approach experiment was +/- 38%. Treating the mass balance experiments, which were repeated seven times within 9 days, as individual quantifications of the Balt-Wash CO2 emissions, the estimation uncertainty was +/- 16% (standard error of the mean at 95% CL). Our aircraft-based estimate was compared to various bottom-up fossil fuel CO2 (FFCO2) emission inventories. Based on the FLAGG-MD aircraft observations, we estimate 1.9 +/- 0.3 MtC of FFCO2 from the Balt-Wash area during the month of February 2015. The mean estimate of FFCO2 from the four bottom-up models was 2.2 +/- 0.3 MtC. | |||||
BibTeX:
@article{ahn20a,
author = {Ahn, D. Y. and Hansford, J. R. and Howe, S. T. and Ren, X. R. and Salawitch, R. J. and Zeng, N. and Cohen, M. D. and Stunder, B. and Salmon, O. E. and Shepson, P. B. and Gurney, K. R. and Oda, T. and Lopez-Coto, I and Whetstone, J. and Dickerson, R. R.},
title = {Fluxes of Atmospheric Greenhouse-Gases in Maryland (FLAGG-MD): Emissions of Carbon Dioxide in the Baltimore, MD-Washington, DC Area},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {125},
number = {9},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD032004},
doi = {https://doi.org/10.1029/2019JD032004}
}
|
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| Ahue, W.K. | Regional carbon fluxes and boundary layer heights from the Airborne Carbon in the Mountains Experiment 2007 [BibTeX] |
2010 | School: University of Wisconsin--Madison | phdthesis | |
BibTeX:
@phdthesis{ahue10a,
author = {Ahue, William KM},
title = {Regional carbon fluxes and boundary layer heights from the Airborne Carbon in the Mountains Experiment 2007},
school = {University of Wisconsin--Madison},
year = {2010}
}
|
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| Alden, C.B., Miller, J.B. and White, J.W.C. | Can bottom-up ocean CO2 fluxes be reconciled with atmospheric 13C observations? | {2010} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {62}({5, SI}), pp. 369-388 |
article | DOI |
| Abstract: The rare stable carbon isotope, 13C, has been used previously to partition CO2 fluxes into land and ocean components. Net ocean and land fluxes impose distinctive and predictable fractionation patterns upon the stable isotope ratio, making it an excellent tool for distinguishing between them. Historically, isotope constrained inverse methods for calculating CO2 surface fluxes-the `double deconvolution'-have disagreed with bottom-up ocean flux estimates. In this study, we use the double deconvolution framework, but add, as a constraint, independent estimates of time histories of ocean fluxes to the atmospheric observations of CO2 and 13CO(2). We calculate timeseries of net land flux, total disequilibrium flux and terrestrial disequilibrium flux from 1991 to 2008 that are consistent with bottom-up net ocean fluxes. We investigate possible drivers of interannual variability in terrestrial disequilibrium flux, including terrestrial discrimination, and test the sensitivity of our results to those mechanisms. We find that C-3 plant discrimination and shifts in the global composition of C-3 and C-4 vegetation are likely drivers of interannual variability in terrestrial disequilibrium flux, while contributions from heterotrophic respiration and disturbance anomalies are also possible. |
|||||
BibTeX:
@article{alden10a,
author = {Alden, Caroline B. and Miller, John B. and White, James W. C.},
title = {Can bottom-up ocean CO2 fluxes be reconciled with atmospheric 13C observations?},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2010},
volume = {62},
number = {5, SI},
pages = {369--388},
doi = {https://doi.org/10.1111/j.1600-0889.2010.00481.x}
}
|
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| Alden, C.B., Miller, J.B., Gatti, L.V., Gloor, M.M., Guan, K., Michalak, A.M., van der Laan-Luijkx, I.T., Touma, D., Andrews, A., Basso, L.S., Correia, C.S.C., Domingues, L.G., Joiner, J., Krol, M.C., Lyapustin, A.I., Peters, W., Shiga, Y.P., Thoning, K., van der Velde, I.R., van Leeuwen, T.T., Yadav, V. and Diffenbaugh, N.S. | Regional atmospheric CO2 inversion reveals seasonal and geographic differences in Amazon net biome exchange | {2016} | GLOBAL CHANGE BIOLOGY Vol. {22}({10}), pp. 3427-3443 |
article | DOI |
| Abstract: Understanding tropical rainforest carbon exchange and its response to heat and drought is critical for quantifying the effects of climate change on tropical ecosystems, including global climate-carbon feedbacks. Of particular importance for the global carbon budget is net biome exchange of CO2 with the atmosphere ( NBE), which represents nonfire carbon fluxes into and out of biomass and soils. Subannual and sub-Basin Amazon NBE estimates have relied heavily on process-based biosphere models, despite lack of model agreement with plot-scale observations. We present a new analysis of airborne measurements that reveals monthly, regional-scale (similar to 1-8 x 10(6) km(2)) NBE variations. We develop a regional atmospheric CO2 inversion that provides the first analysis of geographic and temporal variability in Amazon biosphere-atmosphere carbon exchange and that is minimally influenced by biosphere model-based first guesses of seasonal and annual mean fluxes. We find little evidence for a clear seasonal cycle in Amazon NBE but do find NBE sensitivity to aberrations from long-term mean climate. In particular, we observe increased NBE ( more carbon emitted to the atmosphere) associated with heat and drought in 2010, and correlations between wet season NBE and precipitation ( negative correlation) and temperature ( positive correlation). In the eastern Amazon, pulses of increased NBE persisted through 2011, suggesting legacy effects of 2010 heat and drought. We also identify regional differences in postdrought NBE that appear related to long-term water availability. We examine satellite proxies and find evidence for higher gross primary productivity ( GPP) during a pulse of increased carbon uptake in 2011, and lower GPP during a period of increased NBE in the 2010 dry season drought, but links between GPP and NBE changes are not conclusive. These results provide novel evidence of NBE sensitivity to short-term temperature and moisture extremes in the Amazon, where monthly and sub-Basin estimates have not been previously available. |
|||||
BibTeX:
@article{alden16a,
author = {Alden, Caroline B. and Miller, John B. and Gatti, Luciana V. and Gloor, Manuel M. and Guan, Kaiyu and Michalak, Anna M. and van der Laan-Luijkx, Ingrid T. and Touma, Danielle and Andrews, Arlyn and Basso, Luana S. and Correia, Caio S. C. and Domingues, Lucas G. and Joiner, Joanna and Krol, Maarten C. and Lyapustin, Alexei I. and Peters, Wouter and Shiga, Yoichi P. and Thoning, Kirk and van der Velde, Ivar R. and van Leeuwen, Thijs T. and Yadav, Vineet and Diffenbaugh, Noah S.},
title = {Regional atmospheric CO2 inversion reveals seasonal and geographic differences in Amazon net biome exchange},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2016},
volume = {22},
number = {10},
pages = {3427--3443},
doi = {https://doi.org/10.1111/gcb.13305}
}
|
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| Alexandrov, G.A. and Matsunaga, T. | Normative productivity of the global vegetation [BibTeX] |
2008 | Carbon balance and management Vol. 3(1), pp. 8 |
article | |
BibTeX:
@article{alexandrov08a,
author = {Alexandrov, Georgii A and Matsunaga, Tsuneo},
title = {Normative productivity of the global vegetation},
journal = {Carbon balance and management},
publisher = {Springer},
year = {2008},
volume = {3},
number = {1},
pages = {8}
}
|
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| Alexe, M., Bergamaschi, P., Segers, A., Detmers, R., Butz, A., Hasekamp, O., Guerlet, S., Parker, R., Boesch, H., Frankenberg, C., Scheepmaker, R.A., Dlugokencky, E., Sweeney, C., Wofsy, S.C. and Kort, E.A. | Inverse modelling of CH4 emissions for 2010-2011 using different satellite retrieval products from GOSAT and SCIAMACHY | {2015} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {15}({1}), pp. 113-133 |
article | DOI |
| Abstract: At the beginning of 2009 new space-borne observations of dry-air column-averaged mole fractions of atmospheric methane (XCH4) became available from the Thermal And Near infrared Sensor for carbon Observations-Fourier Transform Spectrometer (TANSO-FTS) instrument on board the Greenhouse Gases Observing SATellite (GOSAT). Until April 2012 concurrent methane (CH4) retrievals were provided by the SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) instrument on board the ENVironmental SATellite (ENVISAT). The GOSAT and SCIAMACHY XCH4 retrievals can be compared during the period of overlap. We estimate monthly average CH4 emissions between January 2010 and December 2011, using the TM5-4DVAR inverse modelling system. In addition to satellite data, high-accuracy measurements from the Cooperative Air Sampling Network of the National Oceanic and Atmospheric Administration Earth System Research Laboratory (NOAA ESRL) are used, providing strong constraints on the remote surface atmosphere. We discuss five inversion scenarios that make use of different GOSAT and SCIAMACHY XCH4 retrieval products, including two sets of GOSAT proxy retrievals processed independently by the Netherlands Institute for Space Research (SRON)/Karlsruhe Institute of Technology (KIT), and the University of Leicester (UL), and the RemoTeC ``Full-Physics'' (FP) XCH4 retrievals available from SRON/KIT. The GOSAT-based inversions show significant reductions in the root mean square (rms) difference between retrieved and modelled XCH4, and require much smaller bias corrections compared to the inversion using SCIAMACHY retrievals, reflecting the higher precision and relative accuracy of the GOSAT XCH4. Despite the large differences between the GOSAT and SCIAMACHY retrievals, 2-year average emission maps show overall good agreement among all satellite-based inversions, with consistent flux adjustment patterns, particularly across equatorial Africa and North America. Over North America, the satellite inversions result in a significant redistribution of CH4 emissions from North-East to South-Central United States. This result is consistent with recent independent studies suggesting a systematic underestimation of CH4 emissions from North American fossil fuel sources in bottom-up inventories, likely related to natural gas production facilities. Furthermore, all four satellite inversions yield lower CH4 fluxes across the Congo basin compared to the NOAA-only scenario, but higher emissions across tropical East Africa. The GOSAT and SCIAMACHY inversions show similar performance when validated against independent shipboard and aircraft observations, and XCH4 retrievals available from the Total Carbon Column Observing Network (TCCON). |
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BibTeX:
@article{alexe15a,
author = {Alexe, M. and Bergamaschi, P. and Segers, A. and Detmers, R. and Butz, A. and Hasekamp, O. and Guerlet, S. and Parker, R. and Boesch, H. and Frankenberg, C. and Scheepmaker, R. A. and Dlugokencky, E. and Sweeney, C. and Wofsy, S. C. and Kort, E. A.},
title = {Inverse modelling of CH4 emissions for 2010-2011 using different satellite retrieval products from GOSAT and SCIAMACHY},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2015},
volume = {15},
number = {1},
pages = {113--133},
doi = {https://doi.org/10.5194/acp-15-113-2015}
}
|
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| Allen, M., Erickson, D., Kendall, W., Fu, J., Ott, L. and Pawson, S. | The influence of internal model variability in GEOS-5 on interhemispheric CO2 exchange | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {117} |
article | DOI |
| Abstract: An ensemble of eight atmospheric CO2 simulations was completed employing the National Aeronautics and Space Administration (NASA) Goddard Earth Observation System, Version 5 (GEOS-5) for the years 2000-2001, each with initial meteorological conditions corresponding to different days in January 2000 to examine internal model variability. Globally, the model runs show similar concentrations of CO2 for the two years, but in regions of high CO2 concentrations due to fossil fuel emissions, large differences among different model simulations appear. The phasing and amplitude of the CO2 cycle at Northern Hemisphere locations in all of the ensemble members is similar to that of surface observations. In several southern hemisphere locations, however, some of the GEOS-5 model CO2 cycles are out of phase by as much as four months, and large variations occur between the ensemble members. This result indicates that there is large sensitivity to transport in these regions. The differences vary by latitude-the most extreme differences in the Tropics and the least at the South Pole. Examples of these differences among the ensemble members with regard to CO2 uptake and respiration of the terrestrial biosphere and CO2 emissions due to fossil fuel emissions are shown at Cape Grim, Tasmania. Integration-based flow analysis of the atmospheric circulation in the model runs shows widely varying paths of flow into the Tasmania region among the models including sources from North America, South America, South Africa, South Asia and Indonesia. These results suggest that interhemispheric transport can be strongly influenced by internal model variability. |
|||||
BibTeX:
@article{allen12a,
author = {Allen, Melissa and Erickson, David and Kendall, Wesley and Fu, Joshua and Ott, Lesley and Pawson, Steven},
title = {The influence of internal model variability in GEOS-5 on interhemispheric CO2 exchange},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2011JD017059}
}
|
|||||
| Andres, R.J., Boden, T.A., Breon, F.M., Ciais, P., Davis, S., Erickson, D., Gregg, J.S., Jacobson, A., Marland, G., Miller, J., Oda, T., Olivier, J.G.J., Raupach, M.R., Rayner, P. and Treanton, K. | A synthesis of carbon dioxide emissions from fossil-fuel combustion | {2012} | BIOGEOSCIENCES Vol. {9}({5}), pp. 1845-1871 |
article | DOI |
| Abstract: This synthesis discusses the emissions of carbon dioxide from fossil-fuel combustion and cement production. While much is known about these emissions, there is still much that is unknown about the details surrounding these emissions. This synthesis explores our knowledge of these emissions in terms of why there is concern about them; how they are calculated; the major global efforts on inventorying them; their global, regional, and national totals at different spatial and temporal scales; how they are distributed on global grids (i.e., maps); how they are transported in models; and the uncertainties associated with these different aspects of the emissions. The magnitude of emissions from the combustion of fossil fuels has been almost continuously increasing with time since fossil fuels were first used by humans. Despite events in some nations specifically designed to reduce emissions, or which have had emissions reduction as a byproduct of other events, global total emissions continue their general increase with time. Global total fossil-fuel carbon dioxide emissions are known to within 10% uncertainty (95% confidence interval). Uncertainty on individ-ual national total fossil-fuel carbon dioxide emissions range from a few percent to more than 50 %. This manuscript concludes that carbon dioxide emissions from fossil-fuel combustion continue to increase with time and that while much is known about the overall characteristics of these emissions, much is still to be learned about the detailed characteristics of these emissions. |
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BibTeX:
@article{andres12a,
author = {Andres, R. J. and Boden, T. A. and Breon, F. -M. and Ciais, P. and Davis, S. and Erickson, D. and Gregg, J. S. and Jacobson, A. and Marland, G. and Miller, J. and Oda, T. and Olivier, J. G. J. and Raupach, M. R. and Rayner, P. and Treanton, K.},
title = {A synthesis of carbon dioxide emissions from fossil-fuel combustion},
journal = {BIOGEOSCIENCES},
year = {2012},
volume = {9},
number = {5},
pages = {1845--1871},
doi = {https://doi.org/10.5194/bg-9-1845-2012}
}
|
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| Andrews, A.E., Kofler, J.D., Trudeau, M.E., Williams, J.C., Neff, D.H., Masarie, K.A., Chao, D.Y., Kitzis, D.R., Novelli, P.C., Zhao, C.L., Dlugokencky, E.J., Lang, P.M., Crotwell, M.J., Fischer, M.L., Parker, M.J., Lee, J.T., Baumann, D.D., Desai, A.R., Stanier, C.O., De Wekker, S.F.J., Wolfe, D.E., Munger, J.W. and Tans, P.P. | CO2, CO, and CH4 measurements from tall towers in the NOAA Earth System Research Laboratory's Global Greenhouse Gas Reference Network: instrumentation, uncertainty analysis, and recommendations for future high-accuracy greenhouse gas monitoring efforts | {2014} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {7}({2}), pp. 647-687 |
article | DOI |
| Abstract: A reliable and precise in situ CO2 and CO analysis system has been developed and deployed at eight sites in the NOAA Earth System Research Laboratory's (ESRL) Global Greenhouse Gas Reference Network. The network uses very tall (> 300 m) television and radio transmitter towers that provide a convenient platform for mid-boundary-layer trace-gas sampling. Each analyzer has three sample inlets for profile sampling, and a complete vertical profile is obtained every 15 min. The instrument suite at one site has been augmented with a cavity ring-down spectrometer for measuring CO2 and CH4. The long-term stability of the systems in the field is typically better than 0.1 ppm for CO2, 6 ppb for CO, and 0.5 ppb for CH4, as determined from repeated standard gas measurements. The instrumentation is fully automated and includes sensors for measuring a variety of status parameters, such as temperatures, pressures, and flow rates, that are inputs for automated alerts and quality control algorithms. Detailed and time-dependent uncertainty estimates have been constructed for all of the gases, and the uncertainty framework could be readily adapted to other species or analysis systems. The design emphasizes use of off-theshelf parts and modularity to facilitate network operations and ease of maintenance. The systems report high-quality data with > 93% uptime. Recurrent problems and limitations of the current system are discussed along with general recommendations for high-accuracy trace-gas monitoring. The network is a key component of the North American Carbon Program and a useful model for future research-grade operational greenhouse gas monitoring efforts. |
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BibTeX:
@article{andrews14a,
author = {Andrews, A. E. and Kofler, J. D. and Trudeau, M. E. and Williams, J. C. and Neff, D. H. and Masarie, K. A. and Chao, D. Y. and Kitzis, D. R. and Novelli, P. C. and Zhao, C. L. and Dlugokencky, E. J. and Lang, P. M. and Crotwell, M. J. and Fischer, M. L. and Parker, M. J. and Lee, J. T. and Baumann, D. D. and Desai, A. R. and Stanier, C. O. and De Wekker, S. F. J. and Wolfe, D. E. and Munger, J. W. and Tans, P. P.},
title = {CO2, CO, and CH4 measurements from tall towers in the NOAA Earth System Research Laboratory's Global Greenhouse Gas Reference Network: instrumentation, uncertainty analysis, and recommendations for future high-accuracy greenhouse gas monitoring efforts},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2014},
volume = {7},
number = {2},
pages = {647--687},
doi = {https://doi.org/10.5194/amt-7-647-2014}
}
|
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| Babenhauserheide, A., Basu, S., Houweling, S., Peters, W. and Butz, A. | Comparing the CarbonTracker and TM5-4DVar data assimilation systems for CO2 surface flux inversions | {2015} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {15}({17}), pp. 9747-9763 |
article | DOI |
| Abstract: Data assimilation systems allow for estimating surface fluxes of greenhouse gases from atmospheric concentration measurements. Good knowledge about fluxes is essential to understand how climate change affects ecosystems and to characterize feedback mechanisms. Based on the assimilation of more than 1 year of atmospheric in situ concentration measurements, we compare the performance of two established data assimilation models, CarbonTracker and TM5-4DVar (Transport Model 5 - Four-Dimensional Variational model), for CO2 flux estimation. CarbonTracker uses an ensemble Kalman filter method to optimize fluxes on ecoregions. TM5-4DVar employs a 4-D variational method and optimizes fluxes on a 6 degrees x 4 degrees longitude-latitude grid. Harmonizing the input data allows for analyzing the strengths and weaknesses of the two approaches by direct comparison of the modeled concentrations and the estimated fluxes. We further assess the sensitivity of the two approaches to the density of observations and operational parameters such as the length of the assimilation time window. Our results show that both models provide optimized CO2 concentration fields of similar quality. In Antarctica CarbonTracker underestimates the wintertime CO2 concentrations, since its 5-week assimilation window does not allow for adjusting the distant surface fluxes in response to the detected concentration mismatch. Flux estimates by CarbonTracker and TM5-4DVar are consistent and robust for regions with good observation coverage, regions with low observation coverage reveal significant differences. In South America, the fluxes estimated by TM5-4DVar suffer from limited representativeness of the few observations. For the North American continent, mimicking the historical increase of the measurement network density shows improving agreement between CarbonTracker and TM5-4DVar flux estimates for increasing observation density. |
|||||
BibTeX:
@article{babenhauserheide15a,
author = {Babenhauserheide, A. and Basu, S. and Houweling, S. and Peters, W. and Butz, A.},
title = {Comparing the CarbonTracker and TM5-4DVar data assimilation systems for CO2 surface flux inversions},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2015},
volume = {15},
number = {17},
pages = {9747--9763},
doi = {https://doi.org/10.5194/acp-15-9747-2015}
}
|
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| Badawy, B., Polavarapu, S., Jones, D.B.A., Deng, F., Neish, M., Melton, J.R., Nassar, R. and Arora, V.K. | Coupling the Canadian Terrestrial Ecosystem Model (CTEM v. 2.0) to Environment and Climate Change Canada's greenhouse gas forecast model (v.107-glb) | 2018 | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. 11(2), pp. 631-663 |
article | DOI |
| Abstract: The Canadian Land Surface Scheme and the Canadian Terrestrial Ecosystem Model (CLASS-CTEM) together form the land surface component in the family of Canadian Earth system models (CanESMs). Here, CLASS-CTEM is coupled to Environment and Climate Change Canada (ECCC)'s weather and greenhouse gas forecast model (GEM-MACH-GHG) to consistently model atmosphere-land exchange of CO2. The coupling between the land and the atmospheric transport model ensures consistency between meteorological forcing of CO2 fluxes and CO2 transport. The procedure used to spin up carbon pools for CLASS-CTEM for multi-decadal simulations needed to be significantly altered to deal with the limited availability of consistent meteorological information from a constantly changing operational environment in the GEM-MACH-GHG model. Despite the limitations in the spin-up procedure, the simulated fluxes obtained by driving the CLASS-CTEM model with meteorological forcing from GEM-MACH-GHG were comparable to those obtained from CLASS-CTEM when it is driven with standard meteorological forcing from the Climate Research Unit (CRU) combined with reanalysis fields from the National Centers for Environmental Prediction (NCEP) to form CRU-NCEP dataset. This is due to the similarity of the two meteorological datasets in terms of temperature and radiation. However, notable discrepancies in the seasonal variation and spatial patterns of precipitation estimates, especially in the tropics, were reflected in the estimated carbon fluxes, as they significantly affected the mag-nitude of the vegetation productivity and, to a lesser extent, the seasonal variations in carbon fluxes. Nevertheless, the simulated fluxes based on the meteorological forcing from the GEM-MACH-GHG model are consistent to some extent with other estimates from bottom-up or top-down approaches. Indeed, when simulated fluxes obtained by driving the CLASS-CTEM model with meteorological data from the GEM-MACH-GHG model are used as prior estimates for an atmospheric CO2 inversion analysis using the adjoint of the GEOS-Chem model, the retrieved CO2 flux estimates are comparable to those obtained from other systems in terms of the global budget and the total flux estimates for the northern extratropical regions, which have good observational coverage. In data-poor regions, as expected, differences in the retrieved fluxes due to the prior fluxes become apparent. Coupling CLASS-CTEM into the Environment Canada Carbon Assimilation System (EC-CAS) is considered an important step toward understanding how meteorological uncertainties affect both CO2 flux estimates and modeled atmospheric transport. Ultimately, such an approach will provide more direct feedback to the CLASS-CTEM developers and thus help to improve the performance of CLASS-CTEM by identifying the model limitations based on atmospheric constraints. |
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BibTeX:
@article{badawy18a,
author = {Badawy, Bakr and Polavarapu, Saroja and Jones, Dylan B. A. and Deng, Feng and Neish, Michael and Melton, Joe R. and Nassar, Ray and Arora, Vivek K.},
title = {Coupling the Canadian Terrestrial Ecosystem Model (CTEM v. 2.0) to Environment and Climate Change Canada's greenhouse gas forecast model (v.107-glb)},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2018},
volume = {11},
number = {2},
pages = {631-663},
doi = {https://doi.org/10.5194/gmd-11-631-2018}
}
|
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| Baier, B.C., Sweeney, C., Choi, Y., Davis, K.J., DiGangi, J.P., Feng, S., Fried, A., Halliday, H., Higgs, J., Lauvaux, T., Miller, B.R., Montzka, S.A., Newberger, T., Nowak, J.B., Patra, P., Richter, D., Walega, J. and Weibring, P. | Multispecies Assessment of Factors Influencing Regional CO2 and CH4 Enhancements During the Winter 2017 ACT-America Campaign | {2020} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {125}({2}) |
article | DOI URL |
| Abstract: Diagnosing carbon dioxide (CO2) and methane (CH4) fluxes at subcontinental scales is complicated by sparse observations, limited knowledge of prior fluxes and their uncertainties, and background and transport errors. Multispecies measurements in flasks sampled during the wintertime ACT-America campaign were used for background characterization and source apportionment of regional anthropogenic CO2 and CH4 fluxes when ecosystem CO2 exchange is likely to be least active. Continental background trace gas mole fractions for regional enhancements are defined using samples from the upper troposphere and assessed using model products. Trace gas enhancements taken from flask samples in the lower troposphere with background levels subtracted out are then interpreted to inform CO2 and CH4 enhancement variability in the eastern United States. Strong correlations between CO2 and CH4 enhancements in the Midwestern and Mid-Atlantic United States indicated colocated anthropogenic sources. Oil and natural gas influence was also broadly observed throughout the entire observational domain. In the Midwestern United States, agricultural influence on CO2 and CH4 enhancement variability was evident during above-average wintertime temperatures. Weaker correlations between CO2 and anthropogenic tracer enhancements in the Southeastern United States indicated potentially nonnegligible wintertime ecosystem CO2 exchange, with biogenic tracers indicating more active surface processing than other regions. These whole-air flask samples illuminated significant regional CO2 and CH4 sources or sinks during Atmospheric Carbon and Transport-America (ACT-America) and can provide additional information for informing regional inverse modeling efforts. | |||||
BibTeX:
@article{baier20a,
author = {Baier, Bianca C. and Sweeney, Colm and Choi, Yonghoon and Davis, Kenneth J. and DiGangi, Joshua P. and Feng, Sha and Fried, Alan and Halliday, Hannah and Higgs, Jack and Lauvaux, Thomas and Miller, Benjamin R. and Montzka, Stephen A. and Newberger, Timothy and Nowak, John B. and Patra, Prabir and Richter, Dirk and Walega, James and Weibring, Petter},
title = {Multispecies Assessment of Factors Influencing Regional CO2 and CH4 Enhancements During the Winter 2017 ACT-America Campaign},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {125},
number = {2},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD031339},
doi = {https://doi.org/10.1029/2019JD031339}
}
|
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| Baker, I.T., Denning, A.S. and Stoeckli, R. | North American gross primary productivity: regional characterization and interannual variability | {2010} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {62}({5, SI}), pp. 533-549 |
article | DOI |
| Abstract: Seasonality and interannual variability in North American photosynthetic activity reflect potential patterns of climate variability. We simulate 24 yr (1983-2006) and evaluate regional and seasonal contribution to annual mean gross primary productivity (GPP) as well as its interannual variability. The highest productivity occurs in Mexico, the southeast United States and the Pacific Northwest. Annual variability is largest in tropical Mexico, the desert Southwest and the Midwestern corridor. We find that no single region or season consistently determines continental annual GPP anomaly. GPP variability is dependent upon soil moisture availability in low- and mid-latitudes, and temperature in the north. Soil moisture is a better predictor than precipitation as it integrates precipitation events temporally. The springtime anomaly is the most frequent seasonal contributor to the annual GPP variability. No climate mode (i.e. ENSO, NAM) can be associated with annual or seasonal variability over the entire continent. We define a region extending from the Northeast United States through the midwest and into the southwestern United States and northern Mexico that explains a significant fraction of the variability in springtime GPP. We cannot correlate this region to a single mechanism (i.e. temperature, precipitation or soil moisture) or mode of climate variability. |
|||||
BibTeX:
@article{baker10a,
author = {Baker, Ian T. and Denning, A. Scott and Stoeckli, Reto},
title = {North American gross primary productivity: regional characterization and interannual variability},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2010},
volume = {62},
number = {5, SI},
pages = {533--549},
doi = {https://doi.org/10.1111/j.1600-0889.2010.00492.x}
}
|
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| Ballantyne, A.P., Miller, J.B. and Tans, P.P. | Apparent seasonal cycle in isotopic discrimination of carbon in the atmosphere and biosphere due to vapor pressure deficit | {2010} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {24} |
article | DOI |
| Abstract: We explore seasonal variability in isotopic fractionation by analyzing observational data from the atmosphere and the biosphere, as well as simulated data from a global model. Using simulated values of atmospheric CO2 and its carbon isotopic composition, we evaluated different methods for specifying background concentrations when calculating the isotopic signature of source CO2 (delta(s)) to the atmosphere. Based on this evaluation, we determined that free troposphere measurements should be used when available as a background reference when calculating delta(s) from boundary layer observations. We then estimate the seasonal distribution of delta(s) from monthly climatologies derived from several atmospheric sampling sites. This approach yields significant seasonal variations in delta(s) with more enriched values during the summer months that exceed the uncertainty of delta(s) estimated for any given month. Intra-annual measurements of delta C-13 in the cellulose of Pinus taeda growing in the southeastern U.S. also reveal seasonal isotopic variations that are consistent in phase but not necessarily amplitude with atmospherically derived estimates of delta(s). Coherent seasonal patterns in delta(s) inferred from the atmosphere and observed in the biosphere were not consistent with the seasonal isotopic discrimination simulated by a commonly used biosphere model. However, delta(s) seasonality consistent with observations from the atmosphere and biosphere was retrieved with a revised biosphere model when stomatal conductance, and thus isotopic discrimination, was allowed to vary in response to vapor pressure deficit rather than relative humidity. Therefore, in regions where vapor pressure deficit and relative humidity are positively covariant over the growth season, such as the sub-tropics, different stomatal conductance models may yield very different estimates of CO2 and H2O exchange between the biosphere and atmosphere. |
|||||
BibTeX:
@article{ballantyne10a,
author = {Ballantyne, A. P. and Miller, J. B. and Tans, P. P.},
title = {Apparent seasonal cycle in isotopic discrimination of carbon in the atmosphere and biosphere due to vapor pressure deficit},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2010},
volume = {24},
doi = {https://doi.org/10.1029/2009GB003623}
}
|
|||||
| Ballantyne, A.P., Liu, Z., Anderegg, W.R.L., Yu, Z., Stoy, P., Poulter, B., Vanderwall, J., Watts, J., Kelsey, K. and Neff, J. | Reconciling carbon-cycle processes from ecosystem to global scales | {2021} | FRONTIERS IN ECOLOGY AND THE ENVIRONMENT Vol. {19}({1, SI}), pp. {57-64} |
article | DOI URL |
| Abstract: Understanding carbon (C) dynamics from ecosystem to global scales remains a challenge. Although expansion of global carbon dioxide (CO2) observatories makes it possible to estimate C-cycle processes from ecosystem to global scales, these estimates do not necessarily agree. At the continental US scale, only 5% of C fixed through photosynthesis remains as net ecosystem exchange (NEE), but ecosystem measurements indicate that only 2% of fixed C remains in grasslands, whereas as much as 30% remains in needleleaf forests. The wet and warm Southeast has the highest gross primary productivity and the relatively wet and cool Midwest has the highest NEE, indicating important spatial mismatches. Newly available satellite and atmospheric data can be combined in innovative ways to identify potential C loss pathways to reconcile these spatial mismatches. Independent datasets compiled from terrestrial and aquatic environments can now be combined to advance C-cycle science across the land-water interface. | |||||
BibTeX:
@article{ballantyne21a,
author = {Ballantyne, Ashley P. and Liu, Zhihua and Anderegg, William R. L. and Yu, Zicheng and Stoy, Paul and Poulter, Ben and Vanderwall, Joseph and Watts, Jennifer and Kelsey, Kathy and Neff, Jason},
title = {Reconciling carbon-cycle processes from ecosystem to global scales},
journal = {FRONTIERS IN ECOLOGY AND THE ENVIRONMENT},
publisher = {WILEY},
year = {2021},
volume = {19},
number = {1, SI},
pages = {57--64},
note = {Query date: 2021-04-02 15:20:04},
url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/fee.2296},
doi = {https://doi.org/10.1002/fee.2296}
}
|
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| Barichivich, J., Briffa, K.R., Osborn, T.J., Melvin, T.M. and Caesar, J. | Thermal growing season and timing of biospheric carbon uptake across the Northern Hemisphere | {2012} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {26} |
article | DOI |
| Abstract: Gridded daily temperature from 1950 to 2011 and atmospheric CO2 concentration data from high-latitude observing stations and the CarbonTracker assimilation system are used to examine recent spatiotemporal variability of the thermal growing season and its relationship with seasonal biospheric carbon uptake and release in the Northern Hemisphere. The thermal growing season has lengthened substantially since 1950 but most of the lengthening has occurred during the last three decades (2.9 days decade(-1), p < 0.01 for 1980-2011), with stronger rates of extension in Eurasia (4.0 days decade(-1), p < 0.01) than in North America (1.2 days decade(-1), p > 0.05). Unlike most previous studies, which had more limited data coverage over the past decade, we find that strong autumn warming of about 1 degrees C during the second half of the 2000s has led to a significant shift toward later termination of the thermal growing season, resulting in the longest potential growing seasons since 1950. On average, the thermal growing season has extended symmetrically by about a week during this period, starting some 4.0 days earlier and ending about 4.3 days later. The earlier start of the thermal growing season is associated with earlier onset of the biospheric carbon uptake period at high northern latitudes. In contrast, later termination of the growing season is associated with earlier termination of biospheric carbon uptake, but this relationship appears to have decoupled since the beginning of the period of strong autumn warming during the second half of the 2000s. Therefore, owing to these contrasting biospheric responses at the margins of the growing season, the current extension in the thermal growing season length has not led to a concomitant extension of the period of biospheric carbon uptake. |
|||||
BibTeX:
@article{barichivich12a,
author = {Barichivich, J. and Briffa, K. R. and Osborn, T. J. and Melvin, T. M. and Caesar, J.},
title = {Thermal growing season and timing of biospheric carbon uptake across the Northern Hemisphere},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2012},
volume = {26},
doi = {https://doi.org/10.1029/2012GB004312}
}
|
|||||
| Detection and attribution of carbon cycle processes from atmospheric O2 and CO2 measurements at Halley Research Station, Antarctica and Weybourne Atmospheric Observatory, U.K. [BibTeX] |
2018 | phdthesis | |||
BibTeX:
@phdthesis{barningham18a,,
title = {Detection and attribution of carbon cycle processes from atmospheric O2 and CO2 measurements at Halley Research Station, Antarctica and Weybourne Atmospheric Observatory, U.K.},
publisher = {UNIVERSITY OF EAST ANGLIA, U.K.},
year = {2018}
}
|
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| Barthlott, S., Schneider, M., Hase, F., Wiegele, A., Christner, E., Gonzalez, Y., Blumenstock, T., Dohe, S., Garcia, O.E., Sepulveda, E., Strong, K., Mendonca, J., Weaver, D., Palm, M., Deutscher, N.M., Warneke, T., Notholt, J., Lejeune, B., Mahieu, E., Jones, N., Griffith, D.W.T., Velazco, V.A., Smale, D., Robinson, J., Kivi, R., Heikkinen, P. and Raffalski, U. | Using XCO2 retrievals for assessing the long-term consistency of NDACC/FTIR data sets | {2015} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {8}({3}), pp. 1555-1573 |
article | DOI |
| Abstract: Within the NDACC (Network for the Detection of Atmospheric Composition Change), more than 20 FTIR (Fourier-transform infrared) spectrometers, spread worldwide, provide long-term data records of many atmospheric trace gases. We present a method that uses measured and modelled XCO2 for assessing the consistency of these NDACC data records. Our XCO2 retrieval setup is kept simple so that it can easily be adopted for any NDACC/FTIR-like measurement made since the late 1950s. By a comparison to coincident TCCON (Total Carbon Column Observing Network) measurements, we empirically demonstrate the useful quality of this suggested NDACC XCO2 product (empirically obtained scatter between TCCON and NDACC is about 4 parts per thousand for daily mean as well as monthly mean comparisons, and the bias is 25 parts per thousand). Our XCO2 model is a simple regression model fitted to CarbonTracker results and the Mauna Loa CO2 in situ records. A comparison to TCCON data suggests an uncertainty of the model for monthly mean data of below 3 parts per thousand. We apply the method to the NDACC/FTIR spectra that are used within the project MUSICA (multi-platform remote sensing of isotopologues for investigating the cycle of atmospheric water) and demonstrate that there is a good consistency for these globally representative set of spectra measured since 1996: the scatter between the modelled and measured XCO2 on a yearly time scale is only 3 parts per thousand. |
|||||
BibTeX:
@article{barthlott15a,
author = {Barthlott, S. and Schneider, M. and Hase, F. and Wiegele, A. and Christner, E. and Gonzalez, Y. and Blumenstock, T. and Dohe, S. and Garcia, O. E. and Sepulveda, E. and Strong, K. and Mendonca, J. and Weaver, D. and Palm, M. and Deutscher, N. M. and Warneke, T. and Notholt, J. and Lejeune, B. and Mahieu, E. and Jones, N. and Griffith, D. W. T. and Velazco, V. A. and Smale, D. and Robinson, J. and Kivi, R. and Heikkinen, P. and Raffalski, U.},
title = {Using XCO2 retrievals for assessing the long-term consistency of NDACC/FTIR data sets},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2015},
volume = {8},
number = {3},
pages = {1555--1573},
doi = {https://doi.org/10.5194/amt-8-1555-2015}
}
|
|||||
| Basu, S., Houweling, S., Peters, W., Sweeney, C., Machida, T., Maksyutov, S., Patra, P.K., Saito, R., Chevallier, F., Niwa, Y., Matsueda, H. and Sawa, Y. | The seasonal cycle amplitude of total column CO2: Factors behind the model-observation mismatch | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: CO2 surface fluxes that are statistically consistent with surface layer measurements of CO2, when propagated forward in time by atmospheric transport models, underestimate the seasonal cycle amplitude of total column CO2 in the northern temperate latitudes by 1-2 ppm. In this paper we verify the systematic nature of this underestimation at a number of Total Carbon Column Observation Network (TCCON) stations by comparing their measurements with a number of transport models. In particular, at Park Falls, Wisconsin (United States), we estimate this mismatch to be 1.4 ppm and try to attribute portions of this mismatch to different factors affecting the total column. We find that errors due to (1) the averaging kernel and prior profile used in forward models, (2) water vapor in the model atmosphere, (3) incorrect vertical transport by transport models in the free troposphere, (4) incorrect aging of air in transport models in the stratosphere, and (5) air mass dependence in TCCON data can explain up to 1 ppm of this mismatch. The remaining 0.4 ppm mismatch is at the edge of the <= 0.4 ppm accuracy requirement on satellite measurements to improve on our current estimate of surface fluxes. Uncertainties in the biosphere fluxes driving the transport models could explain a part of the remaining 0.4 ppm mismatch, implying that with corrections to the factors behind the accounted-for 1 ppm underestimation, present inverse modeling frameworks could effectively assimilate satellite CO2 measurements. |
|||||
BibTeX:
@article{basu11a,
author = {Basu, Sourish and Houweling, Sander and Peters, Wouter and Sweeney, Colm and Machida, Toshinobu and Maksyutov, Shamil and Patra, Prabir K. and Saito, Ryu and Chevallier, Frederic and Niwa, Yosuke and Matsueda, Hidekazu and Sawa, Yousuke},
title = {The seasonal cycle amplitude of total column CO2: Factors behind the model-observation mismatch},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2011JD016124}
}
|
|||||
| Basu, S., Guerlet, S., Butz, A., Houweling, S., Hasekamp, O., Aben, I., Krummel, P., Steele, P., Langenfelds, R., Torn, M., Biraud, S., Stephens, B., Andrews, A. and Worthy, D. | Global CO2 fluxes estimated from GOSAT retrievals of total column CO2 | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({17}), pp. 8695-8717 |
article | DOI |
| Abstract: We present one of the first estimates of the global distribution of CO2 surface fluxes using total column CO2 measurements retrieved by the SRON-KIT RemoTeC algorithm from the Greenhouse gases Observing SATellite (GOSAT). We derive optimized fluxes from June 2009 to December 2010. We estimate fluxes from surface CO2 measurements to use as baselines for comparing GOSAT data-derived fluxes. Assimilating only GOSAT data, we can reproduce the observed CO2 time series at surface and TC-CON sites in the tropics and the northern extra-tropics. In contrast, in the southern extra-tropics GOSAT X-CO2 leads to enhanced seasonal cycle amplitudes compared to independent measurements, and we identify it as the result of a land-sea bias in our GOSAT X-CO2 retrievals. A bias correction in the form of a global offset between GOSAT land and sea pixels in a joint inversion of satellite and surface measurements of CO2 yields plausible global flux estimates which are more tightly constrained than in an inversion using surface CO2 data alone. We show that assimilating the biascorrected GOSAT data on top of surface CO2 data (a) reduces the estimated global land sink of CO2, and (b) shifts the terrestrial net uptake of carbon from the tropics to the extratropics. It is concluded that while GOSAT total column CO2 provide useful constraints for source-sink inversions, small spatiotemporal biases -beyond what can be detected using current validation techniques - have serious consequences for optimized fluxes, even aggregated over continental scales. |
|||||
BibTeX:
@article{basu13a,
author = {Basu, S. and Guerlet, S. and Butz, A. and Houweling, S. and Hasekamp, O. and Aben, I. and Krummel, P. and Steele, P. and Langenfelds, R. and Torn, M. and Biraud, S. and Stephens, B. and Andrews, A. and Worthy, D.},
title = {Global CO2 fluxes estimated from GOSAT retrievals of total column CO2},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {17},
pages = {8695--8717},
doi = {https://doi.org/10.5194/acp-13-8695-2013}
}
|
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| Basu, S., Miller, J.B. and Lehman, S. | Separation of biospheric and fossil fuel fluxes of CO2 by atmospheric inversion of CO2 and (CO2)-C-14 measurements: Observation System Simulations | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({9}), pp. 5665-5683 |
article | DOI |
| Abstract: National annual total CO2 emissions from combustion of fossil fuels are likely known to within 5-10aEuro-% for most developed countries. However, uncertainties are inevitably larger (by unknown amounts) for emission estimates at regional and monthly scales, or for developing countries. Given recent international efforts to establish emission reduction targets, independent determination and verification of regional and national scale fossil fuel CO2 emissions are likely to become increasingly important. Here, we take advantage of the fact that precise measurements of C-14 in CO2 provide a largely unbiased tracer for recently added fossil-fuel-derived CO2 in the atmosphere and present an atmospheric inversion technique to jointly assimilate observations of CO2 and (CO2)-C-14 in order to simultaneously estimate fossil fuel emissions and biospheric exchange fluxes of CO2. Using this method in a set of Observation System Simulation Experiments (OSSEs), we show that given the coverage of (CO2)-C-14 measurements available in 2010 (969 over North America, 1063 globally), we can recover the US national total fossil fuel emission to better than 1aEuro-% for the year and to within 5aEuro-% for most months. Increasing the number of (CO2)-C-14 observations to similar to 5000 per year over North America, as recently recommended by the National Academy of Science (NAS) (Pacala et al., 2010), we recover monthly emissions to within 5aEuro-% for all months for the US as a whole and also for smaller, highly emissive regions over which the specified data coverage is relatively dense, such as for the New England states or the NY-NJ-PA tri-state area. This result suggests that, given continued improvement in state-of-the art transport models, a measurement program similar in scale to that recommended by the NAS can provide for independent verification of bottom-up inventories of fossil fuel CO2 at the regional and national scale. In addition, we show that the dual tracer inversion framework can detect and minimize biases in estimates of the biospheric flux that would otherwise arise in a traditional CO2-only inversion when prescribing fixed but inaccurate fossil fuel fluxes. |
|||||
BibTeX:
@article{basu16a,
author = {Basu, Sourish and Miller, John Bharat and Lehman, Scott},
title = {Separation of biospheric and fossil fuel fluxes of CO2 by atmospheric inversion of CO2 and (CO2)-C-14 measurements: Observation System Simulations},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {9},
pages = {5665--5683},
doi = {https://doi.org/10.5194/acp-16-5665-2016}
}
|
|||||
| Basu, S., Lehman, S.J., Miller, J.B., Andrews, A.E., Sweeney, C., Gurney, K.R., Xu, X., Southon, J. and Tans, P.P. | Estimating US fossil fuel CO2 emissions from measurements of C-14 in atmospheric CO2 | {2020} | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Vol. {117}({24}), pp. {13300-13307} |
article | DOI URL |
| Abstract: We report national scale estimates of CO2 emissions from fossilfuel combustion and cement production in the United States based directly on atmospheric observations, using a dual-tracer inverse modeling framework and CO2 and Delta(CO2)-C-14 measurements obtained primarily from the North American portion of the National Oceanic and Atmospheric Administration's Global Greenhouse Gas Reference Network. The derived US national total for 2010 is 1,653 +/- 30 TgC yr(-1) with an uncertainty (1 sigma) that takes into account random errors associated with atmospheric transport, atmospheric measurements, and specified prior CO2 and C-14 fluxes. The atmosphere-derived estimate is significantly larger (> 3 sigma) than US national emissions for 2010 from three global inventories widely used for CO2 accounting, even after adjustments for emissions that might be sensed by the atmospheric network, but which are not included in inventory totals. It is also larger (> 2 sigma) than a similarly adjusted total from the US Environmental Protection Agency (EPA), but overlaps EPA's reported upper 95% confidence limit. In contrast, the atmosphere-derived estimate is within 1 sigma of the adjusted 2010 annual total and nine of 12 adjusted monthly totals aggregated from the latest version of the high-resolution, US-specific ``Vulcan'' emission data product. Derived emissions appear to be robust to a range of assumed prior emissions and other parameters of the inversion framework. While we cannot rule out a possible bias from assumed prior Net Ecosystem Exchange over North America, we show that this can be overcome with additional Delta(CO2)-C-14 measurements. These results indicate the strong potential for quantification of US emissions and their multiyear trends from atmospheric observations. | |||||
BibTeX:
@article{basu20a,
author = {Basu, Sourish and Lehman, Scott J. and Miller, John B. and Andrews, Arlyn E. and Sweeney, Colm and Gurney, Kevin R. and Xu, Xiaomei and Southon, John and Tans, Pieter P.},
title = {Estimating US fossil fuel CO2 emissions from measurements of C-14 in atmospheric CO2},
journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
publisher = {NATL ACAD SCIENCES},
year = {2020},
volume = {117},
number = {24},
pages = {13300--13307},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.pnas.org/content/117/24/13300.short},
doi = {https://doi.org/10.1073/pnas.1919032117}
}
|
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| Bednarsek, N., Naish, K.-A., Feely, R.A., Hauri, C., Kimoto, K., Hermann, A.J., Michel, C., Niemi, A. and Pilcher, D. | Integrated Assessment of Ocean Acidification Risks to Pteropods in the Northern High Latitudes: Regional Comparison of Exposure, Sensitivity and Adaptive Capacity | 2021 | FRONTIERS IN MARINE SCIENCE Vol. 8 |
article | DOI |
| Abstract: Exposure to the impact of ocean acidification (OA) is increasing in high-latitudinal productive habitats. Pelagic calcifying snails (pteropods), a significant component of the diet of economically important fish, are found in high abundance in these regions. Pteropods have thin shells that readily dissolve at low aragonite saturation state (omega(ar)), making them susceptible to OA. Here, we conducted a first integrated risk assessment for pteropods in the Eastern Pacific subpolar gyre, the Gulf of Alaska (GoA), Bering Sea, and Amundsen Gulf. We determined the risk for pteropod populations by integrating measures of OA exposure, biological sensitivity, and resilience. Exposure was based on physical-chemical hydrographic observations and regional biogeochemical model outputs, delineating seasonal and decadal changes in carbonate chemistry conditions. Biological sensitivity was based on pteropod morphometrics and shell-building processes, including shell dissolution, density and thickness. Resilience and adaptive capacity were based on species diversity and spatial connectivity, derived from the particle tracking modeling. Extensive shell dissolution was found in the central and western part of the subpolar gyre, parts of the Bering Sea, and Amundsen Gulf. We identified two distinct morphotypes: L. helicina helicina and L. helicina pacifica, with high-spired and flatter shells, respectively. Despite the presence of different morphotypes, genetic analyses based on mitochondrial haplotypes identified a single species, without differentiation between the morphological forms, coinciding with evidence of widespread spatial connectivity. We found that shell morphometric characteristics depends on omega saturation state (omega(ar)); under omega(ar) decline, pteropods build flatter and thicker shells, which is indicative of a certain level of phenotypic plasticity. An integrated risk evaluation based on multiple approaches assumes a high risk for pteropod population persistence with intensification of OA in the high latitude eastern North Pacific because of their known vulnerability, along with limited evidence of species diversity despite their connectivity and our current lack of sufficient knowledge of their adaptive capacity. Such a comprehensive understanding would permit improved prediction of ecosystem change relevant to effective fisheries resource management, as well as a more robust foundation for monitoring ecosystem health and investigating OA impacts in high-latitudinal habitats. |
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BibTeX:
@article{bednarsek21a,
author = {Bednarsek, Nina and Naish, Kerry-Ann and Feely, Richard A. and Hauri, Claudine and Kimoto, Katsunori and Hermann, Albert J. and Michel, Christine and Niemi, Andrea and Pilcher, Darren},
title = {Integrated Assessment of Ocean Acidification Risks to Pteropods in the Northern High Latitudes: Regional Comparison of Exposure, Sensitivity and Adaptive Capacity},
journal = {FRONTIERS IN MARINE SCIENCE},
year = {2021},
volume = {8},
doi = {https://doi.org/10.3389/fmars.2021.671497}
}
|
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| Belikov, D.A., Bril, A., Maksyutov, S., Oshchepkov, S., Saeki, T., Takagi, H., Yoshida, Y., Ganshin, A., Zhuravlev, R., Aoki, S. and Yokota, T. | Column-averaged CO2 concentrations in the subarctic from GOSAT retrievals and NIES transport model simulations | {2014} | POLAR SCIENCE Vol. {8}({2, SI}), pp. 129-145 |
article | DOI |
| Abstract: The distribution of atmospheric carbon dioxide (CO2) in the subarctic was investigated using the National Institute for Environmental Studies (NIBS) three-dimensional transport model (TM) and retrievals from the Greenhouse gases Observing SATellite (GOSAT). Column-averaged dry air mole fractions of subarctic atmospheric CO2 (XCO2) from the NIES TM for four flux combinations were analyzed. Two flux datasets were optimized using only surface observations and two others were optimized using both surface and GOSAT Level 2 data. Two inverse modeling approaches using GOSAT data were compared. In the basic approach adopted in the GOSAT Level 4 product, the GOSAT observations are aggregated into monthly means over 5 degrees x 5 degrees grids. In the alternative method, the model observation misfit is estimated for each observation separately. The XCO2 values simulated with optimized fluxes were validated against Total Carbon Column Observing Network (TCCON) ground-based high-resolution Fourier Transform Spectrometer (FTS) measurements. Optimized fluxes were applied to study XCO2 seasonal variability over the period 2009-2010 in the Arctic and subarctic regions. The impact on CO2 levels of emissions from enhancement of biospheric respiration induced by the high temperature and strong wildfires occurring in the summer of 2010 was analyzed. Use of GOSAT data has a substantial impact on estimates of the level of CO2 interanual variability. (C) 2014 Elsevier B.V. and NIPR. All rights reserved. |
|||||
BibTeX:
@article{belikov14a,
author = {Belikov, D. A. and Bril, A. and Maksyutov, S. and Oshchepkov, S. and Saeki, T. and Takagi, H. and Yoshida, Y. and Ganshin, A. and Zhuravlev, R. and Aoki, S. and Yokota, T.},
title = {Column-averaged CO2 concentrations in the subarctic from GOSAT retrievals and NIES transport model simulations},
journal = {POLAR SCIENCE},
year = {2014},
volume = {8},
number = {2, SI},
pages = {129--145},
doi = {https://doi.org/10.1016/j.polar.2014.02.002}
}
|
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| Belikov, D.A., Maksyutov, S., Yaremchuk, A., Ganshin, A., Kaminski, T., Blessing, S., Sasakawa, M., Gomez-Pelaez, A.J. and Starchenko, A. | Adjoint of the global Eulerian-Lagrangian coupled atmospheric transport model (A-GELCA v1.0): development and validation | {2016} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {9}({2}), pp. 749-764 |
article | DOI |
| Abstract: We present the development of the Adjoint of the Global Eulerian-Lagrangian Coupled Atmospheric (A-GELCA) model that consists of the National Institute for Environmental Studies (NIES) model as an Eulerian three-dimensional transport model (TM), and FLEXPART (FLEXible PARTicle dispersion model) as the Lagrangian Particle Dispersion Model (LPDM). The forward tangent linear and adjoint components of the Eulerian model were constructed directly from the original NIES TM code using an automatic differentiation tool known as TAF (Transformation of Algorithms in Fortran; http://www.FastOpt.com), with additional manual pre- and post-processing aimed at improving transparency and clarity of the code and optimizing the performance of the computing, including MPI (Message Passing Interface). The Lagrangian component did not require any code modification, as LPDMs are self-adjoint and track a significant number of particles backward in time in order to calculate the sensitivity of the observations to the neighboring emission areas. The constructed Eulerian adjoint was coupled with the Lagrangian component at a time boundary in the global domain. The simulations presented in this work were performed using the A-GELCA model in forward and adjoint modes. The forward simulation shows that the coupled model improves reproduction of the seasonal cycle and short-term variability of CO2. Mean bias and standard deviation for five of the six Siberian sites considered decrease roughly by 1 ppm when using the coupled model. The adjoint of the Eulerian model was shown, through several numerical tests, to be very accurate (within machine epsilon with mismatch around to +/- 6 e(-14)) compared to direct forward sensitivity calculations. The developed adjoint of the coupled model combines the flux conservation and stability of an Eulerian discrete adjoint formulation with the flexibility, accuracy, and high resolution of a Lagrangian backward trajectory formulation. A-GELCA will be incorporated into a variational inversion system designed to optimize surface fluxes of greenhouse gases. |
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BibTeX:
@article{belikov16a,
author = {Belikov, Dmitry A. and Maksyutov, Shamil and Yaremchuk, Alexey and Ganshin, Alexander and Kaminski, Thomas and Blessing, Simon and Sasakawa, Motoki and Gomez-Pelaez, Angel J. and Starchenko, Alexander},
title = {Adjoint of the global Eulerian-Lagrangian coupled atmospheric transport model (A-GELCA v1.0): development and validation},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2016},
volume = {9},
number = {2},
pages = {749--764},
doi = {https://doi.org/10.5194/gmd-9-749-2016}
}
|
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| Belikov, D., Arshinov, M., Belan, B., Davydov, D., Fofonov, A., Sasakawa, M. and Machida, T. | Analysis of the Diurnal, Weekly, and Seasonal Cycles and Annual Trends in Atmospheric CO2 and CH4 at Tower Network in Siberia from 2005 to 2016 | {2019} | ATMOSPHERE Vol. {10}({11}) |
article | DOI |
| Abstract: We analyzed 12 years (20052016) of continuous measurements of atmospheric CO2 and CH4 concentrations made at nine tower observation sites in the JapanRussia Siberian Tall Tower Inland Observation Network (JR-STATION), located in Siberia. Since the data are very noisy and have a low temporal resolution due to gaps in instrument operation, we used the recently developed Prophet model, which was designed to handle the common features of time series (multiple strong seasonalities, trend changes, outliers) and has a robust performance in the presence of missing data and trend shifts. By decomposing each sampled time-series into its major components (i.e., annual trend and seasonal, weekly, and hourly variation), we observed periodically changing patterns of tracer concentrations. Specifically, we detected multi-year variability of tracers and identified high-concentration events. The frequency of such events was found to vary throughout the year, reaching up to 20% of days for some months, while the number of such events was found to be different for CO2 and CH4. An analysis of weather conditions showed that, in most cases, high-concentration events were caused by a temperature inversion and low wind speed. Additionally, wind directions were found to be different for high- and low-concentration events. For some sites, the wind direction indicated the location of strong local sources of CO2 and CH4. As well as elucidating the seasonality of greenhouse gas concentrations, this study confirmed the potential of the Prophet model for detecting periodicity in environmental phenomena. | |||||
BibTeX:
@article{belikov19a,
author = {Belikov, Dmitry and Arshinov, Mikhail and Belan, Boris and Davydov, Denis and Fofonov, Aleksandr and Sasakawa, Motoki and Machida, Toshinobu},
title = {Analysis of the Diurnal, Weekly, and Seasonal Cycles and Annual Trends in Atmospheric CO2 and CH4 at Tower Network in Siberia from 2005 to 2016},
journal = {ATMOSPHERE},
publisher = {MDPI},
year = {2019},
volume = {10},
number = {11},
doi = {https://doi.org/10.3390/atmos10110689}
}
|
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| Bell, E. | Evaluation of OCO-2 small-scale XCO2 variability using lidar retrievals from the ACT-America flight campaign | 2018 | School: Colorado State University | phdthesis | URL |
| Abstract: With eight 1.25 x 3 kilometer footprints across its swath and nearly 1 million observations of column-mean carbon dioxide concentration (XCO2) per day, the Orbiting Carbon Observatory (OCO-2) presents exciting possibilities for monitoring the global carbon cycle … | |||||
BibTeX:
@phdthesis{bell18a,
author = {Emily Bell},
title = {Evaluation of OCO-2 small-scale XCO2 variability using lidar retrievals from the ACT-America flight campaign},
school = {Colorado State University},
year = {2018},
url = {https://mountainscholar.org/handle/10217/191457}
}
|
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| Berberoglu, H., Gomez, P.S. and Pilon, L. | Radiation characteristics of Botryococcus braunii, Chlorococcum littorale, and Chlorella sp. used for CO2 fixation and biofuel production | {2009} | JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER Vol. {110}({17}), pp. 1879-1893 |
article | DOI |
| Abstract: This paper reports experimental measurements of the radiation characteristics of green algae Used for carbon dioxide fixation via photosynthesis. The generated biomass can be used to produce not only biofuels but also feed for animal and food supplements for human consumptions. Particular attention was paid to three widely used species namely Botryococcus braunii, Chlorella sp., and Chlorococcum littorale. Their extinction and absorption coefficients were obtained from normal-normal and normal-hemispherical transmittance measurements over the spectral range from 400 to 800 nm. Moreover, a polar nephelometer was used to measure the scattering phase function of the microorganisms at 632.8 nm. It was observed that for all strains, scattering dominates over absorption. The magnitudes of the extinction and scattering cross-section are functions of the size, shape, and chlorophyll content of each strain in a nontrivial manner. Absorption peaks at 435,475, and 676 nm corresponding to chlorophyll a and chlorophyll b. The results can be used for scaling and optimization of CO2 fixation in ponds or photobioreactors as well as in the development of controlled ecological life support systems. (C) 2009 Elsevier Ltd. All rights reserved. |
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BibTeX:
@article{berberoglu09a,
author = {Berberoglu, Halil and Gomez, Pedro S. and Pilon, Laurent},
title = {Radiation characteristics of Botryococcus braunii, Chlorococcum littorale, and Chlorella sp. used for CO2 fixation and biofuel production},
journal = {JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER},
year = {2009},
volume = {110},
number = {17},
pages = {1879--1893},
doi = {https://doi.org/10.1016/j.jqsrt.2009.04.005}
}
|
|||||
| Bergamaschi, P., Frankenberg, C., Meirink, J.F., Krol, M., Villani, M.G., Houweling, S., Dentener, F., Dlugokencky, E.J., Miller, J.B., Gatti, L.V., Engel, A. and Levin, I. | Inverse modeling of global and regional CH4 emissions using SCIAMACHY satellite retrievals | {2009} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {114} |
article | DOI |
| Abstract: Methane retrievals from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instrument onboard ENVISAT provide important information on atmospheric CH4 sources, particularly in tropical regions which are poorly monitored by in situ surface observations. Recently, Frankenberg et al. (2008a, 2008b) reported a major revision of SCIAMACHY retrievals due to an update of spectroscopic parameters of water vapor and CH4. Here, we analyze the impact of this revision on global and regional CH4 emissions estimates in 2004, using the TM5-4DVAR inverse modeling system. Inversions based on the revised SCIAMACHY retrievals yield similar to 20% lower tropical emissions compared to the previous retrievals. The new retrievals improve significantly the consistency between observed and assimilated column average mixing ratios and the agreement with independent validation data. Furthermore, the considerable latitudinal and seasonal bias correction of the previous SCIAMACHY retrievals, derived in the TM5-4DVAR system by simultaneously assimilating high-accuracy surface measurements, is reduced by a factor of similar to 3. The inversions result in significant changes in the spatial patterns of emissions and their seasonality compared to the bottom-up inventories. Sensitivity tests were done to analyze the robustness of retrieved emissions, revealing some dependence on the applied a priori emission inventories and OH fields. Furthermore, we performed a detailed validation of simulated CH4 mixing ratios using NOAA ship and aircraft profile samples, as well as stratospheric balloon samples, showing overall good agreement. We use the new SCIAMACHY retrievals for a regional analysis of CH4 emissions from South America, Africa, and Asia, exploiting the zooming capability of the TM5 model. This allows a more detailed analysis of spatial emission patterns and better comparison with aircraft profiles and independent regional emission estimates available for South America. Large CH4 emissions are attributed to various wetland regions in tropical South America and Africa, seasonally varying and opposite in phase with CH4 emissions from biomass burning. India, China and South East Asia are characterized by pronounced emissions from rice paddies peaking in the third quarter of the year, in addition to further anthropogenic emissions throughout the year. |
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BibTeX:
@article{bergamaschi09a,
author = {Bergamaschi, Peter and Frankenberg, Christian and Meirink, Jan Fokke and Krol, Maarten and Villani, M. Gabriella and Houweling, Sander and Dentener, Frank and Dlugokencky, Edward J. and Miller, John B. and Gatti, Luciana V. and Engel, Andreas and Levin, Ingeborg},
title = {Inverse modeling of global and regional CH4 emissions using SCIAMACHY satellite retrievals},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2009},
volume = {114},
doi = {https://doi.org/10.1029/2009JD012287}
}
|
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| Bergamaschi, P., Houweling, S., Segers, A., Krol, M., Frankenberg, C., Scheepmaker, R.A., Dlugokencky, E., Wofsy, S.C., Kort, E.A., Sweeney, C., Schuck, T., Brenninkmeijer, C., Chen, H., Beck, V. and Gerbig, C. | Atmospheric CH4 in the first decade of the 21st century: Inverse modeling analysis using SCIAMACHY satellite retrievals and NOAA surface measurements | {2013} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {118}({13}), pp. 7350-7369 |
article | DOI |
| Abstract: The causes of renewed growth in the atmospheric CH4 burden since 2007 are still poorly understood and subject of intensive scientific discussion. We present a reanalysis of global CH4 emissions during the 2000s, based on the TM5-4DVAR inverse modeling system. The model is optimized using high-accuracy surface observations from NOAA ESRL's global air sampling network for 2000-2010 combined with retrievals of column-averaged CH4 mole fractions from SCIAMACHY onboard ENVISAT (starting 2003). Using climatological OH fields, derived global total emissions for 2007-2010 are 16-20 Tg CH4/yr higher compared to 2003-2005. Most of the inferred emission increase was located in the tropics (9-14 Tg CH4/yr) and mid- latitudes of the northern hemisphere (6-8 Tg CH4/yr), while no significant trend was derived for Arctic latitudes. The atmospheric increase can be attributed mainly to increased anthropogenic emissions, but the derived trend is significantly smaller than estimated in the EDGARv4.2 emission inventory. Superimposed on the increasing trend in anthropogenic CH4 emissions are significant inter-annual variations (IAV) of emissions from wetlands (up to +/- 10 Tg CH4/yr), and biomass burning (up to +/- 7 Tg CH4/yr). Sensitivity experiments, which investigated the impact of the SCIAMACHY observations (versus inversions using only surface observations), of the OH fields used, and of a priori emission inventories, resulted in differences in the detailed latitudinal attribution of CH4 emissions, but the IAV and trends aggregated over larger latitude bands were reasonably robust. All sensitivity experiments show similar performance against independent shipboard and airborne observations used for validation, except over Amazonia where satellite retrievals improved agreement with observations in the free troposphere. |
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BibTeX:
@article{bergamaschi13a,
author = {Bergamaschi, P. and Houweling, S. and Segers, A. and Krol, M. and Frankenberg, C. and Scheepmaker, R. A. and Dlugokencky, E. and Wofsy, S. C. and Kort, E. A. and Sweeney, C. and Schuck, T. and Brenninkmeijer, C. and Chen, H. and Beck, V. and Gerbig, C.},
title = {Atmospheric CH4 in the first decade of the 21st century: Inverse modeling analysis using SCIAMACHY satellite retrievals and NOAA surface measurements},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2013},
volume = {118},
number = {13},
pages = {7350--7369},
doi = {https://doi.org/10.1002/jgrd.50480}
}
|
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| Bernath, P., Boone, C., Fernando, A. and Jones, S. | Low altitude CO2 from the Atmospheric Chemistry Experiment (ACE) satellite | {2019} | JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER Vol. {238}({SI}) |
article | DOI URL |
| Abstract: The Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) has been measuring atmospheric composition by solar occultation from low Earth orbit since 2004. A new version (4.0) of ACE-FTS processing has added low altitude CO2 as a routine data product. ACE provides a near global data set of altitude profiles of CO(2)( )volume mixing ratios (VMRs) on a 1 km grid from 5 to 18 km. We provide an initial evaluation of these data using occultations from the month of May for 2004-2017 in the 55 degrees-70 degrees S latitude range. Comparisons are made with ground-based measurements at Macquarie Island, the South Pole, the CarbonTracker 2017 model and G. Toon's empirical model. Agreement for trends is good, but ACE FTS VMRs have a low bias at 5.5 and 6.5km in altitude. (C) 2019 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{bernath19a,
author = {Bernath, Peter and Boone, Chris and Fernando, Anton and Jones, Scott},
title = {Low altitude CO2 from the Atmospheric Chemistry Experiment (ACE) satellite},
journal = {JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER},
publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
year = {2019},
volume = {238},
number = {SI},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S0022407319302778},
doi = {https://doi.org/10.1016/j.jqsrt.2019.06.007}
}
|
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| Berry, J.A. | There Ought to Be an Equation for That | {2012} | Annual Review of Plant Biology Vol. {63}(1)ANNUAL REVIEW OF PLANT BIOLOGY, VOL 63, pp. 1-17 |
article | DOI |
| Abstract: An overriding interest in photosynthesis has propelled my wanderings from chemist to biochemist to plant physiologist and on to global topics. Equations and models have been organizing principles along the way. This fascination started as a reaction to difficulties with written communication, but it has proven to be quite useful in moving across different levels of organization. I conclude with some discussion of the importance of Earth system models for understanding and predicting how human activities may influence the climate, environment, and biota in the future, and some ideas about how disciplinary science might make larger contributions to this interdisciplinary problem. |
|||||
BibTeX:
@article{berry12a,
author = {Berry, Joseph A.},
title = {There Ought to Be an Equation for That},
booktitle = {ANNUAL REVIEW OF PLANT BIOLOGY, VOL 63},
journal = {Annual Review of Plant Biology},
year = {2012},
volume = {63},
number = {1},
pages = {1--17},
doi = {https://doi.org/10.1146/annurev-arplant-042811-105547}
}
|
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| Bhattacharjee, S. and Chen, J. | Prediction of Satellite-Based Column CO2 Concentration by Combining Emission Inventory and LULC Information | {2020} | IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Vol. {58}({12}), pp. {8285-8300} |
article | DOI URL |
| Abstract: In this article, we generate a regional mapping of space-borne carbon dioxide (CO2) concentration through a data fusion approach, including emission estimates and Land Use and Land Cover (LULC) information. NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite measures the column-averaged CO2 dry air mole fraction (XCO2) as contiguous parallelogram footprints. A major hindrance of this data set, specifically with its Level-2 observations, is missing footprints at certain time instants and the sparse sampling density in time. This article aims to generate Level-3 XCO2 maps on a regional scale for different locations worldwide through spatial interpolation of the OCO-2 retrievals. To deal with the sparse OCO-2 sampling, the cokriging-based spatial interpolation methods are suitable, which models auxiliary densely-sampled variables to predict the primary variable. In this article, a cokriging-based approach is applied using auxiliary emission data sets and the principles of the semantic kriging (SemK) method. Two global high-resolution emission data sets, the Open-source Data Inventory for Anthropogenic CO2 (ODIAC) and the Emissions Database for Global Atmospheric Research (EDGAR), are used here. The ontology-based semantic analysis of the SemK method quantifies the interrelationships of LULC classes for analyzing the local XCO2 pattern. Validations have been carried out in different regions worldwide, where the OCO-2 and the Total Carbon Column Observing Network (TCCON) measurements coexist. It is observed that the modeling of auxiliary emission data sets enhances the prediction accuracy of XCO2. This article is one of the initial attempts to generate Level-3 XCO2 mapping of OCO-2 through a data fusion approach using emission data sets. | |||||
BibTeX:
@article{bhattacharjee20a,
author = {Bhattacharjee, Shrutilipi and Chen, Jia},
title = {Prediction of Satellite-Based Column CO2 Concentration by Combining Emission Inventory and LULC Information},
journal = {IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING},
publisher = {IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC},
year = {2020},
volume = {58},
number = {12},
pages = {8285--8300},
note = {Query date: 2021-04-02 15:20:04},
url = {https://ieeexplore.ieee.org/abstract/document/9094001/},
doi = {https://doi.org/10.1109/TGRS.2020.2985047}
}
|
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| Biavati, G., Feist, D.G., Gerbig, C. and Kretschmer, R. | Error estimation for localized signal properties: application to atmospheric mixing height retrievals | {2015} | Atmospheric Measurement Techniques Vol. {8}({10}), pp. 4215-4230 |
article | DOI |
| Abstract: The mixing height is a key parameter for many applications that relate surface-atmosphere exchange fluxes to atmospheric mixing ratios, e.g., in atmospheric transport modeling of pollutants. The mixing height can be estimated with various methods: profile measurements from radiosondes as well as remote sensing (e.g., optical backscatter measurements). For quantitative applications, it is important to estimate not only the mixing height itself but also the uncertainty associated with this estimate. However, classical error propagation typically fails on mixing height estimates that use thresholds in vertical profiles of some measured or measurement-derived quantity. Therefore, we propose a method to estimate the uncertainty of an estimation of the mixing height. The uncertainty we calculate is related not to the physics of the boundary layer (e.g., entrainment zone thickness) but to the quality of the analyzed signals. The method relies on the concept of statistical confidence and on the knowledge of the measurement errors. It can also be applied to problems outside atmospheric mixing height retrievals where properties have to be assigned to a specific position, e.g., the location of a local extreme. |
|||||
BibTeX:
@article{biavati15a,
author = {Biavati, G. and Feist, D. G. and Gerbig, C. and Kretschmer, R.},
title = {Error estimation for localized signal properties: application to atmospheric mixing height retrievals},
journal = {Atmospheric Measurement Techniques},
year = {2015},
volume = {8},
number = {10},
pages = {4215--4230},
doi = {https://doi.org/10.5194/amt-8-4215-2015}
}
|
|||||
| Biraud, S.C., Torn, M.S., Smith, J.R., Sweeney, C., Riley, W.J. and Tans, P.P. | A multi-year record of airborne CO2 observations in the US Southern Great Plains | {2013} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {6}({3}), pp. 751-763 |
article | DOI |
| Abstract: We report on 10 yr of airborne measurements of atmospheric CO2 mole fraction from continuous and flask systems, collected between 2002 and 2012 over the Atmospheric Radiation Measurement Program Climate Research Facility in the US Southern Great Plains (SGP). These observations were designed to quantify trends and variability in atmospheric mole fraction of CO2 and other greenhouse gases with the precision and accuracy needed to evaluate ground-based and satellite-based column CO2 estimates, test forward and inverse models, and help with the interpretation of ground-based CO2 mole-fraction measurements. During flights, we measured CO2 and meteorological data continuously and collected flasks for a rich suite of additional gases: CO2, CO, CH4, N2O, (CO2)-C-13, carbonyl sulfide (COS), and trace hydrocarbon species. These measurements were collected approximately twice per week by small aircraft (Cessna 172 initially, then Cessna 206) on a series of horizontal legs ranging in altitude from 460 m to 5500 m a.m.s.l. Since the beginning of the program, more than 400 continuous CO2 vertical profiles have been collected (2007-2012), along with about 330 profiles from NOAA/ESRL 12-flask (2006-2012) and 284 from NOAA/ESRL 2-flask (2002-2006) packages for carbon cycle gases and isotopes. Averaged over the entire record, there were no systematic differences between the continuous and flask CO2 observations when they were sampling the same air, i.e., over the one-minute flask-sampling time. Using multiple technologies (a flask sampler and two continuous analyzers), we documented a mean difference of < 0.2 ppm between instruments. However, flask data were not equivalent in all regards; horizontal variability in CO2 mole fraction within the 5-10 min legs sometimes resulted in significant differences between flask and continuous measurement values for those legs, and the information contained in fine-scale variability about atmospheric transport was not captured by flask-based observations. The CO2 mole fraction trend at 3000 m a.m.s.l. was 1.91 ppm yr(-1) between 2008 and 2010, very close to the concurrent trend at Mauna Loa of 1.95 ppm yr(-1). The seasonal amplitude of CO2 mole fraction in the free troposphere (FT) was half that in the planetary boundary layer (PBL) (similar to 15 ppm vs. similar to 30 ppm) and twice that at Mauna Loa (approximately 8 ppm). The CO2 horizontal variability was up to 10 ppm in the PBL and less than 1 ppm at the top of the vertical profiles in the FT. |
|||||
BibTeX:
@article{biraud13a,
author = {Biraud, S. C. and Torn, M. S. and Smith, J. R. and Sweeney, C. and Riley, W. J. and Tans, P. P.},
title = {A multi-year record of airborne CO2 observations in the US Southern Great Plains},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2013},
volume = {6},
number = {3},
pages = {751--763},
doi = {https://doi.org/10.5194/amt-6-751-2013}
}
|
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| Bodesheim, P., Jung, M., Gans, F., Mahecha, M.D. and Reichstein, M. | Upscaled diurnal cycles of land-atmosphere fluxes: a new global half-hourly data product | 2018 | Earth System Science Data Vol. 10(3), pp. 1327-1365 |
article | DOI |
| Abstract: Interactions between the biosphere and the atmosphere can be well characterized by fluxes between the two. In particular, carbon and energy fluxes play a major role in understanding biogeochemical processes on an ecosystem level or global scale. However, the fluxes can only be measured at individual sites, e.g., by eddy covariance towers, and an upscaling of these local observations is required to analyze global patterns. Previous work focused on upscaling monthly, 8-day, or daily average values, and global maps for each flux have been provided accordingly. In this paper, we raise the upscaling of carbon and energy fluxes between land and atmosphere to the next level by increasing the temporal resolution to subdaily timescales. We provide continuous half-hourly fluxes for the period from 2001 to 2014 at 0.5 degrees spatial resolution, which allows for analyzing diurnal cycles globally. The data set contains four fluxes: gross primary production (GPP), net ecosystem exchange (NEE), latent heat (LE), and sensible heat (H). We propose two prediction approaches for the diurnal cycles based on large-scale regression models and compare them in extensive cross-validation experiments using different sets of predictor variables. We analyze the results for a set of FLUXNET tower sites showing the suitability of our approaches for this upscaling task. Finally, we have selected one approach to calculate the global half-hourly data products based on predictor variables from remote sensing and meteorology at daily resolution as well as half-hourly potential radiation. In addition, we provide a derived product that only contains monthly average diurnal cycles, which is a lightweight version in terms of data storage that still allows studying the important characteristics of diurnal patterns globally. We recommend to primarily use these monthly average diurnal cycles, because they are less affected by the impacts of day-to-day variation, observation noise, and short-term fluctuations on subdaily timescales compared to the full half-hourly flux products. The global half-hourly data products are available at https://doi.org/10.17871/BACI.224. |
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BibTeX:
@article{bodesheim18a,
author = {Bodesheim, Paul and Jung, Martin and Gans, Fabian and Mahecha, Miguel D. and Reichstein, Markus},
title = {Upscaled diurnal cycles of land-atmosphere fluxes: a new global half-hourly data product},
journal = {Earth System Science Data},
year = {2018},
volume = {10},
number = {3},
pages = {1327-1365},
doi = {https://doi.org/10.5194/essd-10-1327-2018}
}
|
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| Boland, S., Bösch, H., Brown, L., Burrows, J., Ciais, P., Connor, B., Crisp, D., Denning, S., Doney, S., Engelen, R. and others | The need for atmospheric carbon dioxide measurements from space: Contributions from a rapid reflight of the Orbiting Carbon Observatory [BibTeX] |
2009 | White paper to NASA | article | |
BibTeX:
@article{boland09a,
author = {Boland, Stacey and Bösch, Hartmut and Brown, Linda and Burrows, John and Ciais, Philippe and Connor, Brian and Crisp, David and Denning, Scott and Doney, Scott and Engelen, Richard and others},
title = {The need for atmospheric carbon dioxide measurements from space: Contributions from a rapid reflight of the Orbiting Carbon Observatory},
journal = {White paper to NASA},
year = {2009}
}
|
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| Boone, C.D. and Bernath, P.F. | Tangent height determination from the N-2-continuum for the Atmospheric Chemistry Experiment Fourier transform spectrometer | {2019} | JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER Vol. {238}({SI}) |
article | DOI URL |
| Abstract: With inadequate information from sensors onboard the SCISAT satellite to generate accurate pointing information, tangent heights for the solar occultation measurements collected by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) are determined from features in the measured spectra. For version 4.0 processing of the ACE-FTS data, tangent heights below 18 km are generated from the N-2 collision induced absorption continuum near 2500 cm(-1). Because this tangent height determination requires no assumptions on CO2 concentrations in this altitude region (unlike previous processing versions), ACE-FTS version 4.0 includes retrieved CO2 volume mixing ratio profiles below 18 km as a standard product. (C) 2019 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{boone19a,
author = {Boone, C. D. and Bernath, P. F.},
title = {Tangent height determination from the N-2-continuum for the Atmospheric Chemistry Experiment Fourier transform spectrometer},
journal = {JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER},
publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
year = {2019},
volume = {238},
number = {SI},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S0022407319301918},
doi = {https://doi.org/10.1016/j.jqsrt.2019.04.033}
}
|
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| Borbas, E.E., Adler, D.P., Best, F.A., Knuteson, R.O., L'Ecuyer, T.S., Loveless, M., Olson, E.R., Revercomb, H.E. and Taylor, J.K. | Ground-based Far-Infrared Emissivity Measurements with the University of Wisconsin Absolute Radiance Interferometer (ARI) | 2021 | Vol. 11830INFRARED REMOTE SENSING AND INSTRUMENTATION XXIX |
inproceedings | DOI |
| Abstract: The infrared Absolute Radiance Interferometer (ARI) instrument - developed at University of Wisconsin-Madison, Space Science and Engineering Center (SSEC) - measures absolute spectrally resolved infrared radiance (200- 2000 cm(-1) or 5-50 mu m at 0.5 cm(-1) resolution) with ultra-high accuracy (< 0.1 K 3-sigma brightness temperature at scene temperature). The ARI prototype instrument was deployed for field measurements of clear-sky far infrared (FIR) surface emissivity and radiances on the SSEC rooftop. Currently there are very few measurements available in the FIR spectral region. Our targeted samples include snow and ice surfaces which are important for radiative cooling in the polar regions. We will demonstrate the ARI instrument configuration, capability for ground-based measurements in the FIR region, and the retrieval of infrared emissivity spectra. The ARI ground-based FIR measurements would support scientific applications that involve FIR studies, such as the PREFIRE (Polar Radiant Energy in the Far InfraRed Experiment) and the European FORUM (Far-infrared-outgoing Radiation Understating and Monitoring) missions. |
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BibTeX:
@inproceedings{borbas21a,
author = {Borbas, E. Eva and Adler, Douglas P. and Best, Fred A. and Knuteson, Robert O. and L'Ecuyer, Tristan S. and Loveless, Michelle and Olson, Erik R. and Revercomb, Henry E. and Taylor, Joseph K.},
title = {Ground-based Far-Infrared Emissivity Measurements with the University of Wisconsin Absolute Radiance Interferometer (ARI)},
booktitle = {INFRARED REMOTE SENSING AND INSTRUMENTATION XXIX},
year = {2021},
volume = {11830},
note = {Conference on Infrared Remote Sensing and Instrumentation XXIX, San Diego, CA, AUG 01-05, 2021},
doi = {https://doi.org/10.1117/12.2594834}
}
|
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| Botia, S., Komiya, S., Marshall, J., Koch, T., Galkowski, M., Lavric, J., Gomes-Alves, E., Walter, D., Fisch, G., Pinho, D.M., Nelson, B.W., Martins, G., Luijkx, I.T., Koren, G., Florentie, L., de Araujo, A.C., Sa, M., Andreae, M.O., Heimann, M., Peters, W. and Gerbig, C. | The CO2 record at the Amazon Tall Tower Observatory: A new opportunity to study processes on seasonal and inter-annual scales | 2022 | GLOBAL CHANGE BIOLOGY Vol. 28(2), pp. 588-611 |
article | DOI |
| Abstract: High-quality atmospheric CO2 measurements are sparse in Amazonia, but can provide critical insights into the spatial and temporal variability of sources and sinks of CO2. In this study, we present the first 6 years (2014-2019) of continuous, high-precision measurements of atmospheric CO2 at the Amazon Tall Tower Observatory (ATTO, 2.1 degrees S, 58.9 degrees W). After subtracting the simulated background concentrations from our observational record, we define a CO2 regional signal (Delta CO2obs) that has a marked seasonal cycle with an amplitude of about 4 ppm. At both seasonal and inter-annual scales, we find differences in phase between Delta CO2obs and the local eddy covariance net ecosystem exchange (EC-NEE), which is interpreted as an indicator of a decoupling between local and non-local drivers of Delta CO2obs. In addition, we present how the 2015-2016 El Nino-induced drought was captured by our atmospheric record as a positive 2 sigma anomaly in both the wet and dry season of 2016. Furthermore, we analyzed the observed seasonal cycle and inter-annual variability of Delta CO2obs together with net ecosystem exchange (NEE) using a suite of modeled flux products representing biospheric and aquatic CO2 exchange. We use both non-optimized and optimized (i.e., resulting from atmospheric inverse modeling) NEE fluxes as input in an atmospheric transport model (STILT). The observed shape and amplitude of the seasonal cycle was captured neither by the simulations using the optimized fluxes nor by those using the diagnostic Vegetation and Photosynthesis Respiration Model (VPRM). We show that including the contribution of CO2 from river evasion improves the simulated shape (not the magnitude) of the seasonal cycle when using a data-driven non-optimized NEE product (FLUXCOM). The simulated contribution from river evasion was found to be 25% of the seasonal cycle amplitude. Our study demonstrates the importance of the ATTO record to better understand the Amazon carbon cycle at various spatial and temporal scales. |
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BibTeX:
@article{botia22a,
author = {Botia, Santiago and Komiya, Shujiro and Marshall, Julia and Koch, Thomas and Galkowski, Michal and Lavric, Jost and Gomes-Alves, Eliane and Walter, David and Fisch, Gilberto and Pinho, Davieliton M. and Nelson, Bruce W. and Martins, Giordane and Luijkx, Ingrid T. and Koren, Gerbrand and Florentie, Liesbeth and de Araujo, Alessandro Carioca and Sa, Marta and Andreae, Meinrat O. and Heimann, Martin and Peters, Wouter and Gerbig, Christoph},
title = {The CO2 record at the Amazon Tall Tower Observatory: A new opportunity to study processes on seasonal and inter-annual scales},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2022},
volume = {28},
number = {2},
pages = {588-611},
doi = {https://doi.org/10.1111/gcb.15905}
}
|
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| Bouche, A., Beck-Winchatz, B. and Potosnak, M.J. | A high-altitude balloon platform for determining exchange of carbon dioxide over agricultural landscapes | {2016} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {9}({12}), pp. 5707-5719 |
article | DOI |
| Abstract: The exchange of carbon dioxide between the terrestrial biosphere and the atmosphere is a key process in the global carbon cycle. Given emissions from fossil fuel combustion and the appropriation of net primary productivity by human activities, understanding the carbon dioxide exchange of cropland agroecosystems is critical for evaluating future trajectories of climate change. In addition, human manipulation of agroecosystems has been proposed as a technique of removing carbon dioxide from the atmosphere via practices such as no-tillage and cover crops. We propose a novel method of measuring the exchange of carbon dioxide over croplands using a high-altitude balloon (HAB) platform. The HAB methodology measures two sequential vertical profiles of carbon dioxide mixing ratio, and the surface exchange is calculated using a fixed-mass column approach. This methodology is relatively inexpensive, does not rely on any assumptions besides spatial homogeneity (no horizontal advection) and provides data over a spatial scale between stationary flux towers and satellite-based inversion calculations. The HAB methodology was employed during the 2014 and 2015 growing seasons in central Illinois, and the results are compared to satellite-based NDVI values and a flux tower located relatively near the launch site in Bondville, Illinois. These initial favorable results demonstrate the utility of the methodology for providing carbon dioxide exchange data over a large (10-100 km) spatial area. One drawback is its relatively limited temporal coverage. While recruiting citizen scientists to perform the launches could provide a more extensive dataset, the HAB methodology is not appropriate for providing estimates of net annual carbon dioxide exchange. Instead, a HAB dataset could provide an important check for upscaling flux tower results and verifying satellite-derived exchange estimates. |
|||||
BibTeX:
@article{bouche16a,
author = {Bouche, Angie and Beck-Winchatz, Bernhard and Potosnak, Mark J.},
title = {A high-altitude balloon platform for determining exchange of carbon dioxide over agricultural landscapes},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2016},
volume = {9},
number = {12},
pages = {5707--5719},
doi = {https://doi.org/10.5194/amt-9-5707-2016}
}
|
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| Bovensmann, H., Buchwitz, M., Burrows, J.P., Reuter, M., Krings, T., Gerilowski, K., Schneising, O., Heymann, J., Tretner, A. and Erzinger, J. | A remote sensing technique for global monitoring of power plant CO2 emissions from space and related applications | {2010} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {3}({4}), pp. 781-811 |
article | DOI |
| Abstract: Carbon dioxide (CO2) is the most important anthropogenic greenhouse gas (GHG) causing global warming. The atmospheric CO2 concentration increased by more than 30% since pre-industrial times - primarily due to burning of fossil fuels - and still continues to increase. Reporting of CO2 emissions is required by the Kyoto protocol. Independent verification of reported emissions, which are typially not directly measured, by methods such as inverse modeling of measured atmospheric CO2 concentrations is currently not possible globally due to lack of appropriate observations. Existing satellite instruments such as SCIAMACHY/ENVISAT and TANSO/GOSAT focus on advancing our understanding of natural CO2 sources and sinks. The obvious next step for future generation satellites is to also constrain anthropogenic CO2 emissions. Here we present a promising satellite remote sensing concept based on spectroscopic measurements of reflected solar radiation and show, using power plants as an example, that strong localized CO2 point sources can be detected and their emissions quantified. This requires mapping the atmospheric CO2 column distribution at a spatial resolution of 2x2 km(2) with a precision of 0.5% (2 ppm) or better. We indicate that this can be achieved with existing technology. For a single satellite in sun-synchronous orbit with a swath width of 500 km, each power plant (PP) is overflown every 6 days or more frequent. Based on the MODIS cloud mask data product we conservatively estimate that typically 20 sufficiently cloud free overpasses per PP can be achieved every year. We found that for typical wind speeds in the range of 2-6 m/s the statistical uncertainty of the retrieved PP CO2 emission due to instrument noise is in the range 1.6-4.8MtCO(2)/yr for single overpasses. This corresponds to 12-36% of the emission of a mid-size PP (13 MtCO(2)/yr). We have also determined the sensitivity to parameters which may result in systematic errors such as atmospheric transport and aerosol related parameters. We found that the emission error depends linearly on wind speed, i.e., a 10% wind speed error results in a 10% emission error, and that neglecting enhanced aerosol concentrations in the PP plume may result in errors in the range 0.2-2.5 MtCO(2)/yr, depending on PP aerosol emission. The discussed concept has the potential to contribute to an independent verification of reported anthropogenic CO2 emissions and therefore could be an important component of a future global anthropogenic GHG emission monitoring system. This is of relevance in the context of Kyoto protocol follow-on agreements but also allows detection and monitoring of a variety of other strong natural and anthropogenic CO2 and CH4 emitters. The investigated instrument is not limited to these applications as it has been specified to also deliver the data needed for global regional-scale CO2 and CH4 surface flux inverse modeling. |
|||||
BibTeX:
@article{bovensmann10a,
author = {Bovensmann, H. and Buchwitz, M. and Burrows, J. P. and Reuter, M. and Krings, T. and Gerilowski, K. and Schneising, O. and Heymann, J. and Tretner, A. and Erzinger, J.},
title = {A remote sensing technique for global monitoring of power plant CO2 emissions from space and related applications},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2010},
volume = {3},
number = {4},
pages = {781--811},
doi = {https://doi.org/10.5194/amt-3-781-2010}
}
|
|||||
| Bowman, K., Liu, J., Bloom, A., Parazoo, N., Lee, M., Jiang, Z., Menemenlis, D., Gierach, M., Collatz, G., Gurney, K. and others | Global and Brazilian carbon response to El Niño Modoki 2011--2010 [BibTeX] |
2017 | Earth and Space Science Vol. 4(10), pp. 637-660 |
article | |
BibTeX:
@article{bowman17a,
author = {Bowman, KW and Liu, J and Bloom, AA and Parazoo, NC and Lee, M and Jiang, Z and Menemenlis, D and Gierach, MM and Collatz, GJ and Gurney, KR and others},
title = {Global and Brazilian carbon response to El Niño Modoki 2011--2010},
journal = {Earth and Space Science},
year = {2017},
volume = {4},
number = {10},
pages = {637--660}
}
|
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| Bozhinova, D.N. | Interpreting plant-sampled?` 14CO2 to study regional anthropogenic CO2 signals in Europe [BibTeX] |
2015 | book | ||
BibTeX:
@book{bozhinova15a,
author = {Bozhinova, Denica Nikolaeva},
title = {Interpreting plant-sampled?` 14CO2 to study regional anthropogenic CO2 signals in Europe},
publisher = {Wageningen University},
year = {2015}
}
|
|||||
| Bril, A., Oshchepkov, S. and Yokota, T. | Retrieval of atmospheric methane from high spectral resolution satellite measurements: a correction for cirrus cloud effects | {2009} | APPLIED OPTICS Vol. {48}({11}), pp. 2139-2148 |
article | DOI |
| Abstract: We assessed the accuracy of methane (CH4) retrievals from synthetic radiance spectra particular to Greenhouse Gases Observing Satellite observations. We focused on estimating the CH4 vertical column amount from an atmosphere that includes thin cirrus clouds, taking into account uncertain meteorological conditions. A photon path-length probability density function (PPDF)-based method was adapted to correct for atmospheric scattering effects in CH4 retrievals. This method was shown to provide similar retrieval accuracy as compared to a carbon dioxide (CO2)-proxy-based correction approach. It infers some advantages of PPDF-based method for methane retrievals under high variability of CO2 abundance. (C) 2009 Optical Society of America |
|||||
BibTeX:
@article{bril09a,
author = {Bril, Andrey and Oshchepkov, Sergey and Yokota, Tatsuya},
title = {Retrieval of atmospheric methane from high spectral resolution satellite measurements: a correction for cirrus cloud effects},
journal = {APPLIED OPTICS},
year = {2009},
volume = {48},
number = {11},
pages = {2139--2148},
doi = {https://doi.org/10.1364/AO.48.002139}
}
|
|||||
| Brioude, J., Petron, G., Frost, G.J., Ahmadov, R., Angevine, W.M., Hsie, E.Y., Kim, S.W., Lee, S.H., McKeen, S.A., Trainer, M., Fehsenfeld, F.C., Holloway, J.S., Peischl, J., Ryerson, T.B. and Gurney, K.R. | A new inversion method to calculate emission inventories without a prior at mesoscale: Application to the anthropogenic CO2 emission from Houston, Texas | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {117} |
article | DOI |
| Abstract: We developed a new inversion method to calculate an emission inventory for an anthropogenic pollutant without a prior emission estimate at mesoscale. This method employs slopes between mixing ratio enhancements of a given pollutant (CO2, for instance) with other co-emitted tracers in conjunction with the emission inventories of those tracers (CO, NOy, and SO2 are used in this example). The current application of this method employed in situ measurements onboard the NOAA WP-3 research aircraft during the 2006 Texas Air Quality Study (TexAQS 2006). We used 3 different transport models to estimate the uncertainties introduced by the transport models in the inversion. We demonstrated the validity of the new inversion method by calculating a 4 x 4 km(2) emission inventory of anthropogenic CO2 in the Houston area in Texas, and comparing it to the 10 x 10 km(2) Vulcan emission inventory for the same region. The calculated anthropogenic CO2 inventory for the Houston Ship Channel, home to numerous major industrial and port emission sources, showed excellent agreement with Vulcan. The daytime CO2 average flux from the Ship Channel is the largest urban CO2 flux reported in the literature. Compared to Vulcan, the daytime urban area CO2 emissions were higher by 37% +/- 6%. Those differences can be explained by uncertainties in emission factors in Vulcan and by increased emissions from point sources and on-road emitters between 2002, the reference year in Vulcan, and 2006, the year that the TexAQS observations were made. |
|||||
BibTeX:
@article{brioude12a,
author = {Brioude, J. and Petron, G. and Frost, G. J. and Ahmadov, R. and Angevine, W. M. and Hsie, E. -Y. and Kim, S. -W. and Lee, S. -H. and McKeen, S. A. and Trainer, M. and Fehsenfeld, F. C. and Holloway, J. S. and Peischl, J. and Ryerson, T. B. and Gurney, K. R.},
title = {A new inversion method to calculate emission inventories without a prior at mesoscale: Application to the anthropogenic CO2 emission from Houston, Texas},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2011JD016918}
}
|
|||||
| Brioude, J., Angevine, W.M., Ahmadov, R., Kim, S.W., Evan, S., McKeen, S.A., Hsie, E.Y., Frost, G.J., Neuman, J.A., Pollack, I.B., Peischl, J., Ryerson, T.B., Holloway, J., Brown, S.S., Nowak, J.B., Roberts, J.M., Wofsy, S.C., Santoni, G.W., Oda, T. and Trainer, M. | Top-down estimate of surface flux in the Los Angeles Basin using a mesoscale inverse modeling technique: assessing anthropogenic emissions of CO, NOx and CO2 and their impacts | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({7}), pp. 3661-3677 |
article | DOI |
| Abstract: We present top-down estimates of anthropogenic CO, NOx and CO2 surface fluxes at mesoscale using a Lagrangian model in combination with three different WRF model configurations, driven by data from aircraft flights during the CALNEX campaign in southern California in May-June 2010. The US EPA National Emission Inventory 2005 (NEI 2005) was the prior in the CO and NOx inversion calculations. The flux ratio inversion method, based on linear relationships between chemical species, was used to calculate the CO2 inventory without prior knowledge of CO2 surface fluxes. The inversion was applied to each flight to estimate the variability of single-flight-based flux estimates. In Los Angeles (LA) County, the uncertainties on CO and NOx fluxes were 10% and 15 %, respectively. Compared with NEI 2005, the CO posterior emissions were lower by 43% in LA County and by 37% in the South Coast Air Basin (SoCAB). NOx posterior emissions were lower by 32% in LA County and by 27% in the SoCAB. NOx posterior emissions were 40% lower on weekends relative to weekdays. The CO2 posterior estimates were 183 Tgyr(-1) in SoCAB. A flight during ITCT (Intercontinental Transport and Chemical Transformation) in 2002 was used to estimate emissions in the LA Basin in 2002. From 2002 to 2010, the CO and NOx posterior emissions decreased by 41% and 37%, respectively, in agreement with previous studies. Over the same time period, CO2 emissions increased by 10% in LA County but decreased by 4% in the SoCAB, a statistically insignificant change. Overall, the posterior estimates were in good agreement with the California Air Resources Board (CARB) inventory, with differences of 15% or less. However, the posterior spatial distribution in the basin was significantly different from CARB for NOx emissions. WRF-Chem mesoscale chemical-transport model simulations allowed an evaluation of differences in chemistry using different inventory assumptions, including NEI 2005, a gridded CARB inventory and the posterior inventories derived in this study. The biases in WRF-Chem ozone were reduced and correlations were increased using the posterior from this study compared with simulations with the two bottom-up inventories, suggesting that improving the spatial distribution of ozone precursor surface emissions is also important in mesoscale chemistry simulations. |
|||||
BibTeX:
@article{brioude13a,
author = {Brioude, J. and Angevine, W. M. and Ahmadov, R. and Kim, S. -W. and Evan, S. and McKeen, S. A. and Hsie, E. -Y. and Frost, G. J. and Neuman, J. A. and Pollack, I. B. and Peischl, J. and Ryerson, T. B. and Holloway, J. and Brown, S. S. and Nowak, J. B. and Roberts, J. M. and Wofsy, S. C. and Santoni, G. W. and Oda, T. and Trainer, M.},
title = {Top-down estimate of surface flux in the Los Angeles Basin using a mesoscale inverse modeling technique: assessing anthropogenic emissions of CO, NOx and CO2 and their impacts},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {7},
pages = {3661--3677},
doi = {https://doi.org/10.5194/acp-13-3661-2013}
}
|
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| Brondfield, M.N., Hutyra, L.R., Gately, C.K., Raciti, S.M. and Peterson, S.A. | Modeling and validation of on-road CO2 emissions inventories at the urban regional scale | {2012} | ENVIRONMENTAL POLLUTION Vol. {170}, pp. 113-123 |
article | DOI |
| Abstract: On-road emissions are a major contributor to rising concentrations of atmospheric greenhouse gases. In this study, we applied a downscaling methodology based on commonly available spatial parameters to model on-road CO2 emissions at the 1 x 1 km scale for the Boston. MA region and tested our approach with surface-level CO2 observations. Using two previously constructed emissions inventories with differing spatial patterns and underlying data sources, we developed regression models based on impervious surface area and volume-weighted road density that could be scaled to any resolution. We found that the models accurately reflected the inventories at their original scales (R-2 = 0.63 for both models) and exhibited a strong relationship with observed CO2 mixing ratios when downscaled across the region. Moreover, the improved spatial agreement of the models over the original inventories confirmed that either product represents a viable basis for downscaling in other metropolitan regions, even with limited data. (c) 2012 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{brondfield12a,
author = {Brondfield, Max N. and Hutyra, Lucy R. and Gately, Conor K. and Raciti, Steve M. and Peterson, Scott A.},
title = {Modeling and validation of on-road CO2 emissions inventories at the urban regional scale},
journal = {ENVIRONMENTAL POLLUTION},
year = {2012},
volume = {170},
pages = {113--123},
doi = {https://doi.org/10.1016/j.envpol.2012.06.003}
}
|
|||||
| Brooks, B.G.J., Desai, A.R., Stephens, B.B., Bowling, D.R., Burns, S.P., Watt, A.S., Heck, S.L. and Sweeney, C. | Assessing filtering of mountaintop CO2 mole fractions for application to inverse models of biosphere-atmosphere carbon exchange | {2012} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {12}({4}), pp. 2099-2115 |
article | DOI |
| Abstract: There is a widely recognized need to improve our understanding of biosphere-atmosphere carbon exchanges in areas of complex terrain including the United States Mountain West. CO2 fluxes over mountainous terrain are often difficult to measure due to unusual and complicated influences associated with atmospheric transport. Consequently, deriving regional fluxes in mountain regions with carbon cycle inversion of atmospheric CO2 mole fraction is sensitive to filtering of observations to those that can be represented at the transport model resolution. Using five years of CO2 mole fraction observations from the Regional Atmospheric Continuous CO2 Network in the Rocky Mountains (Rocky RACCOON), five statistical filters are used to investigate a range of approaches for identifying regionally representative CO2 mole fractions. Test results from three filters indicate that subsets based on short-term variance and local CO2 gradients across tower inlet heights retain nine-tenths of the total observations and are able to define representative diel variability and seasonal cycles even for difficult-to-model sites where the influence of local fluxes is much larger than regional mole fraction variations. Test results from two other filters that consider measurements from previous and following days using spline fitting or sliding windows are overly selective. Case study examples showed that these windowing-filters rejected measurements representing synoptic changes in CO2, which suggests that they are not well suited to filtering continental CO2 measurements. We present a novel CO2 lapse rate filter that uses CO2 differences between levels in the model atmosphere to select subsets of site measurements that are representative on model scales. Our new filtering techniques provide guidance for novel approaches to assimilating mountain-top CO2 mole fractions in carbon cycle inverse models. |
|||||
BibTeX:
@article{brooks12a,
author = {Brooks, B. -G. J. and Desai, A. R. and Stephens, B. B. and Bowling, D. R. and Burns, S. P. and Watt, A. S. and Heck, S. L. and Sweeney, C.},
title = {Assessing filtering of mountaintop CO2 mole fractions for application to inverse models of biosphere-atmosphere carbon exchange},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2012},
volume = {12},
number = {4},
pages = {2099--2115},
doi = {https://doi.org/10.5194/acp-12-2099-2012}
}
|
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| Brophy, K. | Development of atmospheric inversions to evaluate fossil fuel CO2 emissions in California | 2018 | School: Imperial College London | phdthesis | URL |
| Abstract: The aim of this thesis is to explore the use of atmospheric inversions to quantify emissions of fossil fuel CO2 (ffCO2) for the US state of California and assess its implications for the monitoring and verification of emissions. California is of particular interest to atmospheric … | |||||
BibTeX:
@phdthesis{brophy18a,
author = {Kieran Brophy},
title = {Development of atmospheric inversions to evaluate fossil fuel CO2 emissions in California},
school = {Imperial College London},
year = {2018},
url = {https://spiral.imperial.ac.uk/handle/10044/1/64778}
}
|
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| Bruhwiler, L., Dlugokencky, E., Masarie, K., Ishizawa, M., Andrews, A., Miller, J., Sweeney, C., Tans, P. and Worthy, D. | CarbonTracker-CH4: an assimilation system for estimating emissions of atmospheric methane | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({16}), pp. 8269-8293 |
article | DOI |
| Abstract: We describe an assimilation system for atmospheric methane (CH4), CarbonTracker-CH4, and demonstrate the diagnostic value of global or zonally averaged CH4 abundances for evaluating the results. We show that CarbonTracker-CH4 is able to simulate the observed zonal average mole fractions and capture inter-annual variability in emissions quite well at high northern latitudes (53-90 degrees N). In contrast, CarbonTracker-CH4 is less successful in the tropics where there are few observations and therefore misses significant variability and is more influenced by prior flux estimates. CarbonTracker-CH4 estimates of total fluxes at high northern latitudes are about 81+/- 7 TgCH(4) yr-1, about 12 TgCH(4) yr-1 (13 %) lower than prior estimates, a result that is consistent with other atmospheric inversions. Emissions from European wetlands are decreased by 30 %, a result consistent with previous work by Bergamaschi et al. (2005); however, unlike their results, emissions from wetlands in boreal Eurasia are increased relative to the prior estimate. Although CarbonTracker-CH4 does not estimate an increasing trend in emissions from high northern latitudes for 2000 through 2010, significant inter-annual variability in high northern latitude fluxes is recovered. Exceptionally warm growing season temperatures in the Arctic occurred in 2007, a year that was also anonymously wet. Estimated emissions from natural sources were greater than the decadal average by 4.4+/- 3.8 TgCH(4) yr(-1) in 2007. CarbonTracker-CH4 estimates for temperate latitudes are only slightly increased over prior estimates, but about 10 TgCH(4) yr(-1) is redistributed from Asia to North America. This difference exceeds the estimated uncertainty for North America (+/- 3.5 TgCH(4) yr(-1)). We used time invariant prior flux estimates, so for the period from 2000 to 2006, when the growth rate of global atmospheric CH4 was very small, the assimilation does not produce increases in natural or anthropogenic emissions in contrast to bottom-up emission data sets. After 2006, when atmospheric CH4 began its recent increases, CarbonTracker-CH4 allocates some of the increases to anthropogenic emissions at temperate latitudes, and some to tropical wetland emissions. For temperate North America the prior flux increases by about 4 TgCH(4) yr(-1) during winter when biogenic emissions are small. Examination of the residuals at some North American observation sites suggests that increased gas and oil exploration may play a role since sites near fossil fuel production are particularly hard for the inversion to fit and the prior flux estimates at these sites are apparently lower and lower over time than what the atmospheric measurements imply. The tropics are not currently well resolved by CarbonTracker-CH4 due to sparse observational coverage and a short assimilation window. However, there is a small uncertainty reduction and posterior emissions are about 18% higher than prior estimates. Most of this increase is allocated to tropical South America rather than being distributed among the global tropics. Our estimates for this source region are about 32+/- 4 TgCH(4) yr(-1), in good agreement with the analysis of Melack et al. (2004) who obtained 29 TgCH(4) yr(-1) for the most productive region, the Amazon Basin. |
|||||
BibTeX:
@article{bruhwiler14a,
author = {Bruhwiler, L. and Dlugokencky, E. and Masarie, K. and Ishizawa, M. and Andrews, A. and Miller, J. and Sweeney, C. and Tans, P. and Worthy, D.},
title = {CarbonTracker-CH4: an assimilation system for estimating emissions of atmospheric methane},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {16},
pages = {8269--8293},
doi = {https://doi.org/10.5194/acp-14-8269-2014}
}
|
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| Bruhwiler, L., Parmentier, F.-J.W., Cril, P., Leonard, M. and Palmer, P.I. | The Arctic Carbon Cycle and Its Response to Changing Climate | 2021 | Current Climate Change Reports Vol. 7(14-34) |
article | URL |
| Abstract: Long-term observations using both bottom-up (eg, flux) and top-down (atmospheric abundance) approaches are essential for understanding changing carbon cycle budgets. Consideration of atmospheric transport is critical for interpretation of top-down observations … | |||||
BibTeX:
@article{bruhwiler21a,
author = {Lori Bruhwiler and Frans-Jan W. Parmentier and Patrick Cril and Mark Leonard and Paul I. Palmer},
title = {The Arctic Carbon Cycle and Its Response to Changing Climate},
journal = {Current Climate Change Reports},
year = {2021},
volume = {7},
number = {14-34},
url = {https://link.springer.com/article/10.1007/s40641-020-00169-5}
}
|
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| Buchwitz, M., Schneising, O., Burrows, J.P., Bovensmann, H., Reuter, M. and Notholt, J. | First direct observation of the atmospheric CO2 year-to-year increase from space [BibTeX] |
{2007} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {7}({16}), pp. 4249-4256 |
article | |
BibTeX:
@article{buchwitz07a,
author = {Buchwitz, M. and Schneising, O. and Burrows, J. P. and Bovensmann, H. and Reuter, M. and Notholt, J.},
title = {First direct observation of the atmospheric CO2 year-to-year increase from space},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2007},
volume = {7},
number = {16},
pages = {4249--4256}
}
|
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| Buchwitz, M., Reuter, M., Schneising, O., Heymann, J., Bovensmann, H. and Burrows, J. | Towards an improved CO2 retrieval algorithm for SCIAMACHY on ENVISAT [BibTeX] |
2009 | Proceedings Atmospheric Science Conference, Barcelona, Spain, pp. 7-11 | inproceedings | |
BibTeX:
@inproceedings{buchwitz09a,
author = {Buchwitz, M and Reuter, M and Schneising, O and Heymann, J and Bovensmann, H and Burrows, JP},
title = {Towards an improved CO2 retrieval algorithm for SCIAMACHY on ENVISAT},
booktitle = {Proceedings Atmospheric Science Conference, Barcelona, Spain},
year = {2009},
pages = {7--11}
}
|
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| Buchwitz, M., Bovensmann, H., Burrows, J., Schneising, O. and Reuter, M. | Global mapping of methane and carbon dioxide: from SCIAMACHY to CarbonSat [BibTeX] |
2010 | Proceedings ESA-iLEAPS-EGU conference on earth observation for land-atmosphere interaction science, ESA Special Publications SP-688, ESRIN, Italy, pp. 3-5 | inproceedings | URL |
BibTeX:
@inproceedings{buchwitz10a,
author = {Buchwitz, M and Bovensmann, H and Burrows, JP and Schneising, O and Reuter, M},
title = {Global mapping of methane and carbon dioxide: from SCIAMACHY to CarbonSat},
booktitle = {Proceedings ESA-iLEAPS-EGU conference on earth observation for land-atmosphere interaction science, ESA Special Publications SP-688, ESRIN, Italy},
year = {2010},
pages = {3--5},
url = {http://tratin.cinvestav.mx/Portals/0/PapersADM/B/Buchwitz%20et%20al%202011%20global%20mapping%20sciamachy%20carbonsat.pdf}
}
|
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| Buchwitz, M., Reuter, M., Schneising, O., Boesch, H., Aben, I., Alexe, M., Armante, R., Bergamaschi, P., Bovensmann, H., Brunner, D., Buchmann, B., Burrows, J.P., Butz, A., Chevallier, F., Chedin, A., Crevoisier, C.D., Gonzi, S., De Maziere, M., De Wachter, E., Detmers, R., Dils, B., Frankenberg, C., Hahne, P., Hasekamp, O.P., Hewson, W., Heymann, J., Houweling, S., Hilker, M., Kaminski, T., Kuhlmann, G., Laeng, A., v Leeuwen, T.T., Lichtenberg, G., Marshall, J., Noel, S., Notholt, J., Palmer, P., Parker, R., Scholze, M., Stiller, G.P., Warneke, T. and Zehner, C. | THE GREENHOUSE GAS PROJECT OF ESA'S CLIMATE CHANGE INITIATIVE (GHG-CCI): OVERVIEW, ACHIEVEMENTS AND FUTURE PLANS | {2015} | Vol. {47}({W3})36TH INTERNATIONAL SYMPOSIUM ON REMOTE SENSING OF ENVIRONMENT, pp. 165-172 |
inproceedings | DOI |
| Abstract: The GHG-CCI project (http://www.esa-ghg-cci.org/) is one of several projects of the European Space Agency's (ESA) Climate Change Initiative (CCI). The goal of the CCI is to generate and deliver data sets of various satellite-derived Essential Climate Variables (ECVs) in line with GCOS (Global Climate Observing System) requirements. The ``ECV Greenhouse Gases'' (ECV GHG) is the global distribution of important climate relevant gases - namely atmospheric CO2 and CH4 - with a quality sufficient to obtain information on regional CO2 and CH4 sources and sinks. The main goal of GHG-CCI is to generate long-term highly accurate and precise time series of global near-surface-sensitive satellite observations of CO2 and CH4, i.e., XCO2 and XCH4, starting with the launch of ESA's ENVISAT satellite. These products are currently retrieved from SCIAMACHY/ENVISAT (2002-2012) and TANSO-FTS/GOSAT (2009-today) nadir mode observations in the near-infrared/shortwave-infrared spectral region. In addition, other sensors (e.g., IASI and MIPAS) and viewing modes (e.g., SCIAMACHY solar occultation) are also considered and in the future also data from other satellites. The GHG-CCI data products and related documentation are freely available via the GHG-CCI website and yearly updates are foreseen. Here we present an overview about the latest data set (Climate Research Data Package No. 2 (CRDP#2)) and summarize key findings from using satellite CO2 and CH4 retrievals to improve our understanding of the natural and anthropogenic sources and sinks of these important atmospheric greenhouse gases. We also shortly mention ongoing activities related to validation and initial user assessment of CRDP#2 and future plans. |
|||||
BibTeX:
@inproceedings{buchwitz15a,
author = {Buchwitz, M. and Reuter, M. and Schneising, O. and Boesch, H. and Aben, I. and Alexe, M. and Armante, R. and Bergamaschi, P. and Bovensmann, H. and Brunner, D. and Buchmann, B. and Burrows, J. P. and Butz, A. and Chevallier, F. and Chedin, A. and Crevoisier, C. D. and Gonzi, S. and De Maziere, M. and De Wachter, E. and Detmers, R. and Dils, B. and Frankenberg, C. and Hahne, P. and Hasekamp, O. P. and Hewson, W. and Heymann, J. and Houweling, S. and Hilker, M. and Kaminski, T. and Kuhlmann, G. and Laeng, A. and v Leeuwen, T. T. and Lichtenberg, G. and Marshall, J. and Noel, S. and Notholt, J. and Palmer, P. and Parker, R. and Scholze, M. and Stiller, G. P. and Warneke, T. and Zehner, C.},
title = {THE GREENHOUSE GAS PROJECT OF ESA'S CLIMATE CHANGE INITIATIVE (GHG-CCI): OVERVIEW, ACHIEVEMENTS AND FUTURE PLANS},
booktitle = {36TH INTERNATIONAL SYMPOSIUM ON REMOTE SENSING OF ENVIRONMENT},
year = {2015},
volume = {47},
number = {W3},
pages = {165--172},
note = {36th International Symposium on Remote Sensing of the Environment (ISRSE), Berlin, GERMANY, MAY 11-15, 2015},
doi = {https://doi.org/10.5194/isprsarchives-XL-7-W3-165-2015}
}
|
|||||
| Buchwitz, M., Reuter, M., Schneising, O., Hewson, W., Detmers, R.G., Boesch, H., Hasekamp, O.P., Aben, I., Bovensmann, H., Burrows, J.P., Butz, A., Chevallier, F., Dils, B., Frankenberg, C., Heymann, J., Lichtenberg, G., De Maziere, M., Notholt, J., Parker, R., Warneke, T., Zehner, C., Griffith, D.W.T., Deutscher, N.M., Kuze, A., Suto, H. and Wunch, D. | Global satellite observations of column-averaged carbon dioxide and methane: The GHG-CCI XCO2 and XCH4 CRDP3 data set | {2017} | REMOTE SENSING OF ENVIRONMENT Vol. {203}, pp. 276-295 |
article | DOI |
| Abstract: Carbon dioxide (CO2) and methane (CH4) are the two most important greenhouse gases emitted by mankind. Better knowledge of the surface sources and sinks of these Essential Climate Variables (ECVs) and related carbon uptake and release processes is needed for important climate change related applications such as improved climate modelling and prediction. Some satellites provide near-surface-sensitive atmospheric CO2 and CH4 observations that can be used to obtain information on CQ(2) and CH4 surface fluxes. The goal of the GHG-CCI project of the European Space Agency's (ESA) Climate Change Initiative (CCI) is to use satellite data to generate atmospheric CO2 and CH4 data products meeting demanding GCOS (Global Climate Observing System) greenhouse gas (GHG) ECV requirements. To achieve this, retrieval algorithms are regularly being improved followed by annual data reprocessing and analysis cycles to generate better products in terms of extended time series and continuously improved data quality. Here we present an overview about the latest GHG-CCI data set called Climate Research Data Package No.3 (CRDP3) focusing on the GHG-CCI core data products, which are column-averaged dry air mole fractions of CO2 and CH4, i.e., XCO2 and XCH4, as retrieved from SCIAMACHY/ENVISAT and TANSO/GOSAT satellite radiances covering the time period end of 2002 to end of 2014. We present global maps and time series including initial validation results obtained by comparisons with Total Carbon Column Observing Network (TCCON) ground-based observations. We show that the GCOS requirements for systematic error (<1 ppm for XCO2, <10 ppb for XCH4) and long-term stability (<0.2 ppm/year for XCO2, <2 ppb/year for XCH4) are met for nearly all products (an exception is SCIAMACHY methane especially since 2010). For XCO2 we present comparisons with global models using the output of two CO2 assimilation systems (MACC version 14r2 and CarbonTracker version CT2013B). We show that overall there is reasonable consistency and agreement between all data sets (within-1-2 ppm) but we also found significant differences depending on region and time period. (C) 2017 Elsevier Inc. All rights reserved. |
|||||
BibTeX:
@article{buchwitz17a,
author = {Buchwitz, M. and Reuter, M. and Schneising, O. and Hewson, W. and Detmers, R. G. and Boesch, H. and Hasekamp, O. P. and Aben, I. and Bovensmann, H. and Burrows, J. P. and Butz, A. and Chevallier, F. and Dils, B. and Frankenberg, C. and Heymann, J. and Lichtenberg, G. and De Maziere, M. and Notholt, J. and Parker, R. and Warneke, T. and Zehner, C. and Griffith, D. W. T. and Deutscher, N. M. and Kuze, A. and Suto, H. and Wunch, D.},
title = {Global satellite observations of column-averaged carbon dioxide and methane: The GHG-CCI XCO2 and XCH4 CRDP3 data set},
journal = {REMOTE SENSING OF ENVIRONMENT},
year = {2017},
volume = {203},
pages = {276--295},
doi = {https://doi.org/10.1016/j.rse.2016.12.027}
}
|
|||||
| Buchwitz, M., Reuter, M., Schneising, O., Noel, S., Gier, B., Bovensmann, H., Burrows, J.P., Boesch, H., Anand, J., Parker, R.J., Somkuti, P., Detmers, R.G., Hasekamp, O.P., Aben, I., Butz, A., Kuze, A., Suto, H., Yoshida, Y., Crisp, D. and O'Dell, C. | Computation and analysis of atmospheric carbon dioxide annual mean growth rates from satellite observations during 2003-2016 | {2018} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {18}({23}), pp. 17355-17370 |
article | DOI |
| Abstract: The growth rate of atmospheric carbon dioxide (CO2) reflects the net effect of emissions and uptake resulting from anthropogenic and natural carbon sources and sinks. Annual mean CO2 growth rates have been determined from satellite retrievals of column-averaged dry-air mole fractions of CO2, i.e. XCO2, for the years 2003 to 2016. The XCO2 growth rates agree with National Oceanic and Atmospheric Administration (NOAA) growth rates from CO2 surface observations within the uncertainty of the satellite-derived growth rates (mean difference +/- standard deviation: 0.0 +/- 0.3 ppm year(-1); R: 0.82). This new and independent data set confirms record-large growth rates of around 3 ppm year(-1) in 2015 and 2016, which are attributed to the 2015-2016 El Nino. Based on a comparison of the satellite-derived growth rates with human CO2 emissions from fossil fuel combustion and with El Nino Southern Oscillation (ENSO) indices, we estimate by how much the impact of ENSO dominates the impact of fossil-fuel-burning-related emissions in explaining the variance of the atmospheric CO2 growth rate. Our analysis shows that the ENSO impact on CO2 growth rate variations dominates that of human emissions throughout the period 2003-2016 but in particular during the period 2010-2016 due to strong La Nina and El Nino events. Using the derived growth rates and their uncertainties, we estimate the probability that the impact of ENSO on the variability is larger than the impact of human emissions to be 63 % for the time period 2003-2016. If the time period is restricted to 2010-2016, this probability increases to 94%. |
|||||
BibTeX:
@article{buchwitz18a,
author = {Buchwitz, Michael and Reuter, Maximilian and Schneising, Oliver and Noel, Stefan and Gier, Bettina and Bovensmann, Heinrich and Burrows, John P. and Boesch, Hartmut and Anand, Jasdeep and Parker, Robert J. and Somkuti, Peter and Detmers, Rob G. and Hasekamp, Otto P. and Aben, Ilse and Butz, Andre and Kuze, Akihiko and Suto, Hiroshi and Yoshida, Yukio and Crisp, David and O'Dell, Christopher},
title = {Computation and analysis of atmospheric carbon dioxide annual mean growth rates from satellite observations during 2003-2016},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2018},
volume = {18},
number = {23},
pages = {17355--17370},
doi = {https://doi.org/10.5194/acp-18-17355-2018}
}
|
|||||
| Buchwitz, M., Reuter, M., Noël, S., Bramstedt, K., Schneising, O., Hilker, M., Andrade, B.F., Bovensmann, H., Burrows, J.P., Noia, A.D., Boesch, H., Wu, L., Landgraf, J., Aben, I., Retscher, C., O'Dell, C.W. and Crisp, D. | Can a regional-scale reduction of atmospheric CO2 during the COVID-19 pandemic be detected from space? A case study for East China using satellite XCO2 retrievals | 2021 | Atmospheric Measurement Techniques | article | URL |
| Abstract: The COVID-19 pandemic resulted in reduced anthropogenic carbon dioxide (CO 2) emissions during 2020 in large parts of the world. To investigate whether a regional-scale reduction of anthropogenic CO 2 emissions during the COVID-19 pandemic can be detected … | |||||
BibTeX:
@article{buchwitz21a,
author = {Michael Buchwitz and Maximilian Reuter and Stefan Noël and Klaus Bramstedt and Oliver Schneising and Michael Hilker and Blanca Fuentes Andrade and Heinrich Bovensmann and John P. Burrows and Antonio Di Noia and Hartmut Boesch and Lianghai Wu and Jochen Landgraf and Ilse Aben and Christian Retscher and Christopher W. O'Dell and David Crisp},
title = {Can a regional-scale reduction of atmospheric CO2 during the COVID-19 pandemic be detected from space? A case study for East China using satellite XCO2 retrievals},
journal = {Atmospheric Measurement Techniques},
year = {2021},
url = {https://amt.copernicus.org/articles/14/2141/2021/}
}
|
|||||
| Burgin, M.S. | Physics-based modeling for high-fidelity radar retrievals [BibTeX] |
2014 | School: University of Michigan | phdthesis | |
BibTeX:
@phdthesis{burgin14a,
author = {Burgin, Mariko Sofie},
title = {Physics-based modeling for high-fidelity radar retrievals},
school = {University of Michigan},
year = {2014}
}
|
|||||
| Burman, P.K.D. | Estimation of Net Primary Productivity: An Introduction to Different Approaches | 2020 | Spatial Modeling in Forest Resources Management | article | URL |
| Abstract: The net primary productivity (NPP) is defined as the net carbon gain by plants in natural and agricultural ecosystems, which is computed by subtracting the autotrophic respiration from the gross photosynthetic carbon uptake by the ecosystems. It acts as the indicators of carbon … | |||||
BibTeX:
@article{burman20a,
author = {Pramit Kumar Deb Burman},
title = {Estimation of Net Primary Productivity: An Introduction to Different Approaches},
journal = {Spatial Modeling in Forest Resources Management},
publisher = {Springer},
year = {2020},
url = {https://link.springer.com/chapter/10.1007/978-3-030-56542-8_2}
}
|
|||||
| Buschmann, M., Deutscher, N.M., Sherlock, V., Palm, M., Warneke, T. and Notholt, J. | Retrieval of xCO(2) from ground-based mid-infrared (NDACC) solar absorption spectra and comparison to TCCON | {2016} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {9}({2}), pp. 577-585 |
article | DOI |
| Abstract: High-resolution solar absorption spectra, taken within the Network for the Detection of Atmospheric Composition Change Infrared Working Group (NDACC-IRWG) in the mid-infrared spectral region, are used to infer partial or total column abundances of many gases. In this paper we present the retrieval of a column-averaged mole fraction of carbon dioxide from NDACC-IRWG spectra taken with a Fourier transform infrared (FTIR) spectrometer at the site in Ny-Alesund, Spitsbergen. The retrieved time series is compared to colocated standard TCCON (Total Carbon Column Observing Network) measurements of column-averaged dry-air mole fractions of CO2 (denoted by xCO(2)). Comparing the NDACC and TCCON retrievals, we find that the sensitivity of the NDACC retrieval is lower in the troposphere (by a factor of 2) and higher in the stratosphere, compared to TCCON. Thus, the NDACC retrieval is less sensitive to tropospheric changes (e.g., the seasonal cycle) in the column average. |
|||||
BibTeX:
@article{buschmann16a,
author = {Buschmann, Matthias and Deutscher, Nicholas M. and Sherlock, Vanessa and Palm, Mathias and Warneke, Thorsten and Notholt, Justus},
title = {Retrieval of xCO(2) from ground-based mid-infrared (NDACC) solar absorption spectra and comparison to TCCON},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2016},
volume = {9},
number = {2},
pages = {577--585},
doi = {https://doi.org/10.5194/amt-9-577-2016}
}
|
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| Butler, M.P., Davis, K.J., Denning, A.S. and Kawa, S.R. | Using continental observations in global atmospheric inversions of CO2: North American carbon sources and sinks | {2010} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {62}({5, SI}), pp. 550-572 |
article | DOI |
| Abstract: We evaluate North American carbon fluxes using a monthly global Bayesian synthesis inversion that includes well-calibrated carbon dioxide concentrations measured at continental flux towers. We employ the NASA Parametrized Chemistry Tracer Model (PCTM) for atmospheric transport and a TransCom-style inversion with subcontinental resolution. We subsample carbon dioxide time series at four North American flux tower sites for mid-day hours to ensure sampling of a deep, well-mixed atmospheric boundary layer. The addition of these flux tower sites to a global network reduces North America mean annual flux uncertainty for 2001-2003 by 20% to 0.4 Pg C yr-1 compared to a network without the tower sites. North American flux is estimated to be a net sink of 1.2 +/- 0.4 Pg C yr-1 which is within the uncertainty bounds of the result without the towers. Uncertainty reduction is found to be local to the regions within North America where the flux towers are located, and including the towers reduces covariances between regions within North America. Mid-day carbon dioxide observations from flux towers provide a viable means of increasing continental observation density and reducing the uncertainty of regional carbon flux estimates in atmospheric inversions. |
|||||
BibTeX:
@article{butler10a,
author = {Butler, M. P. and Davis, K. J. and Denning, A. S. and Kawa, S. R.},
title = {Using continental observations in global atmospheric inversions of CO2: North American carbon sources and sinks},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2010},
volume = {62},
number = {5, SI},
pages = {550--572},
doi = {https://doi.org/10.1111/j.1600-0889.2010.00501.x}
}
|
|||||
| Butler, M.P., Lauvaux, T., Feng, S., Liu, J., Bowman, K.W. and Davis, K.J. | Atmospheric Simulations of Total Column CO2 Mole Fractions from Global to Mesoscale within the Carbon Monitoring System Flux Inversion Framework | {2020} | ATMOSPHERE Vol. {11}({8}) |
article | DOI |
| Abstract: Quantifying the uncertainty of inversion-derived CO2 surface fluxes and attributing the uncertainty to errors in either flux or atmospheric transport simulations continue to be challenges in the characterization of surface sources and sinks of carbon dioxide (CO2). Despite recent studies inferring fluxes while using higher-resolution modeling systems, the utility of regional-scale models remains unclear when compared to existing coarse-resolution global systems. Here, we present an off-line coupling of the mesoscale Weather Research and Forecasting (WRF) model to optimized biogenic CO2 fluxes and mole fractions from the global Carbon Monitoring System inversion system (CMS-Flux). The coupling framework consists of methods to constrain the mass of CO2 introduced into WRF, effectively nesting our regional domain covering most of North America (except the northern half of Canada) within the CMS global model. We test the coupling by simulating Greenhouse gases Observing SATellite (GOSAT) column-averaged dry-air mole fractions (XCO2) over North America for 2010. We find mean model-model differences in summer of similar to 0.12 ppm, significantly lower than the original coupling scheme (from 0.5 to 1.5 ppm, depending on the boundary). While 85% of the XCO2 values are due to long-range transport from outside our North American domain, most of the model-model differences appear to be due to transport differences in the fraction of the troposphere below 850 hPa. Satellite data from GOSAT and tower and aircraft data are used to show that vertical transport above the Planetary Boundary Layer is responsible for significant model-model differences in the horizontal distribution of column XCO2 across North America. | |||||
BibTeX:
@article{butler20a,
author = {Butler, Martha P. and Lauvaux, Thomas and Feng, Sha and Liu, Junjie and Bowman, Kevin W. and Davis, Kenneth J.},
title = {Atmospheric Simulations of Total Column CO2 Mole Fractions from Global to Mesoscale within the Carbon Monitoring System Flux Inversion Framework},
journal = {ATMOSPHERE},
publisher = {MDPI},
year = {2020},
volume = {11},
number = {8},
doi = {https://doi.org/10.3390/atmos11080787}
}
|
|||||
| Butz, A., Hasekamp, O.P., Frankenberg, C., Vidot, J. and Aben, I. | CH4 retrievals from space-based solar backscatter measurements: Performance evaluation against simulated aerosol and cirrus loaded scenes | {2010} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {115} |
article | DOI |
| Abstract: Monitoring of atmospheric methane (CH4) concentrations from space-based instruments such as the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) and the Greenhouse Gases Observing Satellite (GOSAT) relies on observations of sunlight backscattered to space by the Earth's surface and atmosphere. Retrieval biases occur due to unaccounted scattering effects by aerosols and thin cirrus that modify the lightpath. Here, we evaluate the accuracy of two retrieval methods that aim at minimizing such scattering induced errors. The lightpath ``proxy'' method, applicable to SCIAMACHY and GOSAT, retrieves CH4 and carbon dioxide (CO2) simultaneously and uses CO2 as a proxy for lightpath modification. The ``physics-based'' method, which we propose for GOSAT, aims at simultaneously retrieving CH4 concentrations and scattering properties of the atmosphere. We evaluate performance of the methods against a trial ensemble of simulated aerosol and cirrus loaded scenes. More than 80% of the trials yield residual scattering induced CH4 errors below 0.6% and 0.8% for the proxy and the physics-based approach, respectively. Very few cases result in errors greater than 2% for both methods. Advantages of the proxy approach are efficient and robust performance yielding more useful retrievals than the physics-based method which reveals some nonconvergent cases. The major disadvantage of the proxy method is the uncertainty of the proxy CO2 concentration contributing to the overall error budget. Residual errors generally correlate with particle and surface properties and thus might impact inverse modeling of CH4 sources and sinks. |
|||||
BibTeX:
@article{butz10a,
author = {Butz, A. and Hasekamp, O. P. and Frankenberg, C. and Vidot, J. and Aben, I.},
title = {CH4 retrievals from space-based solar backscatter measurements: Performance evaluation against simulated aerosol and cirrus loaded scenes},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2010},
volume = {115},
doi = {https://doi.org/10.1029/2010JD014514}
}
|
|||||
| Butz, A., Guerlet, S., Hasekamp, O., Schepers, D., Galli, A., Aben, I., Frankenberg, C., Hartmann, J.M., Tran, H., Kuze, A., Keppel-Aleks, G., Toon, G., Wunch, D., Wennberg, P., Deutscher, N., Griffith, D., Macatangay, R., Messerschmidt, J., Notholt, J. and Warneke, T. | Toward accurate CO2 and CH4 observations from GOSAT | {2011} | GEOPHYSICAL RESEARCH LETTERS Vol. {38} |
article | DOI |
| Abstract: The column-average dry air mole fractions of atmospheric carbon dioxide and methane (X-CO2 and X-CH4) are inferred from observations of backscattered sunlight conducted by the Greenhouse gases Observing SATellite (GOSAT). Comparing the first year of GOSAT retrievals over land with colocated ground-based observations of the Total Carbon Column Observing Network (TCCON), we find an average difference (bias) of -0.05% and -0.30% for X-CO2 and X-CH4 with a station-to-station variability (standard deviation of the bias) of 0.37% and 0.26% among the 6 considered TCCON sites. The root-mean square deviation of the bias-corrected satellite retrievals from colocated TCCON observations amounts to 2.8 ppm for X-CO2 and 0.015 ppm for X-CH4. Without any data averaging, the GOSAT records reproduce general source/sink patterns such as the seasonal cycle of X-CO2 suggesting the use of the satellite retrievals for constraining surface fluxes. Citation: Butz, A., et al. (2011), Toward accurate CO2 and CH4 observations from GOSAT, Geophys. Res. Lett., 38, L14812, doi:10.1029/2011GL047888. |
|||||
BibTeX:
@article{butz11a,
author = {Butz, A. and Guerlet, S. and Hasekamp, O. and Schepers, D. and Galli, A. and Aben, I. and Frankenberg, C. and Hartmann, J. -M. and Tran, H. and Kuze, A. and Keppel-Aleks, G. and Toon, G. and Wunch, D. and Wennberg, P. and Deutscher, N. and Griffith, D. and Macatangay, R. and Messerschmidt, J. and Notholt, J. and Warneke, T.},
title = {Toward accurate CO2 and CH4 observations from GOSAT},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2011},
volume = {38},
doi = {https://doi.org/10.1029/2011GL047888}
}
|
|||||
| Butz, A., Guerlet, S., Hasekamp, O.P., Kuze, A. and Suto, H. | Using ocean-glint scattered sunlight as a diagnostic tool for satellite remote sensing of greenhouse gases | {2013} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {6}({9}), pp. 2509-2520 |
article | DOI |
| Abstract: Spectroscopic measurements of sunlight backscattered by the Earth's surface is a technique widely used for remote sensing of atmospheric constituent concentrations from space. Thereby, remote sensing of greenhouse gases poses particularly challenging accuracy requirements for instrumentation and retrieval algorithms which, in general, suffer from various error sources. Here, we investigate a method that helps disentangle sources of error for observations of sunlight backscattered from the glint spot on the ocean surface. The method exploits the backscattering characteristics of the ocean surface, which is bright for glint geometry but dark for off-glint angles. This property allows for identifying a set of clean scenes where light scattering due to particles in the atmosphere is negligible such that uncertain knowledge of the lightpath can be excluded as a source of error. We apply the method to more than 3 yr of ocean-glint measurements by the Thermal And Near infrared Sensor for carbon Observation (TANSO) Fourier Transform Spectrometer (FTS) onboard the Greenhouse Gases Observing Satellite (GOSAT), which aims at measuring carbon dioxide (CO2) and methane (CH4) concentrations. The proposed method is able to clearly monitor recent improvements in the instrument calibration of the oxygen (O-2) A-band channel and suggests some residual uncertainty in our knowledge about the instrument. We further assess the consistency of CO2 retrievals from several absorption bands between 6400 cm(-1) (1565 nm) and 4800 cm(-1) (2100 nm) and find that the absorption bands commonly used for monitoring of CO2 dry air mole fractions from GOSAT allow for consistency better than 1.5 ppm. Usage of other bands reveals significant inconsistency among retrieved CO2 concentrations pointing at inconsistency of spectroscopic parameters. |
|||||
BibTeX:
@article{butz13a,
author = {Butz, A. and Guerlet, S. and Hasekamp, O. P. and Kuze, A. and Suto, H.},
title = {Using ocean-glint scattered sunlight as a diagnostic tool for satellite remote sensing of greenhouse gases},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2013},
volume = {6},
number = {9},
pages = {2509--2520},
doi = {https://doi.org/10.5194/amt-6-2509-2013}
}
|
|||||
| Butz, A., Orphal, J., Checa-Garcia, R., Friedl-Vallon, F., von Clarmann, T., Bovensmann, H., Hasekamp, O., Landgraf, J., Knigge, T., Weise, D., Sqalli-Houssini, O. and Kemper, D. | Geostationary Emission Explorer for Europe (G3E): mission concept and initial performance assessment | {2015} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {8}({11}), pp. 4719-4734 |
article | DOI |
| Abstract: The Geostationary Emission Explorer for Europe (G3E) is a concept for a geostationary satellite sounder that aims to constrain the sources and sinks of greenhouse gases carbon dioxide (CO2) and methane (CH4) for continental-scale regions. Its primary focus is on central Europe. G3E carries a spectrometer system that collects sunlight backscattered from the Earth's surface and atmosphere in the near-infrared (NIR) and shortwave-infrared (SWIR) spectral range. Solar absorption spectra allow for spatiotemporally dense observations of the column-average concentrations of carbon dioxide (XCO2), methane (XCH4), and carbon monoxide (XCO). The mission concept in particular facilitates sampling of the diurnal variation with several measurements per day during summer. Here, we present the mission concept and carry out an initial performance assessment of the retrieval capabilities. The radiometric performance of the 4 grating spectrometers is tuned to reconcile small ground-pixel sizes (similar to 2 km x 3 km at 50 degrees latitude) with short single-shot exposures (similar to 2.9 s) that allow for sampling continental regions such as central Europe within 2 h while providing a sufficient signal-to-noise ratio. The noise errors to be expected for XCO2, XCH4, and XCO are assessed through retrieval simulations for a European trial ensemble. Generally, single-shot precision for the targeted XCO2 and XCH4 is better than 0.5% with some exception for scenes with low infrared surface albedo observed under low sun conditions in winter. For XCO, precision is generally better than 10 %. Performance for aerosol and cirrus loaded atmospheres is assessed by mimicking G3E's slant view on Europe for an ensemble of atmospheric scattering properties used previously for evaluating nadir-viewing low-Earth-orbit (LEO) satellites. While retrieval concepts developed for LEO configurations generally succeed in mitigating aerosol- and cirrus-induced retrieval errors for G3E's setup, residual errors are somewhat greater in geostationary orbit (GEO) than in LEO. G3E's deployment in the vicinity of the Meteosat Third Generation (MTG) satellites has the potential to make synergistic use of MTG's sounding capabilities e.g. with respect to characterization of aerosol and cloud properties or with respect to enhancing carbon monoxide retrievals by combining G3E's solar and MTG's thermal infrared spectra. |
|||||
BibTeX:
@article{butz15a,
author = {Butz, A. and Orphal, J. and Checa-Garcia, R. and Friedl-Vallon, F. and von Clarmann, T. and Bovensmann, H. and Hasekamp, O. and Landgraf, J. and Knigge, T. and Weise, D. and Sqalli-Houssini, O. and Kemper, D.},
title = {Geostationary Emission Explorer for Europe (G3E): mission concept and initial performance assessment},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2015},
volume = {8},
number = {11},
pages = {4719--4734},
doi = {https://doi.org/10.5194/amt-8-4719-2015}
}
|
|||||
| Byrne, B., Jones, D.B.A., Strong, K., Zeng, Z.C., Deng, F. and Liu, J. | Sensitivity of CO2 surface flux constraints to observational coverage | {2017} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {122}({12}), pp. 6672-6694 |
article | DOI |
| Abstract: Inverse modeling of regional CO2 fluxes using atmospheric CO2 data is sensitive to the observational coverage of the observing network. Here we use the GEOS-Chem adjoint model to examine the sensitivity to CO2 fluxes of observations from the in situ surface network, the Total Carbon Column Observing Network (TCCON), the Greenhouse Gases Observing Satellite (GOSAT), and the Orbiting Carbon Observatory (OCO-2). We find that OCO-2 has high sensitivity to fluxes throughout the tropics and Southern Hemisphere, while surface observations have high sensitivity to fluxes in the northern extratropics throughout the year. For GOSAT viewing modes, ocean glint data provide the strongest constraints on fluxes in the tropics and Southern Hemisphere during Northern Hemisphere fall and winter relative to other viewing modes. In contrast, GOSAT nadir land data offer the greater sensitivity to fluxes in these regions during Northern Hemisphere spring and summer. For OCO-2 viewing modes, ocean glint data provided the dominant sensitivity to the surface fluxes in the northern subtropics, tropics, and Southern Hemisphere. We performed a series of inversion analyses using pseudodata and found that the varying sensitivities can result in large differences in regional flux estimates. However, combining measurements from different observing systems to exploit their complementarity may lead to a posteriori flux estimates with improved accuracy. |
|||||
BibTeX:
@article{byrne17a,
author = {Byrne, B. and Jones, D. B. A. and Strong, K. and Zeng, Z. -C. and Deng, F. and Liu, J.},
title = {Sensitivity of CO2 surface flux constraints to observational coverage},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2017},
volume = {122},
number = {12},
pages = {6672--6694},
doi = {https://doi.org/10.1002/2016JD026164}
}
|
|||||
| Byrne, B., Wunch, D., Jones, D.B.A., Strong, K., Deng, F., Baker, I., Kohler, P., Frankenberg, C., Joiner, J., Arora, V.K., Badawy, B., Harper, A.B., Warneke, T., Petri, C., Kivi, R. and Roehl, C.M. | Evaluating GPP and Respiration Estimates Over Northern Midlatitude Ecosystems Using Solar-Induced Fluorescence and Atmospheric CO2 Measurements | {2018} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {123}({9}), pp. {2976-2997} |
article | DOI |
| Abstract: On regional to global scales, few constraints exist on gross primary productivity (GPP) and ecosystem respiration (R-e) fluxes. Yet constraints on these fluxes are critical for evaluating and improving terrestrial biosphere models. In this study, we evaluate the seasonal cycle of GPP, R-e, and net ecosystem exchange (NEE) produced by four terrestrial biosphere models and FLUXCOM, a data-driven model, over northern midlatitude ecosystems. We evaluate the seasonal cycle of GPP and NEE using solar-induced fluorescence retrieved from the Global Ozone Monitoring Experiment-2 and column-averaged dry-air mole fractions of CO2 (X-CO2) from the Total Carbon Column Observing Network, respectively. We then infer R-e by combining constraints on GPP with constraints on NEE from two flux inversions. An ensemble of optimized R-e seasonal cycles is generated using five GPP estimates and two NEE estimates. The optimized R-e curves generally show high consistency with each other, with the largest differences due to the magnitude of GPP. We find optimized R-e exhibits a systematically broader summer maximum than modeled R-e, with values lower during June-July and higher during the fall than R-e. Further analysis suggests that the differences could be due to seasonal variations in the carbon use efficiency (possibly due to an ecosystem-scale Kok effect) and to seasonal variations in the leaf litter and fine root carbon pool. The results suggest that the inclusion of variable carbon use efficiency for autotrophic respiration and carbon pool dependence for heterotrophic respiration is important for accurately simulating R-e. |
|||||
BibTeX:
@article{byrne18a,
author = {Byrne, B. and Wunch, D. and Jones, D. B. A. and Strong, K. and Deng, F. and Baker, I. and Kohler, P. and Frankenberg, C. and Joiner, J. and Arora, V. K. and Badawy, B. and Harper, A. B. and Warneke, T. and Petri, C. and Kivi, R. and Roehl, C. M.},
title = {Evaluating GPP and Respiration Estimates Over Northern Midlatitude Ecosystems Using Solar-Induced Fluorescence and Atmospheric CO2 Measurements},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2018},
volume = {123},
number = {9},
pages = {2976-2997},
doi = {https://doi.org/10.1029/2018JG004472}
}
|
|||||
| Byrne, B. | Monitoring the carbon cycle: Evaluation of terrestrial biosphere models and anthropogenic greenhouse gas emissions with atmospheric observations | 2018 | School: University of Toronto | phdthesis | URL |
| Abstract: Reliable projections of climate change will require terrestrial biosphere models (TBMs) that produce robust projections of changes in the exchange of CO2 between the atmosphere and terrestrial biosphere. In this thesis, atmospheric CO2 observations are used to evaluate … | |||||
BibTeX:
@phdthesis{byrne18b,
author = {Brendan Byrne},
title = {Monitoring the carbon cycle: Evaluation of terrestrial biosphere models and anthropogenic greenhouse gas emissions with atmospheric observations},
school = {University of Toronto},
year = {2018},
url = {https://tspace.library.utoronto.ca/handle/1807/91885}
}
|
|||||
| Byrne, B., Jones, D.B.A., Strong, K., Polavarapu, S.M., Harper, A.B., Baker, D.F. and Maksyutov, S. | On what scales can GOSAT flux inversions constrain anomalies in terrestrial ecosystems? | {2019} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {19}({20}), pp. {13017-13035} |
article | DOI URL |
| Abstract: Interannual variations in temperature and precipitation impact the carbon balance of terrestrial ecosystems, leaving an imprint in atmospheric CO2. Quantifying the impact of climate anomalies on the net ecosystem exchange (NEE) of terrestrial ecosystems can provide a constraint to evaluate terrestrial biosphere models against and may provide an emergent constraint on the response of terrestrial ecosystems to climate change. We investigate the spatial scales over which interannual variability in NEE can be constrained using atmospheric CO2 observations from the Greenhouse Gases Observing Satellite (GOSAT). NEE anomalies are calculated by performing a series of inversion analyses using the GEOS-Chem adjoint model to assimilate GOSAT observations. Monthly NEE anomalies are compared to ``proxies'', variables that are associated with anomalies in the terrestrial carbon cycle, and to upscaled NEE estimates from FLUXCOM. Statistically significant correlations (P < 0.05) are obtained between posterior NEE anomalies and anomalies in soil temperature and FLUXCOM NEE on continental and larger scales in the tropics, as well as in the northern extratropics on subcontinental scales during the summer (R-2 >= 0.49), suggesting that GOSAT measurements provide a constraint on NEE interannual variability (IAV) on these spatial scales. Furthermore, we show that GOSAT flux inversions are generally better correlated with the environmental proxies and FLUXCOM NEE than NEE anomalies produced by a set of terrestrial biosphere models (TBMs), suggesting that GOSAT flux inversions could be used to evaluate TBM NEE fluxes. | |||||
BibTeX:
@article{byrne19a,
author = {Byrne, Brendan and Jones, Dylan B. A. and Strong, Kimberly and Polavarapu, Saroja M. and Harper, Anna B. and Baker, David F. and Maksyutov, Shamil},
title = {On what scales can GOSAT flux inversions constrain anomalies in terrestrial ecosystems?},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {19},
number = {20},
pages = {13017--13035},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/19/13017/2019/},
doi = {https://doi.org/10.5194/acp-19-13017-2019}
}
|
|||||
| Byrne, B., Liu, J., Bloom, A.A., Bowman, K.W., Butterfield, Z., Joiner, J., Keenan, T.F., Keppel-Aleks, G., Parazoo, N.C. and Yin, Y. | Contrasting Regional Carbon Cycle Responses to Seasonal Climate Anomalies Across the East-West Divide of Temperate North America | {2020} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {34}({11}) |
article | DOI URL |
| Abstract: Across temperate North America, interannual variability (IAV) in gross primary production (GPP) and net ecosystem exchange (NEE) and their relationship with environmental drivers are poorly understood. Here, we examine IAV in GPP and NEE and their relationship to environmental drivers using two state-of-the-science flux products: NEE constrained by surface and space-based atmospheric CO2 measurements over 2010-2015 and satellite up-scaled GPP from FluxSat over 2001-2017. We show that the arid western half of temperate North America provides a larger contribution to IAV in GPP (104% of east) and NEE (127% of east) than the eastern half, in spite of smaller magnitude of annual mean GPP and NEE. This occurs because anomalies in western ecosystems are temporally coherent across the growing season leading to an amplification of GPP and NEE. In contrast, IAV in GPP and NEE in eastern ecosystems is dominated by seasonal compensation effects, associated with opposite responses to temperature anomalies in spring and summer. Terrestrial biosphere models in the MsTMIP ensemble generally capture these differences between eastern and western temperate North America, although there is considerable spread between models. | |||||
BibTeX:
@article{byrne20a,
author = {Byrne, B. and Liu, J. and Bloom, A. A. and Bowman, K. W. and Butterfield, Z. and Joiner, J. and Keenan, T. F. and Keppel-Aleks, G. and Parazoo, N. C. and Yin, Y.},
title = {Contrasting Regional Carbon Cycle Responses to Seasonal Climate Anomalies Across the East-West Divide of Temperate North America},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {34},
number = {11},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GB006598},
doi = {https://doi.org/10.1029/2020GB006598}
}
|
|||||
| Carels, N. | The Challenge of Bioenergies: An Overview [BibTeX] |
{2011} | BIOFUEL'S ENGINEERING PROCESS TECHNOLOGY, pp. 23-64 | incollection | |
BibTeX:
@incollection{carels11a,
author = {Carels, Nicolas},
title = {The Challenge of Bioenergies: An Overview},
booktitle = {BIOFUEL'S ENGINEERING PROCESS TECHNOLOGY},
publisher = {InTech},
year = {2011},
pages = {23--64}
}
|
|||||
| Carouge, C., Rayner, P.J., Peylin, P., Bousquet, P., Chevallier, F. and Ciais, P. | What can we learn from European continuous atmospheric CO2 measurements to quantify regional fluxes - Part 2: Sensitivity of flux accuracy to inverse setup | {2010} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {10}({6}), pp. 3119-3129 |
article | DOI |
| Abstract: An inverse model using atmospheric CO2 observations from a European network of stations to reconstruct daily CO2 fluxes and their uncertainties over Europe at 50 km resolution has been developed within a Bayesian framework. We use the pseudo-data approach in which we try to recover known fluxes using a range of perturbations to the input. In this study, the focus is put on the sensitivity of flux accuracy to the inverse setup, varying the prior flux errors, the pseudo-data errors and the network of stations. We show that, under a range of assumptions about prior error and data error we can recover fluxes reliably at the scale of 1000 km and 10 days. At smaller scales the performance is highly sensitive to details of the inverse set-up. The use of temporal correlations in the flux domain appears to be of the same importance as the spatial correlations. We also note that the use of simple, isotropic correlations on the prior flux errors is more reliable than the use of apparently physically-based errors. Finally, increasing the European atmospheric network density improves the area with significant error reduction in the flux retrieval. |
|||||
BibTeX:
@article{carouge10a,
author = {Carouge, C. and Rayner, P. J. and Peylin, P. and Bousquet, P. and Chevallier, F. and Ciais, P.},
title = {What can we learn from European continuous atmospheric CO2 measurements to quantify regional fluxes - Part 2: Sensitivity of flux accuracy to inverse setup},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2010},
volume = {10},
number = {6},
pages = {3119--3129},
doi = {https://doi.org/10.5194/acp-10-3119-2010}
}
|
|||||
| Cassol, H.L.G., Domingues, L.G., Sanchez, A.H., Basso, L.S., Marani, L., Tejada, G., Arai, E., Correia, C., Alden, C.B., Miller, J.B., Gloor, M., Anderson, L.O., Aragao, L.E.O.C. and Gatti, L.V. | Determination of Region of Influence Obtained by Aircraft Vertical Profiles Using the Density of Trajectories from the HYSPLIT Model | {2020} | ATMOSPHERE Vol. {11}({10}) |
article | DOI URL |
| Abstract: Aircraft atmospheric profiling is a valuable technique for determining greenhouse gas fluxes at regional scales (10(4)-10(6) km(2)). Here, we describe a new, simple method for estimating the surface influence of air samples that uses backward trajectories based on the Lagrangian model Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT). We determined ``regions of influence'' on a quarterly basis between 2010 and 2018 for four aircraft vertical profile sites: SAN and ALF in the eastern Amazon, and RBA and TAB or TEF in the western Amazon. We evaluated regions of influence in terms of their relative sensitivity to areas inside and outside the Amazon and their total area inside the Amazon. Regions of influence varied by quarter and less so by year. In the first and fourth quarters, the contribution of the region of influence inside the Amazon was 83-93% for all sites, while in the second and third quarters, it was 57-75%. The interquarter differences are more evident in the eastern than in the western Amazon. Our analysis indicates that atmospheric profiles from the western sites are sensitive to 42-52.2% of the Amazon. In contrast, eastern Amazon sites are sensitive to only 10.9-25.3%. These results may help to spatially resolve the response of greenhouse gas emissions to climate variability over Amazon. | |||||
BibTeX:
@article{cassol20a,
author = {Cassol, Henrique L. G. and Domingues, Lucas G. and Sanchez, Alber H. and Basso, Luana S. and Marani, Luciano and Tejada, Graciela and Arai, Egidio and Correia, Caio and Alden, Caroline B. and Miller, John B. and Gloor, Manuel and Anderson, Liana O. and Aragao, Luiz E. O. C. and Gatti, Luciana V.},
title = {Determination of Region of Influence Obtained by Aircraft Vertical Profiles Using the Density of Trajectories from the HYSPLIT Model},
journal = {ATMOSPHERE},
publisher = {MDPI},
year = {2020},
volume = {11},
number = {10},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.mdpi.com/2073-4433/11/10/1073},
doi = {https://doi.org/10.3390/atmos11101073}
}
|
|||||
| Cervarich, M., Shu, S., Jain, A.K., Arneth, A., Canadell, J., Friedlingstein, P., Houghton, R.A., Kato, E., Koven, C., Patra, P., Poulter, B., Sitch, S., Stocker, B., Viovy, N., Wiltshire, A. and Zeng, N. | The terrestrial carbon budget of South and Southeast Asia | {2016} | ENVIRONMENTAL RESEARCH LETTERS Vol. {11}({10}) |
article | DOI |
| Abstract: Accomplishing the objective of the current climate policies will require establishing carbon budget and flux estimates in each region and county of the globe by comparing and reconciling multiple estimates including the observations and the results of top-down atmospheric carbon dioxide (CO2) inversions and bottom-up dynamic global vegetation models. With this in view, this study synthesizes the carbon source/sink due to net ecosystem productivity (NEP), land cover land use change (E-LUC), fires and fossil burning (E-FIRE) for the South Asia (SA), Southeast Asia (SEA) and South and Southeast Asia (SSEA = SA + SEA) and each country in these regions using the multiple top-down and bottom-up modeling results. The terrestrial net biome productivity (NBP = NEP - E-LUC - E-FIRE) calculated based on bottom-up models in combination with E-FIRE based on GFED4s data show net carbon sinks of 217 +/- 147, 10 +/- 55, and 227 +/- 279 TgC yr(-1) for SA, SEA, and SSEA. The top-down models estimated NBP net carbon sinks were 20 +/- 170, 4 +/- 90 and 24 +/- 180 TgC yr(-1). In comparison, regional emissions from the combustion of fossil fuels were 495, 275, and 770 TgC yr(-1), which are many times higher than the NBP sink estimates, suggesting that the contribution of the fossil fuel emissions to the carbon budget of SSEA results in a significant net carbon source during the 2000s. When considering both NBP and fossil fuel emissions for the individual countries within the regions, Bhutan and Laos were net carbon sinks and rest of the countries were net carbon source during the 2000s. The relative contributions of each of the fluxes (NBP, NEP, ELUC, and EFIRE, fossil fuel emissions) to a nation's net carbon flux varied greatly from country to country, suggesting a heterogeneous dominant carbon fluxes on the country-level throughout SSEA. |
|||||
BibTeX:
@article{cervarich16a,
author = {Cervarich, Matthew and Shu, Shijie and Jain, Atul K. and Arneth, Almut and Canadell, Josep and Friedlingstein, Pierre and Houghton, Richard A. and Kato, Etsushi and Koven, Charles and Patra, Prabir and Poulter, Ben and Sitch, Stephen and Stocker, Beni and Viovy, Nicolas and Wiltshire, Andy and Zeng, Ning},
title = {The terrestrial carbon budget of South and Southeast Asia},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
year = {2016},
volume = {11},
number = {10},
doi = {https://doi.org/10.1088/1748-9326/11/10/105006}
}
|
|||||
| Chatterjee, A., Michalak, A.M., Anderson, J.L., Mueller, K.L. and Yadav, V. | Toward reliable ensemble Kalman filter estimates of CO2 fluxes | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {117} |
article | DOI |
| Abstract: The use of ensemble filters for estimating sources and sinks of carbon dioxide (CO2) is becoming increasingly common, because they provide a relatively computationally efficient framework for assimilating high-density observations of CO2. Their applicability for estimating fluxes at high-resolutions and the equivalence of their estimates to those from more traditional ``batch'' inversion methods have not been demonstrated, however. In this study, we introduce a Geostatistical Ensemble Square Root Filter (GEnSRF) as a prototypical filter and examine its performance using a synthetic data study over North America at a high spatial (1 degrees x 1 degrees) and temporal (3-hourly) resolution. The ensemble performance, both in terms of estimates and associated uncertainties, is benchmarked against a batch inverse modeling setup in order to isolate and quantify the degradation in the estimates due to the numerical approximations and parameter choices in the ensemble filter. The examined case studies demonstrate that adopting state-of-the-art covariance inflation and localization schemes is a necessary but not sufficient condition for ensuring good filter performance, as defined by its ability to yield reliable flux estimates and uncertainties across a range of resolutions. Observational density is found to be another critical factor for stabilizing the ensemble performance, which is attributed to the lack of a dynamical model for evolving the ensemble between assimilation times. This and other results point to key differences between the applicability of ensemble approaches to carbon cycle science relative to its use in meteorological applications where these tools were originally developed. |
|||||
BibTeX:
@article{chatterjee12a,
author = {Chatterjee, Abhishek and Michalak, Anna M. and Anderson, Jeffrey L. and Mueller, Kim L. and Yadav, Vineet},
title = {Toward reliable ensemble Kalman filter estimates of CO2 fluxes},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2012JD018176}
}
|
|||||
| Chatterjee, A. | Data Assimilation for Atmospheric CO2: Towards Improved Estimates of CO2 Concentrations and Fluxes. [BibTeX] |
2012 | School: University of Michigan | phdthesis | URL |
BibTeX:
@phdthesis{chatterjee12b,
author = {A Chatterjee},
title = {Data Assimilation for Atmospheric CO2: Towards Improved Estimates of CO2 Concentrations and Fluxes.},
school = {University of Michigan},
year = {2012},
url = {https://deepblue.lib.umich.edu/handle/2027.42/96172}
}
|
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| Checa-Garcia, R., Landgraf, J., Galli, A., Hase, F., Velazco, V.A., Tran, H., Boudon, V., Alkemade, F. and Butz, A. | Mapping spectroscopic uncertainties into prospective methane retrieval errors from Sentinel-5 and its precursor | {2015} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {8}({9}), pp. 3617-3629 |
article | DOI |
| Abstract: Sentinel-5 (S5) and its precursor (S5P) are future European satellite missions aiming at global monitoring of methane (CH4) column-average dry air mole fractions (XCH4). The spectrometers to be deployed onboard the satellites record spectra of sunlight backscattered from the Earth's surface and atmosphere. In particular, they exploit CH4 absorption in the shortwave infrared spectral range around 1.65 mu m (S5 only) and 2.35 mu m (both S5 and S5P) wavelength. Given an accuracy goal of better than 2% for XCH4 to be delivered on regional scales, assessment and reduction of potential sources of systematic error such as spectroscopic uncertainties is crucial. Here, we investigate how spectroscopic errors propagate into retrieval errors on the global scale. To this end, absorption spectra of a ground-based Fourier transform spectrometer (FTS) operating at very high spectral resolution serve as estimate for the quality of the spectroscopic parameters. Feeding the FTS fitting residuals as a perturbation into a global ensemble of simulated S5- and S5P-like spectra at relatively low spectral resolution, XCH4 retrieval errors exceed 0.6% in large parts of the world and show systematic correlations on regional scales, calling for improved spectroscopic parameters. |
|||||
BibTeX:
@article{checa-garcia15a,
author = {Checa-Garcia, R. and Landgraf, J. and Galli, A. and Hase, F. and Velazco, V. A. and Tran, H. and Boudon, V. and Alkemade, F. and Butz, A.},
title = {Mapping spectroscopic uncertainties into prospective methane retrieval errors from Sentinel-5 and its precursor},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2015},
volume = {8},
number = {9},
pages = {3617--3629},
doi = {https://doi.org/10.5194/amt-8-3617-2015}
}
|
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| Chen, B. and Coops, N.C. | Understanding of Coupled Terrestrial Carbon, Nitrogen and Water Dynamics-An Overview | {2009} | SENSORS Vol. {9}({11}), pp. 8624-8657 |
article | DOI |
| Abstract: Coupled terrestrial carbon (C), nitrogen (N) and hydrological processes play a crucial role in the climate system, providing both positive and negative feedbacks to climate change. In this review we summarize published research results to gain an increased understanding of the dynamics between vegetation and atmosphere processes. A variety of methods, including monitoring (e. g., eddy covariance flux tower, remote sensing, etc.) and modeling (i.e., ecosystem, hydrology and atmospheric inversion modeling) the terrestrial carbon and water budgeting, are evaluated and compared. We highlight two major research areas where additional research could be focused: (i) Conceptually, the hydrological and biogeochemical processes are closely linked, however, the coupling processes between terrestrial C, N and hydrological processes are far from well understood; and (ii) there are significant uncertainties in estimates of the components of the C balance, especially at landscape and regional scales. To address these two questions, a synthetic research framework is needed which includes both bottom-up and top-down approaches integrating scalable (footprint and ecosystem) models and a spatially nested hierarchy of observations which include multispectral remote sensing, inventories, existing regional clusters of eddy-covariance flux towers and CO2 mixing ratio towers and chambers. |
|||||
BibTeX:
@article{chen09a,
author = {Chen, Baozhang and Coops, Nicholas C.},
title = {Understanding of Coupled Terrestrial Carbon, Nitrogen and Water Dynamics-An Overview},
journal = {SENSORS},
year = {2009},
volume = {9},
number = {11},
pages = {8624--8657},
doi = {https://doi.org/10.3390/s91108624}
}
|
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| Chen, H., Winderlich, J., Gerbig, C., Katrynski, K., Jordan, A. and Heimann, M. | Validation of routine continuous airborne CO2 observations near the Bialystok Tall Tower | {2012} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {5}({4}), pp. 873-889 |
article | DOI |
| Abstract: Since 2002 in situ airborne measurements of atmospheric CO2 mixing ratios have been performed regularly aboard a rental aircraft near Bialystok (53A degrees 08A ` N, 23A degrees 09A ` E), a city in northeastern Poland. Since August 2008, the in situ CO2 measurements have been made by a modified commercially available and fully automated non-dispersive infrared (NDIR) analyzer system. The response of the analyzer has been characterized and the CO2 mixing ratio stability of the associated calibration system has been fully tested, which results in an optimal calibration strategy and allows for an accuracy of the CO2 measurements within 0.2 ppm. Besides the in situ measurements, air samples have been collected in glass flasks and analyzed in the laboratory for CO2 and other trace gases. To validate the in situ CO2 measurements against reliable discrete flask measurements, we developed weighting functions that mimic the temporal averaging of the flask sampling process. Comparisons between in situ and flask CO2 measurements demonstrate that these weighting functions can compensate for atmospheric variability, and provide an effective method for validating airborne in situ CO2 measurements. In addition, we show the nine-year records of flask CO2 measurements. The new system, automated since August 2008, has eliminated the need for manual in-flight calibrations, and thus enables an additional vertical profile, 20 km away, to be sampled at no additional cost in terms of flight hours. This sampling strategy provides an opportunity to investigate both temporal and spatial variability on a regular basis. |
|||||
BibTeX:
@article{chen12a,
author = {Chen, H. and Winderlich, J. and Gerbig, C. and Katrynski, K. and Jordan, A. and Heimann, M.},
title = {Validation of routine continuous airborne CO2 observations near the Bialystok Tall Tower},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2012},
volume = {5},
number = {4},
pages = {873--889},
doi = {https://doi.org/10.5194/amt-5-873-2012}
}
|
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| Chen, B. | Towards an understanding of coupled carbon, water and nitrogen dynamics at sand, landscape and regional scales [BibTeX] |
2012 | School: THE UNIVERSITY OF BRITISH COLUMBIA | phdthesis | URL |
BibTeX:
@phdthesis{chen12b,
author = {B Chen},
title = {Towards an understanding of coupled carbon, water and nitrogen dynamics at sand, landscape and regional scales},
school = {THE UNIVERSITY OF BRITISH COLUMBIA},
year = {2012},
url = {https://open.library.ubc.ca/collections/ubctheses/24/items/1.0103459}
}
|
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| Chen, B., Zhang, H., Coops, N.C., Fu, D., Worthy, D.E.J., Xu, G. and Black, T.A. | Assessing scalar concentration footprint climatology and land surface impacts on tall-tower CO2 concentration measurements in the boreal forest of central Saskatchewan, Canada | {2014} | THEORETICAL AND APPLIED CLIMATOLOGY Vol. {118}({1-2}), pp. 115-132 |
article | DOI |
| Abstract: Reducing the large uncertainties in current estimates of CO2 sources and sinks at regional scales (10(2)-10(5) km(2)) is fundamental to improving our understanding of the terrestrial carbon cycle. Continuous high-precision CO2 concentration measurements on a tower within the planetary boundary layer contain information on regional carbon fluxes; however, its spatial representativeness is generally unknown. In this study, we developed a footprint model (Simple Analytical Footprint model based on Eulerian coordinates for scalar Concentration [SAFE-C]) and applied it to two CO2 concentration towers in central Canada: the East Trout Lake 106-m-tall tower (54A degrees 21'N, 104A degrees 59'W) and the Candle Lake 28-m-high tower (53A degrees 59'N, 105A degrees 07'W). Results show that the ETL tower's annual concentration footprints were around 10(3)-10(5) km(2). The monthly footprint climatologies in summer were 1.5-2 times larger than in winter. The impacts of land surface carbon flux associated with heterogeneous distribution of vegetation types on the CO2 concentration measurements were different for the different heights, varied with a range of +/- 5 % to +/- 10 % among four heights. This study indicates that concentration footprint climatology analysis is important in interpreting the seasonal, annual and inter-annual variations of tower measured CO2 concentration data and is essential for comparing and scaling regional carbon flux estimates using top-down or bottom-up approaches. |
|||||
BibTeX:
@article{chen14a,
author = {Chen, Baozhang and Zhang, Huifang and Coops, Nicholas C. and Fu, Dongjie and Worthy, Douglas E. J. and Xu, Guang and Black, T. Andy},
title = {Assessing scalar concentration footprint climatology and land surface impacts on tall-tower CO2 concentration measurements in the boreal forest of central Saskatchewan, Canada},
journal = {THEORETICAL AND APPLIED CLIMATOLOGY},
year = {2014},
volume = {118},
number = {1-2},
pages = {115--132},
doi = {https://doi.org/10.1007/s00704-013-1038-2}
}
|
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| Chen, J.M., Fung, J.W., Mo, G., Deng, F. and West, T.O. | Atmospheric inversion of surface carbon flux with consideration of the spatial distribution of US crop production and consumption | {2015} | BIOGEOSCIENCES Vol. {12}({2}), pp. 323-343 |
article | DOI |
| Abstract: In order to improve quantification of the spatial distribution of carbon sinks and sources in the conterminous US, we conduct a nested global atmospheric inversion with detailed spatial information on crop production and consumption. County-level cropland net primary productivity, harvested biomass, soil carbon change, and human and livestock consumption data over the conterminous US are used for this purpose. Time-dependent Bayesian synthesis inversions are conducted based on CO2 observations at 210 stations to infer CO2 fluxes globally at monthly time steps with a nested focus on 30 regions in North America. Prior land surface carbon fluxes are first generated using a bio-spheric model, and the inversions are constrained using prior fluxes with and without adjustments for crop production and consumption over the 2002-2007 period. After these adjustments, the inverted regional carbon sink in the US Midwest increases from 0.25 +/- 0.03 to 0.42 +/- 0.13 PgC yr(-1), whereas the large sink in the US southeast forest region is weakened from 0.41 +/- 0.12 to 0.29 +/- 0.12 PgC yr(-1). These adjustments also reduce the inverted sink in the west region from 0.066 +/- 0.04 to 0.040 +/- 0.02 PgC yr(-1) because of high crop consumption and respiration by humans and livestock. The general pattern of sink increases in crop production areas and sink decreases (or source increases) in crop consumption areas highlights the importance of considering the lateral carbon transfer in crop products in atmospheric inverse modeling, which provides a reliable atmospheric perspective of the overall carbon balance at the continental scale but is unreliable for separating fluxes from different ecosystems. |
|||||
BibTeX:
@article{chen15a,
author = {Chen, J. M. and Fung, J. W. and Mo, G. and Deng, F. and West, T. O.},
title = {Atmospheric inversion of surface carbon flux with consideration of the spatial distribution of US crop production and consumption},
journal = {BIOGEOSCIENCES},
year = {2015},
volume = {12},
number = {2},
pages = {323--343},
doi = {https://doi.org/10.5194/bg-12-323-2015}
}
|
|||||
| Chen, M. | Evaluation and Application of the Community Land Model for Simulating Energy and Carbon Exchange in Agricultural Ecosystems [BibTeX] |
2016 | School: UNIVERSITY OF MINNESOTA | phdthesis | URL |
BibTeX:
@phdthesis{chen16a,
author = {M Chen},
title = {Evaluation and Application of the Community Land Model for Simulating Energy and Carbon Exchange in Agricultural Ecosystems},
school = {UNIVERSITY OF MINNESOTA},
year = {2016},
url = {http://search.proquest.com/openview/4e5113263c4ca244a5b38a8271693056/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Chen, Z., Chen, J.M., Zhang, S., Zheng, X., Ju, W., Mo, G. and Lu, X. | Optimization of terrestrial ecosystem model parameters using atmospheric CO2 concentration data with the Global Carbon Assimilation System (GCAS) [BibTeX] |
2016 | Journal of Geophysical Research: Biogeosciences Vol. 122(12), pp. 3218-3237 |
article | DOI |
BibTeX:
@article{chen16b,
author = {Chen, Zhuoqi and Chen, Jing M and Zhang, Shupeng and Zheng, Xiaogu and Ju, Weiming and Mo, Gang and Lu, Xiaoliang},
title = {Optimization of terrestrial ecosystem model parameters using atmospheric CO2 concentration data with the Global Carbon Assimilation System (GCAS)},
journal = {Journal of Geophysical Research: Biogeosciences},
publisher = {Wiley Online Library},
year = {2016},
volume = {122},
number = {12},
pages = {3218--3237},
doi = {https://doi.org/10.1002/2016JG003716/full}
}
|
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| Chen, J.M., Mo, G. and Deng, F. | A joint global carbon inversion system using both CO2 and (CO2)-C-13 atmospheric concentration data | {2017} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {10}({3}), pp. 1131-1156 |
article | DOI |
| Abstract: Observations of (CO2)-C-13 at 73 sites compiled in the GLOBALVIEW database are used for an additional constraint in a global atmospheric inversion of the surface CO2 flux using CO2 observations at 210 sites (62 collocated with (CO2)-C-13 sites) for the 2002-2004 period for 39 land regions and 11 ocean regions. This constraint is implemented using prior CO2 fluxes estimated with a terrestrial ecosystem model and an ocean model. These models simulate (CO2)-C-13 discrimination rates of terrestrial photosynthesis and oceanatmosphere diffusion processes. In both models, the (CO2)-C-13 disequilibrium between fluxes to and from the atmosphere is considered due to the historical change in atmospheric (CO2)-C-13 concentration. This joint inversion system using both(13)CO(2) and CO2 observations is effectively a double deconvolution system with consideration of the spatial variations of isotopic discrimination and disequilibrium. Compared to the CO2-only inversion, this (CO2)-C-13 constraint on the inversion considerably reduces the total land carbon sink from 3.40 +/- 0.84 to 2.53 +/- 0.93 Pg Cyear 1 but increases the total oceanic carbon sink from 1.48 +/- 0.40 to 2.36 +/- 0.49 Pg C year 1. This constraint also changes the spatial distribution of the carbon sink. The largest sink increase occurs in the Amazon, while the largest source increases are in southern Africa, and Asia, where CO2 data are sparse. Through a case study, in which the spatial distribution of the annual (CO2)-C-13 discrimination rate over land is ignored by treating it as a constant at the global average of 14 : 1 %, the spatial distribution of the inverted CO2 flux over land was found to be significantly modified (up to 15% for some regions). The uncertainties in our disequilibrium flux estimation are 8.0 and 12.7 Pg C year 1% for land and ocean, respectively. These uncertainties induced the unpredictability of 0.47 and 0.54 Pg Cyear(-1) in the inverted CO2 fluxes for land and ocean, respectively. Our joint inversion system is therefore useful for improving the partitioning between ocean and land sinks and the spatial distribution of the inverted carbon flux. |
|||||
BibTeX:
@article{chen17a,
author = {Chen, Jing M. and Mo, Gang and Deng, Feng},
title = {A joint global carbon inversion system using both CO2 and (CO2)-C-13 atmospheric concentration data},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2017},
volume = {10},
number = {3},
pages = {1131--1156},
doi = {https://doi.org/10.5194/gmd-10-1131-2017}
}
|
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| Chen, X., Liu, Y., Yang, D., Cai, Z., Chen, H. and Wang, M. | A Theoretical Analysis for Improving Aerosol-Induced CO2 Retrieval Uncertainties Over Land Based on TanSat Nadir Observations Under Clear Sky Conditions | {2019} | REMOTE SENSING Vol. {11}({9}) |
article | DOI |
| Abstract: Aerosols significantly affect carbon dioxide (CO2) retrieval accuracy and precision by modifying the light path. Hyperspectral measurements in the near infrared and shortwave infrared (NIR/SWIR) bands from the generation of new greenhouse gas satellites (e.g., the Chinese Global Carbon Dioxide Monitoring Scientific Experimental Satellite, TanSat) contain aerosol information for correction of scattering effects in the retrieval. Herein, a new approach is proposed for optimizing the aerosol model used in the TanSat CO2 retrieval algorithm to reduce CO2 uncertainties associated with aerosols. The weighting functions of hyperspectral observations with respect to elements in the state vector are simulated by a forward radiative transfer model. Using the optimal estimation method (OEM), the information content and each component of the CO2 column-averaged dry-air mole fraction (XCO2) retrieval errors from the TanSat simulations are calculated for typical aerosols which are described by Aerosol Robotic Network (AERONET) inversion products at selected sites based on the a priori and measurement assumptions. The results indicate that the size distribution parameters (r(eff), v(eff)), real refractive index coefficient of fine mode (a(r)(f)) and fine mode fraction (fmf) dominate the interference errors, with each causing 0.2-0.8 ppm of XCO2 errors. Given that only 4-7 degrees of freedom for signal (DFS) of aerosols can be obtained simultaneously and CO2 information decreases as more aerosol parameters are retrieved, four to seven aerosol parameters are suggested as the most appropriate for inclusion in CO2 retrieval. Focusing on only aerosol-induced XCO2 errors, forward model parameter errors, rather than interference errors, are dominant. A comparison of these errors across different aerosol parameter combination groups reveals that fewer aerosol-induced XCO2 errors are found when retrieving seven aerosol parameters. Therefore, the model selected as the optimal aerosol model includes aerosol optical depth (AOD), peak height of aerosol profile (H-p), width of aerosol profile (H-w), effective variance of fine mode aerosol (v(eff)(f)), effective radius of coarse mode aerosol (r(eff)(c)), coefficient a of the real part of the refractive index for the fine mode and coarse mode (a(r)(f) and a(r)(c)), with the lowest error of less than 1.7 ppm for all aerosol and surface types. For marine aerosols, only five parameters (AOD, H-p, H-w, r(eff)(c) and a(r)(c)) are recommended for the low aerosol information. This optimal aerosol model therefore offers a theoretical foundation for improving CO2 retrieval precision from real TanSat observations in the future. | |||||
BibTeX:
@article{chen19a,
author = {Chen, Xi and Liu, Yi and Yang, Dongxu and Cai, Zhaonan and Chen, Hongbin and Wang, Maohua},
title = {A Theoretical Analysis for Improving Aerosol-Induced CO2 Retrieval Uncertainties Over Land Based on TanSat Nadir Observations Under Clear Sky Conditions},
journal = {REMOTE SENSING},
publisher = {MDPI},
year = {2019},
volume = {11},
number = {9},
doi = {https://doi.org/10.3390/rs11091061}
}
|
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| Chen, H.W., Zhang, F., Lauvaux, T., Davis, K.J., Feng, S., Butler, M.P. and Alley, R.B. | Characterization of Regional-Scale CO2 Transport Uncertainties in an Ensemble with Flow-Dependent Transport Errors | {2019} | GEOPHYSICAL RESEARCH LETTERS Vol. {46}({7}), pp. {4049-4058} |
article | DOI URL |
| Abstract: Inference of CO2 surface fluxes using atmospheric CO2 observations in atmospheric inversions depends critically on accurate representation of atmospheric transport. Here we characterize regional-scale CO2 transport uncertainties due to uncertainties in meteorological fields using a mesoscale atmospheric model and an ensemble of simulations with flow-dependent transport errors. During a 1-month summer period over North America, transport uncertainties yield an ensemble spread in instantaneous CO2 at 100 m above ground level comparable to the CO2 uncertainties resulting from 48% relative uncertainty in 3-hourly natural CO2 fluxes. Temporal averaging reduces transport uncertainties but increases the influence of CO2 uncertainties from the lateral boundaries. The influence of CO2 background uncertainties is especially large for column-averaged CO2. These results suggest that transport errors and CO2 background errors limit regional atmospheric inversions at two distinct timescales and that the error characteristics of transport and background errors should guide the design of regional inversion systems. | |||||
BibTeX:
@article{chen19b,
author = {Chen, Hans W. and Zhang, Fuqing and Lauvaux, Thomas and Davis, Kenneth J. and Feng, Sha and Butler, Martha P. and Alley, Richard B.},
title = {Characterization of Regional-Scale CO2 Transport Uncertainties in an Ensemble with Flow-Dependent Transport Errors},
journal = {GEOPHYSICAL RESEARCH LETTERS},
publisher = {AMER GEOPHYSICAL UNION},
year = {2019},
volume = {46},
number = {7},
pages = {4049--4058},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081341},
doi = {https://doi.org/10.1029/2018GL081341}
}
|
|||||
| Chen, H.W., Zhang, L.N., Zhang, F., Davis, K.J., Lauvaux, T., Pal, S., Gaudet, B. and DiGangi, J.P. | Evaluation of Regional CO2 Mole Fractions in the ECMWF CAMS Real-Time Atmospheric Analysis and NOAA CarbonTracker Near-Real-Time Reanalysis With Airborne Observations From ACT-America Field Campaigns | {2019} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {124}({14}), pp. {8119-8133} |
article | DOI URL |
| Abstract: This study systematically examines the regional uncertainties and biases in carbon dioxide (CO2) mole fractions from two of the state-of-the-art global CO2 analysis products, namely, the Copernicus Atmosphere Monitoring Service (CAMS) real-time atmospheric analysis from the European Centre for Medium-Range Weather Forecasts (ECMWF) and the CarbonTracker Near-Real-Time (CT-NRT) reanalysis from the National Oceanic and Atmospheric Administration (NOAA), by evaluation against hundreds of hours of airborne in situ measurements from the summer 2016 and winter 2017 Atmospheric Carbon and Transport (ACT)-America field campaigns. Both the CAMS and CT-NRT analyses agree reasonably well with the independent ACT-America airborne CO2 measurements in the free troposphere, with root-mean-square deviations (RMSDs) between analyses and observations generally between 1 and 2 ppm but show considerably larger uncertainties in the atmospheric boundary layer where the RMSDs exceed 8 ppm in the lowermost 1 km of the troposphere in summer. There are strong variations in accuracy and bias between seasons, and across three different subregions in the United States (Mid-Atlantic, Midwest, and South), with the largest uncertainties in the Mid-Atlantic region in summer. Overall, the RMSDs of the CAMS and CT-NRT analyses against airborne data are comparable to each other and largely consistent with the differences between the two analyses. The current study provides uncertainty estimates for both analysis products over North America and suggests that these two independent estimates can be used to approximate regional CO2 analysis uncertainties. Both statistics are important in future studies in quantifying the uncertainties in regional CO2 mole fraction and flux estimates. | |||||
BibTeX:
@article{chen19c,
author = {Chen, Hans W. and Zhang, Lily N. and Zhang, Fuqing and Davis, Kenneth J. and Lauvaux, Thomas and Pal, Sandip and Gaudet, Brian and DiGangi, Joshua P.},
title = {Evaluation of Regional CO2 Mole Fractions in the ECMWF CAMS Real-Time Atmospheric Analysis and NOAA CarbonTracker Near-Real-Time Reanalysis With Airborne Observations From ACT-America Field Campaigns},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2019},
volume = {124},
number = {14},
pages = {8119--8133},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JD029992},
doi = {https://doi.org/10.1029/2018JD029992}
}
|
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| Chen, Z., Liu, J., Henze, D.K., Huntzinger, D.N., Wells, K.C. and Miller, S.M. | Linking global terrestrial CO2 fluxes and environmental drivers using OCO-2 and a geostatistical inverse model | 2020 | ATMOSPHERIC CHEMISTRY AND PHYSICS | article | URL |
| Abstract: Observations from the OCO-2 satellite, launched in July 2014, have been used to estimate CO 2 fluxes in many regions of the globe and provide new insight on the global carbon cycle. A challenge now is to not only estimate fluxes using satellite observations but also to … | |||||
BibTeX:
@article{chen20a,
author = {Zichong Chen and Junjie Liu and Daven K. Henze and Deborah N. Huntzinger and Kelley C. Wells and Scot M. Miller},
title = {Linking global terrestrial CO2 fluxes and environmental drivers using OCO-2 and a geostatistical inverse model},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2020},
url = {https://acp.copernicus.org/preprints/acp-2020-285/}
}
|
|||||
| Chen, B., Zhang, H., Wang, T. and Zhang, X. | An atmospheric perspective on the carbon budgets of terrestrial ecosystems in China: progress and challenges [BibTeX] |
2021 | SCIENCE BULLETIN Vol. 66(17), pp. 1713-1718 |
article | DOI |
BibTeX:
@article{chen21a,
author = {Chen, Baozhang and Zhang, Huifang and Wang, Tao and Zhang, Xiaoye},
title = {An atmospheric perspective on the carbon budgets of terrestrial ecosystems in China: progress and challenges},
journal = {SCIENCE BULLETIN},
year = {2021},
volume = {66},
number = {17},
pages = {1713-1718},
doi = {https://doi.org/10.1016/j.scib.2021.05.017}
}
|
|||||
| Cheng, Y., An, X., Yun, F., Zhou, L., Liu, L., Fang, S. and Xu, L. | Simulation of CO2 variations at Chinese background atmospheric monitoring stations between 2000 and 2009: Applying a CarbonTracker model [BibTeX] |
2013 | Chin. Sci. Bull Vol. 58(32), pp. 3986-3993 |
article | |
BibTeX:
@article{cheng13a,
author = {Cheng, Y and An, X and Yun, F and Zhou, L and Liu, L and Fang, S and Xu, Lin},
title = {Simulation of CO2 variations at Chinese background atmospheric monitoring stations between 2000 and 2009: Applying a CarbonTracker model},
journal = {Chin. Sci. Bull},
year = {2013},
volume = {58},
number = {32},
pages = {3986--3993}
}
|
|||||
| Cheng, S., An, X., Zhou, L., Liu, L., Fang, S., Yao, B. and Liu, Z. | CO2 concentration representation of source and sink area at Shangdianzi atmospheric background station in Beijing [BibTeX] |
2015 | China Environmental Science | article | URL |
BibTeX:
@article{cheng15a,
author = {Cheng, Siyang and An, Xingqin and Zhou, Lingxi and Liu, LiXin and Fang, Shuangxi and Yao, Bo and Liu, Zhao},
title = {CO2 concentration representation of source and sink area at Shangdianzi atmospheric background station in Beijing},
journal = {China Environmental Science},
year = {2015},
url = {http://or.nsfc.gov.cn/bitstream/00001903-5/261235/1/1000014841151.pdf}
}
|
|||||
| Cheng, S., An, X., Zhou, L., Tans, P.P. and Jacobson, A. | Atmospheric CO2 at Waliguan station in China: Transport climatology, temporal patterns and source-sink region representativeness | {2017} | ATMOSPHERIC ENVIRONMENT Vol. {159}, pp. 107-116 |
article | DOI |
| Abstract: In order to explore where the source and sink have the greatest impact on CO2 background concentration at Waliguan (WLG) station, a statistical method is here proposed to calculate the representative source sink region. The key to this method is to find the best footprint threshold, and the study is carried out in four parts. Firstly, transport climatology, expressed by total monthly footprint, was simulated by FLEX PART on a 7-day time scale. Surface CO2 emissions in Eurasia frequently transported to WLG station. WLG station was mainly influenced by the westerlies in winter and partly controlled by the Southeast Asian monsoon in summer. Secondly, CO2 concentrations, simulated by CT2015, were processed and analyzed through data quality control, screening, fitting and comparing. CO2 concentrations displayed obvious seasonal variation, with the maximum and minimum concentration appearing in April and August, respectively. The correlation of CO2 fitting background concentrations was R-2 = 0.91 between simulation and observation. The temporal patterns were mainly correlated with CO2 exchange of biosphere atmosphere, human activities and air transport. Thirdly, for the monthly CO2 fitting background concentrations from CT2015, a best footprint threshold was found based on correlation analysis and numerical iteration using the data of footprints and emissions. The grid cells where monthly footprints were greater than the best footprint threshold were the best threshold area corresponding to representative source-sink region. The representative source-sink region of maximum CO2 concentration in April was primarily located in Qinghai province, but the minimum CO2 concentration in August was mainly influenced by emissions in a wider region. Finally, we briefly presented the CO2 source-sink characteristics in the best threshold area. Generally, the best threshold area was a carbon sink. The major source and sink were relatively weak owing to less human activities and vegetation types in this high altitude area. CO2 concentrations were more influenced by human activities when air mass passed through many urban areas in summer. Therefore, the combination of footprints and emissions is an effective approach for assessing the source-sink region representativeness of CO2 background concentration. (C) 2017 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{cheng17a,
author = {Cheng, Siyang and An, Xingqin and Zhou, Lingxi and Tans, Pieter P. and Jacobson, Andy},
title = {Atmospheric CO2 at Waliguan station in China: Transport climatology, temporal patterns and source-sink region representativeness},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2017},
volume = {159},
pages = {107--116},
doi = {https://doi.org/10.1016/j.atmosenv.2017.03.055}
}
|
|||||
| Cheng, H., Mi, Z., Wei, X., Yong-wei, W., Wei, W., Griffis, T., Shou-dong, L. and Xu-hui, L. | Effect of Flux and its Uncertainty on Tall Tower CO2 Concentration Simulation in the Agricultural Domain [BibTeX] |
2017 | 中国农业气象 (Chinese Journal of Agrometeorology) | article | URL |
BibTeX:
@article{cheng17b,
author = {Hu Cheng and Zhang Mi and Xiao Wei and Wang Yong-wei and Wang Wei and Tim Griffis and Liu Shou-dong and Li Xu-hui},
title = {Effect of Flux and its Uncertainty on Tall Tower CO2 Concentration Simulation in the Agricultural Domain},
journal = {中国农业气象 (Chinese Journal of Agrometeorology)},
year = {2017},
url = {https://yncenter.sites.yale.edu/sites/default/files/files/hu_cheng_2017-2.pdf}
}
|
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| Cheng, H., Mi, Z., Wei, X., Yong-wei, W., Wei, W., Griffis, T., Shou-dong, L. and Xu-hui, L. | Tall tower CO2 concentration simulation using the WRF-STILT model [BibTeX] |
2017 | China Environmental Science Vol. 37(7), pp. 2424-24-37 |
article | URL |
BibTeX:
@article{cheng17c,
author = {Hu Cheng and Zhang Mi and Xiao Wei and Wang Yong-wei and Wang Wei and Tim Griffis and Liu Shou-dong and Li Xu-hui},
title = {Tall tower CO2 concentration simulation using the WRF-STILT model},
journal = {China Environmental Science},
year = {2017},
volume = {37},
number = {7},
pages = {2424-24-37},
url = {http://manu36.magtech.com.cn/Jweb_zghjkx/CN/article/downloadArticleFile.do?attachType=PDF&id=15218}
}
|
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| Cheng, H., Shoudong, L., Chang, C., Jingzheng, X., Zhengda, C., Wengian, L., Jiaping, X., mi , Z., Wei, X. and Xuhui, L. | Simulation of atmospheric CO2 concentration and source apportionment analysis in Nanjing City [BibTeX] |
2017 | Acta Scientiae Circumstantiae Vol. 37(10), pp. 3862-3875 |
article | URL |
BibTeX:
@article{cheng17d,
author = {Hu Cheng and Liu Shoudong and Cao Chang and Xu Jingzheng and Cao Zhengda and Li Wengian and Xu Jiaping and Zhang mi and Xiao Wei and Li Xuhui},
title = {Simulation of atmospheric CO2 concentration and source apportionment analysis in Nanjing City},
journal = {Acta Scientiae Circumstantiae},
year = {2017},
volume = {37},
number = {10},
pages = {3862-3875},
url = {http://html.rhhz.net/hjkxxb/html/20170224004.htm}
}
|
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| Cheng, S., Zhou, L., Tans, P.P., An, X. and Liu, Y. | Comparison of atmospheric CO2 mole fractions and source sink characteristics at four WMO/GAW stations in China | {2018} | ATMOSPHERIC ENVIRONMENT Vol. {180}, pp. {216-225} |
article | DOI |
| Abstract: As CO2 is a primary driving factor of climate change, the mole fraction and source-sink characteristics of atmospheric CO2 over China are constantly inferred from multi-source and multi-site data. In this paper, we compared ground-based CO2 measurements with satellite retrievals and investigated the source-sink regional representativeness at China's four WMO/GAW stations. The results indicate that, firstly, atmospheric CO2 mole fractions from ground-based sampling measurement and Greenhouse Gases Observing Satellite (GOSAT) products reveal similar seasonal variation. The seasonal amplitude of the column-averaged CO2 mole fractions is smaller than that of the ground-based CO2 at all stations. The extrema of the seasonal cycle of ground-based and column CO2 mole fractions are basically synchronous except a slight phase delay at Lin'an (LAN) station. For the two-year average, the column CO2 is lower than ground-based CO2, and both of them reveal the lowest CO2 mole fraction at Waliguan (WLG) station. The lowest (similar to 4 ppm) and largest (similar to 8 ppm) differences between the column and ground-based CO2 appear at WLG and Longfengshan (LFS) stations, respectively. The CO2 mole fraction and its difference between GOSAT and ground-based measurement are smaller in summer than in winter. The differences of summer column CO2 among these stations are also much smaller than their ground-based counterparts. In winter, the maximum of ground-based CO2 mole fractions and the greatest difference between the two (ground-based and column) datasets appear at the LFS station. Secondly, the representative areas of the monthly CO2 background mole fractions at each station were found by employing footprints and emissions. Smaller representative areas appeared at Shangdianzi (SDZ) and LFS, whereas larger ones were seen at WLG and LAN. The representative areas in summer are larger than those in winter at WLG and SDZ, but the situation is opposite at LAN and LFS. The representative areas for the stations are different in summer and winter, distributed in four typical regions. The CO2 net fluxes in these representative areas show obvious seasonal cycles with similar trends but different varying ranges and different time of the strongest sink. The intensities and uncertainties of the CO2 fluxes are different at different stations in different months and source-sink sectors. Overall, the WLG station is almost a carbon sink, but the other three stations present stronger carbon sources for most of the year. These findings could be conducive to the application of multi-source CO2 data and the understanding of regional CO2 source-sink characteristics and patterns over China. |
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BibTeX:
@article{cheng18a,
author = {Cheng, Siyang and Zhou, Lingxi and Tans, Pieter P. and An, Xingqin and Liu, Yunsong},
title = {Comparison of atmospheric CO2 mole fractions and source sink characteristics at four WMO/GAW stations in China},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2018},
volume = {180},
pages = {216-225},
doi = {https://doi.org/10.1016/j.atmosenv.2018.03.010}
}
|
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| Chevallier, F., Engelen, R.J., Carouge, C., Conway, T.J., Peylin, P., Pickett-Heaps, C., Ramonet, M., Rayner, P.J. and Xueref-Remy, I. | AIRS-based versus flask-based estimation of carbon surface fluxes | {2009} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {114} |
article | DOI |
| Abstract: This paper demonstrates an inversion of surface CO2 fluxes using concentrations derived from assimilation of satellite radiances. Radiances come from the Atmospheric Infrared Sounder (AIRS) and are assimilated within the system of the European Centre for Medium-Range Weather Forecasts. We evaluate the quality of the inverted fluxes by comparing simulated concentrations with independent airborne measurements. As a benchmark we use an inversion based on surface flask measurements and another using only the global concentration trend. We show that the AIRS-based inversion is able to improve the match to the independent data compared to the prior estimate but that it usually performs worse than either the flask-based or trend-based inversion. |
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BibTeX:
@article{chevallier09a,
author = {Chevallier, Frederic and Engelen, Richard J. and Carouge, Claire and Conway, Thomas J. and Peylin, Philippe and Pickett-Heaps, Christopher and Ramonet, Michel and Rayner, Peter J. and Xueref-Remy, Irene},
title = {AIRS-based versus flask-based estimation of carbon surface fluxes},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2009},
volume = {114},
doi = {https://doi.org/10.1029/2009JD012311}
}
|
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| Chevallier, F., Ciais, P., Conway, T.J., Aalto, T., Anderson, B.E., Bousquet, P., Brunke, E.G., Ciattaglia, L., Esaki, Y., Froehlich, M., Gomez, A., Gomez-Pelaez, A.J., Haszpra, L., Krummel, P.B., Langenfelds, R.L., Leuenberger, M., Machida, T., Maignan, F., Matsueda, H., Morgui, J.A., Mukai, H., Nakazawa, T., Peylin, P., Ramonet, M., Rivier, L., Sawa, Y., Schmidt, M., Steele, L.P., Vay, S.A., Vermeulen, A.T., Wofsy, S. and Worthy, D. | CO2 surface fluxes at grid point scale estimated from a global 21 year reanalysis of atmospheric measurements | {2010} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {115} |
article | DOI |
| Abstract: This paper documents a global Bayesian variational inversion of CO2 surface fluxes during the period 1988-2008. Weekly fluxes are estimated on a 3.75 degrees x 2.5 degrees (longitude-latitude) grid throughout the 21 years. The assimilated observations include 128 station records from three large data sets of surface CO2 mixing ratio measurements. A Monte Carlo approach rigorously quantifies the theoretical uncertainty of the inverted fluxes at various space and time scales, which is particularly important for proper interpretation of the inverted fluxes. Fluxes are evaluated indirectly against two independent CO2 vertical profile data sets constructed from aircraft measurements in the boundary layer and in the free troposphere. The skill of the inversion is evaluated by the improvement brought over a simple benchmark flux estimation based on the observed atmospheric growth rate. Our error analysis indicates that the carbon budget from the inversion should be more accurate than the a priori carbon budget by 20% to 60% for terrestrial fluxes aggregated at the scale of subcontinental regions in the Northern Hemisphere and over a year, but the inversion cannot clearly distinguish between the regional carbon budgets within a continent. On the basis of the independent observations, the inversion is seen to improve the fluxes compared to the benchmark: the atmospheric simulation of CO2 with the Bayesian inversion method is better by about 1 ppm than the benchmark in the free troposphere, despite possible systematic transport errors. The inversion achieves this improvement by changing the regional fluxes over land at the seasonal and at the interannual time scales. |
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BibTeX:
@article{chevallier10a,
author = {Chevallier, F. and Ciais, P. and Conway, T. J. and Aalto, T. and Anderson, B. E. and Bousquet, P. and Brunke, E. G. and Ciattaglia, L. and Esaki, Y. and Froehlich, M. and Gomez, A. and Gomez-Pelaez, A. J. and Haszpra, L. and Krummel, P. B. and Langenfelds, R. L. and Leuenberger, M. and Machida, T. and Maignan, F. and Matsueda, H. and Morgui, J. A. and Mukai, H. and Nakazawa, T. and Peylin, P. and Ramonet, M. and Rivier, L. and Sawa, Y. and Schmidt, M. and Steele, L. P. and Vay, S. A. and Vermeulen, A. T. and Wofsy, S. and Worthy, D.},
title = {CO2 surface fluxes at grid point scale estimated from a global 21 year reanalysis of atmospheric measurements},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2010},
volume = {115},
doi = {https://doi.org/10.1029/2010JD013887}
}
|
|||||
| Chevallier, F., Wang, T., Ciais, P., Maignan, F., Bocquet, M., Arain, M.A., Cescatti, A., Chen, J., Dolman, A.J., Law, B.E., Margolis, H.A., Montagnani, L. and Moors, E.J. | What eddy-covariance measurements tell us about prior land flux errors in CO2-flux inversion schemes | {2012} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {26} |
article | DOI |
| Abstract: To guide the future development of CO2-atmospheric inversion modeling systems, we analyzed the errors arising from prior information about terrestrial ecosystem fluxes. We compared the surface fluxes calculated by a process-based terrestrial ecosystem model with daily averages of CO2 flux measurements at 156 sites across the world in the FLUXNET network. At the daily scale, the standard deviation of the model-data fit was 2.5 gC.m(2).d(-1); temporal autocorrelations were significant at the weekly scale (>0.3 for lags less than four weeks), while spatial correlations were confined to within the first few hundred kilometers (<0.2 after 200 km). Separating out the plant functional types did not increase the spatial correlations, except for the deciduous broad-leaved forests. Using the statistics of the flux measurements as a proxy for the statistics of the prior flux errors was shown not to be a viable approach. A statistical model allowed us to upscale the site-level flux error statistics to the coarser spatial and temporal resolutions used in regional or global models. This approach allowed us to quantify how aggregation reduces error variances, while increasing correlations. As an example, for a typical inversion of grid point (300 km x 300 km) monthly fluxes, we found that the prior flux error follows an approximate e-folding correlation length of 500 km only, with correlations from one month to the next as large as 0.6. |
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BibTeX:
@article{chevallier12a,
author = {Chevallier, Frederic and Wang, Tao and Ciais, Philippe and Maignan, Fabienne and Bocquet, Marc and Arain, M. Altaf and Cescatti, Alessandro and Chen, Jiquan and Dolman, A. Johannes and Law, Beverly E. and Margolis, Hank A. and Montagnani, Leonardo and Moors, Eddy J.},
title = {What eddy-covariance measurements tell us about prior land flux errors in CO2-flux inversion schemes},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2012},
volume = {26},
doi = {https://doi.org/10.1029/2010GB003974}
}
|
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| Chevallier, F. and O'Dell, C.W. | Error statistics of Bayesian CO2 flux inversion schemes as seen from GOSAT | {2013} | GEOPHYSICAL RESEARCH LETTERS Vol. {40}({6}), pp. 1252-1256 |
article | DOI |
| Abstract: Statistical modeling is at the root of CO2 atmospheric inversion systems, but few studies have focused on the quality of their assigned probability distributions. In this paper, we assess the reliability of the error models that are in input and in output of a specific CO2 atmospheric inversion system when it assimilates surface air sample measurements. We confront these error models with the mismatch between 4D simulations of CO2 and independent satellite retrievals of the total CO2 column. Taking all sources of uncertainties into account, it is shown that both prior and posterior errors are consistent with the actual departures, to the point that the theoretical error reduction brought by the surface measurements on the simulation of the Greenhouse gases Observing SATellite (GOSAT) total column measurements (15%) corresponds to the actual reduction seen over the midlatitude and tropical lands and over the tropical oceans. |
|||||
BibTeX:
@article{chevallier13a,
author = {Chevallier, Frederic and O'Dell, Christopher W.},
title = {Error statistics of Bayesian CO2 flux inversion schemes as seen from GOSAT},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2013},
volume = {40},
number = {6},
pages = {1252--1256},
doi = {https://doi.org/10.1002/grl.50228}
}
|
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| Chevallier, F. | On the parallelization of atmospheric inversions of CO2 surface fluxes within a variational framework | {2013} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {6}({3}), pp. 783-790 |
article | DOI |
| Abstract: The variational formulation of Bayes' theorem allows inferring CO2 sources and sinks from atmospheric concentrations at much higher time-space resolution than the ensemble or analytical approaches. However, it usually exhibits limited scalable parallelism. This limitation hinders global atmospheric inversions operated on decadal time scales and regional ones with kilometric spatial scales because of the computational cost of the underlying transport model that has to be run at each iteration of the variational minimization. Here, we introduce a physical parallelization (PP) of variational atmospheric inversions. In the PP, the inversion still manages a single physically and statistically consistent window, but the transport model is run in parallel overlapping sub-segments in order to massively reduce the computation wall-clock time of the inversion. For global inversions, a simplification of transport modelling is described to connect the output of all segments. We demonstrate the performance of the approach on a global inversion for CO2 with a 32 yr inversion window (1979-2010) with atmospheric measurements from 81 sites of the NOAA global cooperative air sampling network. In this case, we show that the duration of the inversion is reduced by a seven-fold factor (from months to days), while still processing the three decades consistently and with improved numerical stability. |
|||||
BibTeX:
@article{chevallier13b,
author = {Chevallier, F.},
title = {On the parallelization of atmospheric inversions of CO2 surface fluxes within a variational framework},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2013},
volume = {6},
number = {3},
pages = {783--790},
doi = {https://doi.org/10.5194/gmd-6-783-2013}
}
|
|||||
| Chevallier, F. | Report on the quality of the inverted CO2 fluxes [BibTeX] |
2013 | MACC-II delivrable D Vol. 43 |
article | URL |
BibTeX:
@article{chevallier13c,
author = {F Chevallier},
title = {Report on the quality of the inverted CO2 fluxes},
journal = {MACC-II delivrable D},
year = {2013},
volume = {43},
url = {https://www-gmes-atmosphere-eu.ecmwf.int/documents/maccii/deliverables/ghg/MACCII_GHG_DEL_D43.4_20120430_Chevallier.pdf}
}
|
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| Cho, M. and Kim, H.M. | Effect of assimilating CO2 observations in the Korean Peninsula on the inverse modeling to estimate surface CO2 flux over Asia | 2022 | PLOS ONE Vol. 17(2) |
article | DOI |
| Abstract: To investigate the impact of two CO2 observation datasets obtained from the Korean Peninsula on the surface CO2 flux estimation over Asia, the two datasets are assimilated into the CarbonTracker (CT) inverse modeling system and the estimated surface CO2 fluxes are analyzed. Anmyeon-do (AMY) and Gosan (GSN) sites in the Korean Peninsula have observed surface CO2 mole fraction since the late 1990s. To investigate the effect of assimilating the additional Korean observations on the surface CO2 flux estimation over Asia, two experiments are conducted. The reference experiment (CNTL) only assimilates observations provided by National Oceanic and Atmospheric Administration (NOAA), while the other experiment (EXP1) assimilates both NOAA observations and two Korean observation datasets. The results are analyzed for 9 years from 2003 to 2011 in Asia region because both AMY and GSN datasets exist almost completely for this period. The annual average of estimated biosphere CO2 flux of EXP1 shows more flux absorption in summer and less flux emission from fall to spring compared to CNTL, mainly on Eurasia Temperate and Eurasia Boreal regions. When comparing model results to independent CO2 concentration data from surface stations and aircraft, the root mean square error is smaller for EXP1 than CNTL. The EXP1 yields more reduction on uncertainty of estimated biosphere CO2 flux over Asia, and the observation impact of AMY, GSN sites on flux estimation is approximately 11%, which is greater than other observation sites around the world. Therefore, the two CO2 observation sets in the Korean Peninsula are useful in reducing uncertainties for regional as well as global scale CO2 flux estimation. |
|||||
BibTeX:
@article{cho22a,
author = {Cho, Minkwang and Kim, Hyun Mee},
title = {Effect of assimilating CO2 observations in the Korean Peninsula on the inverse modeling to estimate surface CO2 flux over Asia},
journal = {PLOS ONE},
year = {2022},
volume = {17},
number = {2},
doi = {https://doi.org/10.1371/journal.pone.0263925}
}
|
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| Ciais, P., Canadell, J.G., Luyssaert, S., Chevallier, F., Shvidenko, A., Poussi, Z., Jonas, M., Peylin, P., King, A.W., Schulze, E.-D., Piao, S., Roedenbeck, C., Peters, W. and Breon, F.-M. | Can we reconcile atmospheric estimates of the Northern terrestrial carbon sink with land-based accounting? | {2010} | CURRENT OPINION IN ENVIRONMENTAL SUSTAINABILITY Vol. {2}({4}), pp. 225-230 |
article | DOI |
| Abstract: We estimate the northern hemisphere (NH) terrestrial carbon sink by comparing four recent atmospheric inversions with land-based C accounting data for six large northern regions. The mean NH terrestrial CO2 sink from the inversion models is 1.7 Pg C year(-1) over the period 2000-2004. The uncertainty of this estimate is based on the typical individual (1-sigma) precision of one inversion (0.9 Pg C year(-1)) and is consistent with the min-max range of the four inversion mean estimates (0.8 Pg C year(-1)). Inversions agree within their uncertainty for the distribution of the NH sink of CO2 in longitude, with Russia being the largest sink. The land-based accounting estimate of NH carbon sink is 1.7 Pg C year(-1) for the sum of the six regions studied. The 1-sigma uncertainty of the land-based estimate (0.3 Pg C year(-1)) is smaller than that of atmospheric inversions, but no independent land-based flux estimate is available to derive a `between accounting model' uncertainty. Encouragingly, the top-down atmospheric and the bottom-up land-based methods converge to consistent mean estimates within their respective errors, increasing the confidence in the overall budget. These results also confirm the continued critical role of NH terrestrial ecosystems in slowing down the atmospheric accumulation of anthropogenic CO2. |
|||||
BibTeX:
@article{ciais10a,
author = {Ciais, Philippe and Canadell, Josep G. and Luyssaert, Sebastiaan and Chevallier, Frederic and Shvidenko, Anatoly and Poussi, Zegbeu and Jonas, Matthias and Peylin, Philippe and King, Anthony Wayne and Schulze, Ernest-Detlef and Piao, Shilong and Roedenbeck, Christian and Peters, Wouter and Breon, Francois-Marie},
title = {Can we reconcile atmospheric estimates of the Northern terrestrial carbon sink with land-based accounting?},
journal = {CURRENT OPINION IN ENVIRONMENTAL SUSTAINABILITY},
year = {2010},
volume = {2},
number = {4},
pages = {225--230},
doi = {https://doi.org/10.1016/j.cosust.2010.06.008}
}
|
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| Ciais, P., Dolman, A.J., Bombelli, A., Duren, R., Peregon, A., Rayner, P.J., Miller, C., Gobron, N., Kinderman, G., Marland, G., Gruber, N., Chevallier, F., Andres, R.J., Balsamo, G., Bopp, L., Breon, F.M., Broquet, G., Dargaville, R., Battin, T.J., Borges, A., Bovensmann, H., Buchwitz, M., Butler, J., Canadell, J.G., Cook, R.B., DeFries, R., Engelen, R., Gurney, K.R., Heinze, C., Heimann, M., Held, A., Henry, M., Law, B., Luyssaert, S., Miller, J., Moriyama, T., Moulin, C., Myneni, R.B., Nussli, C., Obersteiner, M., Ojima, D., Pan, Y., Paris, J.D., Piao, S.L., Poulter, B., Plummer, S., Quegan, S., Raymond, P., Reichstein, M., Rivier, L., Sabine, C., Schimel, D., Tarasova, O., Valentini, R., Wang, R., van der Werf, G., Wickland, D., Williams, M. and Zehner, C. | Current systematic carbon-cycle observations and the need for implementing a policy-relevant carbon observing system | {2014} | BIOGEOSCIENCES Vol. {11}({13}), pp. 3547-3602 |
article | DOI |
| Abstract: A globally integrated carbon observation and analysis system is needed to improve the fundamental understanding of the global carbon cycle, to improve our ability to project future changes, and to verify the effectiveness of policies aiming to reduce greenhouse gas emissions and increase carbon sequestration. Building an integrated carbon observation system requires transformational advances from the existing sparse, exploratory framework towards a dense, robust, and sustained system in all components: anthropogenic emissions, the atmosphere, the ocean, and the terrestrial biosphere. The paper is addressed to scientists, policymakers, and funding agencies who need to have a global picture of the current state of the (diverse) carbon observations. We identify the current state of carbon observations, and the needs and notional requirements for a global integrated carbon observation system that can be built in the next decade. A key conclusion is the substantial expansion of the ground-based observation networks required to reach the high spatial resolution for CO2 and CH4 fluxes, and for carbon stocks for addressing policy-relevant objectives, and attributing flux changes to underlying processes in each region. In order to establish flux and stock diagnostics over areas such as the southern oceans, tropical forests, and the Arctic, in situ observations will have to be complemented with remote-sensing measurements. Remote sensing offers the advantage of dense spatial coverage and frequent revisit. A key challenge is to bring remote-sensing measurements to a level of long-term consistency and accuracy so that they can be efficiently combined in models to reduce uncertainties, in synergy with ground-based data. Bringing tight observational constraints on fossil fuel and land use change emissions will be the biggest challenge for deployment of a policy-relevant integrated carbon observation system. This will require in situ and remotely sensed data at much higher resolution and density than currently achieved for natural fluxes, although over a small land area (cities, industrial sites, power plants), as well as the inclusion of fossil fuel CO2 proxy measurements such as radiocarbon in CO2 and carbon-fuel combustion tracers. Additionally, a policy-relevant carbon monitoring system should also provide mechanisms for reconciling regional top-down (atmosphere-based) and bottom-up (surface-based) flux estimates across the range of spatial and temporal scales relevant to mitigation policies. In addition, uncertainties for each observation data-stream should be assessed. The success of the system will rely on long-term commitments to monitoring, on improved international collaboration to fill gaps in the current observations, on sustained efforts to improve access to the different data streams and make databases interoperable, and on the calibration of each component of the system to agreed-upon international scales. |
|||||
BibTeX:
@article{ciais14a,
author = {Ciais, P. and Dolman, A. J. and Bombelli, A. and Duren, R. and Peregon, A. and Rayner, P. J. and Miller, C. and Gobron, N. and Kinderman, G. and Marland, G. and Gruber, N. and Chevallier, F. and Andres, R. J. and Balsamo, G. and Bopp, L. and Breon, F. -M. and Broquet, G. and Dargaville, R. and Battin, T. J. and Borges, A. and Bovensmann, H. and Buchwitz, M. and Butler, J. and Canadell, J. G. and Cook, R. B. and DeFries, R. and Engelen, R. and Gurney, K. R. and Heinze, C. and Heimann, M. and Held, A. and Henry, M. and Law, B. and Luyssaert, S. and Miller, J. and Moriyama, T. and Moulin, C. and Myneni, R. B. and Nussli, C. and Obersteiner, M. and Ojima, D. and Pan, Y. and Paris, J. -D. and Piao, S. L. and Poulter, B. and Plummer, S. and Quegan, S. and Raymond, P. and Reichstein, M. and Rivier, L. and Sabine, C. and Schimel, D. and Tarasova, O. and Valentini, R. and Wang, R. and van der Werf, G. and Wickland, D. and Williams, M. and Zehner, C.},
title = {Current systematic carbon-cycle observations and the need for implementing a policy-relevant carbon observing system},
journal = {BIOGEOSCIENCES},
year = {2014},
volume = {11},
number = {13},
pages = {3547--3602},
doi = {https://doi.org/10.5194/bg-11-3547-2014}
}
|
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| Cochran, F.V. and Brunsell, N.A. | Temporal scales of tropospheric CO2, precipitation, and ecosystem responses in the central Great Plains | {2012} | REMOTE SENSING OF ENVIRONMENT Vol. {127}, pp. 316-328 |
article | DOI |
| Abstract: Natural and anthropogenic sources of CO2 around the globe contribute to mid-tropospheric concentrations, yet it remains unknown how measurements of mid-tropospheric CO2 relate to regional ecosystem dynamics. NASA Atmospheric Infrared Sounder (AIRS) measurements of CO2 concentrations in the mid-troposphere from 2002 to 2010 were examined in relation to precipitation and vegetation phenology across the US Great Plains. Wavelet multi-resolution analysis and the information theory metric of relative entropy were applied to assess regional relationships between mid-tropospheric CO2, Normalized Difference Vegetation Index (NDVI), and precipitation (PPT). Results show that AIRS observations of mid-tropospheric CO2 exchange greater amounts of information with regional PPT and NDVI at seasonal, annual, and longer time scales compared to shorter time scales. PPT and NDVI contribute to mid-tropospheric CO2 at the 18-month time scale, while spatial patterns seen at this time scale for PIT and mid-tropospheric CO2 are reflective of the influence of PPT on NDVI at the annual scale. Identification of these dominant temporal scales may facilitate utilization of AIRS CO2 for monitoring regional source/sink dynamics related to climate and land-use/cover change. (c) 2012 Elsevier Inc. All rights reserved. |
|||||
BibTeX:
@article{cochran12a,
author = {Cochran, Ferdouz V. and Brunsell, Nathaniel A.},
title = {Temporal scales of tropospheric CO2, precipitation, and ecosystem responses in the central Great Plains},
journal = {REMOTE SENSING OF ENVIRONMENT},
year = {2012},
volume = {127},
pages = {316--328},
doi = {https://doi.org/10.1016/j.rse.2012.09.012}
}
|
|||||
| Collalti, A., Marconi, S., Ibrom, A., Trotta, C., Anav, A., D'Andrea, E., Matteucci, G., Montagnani, L., Gielen, B., Mammarella, I., Gruenwald, T., Knohl, A., Berninger, F., Zhao, Y., Valentini, R. and Santini, M. | Validation of 3D-CMCC Forest Ecosystem Model (v.5.1) against eddy covariance data for 10 European forest sites | {2016} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {9}({2}), pp. 479-504 |
article | DOI |
| Abstract: This study evaluates the performances of the new version (v.5.1) of 3D-CMCC Forest Ecosystem Model (FEM) in simulating gross primary productivity (GPP), against eddy covariance GPP data for 10 FLUXNET forest sites across Europe. A new carbon allocation module, coupled with new both phenological and autotrophic respiration schemes, was implemented in this new daily version. Model ability in reproducing timing and magnitude of daily and monthly GPP fluctuations is validated at intra-annual and inter-annual scale, including extreme anomalous seasons. With the purpose to test the 3D-CMCC FEM applicability over Europe without a site-related calibration, the model has been deliberately parametrized with a single set of species-specific parametrizations for each forest ecosystem. The model consistently reproduces both in timing and in magnitude daily and monthly GPP variability across all sites, with the exception of the two Mediterranean sites. We find that 3D-CMCC FEM tends to better simulate the timing of inter-annual anomalies than their magnitude within measurements' uncertainty. In six of eight sites where data are available, the model well reproduces the 2003 summer drought event. Finally, for three sites we evaluate whether a more accurate representation of forest structural characteristics (i.e. cohorts, forest layers) and species composition can improve model results. In two of the three sites results reveal that model slightly increases its performances although, statistically speaking, not in a relevant way. |
|||||
BibTeX:
@article{collalti16a,
author = {Collalti, A. and Marconi, S. and Ibrom, A. and Trotta, C. and Anav, A. and D'Andrea, E. and Matteucci, G. and Montagnani, L. and Gielen, B. and Mammarella, I. and Gruenwald, T. and Knohl, A. and Berninger, F. and Zhao, Y. and Valentini, R. and Santini, M.},
title = {Validation of 3D-CMCC Forest Ecosystem Model (v.5.1) against eddy covariance data for 10 European forest sites},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2016},
volume = {9},
number = {2},
pages = {479--504},
doi = {https://doi.org/10.5194/gmd-9-479-2016}
}
|
|||||
| Combe, M., de wit , A.J.W., de Arellano, J.V.-G., van der Molen, M.K., Magliulo, V. and Peters, W. | Grain Yield Observations Constrain Cropland CO2 Fluxes Over Europe | {2017} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {122}({12}), pp. {3238-3259} |
article | DOI |
| Abstract: Carbon exchange over croplands plays an important role in the European carbon cycle over daily to seasonal time scales. A better description of this exchange in terrestrial biosphere models-most of which currently treat crops as unmanaged grasslands-is needed to improve atmospheric CO2 simulations. In the framework we present here, we model gross European cropland CO2 fluxes with a crop growth model constrained by grain yield observations. Our approach follows a two-step procedure. In the first step, we calculate day-to-day crop carbon fluxes and pools with the WOrld FOod STudies (WOFOST) model. A scaling factor of crop growth is optimized regionally by minimizing the final grain carbon pool difference to crop yield observations from the Statistical Office of the European Union. In a second step, we re-run our WOFOST model for the full European 25 x 25 km gridded domain using the optimized scaling factors. We combine our optimized crop CO2 fluxes with a simple soil respiration model to obtain the net cropland CO2 exchange. We assess our model's ability to represent cropland CO2 exchange using 40 years of observations at seven European FluxNet sites and compare it with carbon fluxes produced by a typical terrestrial biosphere model. We conclude that our new model framework provides a more realistic and strongly observation-driven estimate of carbon exchange over European croplands. Its products will be made available to the scientific community through the ICOS Carbon Portal and serve as a new cropland component in the CarbonTracker Europe inverse model. |
|||||
BibTeX:
@article{combe17a,
author = {Combe, M. and de wit, A. J. W. and de Arellano, J. Vila-Guerau and van der Molen, M. K. and Magliulo, V. and Peters, W.},
title = {Grain Yield Observations Constrain Cropland CO2 Fluxes Over Europe},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2017},
volume = {122},
number = {12},
pages = {3238-3259},
doi = {https://doi.org/10.1002/2017JG003937}
}
|
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| Cooley, D., Breidt, F.J., Ogle, S.M., Schuh, A.E. and Lauvaux, T. | A constrained least-squares approach to combine bottom-up and top-down CO2 flux estimates | {2013} | ENVIRONMENTAL AND ECOLOGICAL STATISTICS Vol. {20}({1}), pp. 129-146 |
article | DOI |
| Abstract: Terrestrial CO2 flux estimates are obtained from two fundamentally different methods generally termed bottom-up and top-down approaches. Inventory methods are one type of bottom-up approach which uses various sources of information such as crop production surveys and forest monitoring data to estimate the annual CO2 flux at locations covering a study region. Top-down approaches are various types of atmospheric inversion methods which use CO2 concentration measurements from monitoring towers and atmospheric transport models to estimate CO2 flux over a study region. Both methods can also quantify the uncertainty associated with their estimates. Historically, these two approaches have produced estimates that differ considerably. The goal of this work is to construct a statistical model which sensibly combines estimates from the two approaches to produce a new estimate of CO2 flux for our study region. The two approaches have complementary strengths and weaknesses, and our results show that certain aspects of the uncertainty associated with each of the approaches are greatly reduced by combining the methods. Our model is purposefully simple and designed to take the two approaches' estimates and measures of uncertainty at `face value'. Specifically, we use a constrained least-squares approach to appropriately weigh the estimates by the inverse of their variance, and the constraint imposes agreement between the two sources. Our application involves nearly 18,000 flux estimates for the upper midwest United States. The constrained dependencies result in a non-sparse covariance matrix, but computation requires only minutes due to the structure of the model. |
|||||
BibTeX:
@article{cooley13a,
author = {Cooley, Daniel and Breidt, F. Jay and Ogle, Stephen M. and Schuh, Andrew E. and Lauvaux, Thomas},
title = {A constrained least-squares approach to combine bottom-up and top-down CO2 flux estimates},
journal = {ENVIRONMENTAL AND ECOLOGICAL STATISTICS},
year = {2013},
volume = {20},
number = {1},
pages = {129--146},
doi = {https://doi.org/10.1007/s10651-012-0211-6}
}
|
|||||
| Corbin, K.D. | Investigating causes of regional variations in atmospheric carbon dioxide concentrations [BibTeX] |
2008 | School: Colorado State University | phdthesis | |
BibTeX:
@phdthesis{corbin08a,
author = {Corbin, Katherine D},
title = {Investigating causes of regional variations in atmospheric carbon dioxide concentrations},
school = {Colorado State University},
year = {2008}
}
|
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| Crevoisier, C., Sweeney, C., Gloor, M., Sarmiento, J.L. and Tans, P.P. | Regional US carbon sinks from three-dimensional atmospheric CO2 sampling | {2010} | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Vol. {107}({43}), pp. 18348-18353 |
article | DOI |
| Abstract: Studies diverge substantially on the actual magnitude of the North American carbon budget. This is due to the lack of appropriate data and also stems from the difficulty to properly model all the details of the flux distribution and transport inside the region of interest. To sidestep these difficulties, we use here a simple budgeting approach to estimate land-atmosphere fluxes across North America by balancing the inflow and outflow of CO2 from the troposphere. We base our study on the unique sampling strategy of atmospheric CO2 vertical profiles over North America from the National Oceanic and Atmospheric Administration/Earth System Research Laboratory aircraft network, from which we infer the three-dimensional CO2 distribution over the continent. We find a moderate sink of 0.5 +/- 0.4 PgCy(-1) for the period 2004-2006 for the coterminous United States, in good agreement with the forest-inventory-based estimate of the first North American State of the Carbon Cycle Report, and averaged climate conditions. We find that the highest uptake occurs in the Midwest and in the Southeast. This partitioning agrees with independent estimates of crop uptake in the Midwest, which proves to be a significant part of the US atmospheric sink, and of secondary forest regrowth in the Southeast. Provided that vertical profile measurements are continued, our study offers an independent means to link regional carbon uptake to climate drivers. |
|||||
BibTeX:
@article{crevoisier10a,
author = {Crevoisier, Cyril and Sweeney, Colm and Gloor, Manuel and Sarmiento, Jorge L. and Tans, Pieter P.},
title = {Regional US carbon sinks from three-dimensional atmospheric CO2 sampling},
journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
year = {2010},
volume = {107},
number = {43},
pages = {18348--18353},
doi = {https://doi.org/10.1073/pnas.0900062107}
}
|
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| Crowell, S.M.R., Kawa, S.R., Browell, E.V., Hammerling, D.M., Moore, B., Schaefer, K. and Doney, S.C. | On the Ability of Space-Based Passive and Active Remote Sensing Observations of CO2 to Detect Flux Perturbations to the Carbon Cycle | {2018} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {123}({2}), pp. {1460-1477} |
article | DOI |
| Abstract: Space-borne observations of CO2 are vital to gaining understanding of the carbon cycle in regions of the world that are difficult to measure directly, such as the tropical terrestrial biosphere, the high northern and southern latitudes, and in developing nations such as China. Measurements from passive instruments such as GOSAT and OCO-2, however, are constrained by solar zenith angle limitations as well as sensitivity to the presence of clouds and aerosols. Active measurements such as those in development for the Active Sensing of CO2 Emissions over Nights, Days and Seasons (ASCENDS) mission show strong potential for making measurements in the high-latitude winter and in cloudy regions. In this work we examine the enhanced flux constraint provided by the improved coverage from an active measurement such as ASCENDS. The simulation studies presented here show that with sufficient precision, ASCENDS will detect permafrost thaw and fossil fuel emissions shifts at annual and seasonal time scales, even in the presence of transport errors, representativeness errors, and biogenic flux errors. While OCO-2 can detect some of these perturbations at the annual scale, the seasonal sampling provided by ASCENDS provides the stronger constraint. Plain Language Summary Active and passive remote sensors show the potential to provide unprecedented information on the carbon cycle. With the all-season sampling, active remote sensors are more capable of constraining high-latitude emissions. The reduced sensitivity to cloud and aerosol also makes active sensors more capable of providing information in cloudy and polluted scenes with sufficient accuracy. These experiments account for errors that are fundamental to the top-down approach for constraining emissions, and even including these sources of error, we show that satellite remote sensors are critical for understanding the carbon cycle. |
|||||
BibTeX:
@article{crowell18a,
author = {Crowell, Sean M. R. and Kawa, S. Randolph and Browell, Edward V. and Hammerling, Dorit M. and Moore, Berrien and Schaefer, Kevin and Doney, Scott C.},
title = {On the Ability of Space-Based Passive and Active Remote Sensing Observations of CO2 to Detect Flux Perturbations to the Carbon Cycle},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2018},
volume = {123},
number = {2},
pages = {1460-1477},
doi = {https://doi.org/10.1002/2017JD027836}
}
|
|||||
| Crowell, S., Baker, D., Schuh, A., Basu, S., Jacobson, A.R., Chevallier, F., Liu, J., Deng, F., Feng, L., McKain, K., Chatterjee, A., Miller, J.B., Stephens, B.B., Eldering, A., Crisp, D., Schimel, D., Nassar, R., O'Dell, C., Oda, T., Sweeney, C., Palmer, P.I. and Jones, D.B.A. | The 2015-2016 carbon cycle as seen from OCO-2 and the global in situ network | {2019} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {19}({15}), pp. {9797-9831} |
article | DOI URL |
| Abstract: The Orbiting Carbon Observatory-2 has been on orbit since 2014, and its global coverage holds the potential to reveal new information about the carbon cycle through the use of top-down atmospheric inversion methods combined with column average CO2 retrievals. We employ a large ensemble of atmospheric inversions utilizing different transport models, data assimilation techniques, and prior flux distributions in order to quantify the satellite-informed fluxes from OCO-2 Version 7r land observations and their uncertainties at continental scales. Additionally, we use in situ measurements to provide a baseline against which to compare the satellite-constrained results. We find that within the ensemble spread, in situ observations, and satellite retrievals constrain a similar global total carbon sink of 3.7 +/- 0.5 PgC yr(-1), and 1.5 +/- 0.6 PgC yr(-1) for global land, for the 2015-2016 annual mean. This agreement breaks down in smaller regions, and we discuss the differences between the experiments. Of particular interest is the difference between the different assimilation constraints in the tropics, with the largest differences occurring in tropical Africa, which could be an indication of the global perturbation from the 2015-2016 El Nino. Evaluation of posterior concentrations using TCCON and aircraft observations gives some limited insight into the quality of the different assimilation constraints, but the lack of such data in the tropics inhibits our ability to make strong conclusions there. | |||||
BibTeX:
@article{crowell19a,
author = {Crowell, Sean and Baker, David and Schuh, Andrew and Basu, Sourish and Jacobson, Andrew R. and Chevallier, Frederic and Liu, Junjie and Deng, Feng and Feng, Liang and McKain, Kathryn and Chatterjee, Abhishek and Miller, John B. and Stephens, Britton B. and Eldering, Annmarie and Crisp, David and Schimel, David and Nassar, Ray and O'Dell, ChristopherW. and Oda, Tomohiro and Sweeney, Colm and Palmer, Paul I. and Jones, Dylan B. A.},
title = {The 2015-2016 carbon cycle as seen from OCO-2 and the global in situ network},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {19},
number = {15},
pages = {9797--9831},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/19/9797/2019/},
doi = {https://doi.org/10.5194/acp-19-9797-2019}
}
|
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| Cui, Y.Y., Jacobson, A.R., Feng, S., Wesloh, D., Barkley, Z.R., Zhang, L., Gerken, T., Keller, K., Baker, D. and Davis, K.J. | Evaluation of CarbonTracker's Inverse Estimates of North American Net Ecosystem Exchange of CO2 From Different Observing Systems Using ACT-America Airborne Observations | 2021 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 126(12) |
article | DOI |
| Abstract: Quantification of regional terrestrial carbon dioxide (CO2) fluxes is critical to our understanding of the carbon cycle. We evaluate inverse estimates of net ecosystem exchange (NEE) of CO2 fluxes in temperate North America, and their sensitivity to the observational data used to drive the inversions. Specifically, we consider the state-of-the-science CarbonTracker global inversion system, which assimilates (a) in situ measurements (IS), (b) the Orbiting Carbon Observatory-2 (OCO-2) v9 column CO2 (XCO2) retrievals over land (LNLG), (c) OCO-2 v9 XCO2 retrievals ocean-glint (OG), and (d) a combination of all these observational constraints (LNLGOGIS). We use independent CO2 observations from the Atmospheric Carbon and Transport (ACT)-America aircraft mission to evaluate the inversions. We diagnose errors in the flux estimates using the differences between modeled and observed biogenic CO2 mole fractions, influence functions from a Lagrangian transport model, Bayesian inference, and root-mean-square error (RMSE) and bias metrics. The IS fluxes have the smallest RMSE among the four products, followed by LNLG. Both IS and LNLG outperform the OG and LNLGOGIS inversions with regard to RMSE. Regional errors do not differ markedly across the four sets of posterior fluxes. The CarbonTracker inversions appear to overestimate the seasonal cycle of NEE in the Midwest and Western Canada, and overestimate dormant season NEE across the Central and Eastern US. The CarbonTracker inversions may overestimate annual NEE in the Central and Eastern US. The success of the LNLG inversion with respect to independent observations bodes well for satellite-based inversions in regions with more limited in situ observing networks. |
|||||
BibTeX:
@article{cui21a,
author = {Cui, Yu Yan and Jacobson, Andrew R. and Feng, Sha and Wesloh, Daniel and Barkley, Zachary R. and Zhang, Li and Gerken, Tobias and Keller, Klaus and Baker, David and Davis, Kenneth J.},
title = {Evaluation of CarbonTracker's Inverse Estimates of North American Net Ecosystem Exchange of CO2 From Different Observing Systems Using ACT-America Airborne Observations},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2021},
volume = {126},
number = {12},
doi = {https://doi.org/10.1029/2020JD034406}
}
|
|||||
| Cui, Y., Li, N., Fu, Y. and Chen, L. | Carbon neutrality and mitigating contribution of terrestrial carbon sink on anthropogenic climate warming in China, the United States, Russia and Canada | 2021 | JOURNAL OF GEOGRAPHICAL SCIENCES Vol. 31(7), pp. 925-937 |
article | DOI |
| Abstract: Carbon dioxide (CO2) is a major climate forcing factor, closely related to human activities. Quantifying the contribution of CO2 emissions to the global radiative forcing (RF) is therefore important to evaluate climate effects caused by anthropogenic and natural factors. China, the United States (USA), Russia and Canada are the largest countries by land area, at different levels of socio-economic development. In this study, we used data from the CarbonTracker CO2 assimilation model (CT2017 data set) to analyze anthropogenic CO2 emissions and terrestrial ecosystem carbon sinks from 2000 to 2016. We derived net RF contributions and showed that anthropogenic CO2 emissions had increased significantly from 2000 to 2016, at a rate of 0.125 PgC yr(-1). Over the same period, carbon uptake by terrestrial ecosystems increased at a rate of 0.003 PgC yr(-1). Anthropogenic CO2 emissions in China and USA accounted for 87.19% of the total, while Russian terrestrial ecosystems were the largest carbon sink and absorbed 14.69 PgC. The resulting cooling effect was -0.013 W m(-2) in 2016, representing an offset of -45.06% on climate warming induced by anthropogenic CO2. This indicates that net climate warming would be significantly overestimated if terrestrial ecosystems were not included in RF budget analyses. In terms of cumulative effects, we analyzed RFs using reference atmospheres of 1750, at the start of the Industrial Revolution, and 2000, the initial year of this study. Anthropogenic CO2 emissions in the study area contributed by + 0.42 W m(-2) and +0.32 W m(-2) to the global RF, relative to CO2 levels of 1750 and 2000, respectively. We also evaluated correlations between global mean atmospheric temperature and net, anthropogenic and natural RFs. We found that the combined (net) RF caused by CO2 emissions accounted for 30.3% of global mean temperature variations in 2000-2016. |
|||||
BibTeX:
@article{cui21b,
author = {Cui, Yaoping and Li, Nan and Fu, Yiming and Chen, Liangyu},
title = {Carbon neutrality and mitigating contribution of terrestrial carbon sink on anthropogenic climate warming in China, the United States, Russia and Canada},
journal = {JOURNAL OF GEOGRAPHICAL SCIENCES},
year = {2021},
volume = {31},
number = {7},
pages = {925-937},
doi = {https://doi.org/10.1007/s11442-021-1878-0}
}
|
|||||
| Dang, X., Lai, C.-T., Hollinger, D.Y., Schauer, A.J., Xiao, J., Munger, J.W., Owensby, C. and Ehleringer, J.R. | Combining tower mixing ratio and community model data to estimate regional-scale net ecosystem carbon exchange by boundary layer inversion over four flux towers in the United States | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {116} |
article | DOI |
| Abstract: We evaluated an idealized boundary layer (BL) model with simple parameterizations using vertical transport information from community model outputs (NCAR/NCEP Reanalysis and ECMWF Interim Analysis) to estimate regional-scale net CO2 fluxes from 2002 to 2007 at three forest and one grassland flux sites in the United States. The BL modeling approach builds on a mixed-layer model to infer monthly average net CO2 fluxes using high-precision mixing ratio measurements taken on flux towers. We compared BL model net ecosystem exchange (NEE) with estimates from two independent approaches. First, we compared modeled NEE with tower eddy covariance measurements. The second approach (EC-MOD) was a data-driven method that upscaled EC fluxes from towers to regions using MODIS data streams. Comparisons between modeled CO2 and tower NEE fluxes showed that modeled regional CO2 fluxes displayed interannual and intra-annual variations similar to the tower NEE fluxes at the Rannells Prairie and Wind River Forest sites, but model predictions were frequently different from NEE observations at the Harvard Forest and Howland Forest sites. At the Howland Forest site, modeled CO2 fluxes showed a lag in the onset of growing season uptake by 2 months behind that of tower measurements. At the Harvard Forest site, modeled CO2 fluxes agreed with the timing of growing season uptake but underestimated the magnitude of observed NEE seasonal fluctuation. This modeling inconsistency among sites can be partially attributed to the likely misrepresentation of atmospheric transport and/or CO2 gradients between ABL and the free troposphere in the idealized BL model. EC-MOD fluxes showed that spatial heterogeneity in land use and cover very likely explained the majority of the data-model inconsistency. We show a site-dependent atmospheric rectifier effect that appears to have had the largest impact on ABL CO2 inversion in the North American Great Plains. We conclude that a systematic BL modeling approach provided new insights when employed in multiyear, cross-site synthesis studies. These results can be used to develop diagnostic upscaling tools, improving our understanding of the seasonal and interannual variability of surface CO2 fluxes. |
|||||
BibTeX:
@article{dang11a,
author = {Dang, Xuerui and Lai, Chun-Ta and Hollinger, David Y. and Schauer, Andrew J. and Xiao, Jingfeng and Munger, J. William and Owensby, Clenton and Ehleringer, James R.},
title = {Combining tower mixing ratio and community model data to estimate regional-scale net ecosystem carbon exchange by boundary layer inversion over four flux towers in the United States},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2010JG001554}
}
|
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| Dang, Y., Ren, W., Tao, B., Chen, G., Lu, C., Yang, J., Pan, S., Wang, G., Li, S. and Tian, H. | Climate and Land Use Controls on Soil Organic Carbon in the Loess Plateau Region of China | {2014} | PLOS ONE Vol. {9}({5}) |
article | DOI |
| Abstract: The Loess Plateau of China has the highest soil erosion rate in the world where billion tons of soil is annually washed into Yellow River. In recent decades this region has experienced significant climate change and policy-driven land conversion. However, it has not yet been well investigated how these changes in climate and land use have affected soil organic carbon (SOC) storage on the Loess Plateau. By using the Dynamic Land Ecosystem Model (DLEM), we quantified the effects of climate and land use on SOC storage on the Loess Plateau in the context of multiple environmental factors during the period of 1961-2005. Our results show that SOC storage increased by 0.27 Pg C on the Loess Plateau as a result of multiple environmental factors during the study period. About 55% (0.14 Pg C) of the SOC increase was caused by land conversion from cropland to grassland/forest owing to the government efforts to reduce soil erosion and improve the ecological conditions in the region. Historical climate change reduced SOC by 0.05 Pg C (approximately 19% of the total change) primarily due to a significant climate warming and a slight reduction in precipitation. Our results imply that the implementation of ``Grain for Green'' policy may effectively enhance regional soil carbon storage and hence starve off further soil erosion on the Loess Plateau. |
|||||
BibTeX:
@article{dang14a,
author = {Dang, Yaai and Ren, Wei and Tao, Bo and Chen, Guangsheng and Lu, Chaoqun and Yang, Jia and Pan, Shufen and Wang, Guodong and Li, Shiqing and Tian, Hanqin},
title = {Climate and Land Use Controls on Soil Organic Carbon in the Loess Plateau Region of China},
journal = {PLOS ONE},
year = {2014},
volume = {9},
number = {5},
doi = {https://doi.org/10.1371/journal.pone.0095548}
}
|
|||||
| Davidson, G.R., Phillips-Housley, A. and Stevens, M.T. | Soil-zone adsorption of atmospheric CO2 as a terrestrial carbon sink | {2013} | GEOCHIMICA ET COSMOCHIMICA ACTA Vol. {106}, pp. 44-50 |
article | DOI |
| Abstract: Identifying and quantifying sources and sinks of CO2 is integral to developing global carbon budgets and effectively modeling climate change. Adsorption of CO2 onto mineral and soil surfaces has generally been regarded as an insignificant sink, though few studies have investigated adsorption on natural materials at temperatures and CO2 concentrations relevant to atmospheric or soil zone conditions. In this study, annual adsorption at the scale of North America was modeled for the upper 3 m of the Earth's surface (the root zone) based on our own and published adsorption data, and results compared with reported estimates for the North American terrestrial carbon sink during 2000-2005. Our results suggest that adsorption can account for 1-3% of the average annual sink during these years. At smaller regional scales where more adsorptive deposits are present, such as volcanic ash or high-organic soils, the sink may be significantly larger. (C) 2013 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{davidson13a,
author = {Davidson, Gregg R. and Phillips-Housley, Ashley and Stevens, Maria T.},
title = {Soil-zone adsorption of atmospheric CO2 as a terrestrial carbon sink},
journal = {GEOCHIMICA ET COSMOCHIMICA ACTA},
year = {2013},
volume = {106},
pages = {44--50},
doi = {https://doi.org/10.1016/j.gca.2012.12.015}
}
|
|||||
| Davis, K.J., Browell V, E., Feng, S., Lauvaux, T., Obland, M.D., Pal, S., Baier, B.C., Baker, D.F., Baker, I.T., Barkley, Z.R., Bowman, K.W., Cui, Y.Y., Denning, A.S., DiGangi, J.P., Dobler, J.T., Fried, A., Gerken, T., Keller, K., Lin, B., Nehrir, A.R., Normile, C.P., O'Dell, C.W., Ott, L.E., Roiger, A., Schuh, A.E., Sweeney, C., Wei, Y., Weir, B., Xue, M. and Williams, C.A. | The Atmospheric Carbon and Transport (ACT)-America Mission | 2021 | BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY Vol. 102(9), pp. E1714-E1734 |
article | DOI |
| Abstract: The Atmospheric Carbon and Transport (ACT)-America NASA Earth Venture Suborbital Mission set out to improve regional atmospheric greenhouse gas (GHG) inversions by exploring the intersection of the strong GHG fluxes and vigorous atmospheric transport that occurs within the midlatitudes. Two research aircraft instrumented with remote and in situ sensors to measure GHG mole fractions, associated trace gases, and atmospheric state variables collected 1,140.7 flight hours of research data, distributed across 305 individual aircraft sorties, coordinated within 121 research flight days, and spanning five 6-week seasonal flight campaigns in the central and eastern United States. Flights sampled 31 synoptic sequences, including fair-weather and frontal conditions, at altitudes ranging from the atmospheric boundary layer to the upper free troposphere. The observations were complemented with global and regional GHG flux and transport model ensembles. We found that midlatitude weather systems contain large spatial gradients in GHG mole fractions, in patterns that were consistent as a function of season and altitude. We attribute these patterns to a combination of regional terrestrial fluxes and inflow from the continental boundaries. These observations, when segregated according to altitude and air mass, provide a variety of quantitative insights into the realism of regional CO 2 and CH 4 fluxes and atmospheric GHG transport realizations. The ACT-America dataset and ensemble modeling methods provide benchmarks for the development of atmospheric inversion systems. As global and regional atmospheric inversions incorporate ACT-America's findings and methods, we anticipate these systems will produce increasingly accurate and precise subcontinental GHG flux estimates. |
|||||
BibTeX:
@article{davis21a,
author = {Davis, Kenneth J. and Browell, V, Edward and Feng, Sha and Lauvaux, Thomas and Obland, Michael D. and Pal, Sandip and Baier, Bianca C. and Baker, David F. and Baker, Ian T. and Barkley, Zachary R. and Bowman, Kevin W. and Cui, Yu Yan and Denning, A. Scott and DiGangi, Joshua P. and Dobler, Jeremy T. and Fried, Alan and Gerken, Tobias and Keller, Klaus and Lin, Bing and Nehrir, Amin R. and Normile, Caroline P. and O'Dell, Christopher W. and Ott, Lesley E. and Roiger, Anke and Schuh, Andrew E. and Sweeney, Colm and Wei, Yaxing and Weir, Brad and Xue, Ming and Williams, Christopher A.},
title = {The Atmospheric Carbon and Transport (ACT)-America Mission},
journal = {BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY},
year = {2021},
volume = {102},
number = {9},
pages = {E1714-E1734},
doi = {https://doi.org/10.1175/BAMS-D-20-0300.1}
}
|
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| Deng, F. and Chen, J.M. | Recent global CO2 flux inferred from atmospheric CO2 observations and its regional analyses | {2011} | BIOGEOSCIENCES Vol. {8}({11}), pp. 3263-3281 |
article | DOI |
| Abstract: The net surface exchange of CO2 for the years 2002-2007 is inferred from 12 181 atmospheric CO2 concentration data with a time-dependent Bayesian synthesis inversion scheme. Monthly CO2 fluxes are optimized for 30 regions of the North America and 20 regions for the rest of the globe. Although there have been many previous multiyear inversion studies, the reliability of atmospheric inversion techniques has not yet been systematically evaluated for quantifying regional interannual variability in the carbon cycle. In this study, the global interannual variability of the CO2 flux is found to be dominated by terrestrial ecosystems, particularly by tropical land, and the variations of regional terrestrial carbon fluxes are closely related to climate variations. These interannual variations are mostly caused by abnormal meteorological conditions in a few months in the year or part of a growing season and cannot be well represented using annual means, suggesting that we should pay attention to finer temporal climate variations in ecosystem modeling. We find that, excluding fossil fuel and biomass burning emissions, terrestrial ecosystems and oceans absorb an average of 3.63 +/- 0.49 and 1.94 +/- 0.41 PgC yr(-1), respectively. The terrestrial uptake is mainly in northern land while the tropical and southern lands contribute 0.62 +/- 0.47, and 0.67 +/- 0.34 PgC yr(-1) to the sink, respectively. In North America, terrestrial ecosystems absorb 0.89 +/- 0.18 PgC yr(-1) on average with a strong flux density found in the south-east of the continent. |
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BibTeX:
@article{deng11a,
author = {Deng, F. and Chen, J. M.},
title = {Recent global CO2 flux inferred from atmospheric CO2 observations and its regional analyses},
journal = {BIOGEOSCIENCES},
year = {2011},
volume = {8},
number = {11},
pages = {3263--3281},
doi = {https://doi.org/10.5194/bg-8-3263-2011}
}
|
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| Deng, F., Chen, J.M., Pan, Y., Peters, W., Birdsey, R., McCullough, K. and Xiao, J. | The use of forest stand age information in an atmospheric CO2 inversion applied to North America | {2013} | BIOGEOSCIENCES Vol. {10}({8}), pp. 5335-5348 |
article | DOI |
| Abstract: Atmospheric inversions have become an important tool in quantifying carbon dioxide (CO2) sinks and sources at a variety of spatiotemporal scales, but associated large uncertainties restrain the inversion research community from reaching agreement on many important subjects. We enhanced an atmospheric inversion of the CO2 flux for North America by introducing spatially explicit information on forest stand age for US and Canada as an additional constraint, since forest carbon dynamics are closely related to time since disturbance. To use stand age information in the inversion, we converted stand age into an age factor, and included the covariances between subcontinental regions in the inversion based on the similarity of the age factors. Our inversion results show that, considering age factors, regions with recently disturbed or old forests are often nudged towards carbon sources, while regions with middle-aged productive forests are shifted towards sinks. This conforms to stand age effects observed in flux networks. At the subcontinental level, our inverted carbon fluxes agree well with continuous estimates of net ecosystem carbon exchange (NEE) upscaled from eddy covariance flux data based on MODIS data. Inverted fluxes with the age constraint exhibit stronger correlation to these upscaled NEE estimates than those inverted without the age constraint. While the carbon flux at the continental and subcontinental scales is predominantly determined by atmospheric CO2 observations, the age constraint is shown to have potential to improve the inversion of the carbon flux distribution among subcontinental regions, especially for regions lacking atmospheric CO2 observations. |
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BibTeX:
@article{deng13a,
author = {Deng, F. and Chen, J. M. and Pan, Y. and Peters, W. and Birdsey, R. and McCullough, K. and Xiao, J.},
title = {The use of forest stand age information in an atmospheric CO2 inversion applied to North America},
journal = {BIOGEOSCIENCES},
year = {2013},
volume = {10},
number = {8},
pages = {5335--5348},
doi = {https://doi.org/10.5194/bg-10-5335-2013}
}
|
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| Deng, F., Jones, D.B.A., Henze, D.K., Bousserez, N., Bowman, K.W., Fisher, J.B., Nassar, R., O'Dell, C., Wunch, D., Wennberg, P.O., Kort, E.A., Wofsy, S.C., Blumenstock, T., Deutscher, N.M., Griffith, D.W.T., Hase, F., Heikkinen, P., Sherlock, V., Strong, K., Sussmann, R. and Warneke, T. | Inferring regional sources and sinks of atmospheric CO2 from GOSAT XCO2 data | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({7}), pp. 3703-3727 |
article | DOI |
| Abstract: We have examined the utility of retrieved column-averaged, dry-air mole fractions of CO2 (XCO2) from the Greenhouse Gases Observing Satellite (GOSAT) for quantifying monthly, regional flux estimates of CO2, using the GEOS-Chem four-dimensional variational (4D-Var) data assimilation system. We focused on assessing the potential impact of biases in the GOSAT CO2 data on the regional flux estimates. Using different screening and bias correction approaches, we selected three different subsets of the GOSAT XCO2 data for the 4D-Var inversion analyses, and found that the inferred global fluxes were consistent across the three XCO2 inversions. However, the GOSAT observational coverage was a challenge for the regional flux estimates. In the northern extratropics, the inversions were more sensitive to North American fluxes than to European and Asian fluxes due to the lack of observations over Eurasia in winter and over eastern and southern Asia in summer. The regional flux estimates were also sensitive to the treatment of the residual bias in the GOSAT XCO2 data. The largest differences obtained were for temperate North America and temperate South America, for which the largest spread between the inversions was 1.02 and 0.96 Pg C, respectively. In the case of temperate North America, one inversion suggested a strong source, whereas the second and third XCO2 inversions produced a weak and strong sink, respectively. Despite the discrepancies in the regional flux estimates between the three XCO2 inversions, the a posteriori CO2 distributions were in good agreement (with a mean difference between the three inversions of typically less than 0.5 ppm) with independent data from the Total Carbon Column Observing Network (TCCON), the surface flask network, and from the HIAPER Pole-to-Pole Observations (HIPPO) aircraft campaign. The discrepancy in the regional flux estimates from the different inversions, despite the agreement of the global flux estimates suggests the need for additional work to determine the minimum spatial scales at which we can reliably quantify the fluxes using GOSAT XCO2. The fact that the a posteriori CO2 from the different inversions were in good agreement with the independent data although the regional flux estimates differed significantly, suggests that innovative ways of exploiting existing data sets, and possibly additional observations, are needed to better evaluate the inferred regional flux estimates. |
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BibTeX:
@article{deng14a,
author = {Deng, F. and Jones, D. B. A. and Henze, D. K. and Bousserez, N. and Bowman, K. W. and Fisher, J. B. and Nassar, R. and O'Dell, C. and Wunch, D. and Wennberg, P. O. and Kort, E. A. and Wofsy, S. C. and Blumenstock, T. and Deutscher, N. M. and Griffith, D. W. T. and Hase, F. and Heikkinen, P. and Sherlock, V. and Strong, K. and Sussmann, R. and Warneke, T.},
title = {Inferring regional sources and sinks of atmospheric CO2 from GOSAT XCO2 data},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {7},
pages = {3703--3727},
doi = {https://doi.org/10.5194/acp-14-3703-2014}
}
|
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| Deng, F., Jones, D.B.A., O'Dell, C.W., Nassar, R. and Parazoo, N.C. | Combining GOSAT XCO2 observations over land and ocean to improve regional CO2 flux estimates | {2016} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {121}({4}), pp. 1896-1913 |
article | DOI |
| Abstract: We used the GEOS-Chem data assimilation system to examine the impact of combining Greenhouse Gases Observing Satellite (GOSAT) XCO2 data over land and ocean on regional CO2 flux estimates for 2010-2012. We found that compared to assimilating only land data, combining land and ocean data produced an a posteriori CO2 distribution that is in better agreement with independent data and fluxes that are in closer agreement with existing top-down and bottom-up estimates. Adding XCO2 data over oceans changed the tropical land regions from a source of 0.64PgC/yr to a sink of -0.60PgC/yr and produced a corresponding reduction in the estimated sink in northern and southern land regions by 0.49PgC/yr and 0.80PgC/yr, respectively. This highlights the importance of improved observational coverage in the tropics to better quantify the latitudinal distribution of the terrestrial fluxes. Based only on land XCO2 data, we estimated a strong source in northern tropical South America, which experienced wet conditions in 2010-2012. In contrast, with the land and ocean data, we estimated a sink for this wet region in the north, and a source for the seasonally dry regions in the south and east, which is consistent with our understanding of the impact of moisture availability on the carbon balance of the region. Our results suggest that using satellite data with a more zonally balanced observational coverage could help mitigate discrepancies in CO2 flux estimates; further improvement could be expected with the greater observational coverage provided by the Orbiting Carbon Observatory-2. |
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BibTeX:
@article{deng16a,
author = {Deng, Feng and Jones, Dylan B. A. and O'Dell, Christopher W. and Nassar, Ray and Parazoo, Nicholas C.},
title = {Combining GOSAT XCO2 observations over land and ocean to improve regional CO2 flux estimates},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2016},
volume = {121},
number = {4},
pages = {1896--1913},
doi = {https://doi.org/10.1002/2015JD024157}
}
|
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| Deng, A., Lauvaux, T., Davis, K.J., Gaudet, B.J., Miles, N., Richardson, S.J., Wu, K., Sarmiento, D.P., Hardesty, R.M. and Bonin, T.A. | Toward reduced transport errors in a high resolution urban CO2 inversion system [BibTeX] |
2017 | Elem Sci Anth | article | DOI |
BibTeX:
@article{deng17a,
author = {Deng, Aijun and Lauvaux, Thomas and Davis, Kenneth J and Gaudet, Brian J and Miles, Natasha and Richardson, Scott J and Wu, Kai and Sarmiento, Daniel P and Hardesty, R Michael and Bonin, Timothy A},
title = {Toward reduced transport errors in a high resolution urban CO2 inversion system},
journal = {Elem Sci Anth},
year = {2017},
doi = {https://doi.org/10.1525/elementa.133/}
}
|
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| Deng, Z., Ciais, P., Tzompa-Sosa, Z.A., Saunois, M., Qiu, C., Tan, C., Sun, T., Ke, P., Cui, Y., Tanaka, K., Lin, X., Thompson, R.L., Tian, H., Yao, Y., Huang, Y., Lauerwald, R., Jain, A.K., Xu, X., Bastos, A., Sitch, S., Palmer, P.I., Lauvaux, T., d'Aspremont , A., Giron, C., Benoit, A., Poulter, B., Chang, J., Petrescu, A.M.R., Davis, S.J., Liu, Z., Grassi, G., Albergel, C., Tubiello, F.N., Perugini, L., Peters, W. and Chevallier, F. | Comparing national greenhouse gas budgets reported in UNFCCC inventories against atmospheric inversions | 2022 | EARTH SYSTEM SCIENCE DATA Vol. 14(4), pp. 1639-1675 |
article | DOI |
| Abstract: In support of the global stocktake of the Paris Agreement on climate change, this study presents a comprehensive framework to process the results of an ensemble of atmospheric inversions in order to make their net ecosystem exchange (NEE) carbon dioxide (CO2) flux suitable for evaluating national greenhouse gas inventories (NGHGIs) submitted by countries to the United Nations Framework Convention on Climate Change (UNFCCC). From inversions we also deduced anthropogenic methane (CH4) emissions regrouped into fossil and agriculture and waste emissions, as well as anthropogenic nitrous oxide (N2O) emissions. To compare inversion results with national reports, we compiled a new global harmonized database of emissions and removals from periodical UNFCCC inventories by Annex I countries, and from sporadic and less detailed emissions reports by non-Annex I countries, given by national communications and biennial update reports. No gap filling was applied. The method to reconcile inversions with inventories is applied to selected large countries covering similar to 90% of the global land carbon uptake for CO2 and top emitters of CH4 and N2O. Our method uses results from an ensemble of global inversions produced by the Global Carbon Project for the three greenhouse gases, with ancillary data. We examine the role of CO2 fluxes caused by lateral transfer processes from rivers and from trade in crop and wood products and the role of carbon uptake in unmanaged lands, both not accounted for by NGHGIs. Here we show that, despite a large spread across the inversions, the median of available inversion models points to a larger terrestrial carbon sink than inventories over temperate countries or groups of countries of the Northern Hemisphere like Russia, Canada and the European Union. For CH4, we find good consistency between the inversions assimilating only data from the global in situ network and those using satellite CH4 retrievals and a tendency for inversions to diagnose higher CH4 emission estimates than reported by NGHGIs. In particular, oil- and gas-extracting countries in central Asia and the Persian Gulf region tend to systematically report lower emissions compared to those estimated by inversions. For N2O, inversions tend to produce higher anthropogenic emissions than inventories for tropical countries, even when attempting to consider only managed land emissions. In the inventories of many non-Annex I countries, this can be tentatively attributed to a lack of reporting indirect N2O emissions from atmospheric deposition and from leaching to rivers, to the existence of natural sources intertwined with managed lands, or to an underestimation of N2O emission factors for direct agricultural soil emissions. Inversions provide insights into seasonal and interannual greenhouse gas fluxes anomalies, e.g., during extreme events such as drought or abnormal fire episodes, whereas inventory methods are established to estimate trends and multi-annual changes. As a much denser sampling of atmospheric CO2 and CH4 concentrations by different satellites coordinated into a global constellation is expected in the coming years, the methodology proposed here to compare inversion results with inventory reports (e.g., NGHGIs) could be applied regularly for monitoring the effectiveness of mitigation policy and progress by countries to meet the objective of their pledges. The dataset constructed by this study is publicly available at https://doi.org/10.5281/zenodo.5089799 (Deng et al., 2021). |
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BibTeX:
@article{deng22a,
author = {Deng, Zhu and Ciais, Philippe and Tzompa-Sosa, Zitely A. and Saunois, Marielle and Qiu, Chunjing and Tan, Chang and Sun, Taochun and Ke, Piyu and Cui, Yanan and Tanaka, Katsumasa and Lin, Xin and Thompson, Rona L. and Tian, Hanqin and Yao, Yuanzhi and Huang, Yuanyuan and Lauerwald, Ronny and Jain, Atul K. and Xu, Xiaoming and Bastos, Ana and Sitch, Stephen and Palmer, Paul I. and Lauvaux, Thomas and d'Aspremont, Alexandre and Giron, Clement and Benoit, Antoine and Poulter, Benjamin and Chang, Jinfeng and Petrescu, Ana Maria Roxana and Davis, Steven J. and Liu, Zhu and Grassi, Giacomo and Albergel, Clement and Tubiello, Francesco N. and Perugini, Lucia and Peters, Wouter and Chevallier, Frederic},
title = {Comparing national greenhouse gas budgets reported in UNFCCC inventories against atmospheric inversions},
journal = {EARTH SYSTEM SCIENCE DATA},
year = {2022},
volume = {14},
number = {4},
pages = {1639-1675},
doi = {https://doi.org/10.5194/essd-14-1639-2022}
}
|
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| Desai, A.R., Helliker, B.R., Moorcroft, P.R., Andrews, A.E. and Berry, J.A. | Climatic controls of interannual variability in regional carbon fluxes from top-down and bottom-up perspectives | {2010} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {115} |
article | DOI |
| Abstract: Observations of regional net ecosystem exchange (NEE) of CO(2) for 1997-2007 were analyzed for climatic controls on interannual variability (IAV). Quantifying IAV of regional (10(4)-10(6) km(2)) NEE over long time periods is key to understanding potential feedbacks between climate and the carbon cycle. Four independent techniques estimated monthly regional NEE for 10(4) km(2) in a spatially heterogeneous temperate-boreal transition region of the north central United States, centered on the Park Falls, Wisconsin, United States, National Oceanic and Atmospheric Administration tall tower site. These techniques included two bottom-up methods, based on flux tower upscaling and forest inventory based demographic modeling, respectively, and two top-down methods, based on tall tower equilibrium boundary layer budgets and tracer-transport inversion, respectively. While all four methods revealed a moderate carbon sink, they diverged significantly in magnitude. Coherence of relative magnitude and variability of NEE anomalies was strong across the methods. The strongest coherence was a trend of declining carbon sink since 2002. Most climatic controls were not strongly correlated with IAV. Significant controls on IAV were those related to hydrology, such as water table depth, and atmospheric CO(2). Weaker relationships were found with phenological controls such as autumn soil temperature. Hydrologic relationships were strongest with a 1 year lag, potentially highlighting a previously unrecognized predictor of IAV in this region. These results highlight a need for continued development of techniques to estimate regional IAV and incorporation of hydrologic cycling into couple carbon-climate models. |
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BibTeX:
@article{desai10a,
author = {Desai, Ankur R. and Helliker, Brent R. and Moorcroft, Paul R. and Andrews, Arlyn E. and Berry, Joseph A.},
title = {Climatic controls of interannual variability in regional carbon fluxes from top-down and bottom-up perspectives},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2010},
volume = {115},
doi = {https://doi.org/10.1029/2009JG001122}
}
|
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| Desai, A.R., Moore, D.J.P., Ahue, W.K.M., Wilkes, P.T.V., De Wekker, S.F.J., Brooks, B.G., Campos, T.L., Stephens, B.B., Monson, R.K., Burns, S.P., Quaife, T., Aulenbach, S.M. and Schimel, D.S. | Seasonal pattern of regional carbon balance in the central Rocky Mountains from surface and airborne measurements | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {116} |
article | DOI |
| Abstract: High-elevation forests represent a large fraction of potential carbon uptake in North America, but this uptake is not well constrained by observations. Additionally, forests in the Rocky Mountains have recently been severely damaged by drought, fire, and insect outbreaks, which have been quantified at local scales but not assessed in terms of carbon uptake at regional scales. The Airborne Carbon in the Mountains Experiment was carried out in 2007 partly to assess carbon uptake in western U. S. mountain ecosystems. The magnitude and seasonal change of carbon uptake were quantified by (1) paired upwind-downwind airborne CO2 observations applied in a boundary layer budget, (2) a spatially explicit ecosystem model constrained using remote sensing and flux tower observations, and (3) a downscaled global tracer transport inversion. Top-down approaches had mean carbon uptake equivalent to flux tower observations at a subalpine forest, while the ecosystem model showed less. The techniques disagreed on temporal evolution. Regional carbon uptake was greatest in the early summer immediately following snowmelt and tended to lessen as the region experienced dry summer conditions. This reduction was more pronounced in the airborne budget and inversion than in flux tower or upscaling, possibly related to lower snow water availability in forests sampled by the aircraft, which were lower in elevation than the tower site. Changes in vegetative greenness associated with insect outbreaks were detected using satellite reflectance observations, but impacts on regional carbon cycling were unclear, highlighting the need to better quantify this emerging disturbance effect on montane forest carbon cycling. |
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BibTeX:
@article{desai11a,
author = {Desai, Ankur R. and Moore, David J. P. and Ahue, William K. M. and Wilkes, Phillip T. V. and De Wekker, Stephan F. J. and Brooks, Bjorn G. and Campos, Teresa L. and Stephens, Britton B. and Monson, Russell K. and Burns, Sean P. and Quaife, Tristan and Aulenbach, Steven M. and Schimel, David S.},
title = {Seasonal pattern of regional carbon balance in the central Rocky Mountains from surface and airborne measurements},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2011JG001655}
}
|
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| Deutscher, N.M., Sherlock, V., Fletcher, S.E.M., Griffith, D.W.T., Notholt, J., Macatangay, R., Connor, B.J., Robinson, J., Shiona, H., Velazco, V.A., Wang, Y., Wennberg, P.O. and Wunch, D. | Drivers of column-average CO2 variability at Southern Hemispheric Total Carbon Column Observing Network sites | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({18}), pp. 9883-9901 |
article | DOI |
| Abstract: We investigate factors that drive the variability in total column CO2 at the Total Carbon Column Observing Network sites in the Southern Hemisphere using fluxes tagged by process and by source region from the Carbon-Tracker analysed product as well as the Simple Biosphere model. We show that the terrestrial biosphere is the largest driver of variability in the Southern Hemisphere column CO2. However, it does not dominate in the same fashion as in the Northern Hemisphere. Local-and hemispheric-scale biomass burning can also play an important role, particularly at the tropical site, Darwin. The magnitude of seasonal variability in the column-average dry-air mole fraction of CO2, XCO2, is also much smaller in the Southern Hemisphere and comparable in magnitude to the annual increase. Comparison of measurements to the model simulations highlights that there is some discrepancy between the two time series, especially in the early part of the Darwin data record. We show that this mismatch is most likely due to erroneously estimated local fluxes in the Australian tropical region, which are associated with enhanced photosynthesis caused by early rainfall during the tropical monsoon season. |
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BibTeX:
@article{deutscher14a,
author = {Deutscher, N. M. and Sherlock, V. and Fletcher, S. E. Mikaloff and Griffith, D. W. T. and Notholt, J. and Macatangay, R. and Connor, B. J. and Robinson, J. and Shiona, H. and Velazco, V. A. and Wang, Y. and Wennberg, P. O. and Wunch, D.},
title = {Drivers of column-average CO2 variability at Southern Hemispheric Total Carbon Column Observing Network sites},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {18},
pages = {9883--9901},
doi = {https://doi.org/10.5194/acp-14-9883-2014}
}
|
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| Diallo, M., Legras, B., Ray, E., Engel, A. and Anel, J.A. | Global distribution of CO2 in the upper troposphere and stratosphere | {2017} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {17}({6}), pp. 3861-3878 |
article | DOI |
| Abstract: In this study, we construct a new monthly zonal mean carbon dioxide (CO2) distribution from the upper troposphere to the stratosphere over the 2000-2010 time period. This reconstructed CO2 product is based on a Lagrangian backward trajectory model driven by ERA-Interim reanalysis meteorology and tropospheric CO2 measurements. Comparisons of our CO2 product to extratropical in situ measurements from aircraft transects and balloon profiles show remarkably good agreement. The main features of the CO2 distribution include (1) relatively large mixing ratios in the tropical stratosphere; (2) seasonal variability in the extratropics, with relatively high mixing ratios in the summer and autumn hemisphere in the 15-20 km altitude layer; and (3) decreasing mixing ratios with increasing altitude from the upper troposphere to the middle stratosphere (similar to 35 km). These features are consistent with expected variability due to the transport of long-lived trace gases by the stratospheric Brewer-Dobson circulation. The method used here to construct this CO2 product is unique from other modelling efforts and should be useful for model and satellite validation in the upper troposphere and stratosphere as a prior for inversion modelling and to analyse features of stratosphere-troposphere exchange as well as the stratospheric circulation and its variability. |
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BibTeX:
@article{diallo17a,
author = {Diallo, Mohamadou and Legras, Bernard and Ray, Eric and Engel, Andreas and Anel, Juan A.},
title = {Global distribution of CO2 in the upper troposphere and stratosphere},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2017},
volume = {17},
number = {6},
pages = {3861--3878},
doi = {https://doi.org/10.5194/acp-17-3861-2017}
}
|
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| D\iaz-Isaac, L.I., Lauvaux, T. and Davis, K.J. | Impact of physical parameterizations and initial conditions on simulated atmospheric transport and CO2 mole fractions in the US Midwest [BibTeX] |
2018 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 18, pp. 14813 |
article | URL |
BibTeX:
@article{diaz-isaac18a,
author = {Liza I. D\iaz-Isaac and Thomas Lauvaux and Kenneth J. Davis},
title = {Impact of physical parameterizations and initial conditions on simulated atmospheric transport and CO2 mole fractions in the US Midwest},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2018},
volume = {18},
pages = {14813},
url = {https://www.atmos-chem-phys.net/18/14813/2018/acp-18-14813-2018.pdf}
}
|
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| Diaz-Isaac, L.I., Lauvaux, T., Bocquet, M. and Davis, K.J. | Calibration of a multi-physics ensemble for estimating the uncertainty of a greenhouse gas atmospheric transport model | {2019} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {19}({8}), pp. {5695-5718} |
article | DOI URL |
| Abstract: Atmospheric inversions have been used to assess biosphere-atmosphere CO2 surface exchanges at various scales, but variability among inverse flux estimates remains significant, especially at continental scales. Atmospheric transport errors are one of the main contributors to this variability. To characterize transport errors and their spatiotemporal structures, we present an objective method to generate a calibrated ensemble adjusted with meteorological measurements collected across a region, here the upper US Midwest in midsummer. Using multiple model configurations of the Weather Research and Forecasting (WRF) model, we show that a reduced number of simulations (less than 10 members) reproduces the transport error characteristics of a 45-member ensemble while minimizing the size of the ensemble. The large ensemble of 45 members was constructed using different physics parameterization (i.e., land surface models (LSMs), planetary boundary layer (PBL) schemes, cumulus parameterizations and microphysics parameterizations) and meteorological initial/boundary conditions. All the different models were coupled to CO2 fluxes and lateral boundary conditions from CarbonTracker to simulate CO2 mole fractions. Observed meteorological variables critical to inverse flux estimates, PBL wind speed, PBL wind direction and PBL height are used to calibrate our ensemble over the region. Two optimization techniques (i.e., simulated annealing and a genetic algorithm) are used for the selection of the optimal ensemble using the flatness of the rank histograms as the main criterion. We also choose model configurations that minimize the systematic errors (i.e., monthly biases) in the ensemble. We evaluate the impact of transport errors on atmospheric CO2 mole fraction to represent up to 40% of the model-data mismatch (fraction of the total variance). We conclude that a carefully chosen subset of the physics ensemble can represent the uncertainties in the full ensemble, and that transport ensembles calibrated with relevant meteorological variables provide a promising path forward for improving the treatment of transport uncertainties in atmospheric inverse flux estimates. | |||||
BibTeX:
@article{diaz-isaac19a,
author = {Diaz-Isaac, Liza I. and Lauvaux, Thomas and Bocquet, Marc and Davis, Kenneth J.},
title = {Calibration of a multi-physics ensemble for estimating the uncertainty of a greenhouse gas atmospheric transport model},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {19},
number = {8},
pages = {5695--5718},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/19/5695/2019/},
doi = {https://doi.org/10.5194/acp-19-5695-2019}
}
|
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| DiGangi, J.P., Choi, Y., Nowak, J.B., Halliday, H.S., Diskin, G.S., Feng, S., Barkley, Z.R., Lauvaux, T., Pal, S., Davis, K.J., Baier, B.C. and Sweeney, C. | Seasonal Variability in Local Carbon Dioxide Biomass Burning Sources Over Central and Eastern US Using Airborne In Situ Enhancement Ratios | 2021 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 126(24) |
article | DOI |
| Abstract: We present observations of local enhancements in carbon dioxide (CO2) from local emissions sources over three eastern US regions during four deployments of the Atmospheric Carbon Transport-America (ACT-America) campaign between summer 2016 and spring 2018. Local CO2 emissions were characterized by carbon monoxide (CO) to CO2 enhancement ratios (i.e., Delta CO/Delta CO2) in air mass mixing observed during aircraft transects within the planetary boundary layer. By analyzing regional-scale variability of CO2 enhancements as a function of Delta CO/Delta CO2 enhancement ratios, observed relative contributions to CO2 emissions were separated into fossil fuel and biomass burning (BB) regimes across regions and seasons. CO2 emission contributions attributed to biomass burning (Delta CO/Delta CO2 > 4%) were negligible during summer and fall in all regions but climbed to similar to 9%-11% of observed combustion contributions in the South during winter and spring. Relative CO2 fire emission trends matched observed winter and spring BB contributions, but conflictingly predicted similar levels of BB during the fall. Satellite fire data from MODIS and VIIRS suggested the use of higher spatial resolution fire data that might improve modeled BB emissions but were not able to explain the bulk of the discrepancy. |
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BibTeX:
@article{digangi21a,
author = {DiGangi, Joshua P. and Choi, Yonghoon and Nowak, John B. and Halliday, Hannah S. and Diskin, Glenn S. and Feng, Sha and Barkley, Zachary R. and Lauvaux, Thomas and Pal, Sandip and Davis, Kenneth J. and Baier, Bianca C. and Sweeney, Colm},
title = {Seasonal Variability in Local Carbon Dioxide Biomass Burning Sources Over Central and Eastern US Using Airborne In Situ Enhancement Ratios},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2021},
volume = {126},
number = {24},
doi = {https://doi.org/10.1029/2020JD034525}
}
|
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| Dils, B., Buchwitz, M., Reuter, M., Schneising, O., Boesch, H., Parker, R., Guerlet, S., Aben, I., Blumenstock, T., Burrows, J.P., Butz, A., Deutscher, N.M., Frankenberg, C., Hase, F., Hasekamp, O.P., Heymann, J., De Maziere, M., Notholt, J., Sussmann, R., Warneke, T., Griffith, D., Sherlock, V. and Wunch, D. | The Greenhouse Gas Climate Change Initiative (GHG-CCI): comparative validation of GHG-CCI SCIAMACHY/ENVISAT and TANSO-FTS/GOSAT CO2 and CH4 retrieval algorithm products with measurements from the TCCON | {2014} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {7}({6}), pp. 1723-1744 |
article | DOI |
| Abstract: Column-averaged dry-air mole fractions of carbon dioxide and methane have been retrieved from spectra acquired by the TANSO-FTS (Thermal And Near-infrared Sensor for carbon Observations-Fourier Transform Spectrometer) and SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Cartography) instruments on board GOSAT (Greenhouse gases Observing SATellite) and ENVISAT (ENVIronmental SATellite), respectively, using a range of European retrieval algorithms. These retrievals have been compared with data from ground-based high-resolution Fourier transform spectrometers (FTSs) from the Total Carbon Column Observing Network (TCCON). The participating algorithms are the weighting function modified differential optical absorption spectroscopy (DOAS) algorithm (WFMD, University of Bremen), the Bremen optimal estimation DOAS algorithm (BESD, University of Bremen), the iterative maximum a posteriori DOAS (IMAP, Jet Propulsion Laboratory (JPL) and Netherlands Institute for Space Research algorithm (SRON)), the proxy and full-physics versions of SRON's RemoTeC algorithm (SRPR and SRFP, respectively) and the proxy and full-physics versions of the University of Leicester's adaptation of the OCO (Orbiting Carbon Observatory) algorithm (OCPR and OCFP, respectively). The goal of this algorithm inter-comparison was to identify strengths and weaknesses of the various so-called round-robin data sets generated with the various algorithms so as to determine which of the competing algorithms would proceed to the next round of the European Space Agency's (ESA) Greenhouse Gas Climate Change Initiative (GHG-CCI) project, which is the generation of the so-called Climate Research Data Package (CRDP), which is the first version of the Essential Climate Variable (ECV) ``greenhouse gases'' (GHGs). For XCO2, all algorithms reach the precision requirements for inverse modelling (< 8 ppm), with only WFMD having a lower precision (4.7 ppm) than the other algorithm products (2.4-2.5 ppm). When looking at the seasonal relative accuracy (SRA, variability of the bias in space and time), none of the algorithms have reached the demanding < 0.5 ppm threshold. For XCH4, the precision for both SCIAMACHY products (50.2 ppb for IMAP and 76.4 ppb for WFMD) fails to meet the < 34 ppb threshold for inverse modelling, but note that this work focusses on the period after the 2005 SCIAMACHY detector degradation. The GOSAT XCH4 precision ranges between 18.1 and 14.0 ppb. Looking at the SRA, all GOSAT algorithm products reach the < 10 ppm threshold (values ranging between 5.4 and 6.2 ppb). For SCIAMACHY, IMAP and WFMD have a SRA of 17.2 and 10.5 ppb, respectively. |
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BibTeX:
@article{dils14a,
author = {Dils, B. and Buchwitz, M. and Reuter, M. and Schneising, O. and Boesch, H. and Parker, R. and Guerlet, S. and Aben, I. and Blumenstock, T. and Burrows, J. P. and Butz, A. and Deutscher, N. M. and Frankenberg, C. and Hase, F. and Hasekamp, O. P. and Heymann, J. and De Maziere, M. and Notholt, J. and Sussmann, R. and Warneke, T. and Griffith, D. and Sherlock, V. and Wunch, D.},
title = {The Greenhouse Gas Climate Change Initiative (GHG-CCI): comparative validation of GHG-CCI SCIAMACHY/ENVISAT and TANSO-FTS/GOSAT CO2 and CH4 retrieval algorithm products with measurements from the TCCON},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2014},
volume = {7},
number = {6},
pages = {1723--1744},
doi = {https://doi.org/10.5194/amt-7-1723-2014}
}
|
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| Doherty, S.J., Bojinski, S., Henderson-Sellers, A., Noone, K., Goodrich, D., Bindoff, N.L., Church, J.A., Hibbard, K.A., Karl, T.R., Kajefez-Bogataj, L., Lynch, A.H., Parker, D.E., Prentice, I.C., Ramaswamy, V., Saunders, R.W., Smith, M.S., Steffen, K., Stocker, T.F., Thorne, P.W., Trenberth, K.E., Verstraete, M.M. and Zwiers, F.W. | LESSONS LEARNED FROM IPCC AR4 Scientific Developments Needed To Understand, Predict, And Respond To Climate Change | {2009} | BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY Vol. {90}({4}), pp. 497-513 |
article | DOI |
| Abstract: The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) concluded that global warming is ``unequivocal'' and that most of the observed increase since the mid-twentieth century is very likely due to the increase in anthropogenic greenhouse gas concentrations, with discernible human influences on ocean warming, continental-average temperatures, temperature extremes, wind patterns, and other physical and biological indicators, impacting both socioeconomic and ecological systems. It is now clear that we are committed to some level of global climate change, and it is imperative that this be considered when planning future climate research and observational strategies. The Global Climate Observing System program (GCOS), the World Climate Research Programme (WCRP), and the International Geosphere-Biosphere Programme (IGBP) therefore initiated a process to summarize the lessons learned through AR4 Working Groups I and II and to identify a set of high-priority modeling and observational needs. Two classes of recommendations emerged. First is the need to improve climate models, observational and climate monitoring systems, and our understanding of key processes. Second, the framework for climate research and observations must be extended to document impacts and to guide adaptation and mitigation efforts. Research and observational strategies specifically aimed at improving our ability to predict and understand impacts, adaptive capacity, and societal and ecosystem vulnerabilities will serve both purposes and are the subject of the specific recommendations made in this paper. |
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BibTeX:
@article{doherty09a,
author = {Doherty, Sarah J. and Bojinski, Stephan and Henderson-Sellers, Ann and Noone, Kevin and Goodrich, David and Bindoff, Nathaniel L. and Church, John A. and Hibbard, Kathy A. and Karl, Thomas R. and Kajefez-Bogataj, Lucka and Lynch, Amanda H. and Parker, David E. and Prentice, I. Colin and Ramaswamy, Venkatachalam and Saunders, Roger W. and Smith, Mark Stafford and Steffen, Konrad and Stocker, Thomas F. and Thorne, Peter W. and Trenberth, Kevin E. and Verstraete, Michel M. and Zwiers, Francis W.},
title = {LESSONS LEARNED FROM IPCC AR4 Scientific Developments Needed To Understand, Predict, And Respond To Climate Change},
journal = {BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY},
year = {2009},
volume = {90},
number = {4},
pages = {497--513},
doi = {https://doi.org/10.1175/2008BAMS2643.1}
}
|
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| Dolman, A.J., Gerbig, C., Noilhan, J., Sarrat, C. and Miglietta, F. | Detecting regional variability in sources and sinks of carbon dioxide: a synthesis | {2009} | BIOGEOSCIENCES Vol. {6}({6}), pp. 1015-1026 |
article | DOI |
| Abstract: The current paper reviews the experimental setup of the CarboEurope Experimental Strategy (CERES) campaigns with the aim of providing an overview of the instrumentation used, the data-set and associated modelling. It then assesses progress in the field of regional observation and modelling of carbon fluxes, bringing the papers of this special issue into a somewhat broader context of analysis. Instrumental progress has been obtained in the field of remotely monitoring from tall towers and the experimental planning. Flux measurements from aircraft are now capable, within some constraints, to provide regular regional observations of fluxes of CO(2), latent and sensible heat. Considerable effort still needs to be put into calibrating the surface schemes of models, as they have direct impact on the input of energy, moisture and carbon fluxes in the boundary layer. Overall, the mesoscale models appear to be capable of simulating the large scale dynamics of the region, but in the fine detail, like the precise horizontal and vertical CO(2) field differences between the models still exist. These errors translate directly into transport uncertainty, when the forward simulations are used in inverse mode. Quantification of this uncertainty, including that of inadequate boundary layer height modelling, still remains a major challenge for state of the art mesoscale models. Progress in inverse models has been slow, but has shown that it is possible to estimate some of the errors involved, and that using the combination of observations. Overall, the capability to produce regional, high-resolution estimates of carbon exchange, exist in potential, but the routine application will require considerable effort, both in the experimental as in the modelling domain. |
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BibTeX:
@article{dolman09a,
author = {Dolman, A. J. and Gerbig, C. and Noilhan, J. and Sarrat, C. and Miglietta, F.},
title = {Detecting regional variability in sources and sinks of carbon dioxide: a synthesis},
journal = {BIOGEOSCIENCES},
year = {2009},
volume = {6},
number = {6},
pages = {1015--1026},
doi = {https://doi.org/10.5194/bg-6-1015-2009}
}
|
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| Dolman, A.J., van der Werf, G.R., van der Molen, M.K., Ganssen, G., Erisman, J.W. and Strengers, B. | A Carbon Cycle Science Update Since IPCC AR-4 | {2010} | AMBIO Vol. {39}({5-6}), pp. 402-412 |
article | DOI |
| Abstract: We review important advances in our understanding of the global carbon cycle since the publication of the IPCC AR4. We conclude that: the anthropogenic emissions of CO2 due to fossil fuel burning have increased up through 2008 at a rate near to the high end of the IPCC emission scenarios; there are contradictory analyses whether an increase in atmospheric fraction, that might indicate a declining sink strength of ocean and/or land, exists; methane emissions are increasing, possibly through enhanced natural emission from northern wetland, methane emissions from dry plants are negligible; old-growth forest take up more carbon than expected from ecological equilibrium reasoning; tropical forest also take up more carbon than previously thought, however, for the global budget to balance, this would imply a smaller uptake in the northern forest; the exchange fluxes between the atmosphere and ocean are increasingly better understood and bottom up and observation-based top down estimates are getting closer to each other; the North Atlantic and Southern ocean take up less CO2, but it is unclear whether this is part of the `natural' decadal scale variability; large-scale fires and droughts, for instance in Amazonia, but also at Northern latitudes, have lead to significant decreases in carbon uptake on annual timescales; the extra uptake of CO2 stimulated by increased N-deposition is, from a greenhouse gas forcing perspective, counterbalanced by the related additional N2O emissions; the amount of carbon stored in permafrost areas appears much (two times) larger than previously thought; preservation of existing marine ecosystems could require a CO2 stabilization as low as 450 ppm; Dynamic Vegetation Models show a wide divergence for future carbon trajectories, uncertainty in the process description, lack of understanding of the CO2 fertilization effect and nitrogen-carbon interaction are major uncertainties. |
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BibTeX:
@article{dolman10a,
author = {Dolman, A. J. and van der Werf, G. R. and van der Molen, M. K. and Ganssen, G. and Erisman, J. -W. and Strengers, B.},
title = {A Carbon Cycle Science Update Since IPCC AR-4},
journal = {AMBIO},
year = {2010},
volume = {39},
number = {5-6},
pages = {402--412},
doi = {https://doi.org/10.1007/s13280-010-0083-7}
}
|
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| Dong, J. | Impedance Matching Readouts-A New Family of Ultrasensitive Cavity Enhanced Spectroscopy Techniques | 2020 | School: The Australian National University | phdthesis | URL |
| Abstract: Optical cavity enhanced spectroscopy (CES) is a well-established analytical research area, providing powerful and ultra-sensitive tools for the detection and quantification of trace gas concentrations by using optical cavities to effectively enhance the optical absorption. In this … | |||||
BibTeX:
@phdthesis{dong20a,
author = {Jiahao Dong},
title = {Impedance Matching Readouts-A New Family of Ultrasensitive Cavity Enhanced Spectroscopy Techniques},
school = {The Australian National University},
year = {2020},
url = {https://search.proquest.com/openview/13e8bf53ff391312db4a6248f16bafe4/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Dong, X., Yue, M., Jiang, Y., Hu, X.-M., Ma, Q., Pu, J. and Zhou, G. | Analysis of CO2 spatio-temporal variations in China using a weather-biosphere online coupled model | 2021 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 21(9), pp. 7217-7233 |
article | DOI |
| Abstract: The dynamics of atmospheric CO2 has received considerable attention in the literature, yet significant uncertainties remain within the estimates of contribution from the terrestrial flux and the influence of atmospheric mixing. In this study we apply the WRF-Chem model configured with the Vegetation Photosynthesis and Respiration Model (VPRM) option for biomass fluxes in China to characterize the dynamics of CO2 in the atmosphere. The online coupled WRF-Chem model is able to simulate biosphere processes (photosynthetic uptake and ecosystem respiration) and meteorology in one coordinate system. We apply WRF-Chem for a multi-year simulation (2016-2018) with integrated data from a satellite product, flask samplings, and tower measurements to diagnose the spatio-temporal variations of CO2 fluxes and concentrations in China. We find that the spatial distribution of CO2 was dominated by anthropogenic emissions, while its seasonality (with maxima in April 15 ppmv higher than minima in August) was dominated by the terrestrial flux and background CO2. Observations and simulations revealed a consistent increasing trend in column-averaged CO2 (XCO2) of 2.46 ppmv (0.6% yr(-1)) resulting from anthropogenic emission growth and biosphere uptake. WRF-Chem successfully reproduced ground-based measurements of surface CO2 concentration with a mean bias of -0.79 ppmv and satellite-derived XCO2 with a mean bias of 0.76 ppmv. The model-simulated seasonality was also consistent with observations, with correlation coefficients of 0.90 and 0.89 for ground-based measurements and satellite data, respectively. Tower observations from a background site at Lin'an (30.30 degrees N, 119.75 degrees E) revealed a strong correlation (-0.98) between vertical CO2 and temperature gradients, suggesting a significant influence of boundary layer thermal structure on the accumulation and depletion of atmospheric CO2. |
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BibTeX:
@article{dong21a,
author = {Dong, Xinyi and Yue, Man and Jiang, Yujun and Hu, Xiao-Ming and Ma, Qianli and Pu, Jingjiao and Zhou, Guangqiang},
title = {Analysis of CO2 spatio-temporal variations in China using a weather-biosphere online coupled model},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2021},
volume = {21},
number = {9},
pages = {7217-7233},
doi = {https://doi.org/10.5194/acp-21-7217-2021}
}
|
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| Eldering, A., Taylor, T.E., O'Dell, C.W. and Pavlick, R. | The OCO-3 mission: measurement objectives and expected performance based on 1 year of simulated data | {2019} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {12}({4}), pp. {2341-2370} |
article | DOI URL |
| Abstract: The Orbiting Carbon Observatory-3 (OCO-3) is NASA's next instrument dedicated to extending the record of the dry-air mole fraction of column carbon dioxide (XCO2) and solar-induced fluorescence (SIF) measurements from space. The current schedule calls for a launch from the Kennedy Space Center no earlier than April 2019 via a Space-X Falcon 9 and Dragon capsule. The instrument will be installed as an external payload on the Japanese Experimental Module Exposed Facility (JEM-EF) of the International Space Station (ISS) with a nominal mission lifetime of 3 years. The precessing orbit of the ISS will allow for viewing of the Earth at all latitudes less than approximately 52 degrees, with a ground repeat cycle that is much more complicated than the polar-orbiting satellites that so far have carried all of the instruments capable of measuring carbon dioxide from space. The grating spectrometer at the core of OCO-3 is a direct copy of the OCO-2 spectrometer, which was launched into a polar orbit in July 2014. As such, OCO-3 is expected to have similar instrument sensitivity and performance characteristics to OCO-2, which provides measurements of XCO2 with precision better than 1 ppm at 3 Hz, with each viewing frame containing eight footprints approximately 1.6 km by 2.2 km in size. However, the physical configuration of the instrument aboard the ISS, as well as the use of a new pointing mirror assembly (PMA), will alter some of the characteristics of the OCO-3 data compared to OCO-2. Specifically, there will be significant differences from day to day in the sampling locations and time of day. In addition, the flexible PMA system allows for a much more dynamic observation-mode schedule. This paper outlines the science objectives of the OCO-3 mission and, using a simulation of 1 year of global observations, characterizes the spatial sampling, time-of-day coverage, and anticipated data quality of the simulated L1b. After application of cloud and aerosol prescreening, the L1b radiances are run through the operational L2 full physics retrieval algorithm, as well as post-retrieval filtering and bias correction, to examine the expected coverage and quality of the retrieved XCO2 and to show how the measurement objectives are met. In addition, results of the SIF from the IMAP-DOAS algorithm are analyzed. This paper focuses only on the nominal nadir-land and glint-water observation modes, although on-orbit measurements will also be made in transition and target modes, similar to OCO-2, as well as the new snapshot area mapping (SAM) mode. | |||||
BibTeX:
@article{eldering19a,
author = {Eldering, Annmarie and Taylor, Thomas E. and O'Dell, Christopher W. and Pavlick, Ryan},
title = {The OCO-3 mission: measurement objectives and expected performance based on 1 year of simulated data},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {12},
number = {4},
pages = {2341--2370},
note = {Query date: 2021-04-02 15:20:04},
url = {https://amt.copernicus.org/articles/12/2341/2019/},
doi = {https://doi.org/10.5194/amt-12-2341-2019}
}
|
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| Elias, E., Dougherty, M., Srivastava, P. and Laband, D. | The impact of forest to urban land conversion on streamflow, total nitrogen, total phosphorus, and total organic carbon inputs to the converse reservoir, Southern Alabama, USA | {2013} | URBAN ECOSYSTEMS Vol. {16}({1, SI}), pp. 79-107 |
article | DOI |
| Abstract: High total organic carbon (TOC) concentrations in Converse Reservoir, a water source for Mobile, Alabama, have concerned water treatment officials due to the potential for disinfection byproduct (DBP) formation. TOC reacts with chlorine during drinking water treatment to form DBPs. This study evaluated how increased urbanization can alter watershed-derived total nitrogen (TN), total phosphorus (TP) and TOC inputs to the Converse Reservoir. Converse Watershed, on the urban fringe of Mobile, is projected to undergo urbanization increasing watershed urban land from 3% in 1992 to 22% urban land by 2020. A pre-urbanization scenario using 1992 land cover was coupled with 2020 projections of land use. The Loading Simulation Program C++ watershed model was used to evaluate changes in nutrient concentrations (mg L-1) and loads (kg) to Converse Reservoir. Urban and suburban growth of 52 km(2) simulated from 1991 to 2005 (15 year) caused overall TN and TP loads to increase by 109 and 62%, respectively. Simulated urban growth generally increased monthly flows by 15%, but resulted in lower streamflows (2.9%) during drought months. Results indicate that post-urbanization median TN and TP concentrations were 59 and 66% higher than corresponding pre-urbanization concentrations, whereas TOC concentrations were 16% lower. An increase in urban flow caused TOC loads to increase by 26%, despite lower post-urbanization TOC concentrations. |
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BibTeX:
@article{elias13a,
author = {Elias, Emile and Dougherty, Mark and Srivastava, Puneet and Laband, David},
title = {The impact of forest to urban land conversion on streamflow, total nitrogen, total phosphorus, and total organic carbon inputs to the converse reservoir, Southern Alabama, USA},
journal = {URBAN ECOSYSTEMS},
year = {2013},
volume = {16},
number = {1, SI},
pages = {79--107},
doi = {https://doi.org/10.1007/s11252-011-0198-z}
}
|
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| Elshall, A.S., Ye, M., Niu, G.-Y. and Barron-Gafford, G.A. | Bayesian inference and predictive performance of soil respiration models in the presence of model discrepancy | {2019} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {12}({5}), pp. {2009-2032} |
article | DOI URL |
| Abstract: Bayesian inference of microbial soil respiration models is often based on the assumptions that the residuals are independent (i.e., no temporal or spatial correlation), identically distributed (i.e., Gaussian noise), and have constant variance (i.e., homoscedastic). In the presence of model discrepancy, as no model is perfect, this study shows that these assumptions are generally invalid in soil respiration modeling such that residuals have high temporal correlation, an increasing variance with increasing magnitude of CO2 efflux, and non-Gaussian distribution. Relaxing these three assumptions stepwise results in eight data models. Data models are the basis of formulating likelihood functions of Bayesian inference. This study presents a systematic and comprehensive investigation of the impacts of data model selection on Bayesian inference and predictive performance. We use three mechanistic soil respiration models with different levels of model fidelity (i.e., model discrepancy) with respect to the number of carbon pools and the explicit representations of soil moisture controls on carbon degradation; therefore, we have different levels of model complexity with respect to the number of model parameters. The study shows that data models have substantial impacts on Bayesian inference and predictive performance of the soil respiration models such that the following points are true: (i) the level of complexity of the best model is generally justified by the cross-validation results for different data models; (ii) not accounting for heteroscedasticity and autocorrelation might not necessarily result in biased parameter estimates or predictions, but will definitely underestimate uncertainty; (iii) using a non-Gaussian data model improves the parameter estimates and the predictive performance; and (iv) accounting for autocorrelation only or joint inversion of correlation and heteroscedasticity can be problematic and requires special treatment. Although the conclusions of this study are empirical, the analysis may provide insights for selecting appropriate data models for soil respiration modeling. | |||||
BibTeX:
@article{elshall19a,
author = {Elshall, Ahmed S. and Ye, Ming and Niu, Guo-Yue and Barron-Gafford, Greg A.},
title = {Bayesian inference and predictive performance of soil respiration models in the presence of model discrepancy},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {12},
number = {5},
pages = {2009--2032},
note = {Query date: 2021-04-02 15:20:04},
url = {https://gmd.copernicus.org/articles/12/2009/2019/},
doi = {https://doi.org/10.5194/gmd-12-2009-2019}
}
|
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| Fadnavis, S., Kumar, K.R., Tiwari, Y.K. and Pozzoli, L. | Atmospheric CO2 source and sink patterns over the Indian region | {2016} | ANNALES GEOPHYSICAE Vol. {34}({2}), pp. 279-291 |
article | DOI |
| Abstract: In this paper we examine CO2 emission hot spots and sink regions over India as identified from global model simulations during the period 2000-2009. CO2 emission hot spots overlap with locations of densely clustered thermal power plants, coal mines and other industrial and urban centres; CO2 sink regions coincide with the locations of dense forest. Fossil fuel CO2 emissions are compared with two bottom-up inventories: the Regional Emission inventories in ASia (REAS v1.11; 2000-2009) and the Emission Database for Global Atmospheric Research (EDGAR v4.2) (2000-2009). Estimated fossil fuel emissions over the hot spot region are similar to 500-950 gCm(-2) yr(-1) as obtained from the global model simulation, EDGAR v4.2 and REAS v1.11 emission inventory. Simulated total fluxes show increasing trends, from 1.39 +/- 1.01% yr(-1) (19.8 +/- 1.9 TgC yr(-1)) to 6.7 +/- 0.54% yr(-1) (97 +/- 12 TgC yr(-1)) over the hot spot regions and decreasing trends of -0.95 +/- 1.51% yr(-1) (-1 +/- 2 TgC yr(-1)) to 5.7 +/- 2.89% yr(-1) (-2.3 +/- 2 TgC yr(-1)) over the sink regions. Model-simulated terrestrial ecosystem fluxes show decreasing trends (increasing CO2 uptake) over the sink regions. Decreasing trends in terrestrial ecosystem fluxes imply that forest cover is increasing, which is consistent with India State of Forest Report (2009). Fossil fuel emissions show statistically significant increasing trends in all the data sets considered in this study. Estimated trend in simulated total fluxes over the Indian region is similar to 4.72 +/- 2.25% yr(-1) (25.6 TgC yr(-1)) which is slightly higher than global growth rate similar to 3.1%yr(-1) during 2000-2010. |
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BibTeX:
@article{fadnavis16a,
author = {Fadnavis, Suvarna and Kumar, K. Ravi and Tiwari, Yogesh K. and Pozzoli, Luca},
title = {Atmospheric CO2 source and sink patterns over the Indian region},
journal = {ANNALES GEOPHYSICAE},
year = {2016},
volume = {34},
number = {2},
pages = {279--291},
doi = {https://doi.org/10.5194/angeo-34-279-2016}
}
|
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| Fang, S.X., Zhou, L.X., Tans, P.P., Ciais, P., Steinbacher, M., Xu, L. and Luan, T. | In situ measurement of atmospheric CO2 at the four WMO/GAW stations in China | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({5}), pp. 2541-2554 |
article | DOI |
| Abstract: Atmospheric carbon dioxide (CO2) mole fractions were continuously measured from January 2009 to December 2011 at four atmospheric observatories in China using cavity ring-down spectroscopy instruments. The stations are Lin'an (LAN), Longfengshan (LFS), Shangdianzi (SDZ), and Waliguan (WLG), which are regional (LAN, LFS, SDZ) or global (WLG) measurement stations of the World Meteorological Organization's Global Atmosphere Watch program (WMO/ GAW). LAN is located near the megacity of Shanghai, in China's economically most developed region. LFS is in a forest and rice production area, close to the city of Harbin in northeastern China. SDZ is located 150 km northeast of Beijing. WLG, hosting the longest record of measured CO2 mole fractions in China, is a high-altitude site in northwestern China recording background CO2 concentration. The CO2 growth rates are 3.7 +/- 1.2 ppm yr(-1) for LAN, 2.7 +/- 0.8 ppm yr(-1) for LFS, 3.5 +/- 1.6 ppm yr(-1) for SDZ, and 2.2 +/- 0.8 ppm yr(-1) (1 sigma ) for WLG during the period of 2009 to 2011. The highest annual mean CO2 mole fraction of 404.2 +/- 3.9 ppm was observed at LAN in 2011. A comprehensive analysis of CO2 variations, their diurnal and seasonal cycles as well as the analysis of the influence of local sources on the CO2 mole fractions allows a characterization of the sampling sites and of the key processes driving the CO2 mole fractions. These data form a basis to improve our understanding of atmospheric CO2 variations in China and the underlying fluxes using atmospheric inversion models. |
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BibTeX:
@article{fang14a,
author = {Fang, S. X. and Zhou, L. X. and Tans, P. P. and Ciais, P. and Steinbacher, M. and Xu, L. and Luan, T.},
title = {In situ measurement of atmospheric CO2 at the four WMO/GAW stations in China},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {5},
pages = {2541--2554},
doi = {https://doi.org/10.5194/acp-14-2541-2014}
}
|
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| Fang, Y., Michalak, A.M., Shiga, Y.P. and Yadav, V. | Using atmospheric observations to evaluate the spatiotemporal variability of CO2 fluxes simulated by terrestrial biospheric models | {2014} | BIOGEOSCIENCES Vol. {11}({23}), pp. 6985-6997 |
article | DOI |
| Abstract: Terrestrial biospheric models (TBMs) are used to extrapolate local observations and process-level understanding of land-atmosphere carbon exchange to larger regions, and serve as predictive tools for examining carbon-climate interactions. Understanding the performance of TBMs is thus crucial to the carbon cycle and climate science communities. In this study, we present and assess an approach to evaluating the spatiotemporal patterns, rather than aggregated magnitudes, of net ecosystem exchange (NEE) simulated by TBMs using atmospheric CO2 measurements. The approach is based on statistical model selection implemented within a high-resolution atmospheric inverse model. Using synthetic data experiments, we find that current atmospheric observations are sensitive to the underlying spatiotemporal flux variability at sub-biome scales for a large portion of North America, and that atmospheric observations can therefore be used to evaluate simulated spatiotemporal flux patterns as well as to differentiate between multiple competing TBMs. Experiments using real atmospheric observations and four prototypical TBMs further confirm the applicability of the method, and demonstrate that the performance of TBMs in simulating the spatiotemporal patterns of NEE varies substantially across seasons, with best performance during the growing season and more limited skill during transition seasons. This result is consistent with previous work showing that the ability of TBMs to model flux magnitudes is also seasonally-dependent. Overall, the proposed approach provides a new avenue for evaluating TBM performance based on sub-biome-scale flux patterns, presenting an opportunity for assessing and informing model development using atmospheric observations. |
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BibTeX:
@article{fang14b,
author = {Fang, Y. and Michalak, A. M. and Shiga, Y. P. and Yadav, V.},
title = {Using atmospheric observations to evaluate the spatiotemporal variability of CO2 fluxes simulated by terrestrial biospheric models},
journal = {BIOGEOSCIENCES},
year = {2014},
volume = {11},
number = {23},
pages = {6985--6997},
doi = {https://doi.org/10.5194/bg-11-6985-2014}
}
|
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| Fang, Y. and Michalak, A.M. | Atmospheric observations inform CO2 flux responses to enviroclimatic drivers | {2015} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {29}({5}), pp. 555-566 |
article | DOI |
| Abstract: Understanding the response of the terrestrial biospheric carbon cycle to variability in enviroclimatic drivers is critical for predicting climate-carbon interactions. Here we apply an atmospheric-inversion-based framework to assess the relationships between the spatiotemporal patterns of net ecosystem CO2 exchange (NEE) and those of enviroclimatic drivers. We show that those relationships can be directly observed at 1 degrees x1 degrees 3-hourly resolution from atmospheric CO2 measurements for four of seven large biomes in North America, namely, (i) boreal forests and taiga; (ii) temperate coniferous forests; (iii) temperate grasslands, savannas, and shrublands; and (iv) temperate broadleaf and mixed forests. We find that shortwave radiation plays a dominant role during the growing season over all four biomes. Specific humidity and precipitation also play key roles and are associated with decreased CO2 uptake (or increased release). The explanatory power of specific humidity is especially strong during transition seasons, while that of precipitation appears during both the growing and dormant seasons. We further find that the ability of four prototypical terrestrial biospheric models (TBMs) to represent the spatiotemporal variability of NEE improves as the influence of radiation becomes more dominant, implying that TBMs have a better skill in representing the impact of radiation relative to other drivers. Even so, we show that TBMs underestimate the strength of the relationship to radiation and do not fully capture its seasonality. Furthermore, the TBMs appear to misrepresent the relationship to precipitation and specific humidity at the examined scales, with relationships that are not consistent in terms of sign, seasonality, or significance relative to observations. More broadly, we demonstrate the feasibility of directly probing relationships between NEE and enviroclimatic drivers at scales with no direct measurements of NEE, opening the door to the study of emergent processes across scales and to the evaluation of their scaling within TBMs. |
|||||
BibTeX:
@article{fang15a,
author = {Fang, Yuanyuan and Michalak, Anna M.},
title = {Atmospheric observations inform CO2 flux responses to enviroclimatic drivers},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2015},
volume = {29},
number = {5},
pages = {555--566},
doi = {https://doi.org/10.1002/2014GB005034}
}
|
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| Feldman, D.R., Collins, W.D., Gero, P.J., Torn, M.S., Mlawer, E.J. and Shippert, T.R. | Observational determination of surface radiative forcing by CO2 from 2000 to 2010 | {2015} | NATURE Vol. {519}({7543}), pp. {339+} |
article | DOI |
| Abstract: The climatic impact of CO2 and other greenhouse gases is usually quantified in terms of radiative forcing', calculated as the difference between estimates of the Earth's radiation field from pre-industrial and presentday concentrations of these gases. Radiative transfer models calculate that the increase in CO2 since 1750 corresponds to a global annualmean radiative forcing at the tropopause of 1.82 +/- 0.19W m(-2) (ref. 2). However, despite widespread scientific discussion and modelling of the climate impacts of well-mixed greenhouse gases, there is little direct observational evidence of the radiative impact of increasing atmospheric CO2. Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2. The time series of this forcing at the two locations the Southern Great Plains and the North Slope of Alaska are derived from Atmospheric Emitted Radiance Interferometer spectra' together with ancillary measurements and thoroughly corroborated radiative transfer calculations'. The time series both show statistically significant trends of 0.2 W m(-2) per decade (with respective uncertainties of +/- 0.06 W m(-2) per decade and 0.07 W m(-2) per decade) and have seasonal ranges of 0.1-0.2W m(-2). This is approximately ten per cent of the trend in downwelling longwave radiation'''. These results confirm theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions, and provide empirical evidence of how rising CO2 levels, mediated by temporal variations due to photosynthesis and respiration, are affecting the surface energy balance. |
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BibTeX:
@article{feldman15a,
author = {Feldman, D. R. and Collins, W. D. and Gero, P. J. and Torn, M. S. and Mlawer, E. J. and Shippert, T. R.},
title = {Observational determination of surface radiative forcing by CO2 from 2000 to 2010},
journal = {NATURE},
year = {2015},
volume = {519},
number = {7543},
pages = {339+},
doi = {https://doi.org/10.1038/nature14240}
}
|
|||||
| Feldman, D.R., Collins, W.D., Biraud, S.C., Risser, M.D., Turner, D.D., Gero, P.J., Tadic, J., Helmig, D., Xie, S., Mlawer, E.J., Shippert, T.R. and Torn, M.S. | Observationally derived rise in methane surface forcing mediated by water vapour trends | {2018} | NATURE GEOSCIENCE Vol. {11}({4}), pp. {238+} |
article | DOI |
| Abstract: Atmospheric methane (CH4) mixing ratios exhibited a plateau between 1995 and 2006 and have subsequently been increasing. While there are a number of competing explanations for the temporal evolution of this greenhouse gas, these prominent features in the temporal trajectory of atmospheric CH4 are expected to perturb the surface energy balance through radiative forcing, largely due to the infrared radiative absorption features of CH4. However, to date this has been determined strictly through radiative transfer calculations. Here, we present a quantified observation of the time series of clear-sky radiative forcing by CH4 at the surface from 2002 to 2012 at a single site derived from spectroscopic measurements along with line-by-line calculations using ancillary data. There was no significant trend in CH4 forcing between 2002 and 2006, but since then, the trend in forcing was 0.026 +/- 0.006 (99.7% CI) W m(2) yr(-1). The seasonal-cycle amplitude and secular trends in observed forcing are influenced by a corresponding seasonal cycle and trend in atmospheric CH4. However, we find that we must account for the overlapping absorption effects of atmospheric water vapour (H2O) and CH4 to explain the observations fully. Thus, the determination of CH4 radiative forcing requires accurate observations of both the spatiotemporal distribution of CH4 and the vertically resolved trends in H2O. |
|||||
BibTeX:
@article{feldman18a,
author = {Feldman, D. R. and Collins, W. D. and Biraud, S. C. and Risser, M. D. and Turner, D. D. and Gero, P. J. and Tadic, J. and Helmig, D. and Xie, S. and Mlawer, E. J. and Shippert, T. R. and Torn, M. S.},
title = {Observationally derived rise in methane surface forcing mediated by water vapour trends},
journal = {NATURE GEOSCIENCE},
year = {2018},
volume = {11},
number = {4},
pages = {238+},
doi = {https://doi.org/10.1038/s41561-018-0085-9}
}
|
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| Feltz, M.L., Knuteson, R.O. and Revercomb, H.E. | Assessment of COSMIC radio occultation and AIRS hyperspectral IR sounder temperature products in the stratosphere using observed radiances | {2017} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {122}({16}), pp. 8593-8616 |
article | DOI |
| Abstract: Upper air temperature is defined as an essential climate variable by the World Meteorological Organization. Two remote sensing technologies being promoted for monitoring stratospheric temperatures are GPS radio occultation (RO) and spectrally resolved IR radiances. This study assesses RO and hyperspectral IR sounder derived temperature products within the stratosphere by comparing IR spectra calculated from GPS RO and IR sounder products to coincident IR observed radiances, which are used as a reference standard. RO dry temperatures from the University Corporation for Atmospheric Research (UCAR) Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission are compared to NASA Atmospheric Infrared Sounder (AIRS) retrievals using a previously developed profile-to-profile collocation method and vertical temperature averaging kernels. Brightness temperatures (BTs) are calculated for both COSMIC and AIRS temperature products and are then compared to coincident AIRS measurements. The COSMIC calculated minus AIRS measured BTs exceed the estimated 0.5 K measurement uncertainty for the winter time extratropics around 35 hPa. These differences are attributed to seasonal UCAR COSMIC biases. Unphysical vertical oscillations are seen in the AIRS L2 temperature product in austral winter Antarctic regions, and results imply a small AIRS tropical warm bias around similar to 35 hPa in the middle stratosphere. |
|||||
BibTeX:
@article{feltz17a,
author = {Feltz, M. L. and Knuteson, R. O. and Revercomb, H. E.},
title = {Assessment of COSMIC radio occultation and AIRS hyperspectral IR sounder temperature products in the stratosphere using observed radiances},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2017},
volume = {122},
number = {16},
pages = {8593--8616},
doi = {https://doi.org/10.1002/2017JD026704}
}
|
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| Feng, S., Lauvaux, T., Davis, K., Keller, K. and ... | Seasonal Characteristics of Model Uncertainties From Biogenic Fluxes, Transport, and Large‐Scale Boundary Inflow in Atmospheric CO2 Simulations Over North … | 2019 | Journal of Geophysical Research: Atmospheres | article | URL |
| Abstract: Regional estimates of biogenic carbon fluxes over North America from both atmospheric inversions (``top‐down'' approach) and terrestrial biosphere models (``bottom‐up'') remain highly uncertain. We merge these approaches with an ensemble‐based, regional modeling … | |||||
BibTeX:
@article{feng19a,
author = {S Feng and T Lauvaux and KJ Davis and K Keller and ...},
title = {Seasonal Characteristics of Model Uncertainties From Biogenic Fluxes, Transport, and Large‐Scale Boundary Inflow in Atmospheric CO2 Simulations Over North …},
journal = {Journal of Geophysical Research: Atmospheres},
publisher = {Wiley Online Library},
year = {2019},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD031165}
}
|
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| Feng, S., Lauvaux, T., Keller, K., Davis, K. and ... | A road map for improving the treatment of uncertainties in high‐resolution regional carbon flux inverse estimates | 2019 | Geophysical Research Letters | article | URL |
| Abstract: Atmospheric inversions allow us to estimate the terrestrial carbon sink by combining atmospheric observations with atmospheric transport models. However, these inverse estimates remain highly uncertain. Here we quantify uncertainties in simulations of North … | |||||
BibTeX:
@article{feng19b,
author = {S Feng and T Lauvaux and K Keller and KJ Davis and ...},
title = {A road map for improving the treatment of uncertainties in high‐resolution regional carbon flux inverse estimates},
journal = {Geophysical Research Letters},
year = {2019},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082987}
}
|
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| Feng, S., Jiang, F., Wu, Z., Wang, H., Ju, W. and Wang, H. | CO Emissions Inferred From Surface CO Observations Over China in December 2013 and 2017 | {2020} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {125}({7}) |
article | DOI URL |
| Abstract: China has implemented active clean air policies in recent years, and the spatiotemporal patterns of major pollutant emissions have changed substantially. In this study, we construct a regional air pollution data assimilation system based on the WRF/CMAQ model and ensemble Kalman filter algorithm to quantitatively optimize gridded CO emissions using hourly surface CO measurements over China. The Multi-resolution Emission Inventory of China CO emission inventories in December 2012 and 2016 are treated as prior emissions, and the CO emissions in December 2013 and 2017 are optimized using the CO observations of December of 2013 and 2017, respectively. The results show that in both periods, assimilation of CO observations significantly improves the CO simulations and emission estimates. Assimilation increases the CO emissions in most areas of mainland China, especially in northern China, and the spatial patterns of the increases in the two periods are similar. Overall, the posterior CO emissions in December 2017 are 17% lower than those in December 2013. Large emission decreases are mainly found in most key urban areas and developed regions, and emission increases are mainly located in their surrounding areas and certain central and western regions, which might reflect the emission migration from developed regions or urban areas to developing regions or surrounding areas. These changes are not found in the prior emissions but are basically consistent with the emission control strategies and industrial transformation and upgrade phenomena in recent years, indicating that our CO assimilation system could successfully capture the temporal and spatial variations. | |||||
BibTeX:
@article{feng20a,
author = {Feng, Shuzhuang and Jiang, Fei and Wu, Zheng and Wang, Hengmao and Ju, Weimin and Wang, Haikun},
title = {CO Emissions Inferred From Surface CO Observations Over China in December 2013 and 2017},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {125},
number = {7},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD031808},
doi = {https://doi.org/10.1029/2019JD031808}
}
|
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| Feng, S., Lauvaux, T., Williams, C.A., Davis, K.J., Zhou, Y., Baker, I., Barkley, Z.R. and Wesloh, D. | Joint CO2 Mole Fraction and Flux Analysis Confirms Missing Processes in CASA Terrestrial Carbon Uptake Over North America | 2021 | GLOBAL BIOGEOCHEMICAL CYCLES Vol. 35(7) |
article | DOI |
| Abstract: Terrestrial biosphere models (TBMs) play a key role in the detection and attribution of carbon cycle processes at local to global scales and in projections of the coupled carbon-climate system. TBM evaluation commonly involves direct comparison to eddy-covariance flux measurements. We use atmospheric CO2 mole fraction ([CO2]) measured in situ from aircraft and tower, in addition to flux-measurements from summer 2016 to evaluate the Carnegie-Ames-Stanford-Approach (CASA) TBM. WRF-Chem is used to simulate [CO2] using biogenic CO2 fluxes from a CASA parameter-based ensemble and CarbonTracker version 2017 (CT2017) in addition to transport and CO2 boundary condition ensembles. The resulting ``super ensemble'' of modeled [CO2] demonstrates that the biosphere introduces the majority of uncertainty to the simulations. Both aircraft and tower [CO2] data show that the CASA ensemble net ecosystem exchange (NEE) of CO2 is biased high (NEE too positive) and identify the maximum light use efficiency E-max a key parameter that drives the spread of the CASA ensemble in summer 2016. These findings are verified with flux-measurements. The direct comparison of the CASA flux ensemble with flux-measurements confirms missing sink processes in CASA. Separating the daytime and nighttime flux, we discover that the underestimated net uptake results from missing sink processes that result in overestimation of respiration. NEE biases are smaller in the CT2017 posterior biogenic fluxes, which assimilate observed [CO2]. Flux tower analyses reveal an unrealistic overestimation of nighttime respiration in CT2017 which we attribute to limited flexibility in the inversion strategy. |
|||||
BibTeX:
@article{feng21a,
author = {Feng, Sha and Lauvaux, Thomas and Williams, Christopher A. and Davis, Kenneth J. and Zhou, Yu and Baker, Ian and Barkley, Zachary R. and Wesloh, Daniel},
title = {Joint CO2 Mole Fraction and Flux Analysis Confirms Missing Processes in CASA Terrestrial Carbon Uptake Over North America},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2021},
volume = {35},
number = {7},
doi = {https://doi.org/10.1029/2020GB006914}
}
|
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| Feng, S., Jiang, F., Wang, H., Shen, Y., Zheng, Y., Zhang, L., Lou, C. and Ju, W. | Anthropogenic emissions estimated using surface observations and their impacts on PM2.5 source apportionment over the Yangtze River Delta, China | 2022 | SCIENCE OF THE TOTAL ENVIRONMENT Vol. 828 |
article | DOI |
| Abstract: Source-tagged source apportionment (SA) has advantages for quantifying the contribution of various source regions and categories to PM2.5; however, it is highly affected by uncertainty in the emission inventory. In this study, we used a Regional multi-Air Pollutant Assimilation System (RAPAS) to optimize daily SO2, NOx and primary PM2.5 (PPM2.5) emissions in the Yangtze River Delta (YRD) in December 2016 by assimilating hourly in-situ measurements. The CMAQ-ISAM model was implemented with prior and posterior emissions respectively to investigate the impacts of optimizing emissions on PM2.5 SA in the YRD megalopolis (YRDM) and three megacities of Shanghai, Nanjing, and I langzhou in the YRDM. The results showed that RAPAS significantly improved the simulations and reduced the emission uncertainties of the different pollutants. Compared with prior emissions, the posterior emissions in the YRD decreased by 13% and 11% for SO2 and NOx respectively, and increased by 24% for PPM2.5. Compared with SA using prior emissions, the contributions from Hangzhou, northern Zhejiang, and areas outside of the YRD to the YRDM increased. The local contributions from the YRDM, Nanjing and Shanghai decreased by L8%, 9.7%, and 2.3%, respectively, whereas that of Hangzhou increased by 5.6%. The changes in the daily local contributions caused by optimizing emissions ranged from - 18.0% to 23.6%. Generally, under stable weather conditions, the local contribution changed the most, whereas under unstable weather conditions, the contribution from upwind areas changed significantly. Overall, with optimized emissions, we found in Nanjing, Shanghai, and Hangzhou, local emissions contributed 18.2%, 39.6% and 36.8% of their PM2.5 concentrations, respectively; long-range transport from outside the YRDM contributed 59.2%, 48.1%, and 48.2%, respectively. This study emphasizes the importance of improving emission estimations for source-tagged SA and provides more reliable SA results for the main cities in the YRD, which will contribute to pollution control in these regions. |
|||||
BibTeX:
@article{feng22a,
author = {Feng, Shuzhuang and Jiang, Fei and Wang, Hengmao and Shen, Yang and Zheng, Yanhua and Zhang, Lingyu and Lou, Chenxi and Ju, Weimin},
title = {Anthropogenic emissions estimated using surface observations and their impacts on PM2.5 source apportionment over the Yangtze River Delta, China},
journal = {SCIENCE OF THE TOTAL ENVIRONMENT},
year = {2022},
volume = {828},
doi = {https://doi.org/10.1016/j.scitotenv.2022.154522}
}
|
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| Fernando, A.M. | Trend Analyses of the Abundances of Atmospheric Molecules | 2020 | School: OLD DOMINION UNIVERSITY | phdthesis | URL |
| Abstract: A new line list for the A 3 Π-X 3 Σ-electronic transition of NH has been prepared using line positions from the literature and calculated line intensities. High level ab initio calculations were performed with the MOLPRO program to obtain the AX transition dipole moment … | |||||
BibTeX:
@phdthesis{fernando20a,
author = {Anton M. Fernando},
title = {Trend Analyses of the Abundances of Atmospheric Molecules},
school = {OLD DOMINION UNIVERSITY},
year = {2020},
url = {https://digitalcommons.odu.edu/physics_etds/125/}
}
|
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| Flower, C.E. and Gonzalez-Meler, M.A. | Responses of Temperate Forest Productivity to Insect and Pathogen Disturbances | {2015} | Vol. {66}ANNUAL REVIEW OF PLANT BIOLOGY, VOL 66, pp. 547-569 |
incollection | DOI |
| Abstract: Pest and pathogen disturbances are ubiquitous across forest ecosystems, impacting their species composition, structure, and function. Whereas severe abiotic disturbances (e.g., clear-cutting and fire) largely reset successional trajectories, pest and pathogen disturbances cause diffuse mortality, driving forests into nonanalogous system states. Biotic perturbations that disrupt forest carbon dynamics either reduce or enhance net primary production (NPP) and carbon storage, depending on pathogen type. Relative to defoliators, wood borers and invasive pests have the largest negative impact on NPP and the longest recovery time. Forest diversity is an important contributing factor to productivity: NPP is neutral, marginally enhanced, or reduced in high-diversity stands in which a small portion of the canopy is affected (temperate deciduous or mixed forests) but very negative in low-diversity stands in which a large portion of the canopy is affected (western US forests). Pests and pathogens reduce forest structural and functional redundancy, affecting their resilience to future climate change or new outbreaks. Therefore, pests and pathogens can be considered biotic forcing agents capable of causing consequences of similar magnitude to climate forcing factors. |
|||||
BibTeX:
@incollection{flower15a,
author = {Flower, Charles E. and Gonzalez-Meler, Miquel A.},
title = {Responses of Temperate Forest Productivity to Insect and Pathogen Disturbances},
booktitle = {ANNUAL REVIEW OF PLANT BIOLOGY, VOL 66},
publisher = {Annual Reviews},
year = {2015},
volume = {66},
pages = {547--569},
doi = {https://doi.org/10.1146/annurev-arplant-043014-115540}
}
|
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| Font, A., Morgui, J.A., Curcoll, R., Pouchet, I., Casals, I. and Rodo, X. | Daily carbon surface fluxes in the West Ebre (Ebro) watershed from aircraft profiling on late June 2007 | {2010} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {62}({5, SI}), pp. 427-440 |
article | DOI |
| Abstract: An intensive aircraft campaign measuring atmospheric CO(2) mixing ratios was carried out in the central part of the Ebre watershed on late June 2007 to characterize the CO(2) dynamics in the Ebre basin and to calculate the regional cumulative carbon surface flux. CO(2) concentrations were obtained from vertical profiles over La Muela (LMU; 41.60 degrees N, 1.1 degrees W) from 900 to 4000 m above the sea level (masl), horizontal transects at similar to 2000 m 100 km west from LMU, and continuous measurements at similar to 650 masl. Different estimates of surface flux from changes in the convective boundary layer (CBL) CO(2) concentration were obtained following the Integral CBL budgeting equation (ICBL) and the carbon content integration (CCI) method. Values of the mean surface flux calculated from the different approaches range from -2.4 to -7.9 mu molCO(2)/m2s. Regional surface flux calculated from vertical profiling appears to be consistent in a distance of 70 km away from the measurement site. The ICBL method is very sensitive to the accurate determination of the concentration in the entrainment zone. The overall uncertainty from fluxes calculated from the ICBL method rises to a value of 70%, whereas the uncertainty linked to the CCI method is 55%. |
|||||
BibTeX:
@article{font10a,
author = {Font, A. and Morgui, J. -A. and Curcoll, R. and Pouchet, I. and Casals, I. and Rodo, X.},
title = {Daily carbon surface fluxes in the West Ebre (Ebro) watershed from aircraft profiling on late June 2007},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2010},
volume = {62},
number = {5, SI},
pages = {427--440},
doi = {https://doi.org/10.1111/j.1600-0889.2010.00469.x}
}
|
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| Font, A., Morgui, J.A. and Rodo, X. | Assessing the regional surface influence through Backward Lagrangian Dispersion Models for aircraft CO2 vertical profiles observations in NE Spain | {2011} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {11}({4}), pp. 1659-1670 |
article | DOI |
| Abstract: In this study the differences in the measured atmospheric CO2 mixing ratio at three aircraft profiling sites in NE Spain separated by 60 km are analyzed in regard to the variability of the surface fluxes in the regional surface influence area. First, the Regional Potential Surface Influence (RPSI) for fifty-one days in 2006 is calculated to assess the vertical, horizontal and temporal extent of the surface influence for the three sites at the regional scale (10(4) km(2)) at different altitudes of the profile (600, 1200, 2500 and 4000 meters above the sea level, ma.s.l.). Second, three flights carried out in 2006 (7 February, 24 August and 29 November) following the Crown Atmospheric Sampling (CAS) design are presented to study the relation between the measured CO2 variability and the Potential Surface Influence (PSI) and RPSI concepts. At 600 and 1200 ma.s.l. the regional signal is confined up to 50 h before the measurements whereas at higher altitudes (2500 and 4000 ma.s.l.) the regional surface influence is only recovered during spring and summer months. The RPSI from sites separated by similar to 60 km overlap by up to 70% of the regional surface influence at 600 and 1200 ma.s.l., while the overlap decreases to 10-40% at higher altitudes (2500 and 4000 ma.s.l.). The scale of the RPSI area is suitable to understand the differences in the measured CO2 concentration in the three vertices of the CAS, as CO2 differences are attributed to local surrounding fluxes (February) or to the variability of regional surface influence as for the August and November flights. For these two flights, the variability in the regional scale influences the variability measured in the local scale. The CAS sampling design for aircraft measurements appears to be a suitable method to cope with the variability of a typical grid for inversion models as measurements are intensified within the PBL and the background concentration is measured every similar to 10(2) km. |
|||||
BibTeX:
@article{font11a,
author = {Font, A. and Morgui, J. -A. and Rodo, X.},
title = {Assessing the regional surface influence through Backward Lagrangian Dispersion Models for aircraft CO2 vertical profiles observations in NE Spain},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
volume = {11},
number = {4},
pages = {1659--1670},
doi = {https://doi.org/10.5194/acp-11-1659-2011}
}
|
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| Forbes, S.J., Cernusak, L.A., Northfield, T.D., Gleadow, R.M., Lambert, S. and Cheesman, A.W. | Elevated temperature and carbon dioxide alter resource allocation to growth, storage and defence in cassava (Manihot esculenta) | {2020} | ENVIRONMENTAL AND EXPERIMENTAL BOTANY Vol. {173} |
article | DOI URL |
| Abstract: Rising atmospheric CO2 concentrations and global warming can alter how plants partition their resources. This is important for food crops through changes in resource allocation to edible tissues and toxic defence compounds. While research suggests elevated temperature and [CO2] independently drive changes in plant metabolism and stress levels, and photosynthetic rates, respectively, it is less clear how these environmental changes impact plants when combined. Cassava is an important dietary staple for many developing nations. However, the safety of cassava depends on cyanogenic glucoside concentrations. In a climate-controlled greenhouse, the effects of elevated temperature in the presence and absence of elevated [CO2] on the growth, physiology and chemical defence of cassava at two growth stages were examined. Growth in cassava was initially increased by elevated temperature. However, across time, simultaneous elevated [CO2] led to an increasing biomass advantage over plants grown at ambient [CO2] and temperature. Elevated temperature and [CO2] also significantly increased tuber initiation and early tuber expansion. Tuber and leaf cyanide concentrations were significantly reduced under elevated temperature, while elevated temperature and [CO2] produced tuber cyanide concentrations similar to the higher levels found in plants grown at ambient conditions. The findings highlight how future climate change may impact both cassava production and quality. | |||||
BibTeX:
@article{forbes20a,
author = {Forbes, Samantha J. and Cernusak, Lucas A. and Northfield, Tobin D. and Gleadow, Roslyn M. and Lambert, Smilja and Cheesman, Alexander W.},
title = {Elevated temperature and carbon dioxide alter resource allocation to growth, storage and defence in cassava (Manihot esculenta)},
journal = {ENVIRONMENTAL AND EXPERIMENTAL BOTANY},
publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
year = {2020},
volume = {173},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S009884722030023X},
doi = {https://doi.org/10.1016/j.envexpbot.2020.103997}
}
|
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| Forster, F. | Verfahren zur hochgenauen Ableitung von Methan-Säü̈r die Satellitenvalidierung und Trendanalyse | 2019 | School: Universität Augsburg | phdthesis | URL |
| Abstract: Page 1. Frank Forster Verfahren zur hochgenauen Ableitung von Methan-Säulengehalten mit der solaren FTIR-Spektrometrie im mittleren Infrarotbereich: Nutzung für die Satellitenvalidierung und Trendanalyse 96 98 00 02 04 06 08 10 12 Garmisch b) X C H 4 (ppb) X C H 4 (ppb) a) … | |||||
BibTeX:
@phdthesis{forster19a,
author = {Frank Forster},
title = {Verfahren zur hochgenauen Ableitung von Methan-Säü̈r die Satellitenvalidierung und Trendanalyse},
school = {Universität Augsburg},
year = {2019},
url = {https://opus.bibliothek.uni-augsburg.de/opus4/files/47800/Forster_Diss.pdf}
}
|
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| Foucher, P.Y., Chedin, A., Armante, R., Boone, C., Crevoisier, C. and Bernath, P. | Carbon dioxide atmospheric vertical profiles retrieved from space observation using ACE-FTS solar occultation instrument | {2011} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {11}({6}), pp. 2455-2470 |
article | DOI |
| Abstract: Major limitations of our present knowledge of the global distribution of CO2 in the atmosphere are the uncertainty in atmospheric transport and the sparseness of in situ concentration measurements. Limb viewing spaceborne sounders such as the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) offer a vertical resolution of a few kilometres for profiles, which is much better than currently flying or planned nadir sounding instruments can achieve. After having demonstrated the feasibility of obtaining CO2 vertical profiles in the 5-25 km altitude range with an accuracy of about 2 ppm in a previous study, we present here the results of five years of ACE-FTS observations in terms of monthly mean profiles of CO2 averaged over 10 degrees latitude bands for northern mid-latitudes. These results are compared with in-situ aircraft measurements and with simulations from two different air transport models. Key features of the measured altitude distribution of CO2 are shown to be accurately reproduced by the ACE-FTS retrievals: variation in altitude of the seasonal cycle amplitude and extrema, seasonal change of the vertical gradient, and mean growth rate. We show that small but significant differences from model simulations could result from an over estimation of the model circulation strength during the northern hemisphere spring. Coupled with column measurements from a nadir viewing instrument, it is expected that occultation measurements will bring useful constraints to the surface carbon flux determination. |
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BibTeX:
@article{foucher11a,
author = {Foucher, P. Y. and Chedin, A. and Armante, R. and Boone, C. and Crevoisier, C. and Bernath, P.},
title = {Carbon dioxide atmospheric vertical profiles retrieved from space observation using ACE-FTS solar occultation instrument},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
volume = {11},
number = {6},
pages = {2455--2470},
doi = {https://doi.org/10.5194/acp-11-2455-2011}
}
|
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| Frankenberg, C., Bergamaschi, P., Butz, A., Houweling, S., Meirink, J.F., Notholt, J., Petersen, A.K., Schrijver, H., Warneke, T. and Aben, I. | Tropical methane emissions: A revised view from SCIAMACHY onboard ENVISAT | {2008} | GEOPHYSICAL RESEARCH LETTERS Vol. {35}({15}) |
article | DOI |
| Abstract: Methane retrievals from near-infrared spectra recorded by the SCIAMACHY instrument onboard ENVISAT hitherto suggested unexpectedly large tropical emissions. Even though recent studies confirm substantial tropical emissions, there were indications for an unresolved error in the satellite retrievals. Here we identify a retrieval error related to inaccuracies in water vapor spectroscopic parameters, causing a substantial overestimation of methane correlated with high water vapor abundances. We report on the overall implications of an update in water spectroscopy on methane retrievals with special focus on the tropics where the impact is largest. The new retrievals are applied in a four-dimensional variational (4D-VAR) data assimilation system to derive a first estimate of the impact on tropical CH(4) sources. Compared to inversions based on previous SCIAMACHY retrievals, annual tropical emission estimates are reduced from 260 to about 201 Tg CH(4) but still remain higher than previously anticipated. |
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BibTeX:
@article{frankenberg08a,
author = {Frankenberg, Christian and Bergamaschi, Peter and Butz, Andre and Houweling, Sander and Meirink, Jan Fokke and Notholt, Justus and Petersen, Anna Katinka and Schrijver, Hans and Warneke, Thorsten and Aben, Ilse},
title = {Tropical methane emissions: A revised view from SCIAMACHY onboard ENVISAT},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2008},
volume = {35},
number = {15},
doi = {https://doi.org/10.1029/2008GL034300}
}
|
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| Frankenberg, C., Aben, I., Bergamaschi, P., Dlugokencky, E.J., van Hees, R., Houweling, S., van der Meer, P., Snel, R. and Tol, P. | Global column-averaged methane mixing ratios from 2003 to 2009 as derived from SCIAMACHY: Trends and variability | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: After a decade of stable or slightly decreasing global methane concentrations, ground-based in situ data show that CH4 began increasing again in 2007 and that this increase continued through 2009. So far, space-based retrievals sensitive to the lower troposphere in the time period under consideration have not been available. Here we report a long-term data set of column-averaged methane mixing ratios retrieved from spectra of the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) instrument onboard Envisat. The retrieval quality after 2005 was severely affected by degrading detector pixels within the methane 2v(3) absorption band. We identified the most crucial problems in SCIAMACHY detector degradation and overcame the problem by applying a strict pixel mask as well as a new dark current characterization. Even though retrieval precision after the end of 2005 is invariably degraded, consistent methane retrievals from 2003 through 2009 are now possible. Regional time series in the Sahara, Australia, tropical Africa, South America, and Asia show the methane increase in 2007-2009, but we cannot yet draw a firm conclusion concerning the origin of the increase. Tropical Africa even seems to exhibit a negative anomaly in 2006, but an impact from changes in SCIAMACHY detector degradation cannot be excluded yet. Over Assakrem, Algeria, we observed strong similarities between SCIAMACHY measurements and ground-based data in deseasonalized time series. We further show long-term SCIAMACHY xCH(4) averages at high spatial resolution that provide further insight into methane variations on regional scales. The Red Basin in China exhibits, on average, the highest methane abundance worldwide, while other localized features such as the Sudd wetlands in southern Sudan can also be identified in SCIAMACHY xCH(4) averages. |
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BibTeX:
@article{frankenberg11a,
author = {Frankenberg, C. and Aben, I. and Bergamaschi, P. and Dlugokencky, E. J. and van Hees, R. and Houweling, S. and van der Meer, P. and Snel, R. and Tol, P.},
title = {Global column-averaged methane mixing ratios from 2003 to 2009 as derived from SCIAMACHY: Trends and variability},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2010JD014849}
}
|
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| Frankenberg, C., Kulawik, S.S., Wofsy, S.C., Chevallier, F., Daube, B., Kort, E.A., O'Dell, C., Olsen, E.T. and Osterman, G. | Using airborne HIAPER Pole-to-Pole Observations (HIPPO) to evaluate model and remote sensing estimates of atmospheric carbon dioxide | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({12}), pp. 7867-7878 |
article | DOI |
| Abstract: In recent years, space-borne observations of atmospheric carbon dioxide (CO2) have been increasingly used in global carbon-cycle studies. In order to obtain added value from space-borne measurements, they have to suffice stringent accuracy and precision requirements, with the latter being less crucial as it can be reduced by just enhanced sample size. Validation of CO2 column-averaged dry air mole fractions (XCO2) heavily relies on measurements of the Total Carbon Column Observing Network (TCCON). Owing to the sparseness of the network and the requirements imposed on space-based measurements, independent additional validation is highly valuable. Here, we use observations from the High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) flights from 01/2009 through 09/2011 to validate CO2 measurements from satellites (Greenhouse Gases Observing Satellite - GOSAT, Thermal Emission Sounder - TES, Atmospheric Infrared Sounder - AIRS) and atmospheric inversion models (CarbonTracker CT2013B, Monitoring Atmospheric Composition and Climate (MACC) v13r1). We find that the atmospheric models capture the XCO2 variability observed in HIPPO flights very well, with correlation coefficients (r(2)) of 0.93 and 0.95 for CT2013B and MACC, respectively. Some larger discrepancies can be observed in profile comparisons at higher latitudes, in particular at 300aEuro-hPa during the peaks of either carbon uptake or release. These deviations can be up to 4aEuro-ppm and hint at misrepresentation of vertical transport. Comparisons with the GOSAT satellite are of comparable quality, with an r(2) of 0.85, a mean bias mu of -0.06aEuro-ppm, and a standard deviation sigma of 0.45aEuro-ppm. TES exhibits an r(2) of 0.75, mu of 0.34aEuro-ppm, and sigma of 1.13aEuro-ppm. For AIRS, we find an r(2) of 0.37, mu of 1.11aEuro-ppm, and sigma of 1.46aEuro-ppm, with latitude-dependent biases. For these comparisons at least 6, 20, and 50 atmospheric soundings have been averaged for GOSAT, TES, and AIRS, respectively. Overall, we find that GOSAT soundings over the remote Pacific Ocean mostly meet the stringent accuracy requirements of about 0.5aEuro-ppm for space-based CO2 observations. |
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BibTeX:
@article{frankenberg16a,
author = {Frankenberg, Christian and Kulawik, Susan S. and Wofsy, Steven C. and Chevallier, Frederic and Daube, Bruce and Kort, Eric A. and O'Dell, Christopher and Olsen, Edward T. and Osterman, Gregory},
title = {Using airborne HIAPER Pole-to-Pole Observations (HIPPO) to evaluate model and remote sensing estimates of atmospheric carbon dioxide},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {12},
pages = {7867--7878},
doi = {https://doi.org/10.5194/acp-16-7867-2016}
}
|
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| Fraser, A., Palmer, P.I., Feng, L., Boesch, H., Cogan, A., Parker, R., Dlugokencky, E.J., Fraser, P.J., Krummel, P.B., Langenfelds, R.L., O'Doherty, S., Prinn, R.G., Steele, L.P., van der Schoot, M. and Weiss, R.F. | Estimating regional methane surface fluxes: the relative importance of surface and GOSAT mole fraction measurements | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({11}), pp. 5697-5713 |
article | DOI |
| Abstract: We use an ensemble Kalman filter (EnKF), together with the GEOS-Chem chemistry transport model, to estimate regional monthly methane (CH4) fluxes for the period June 2009-December 2010 using proxy dry-air column-averaged mole fractions of methane (XCH4) from GOSAT (Greenhouse gases Observing SATellite) and/or NOAA ESRL (Earth System Research Laboratory) and CSIRO GASLAB (Global Atmospheric Sampling Laboratory) CH4 surface mole fraction measurements. Global posterior estimates using GOSAT and/or surface measurements are between 510-516 Tg yr(-1), which is less than, though within the uncertainty of, the prior global flux of 529 +/- 25 Tg yr(-1). We find larger differences between regional prior and posterior fluxes, with the largest changes in monthly emissions (75 Tg yr(-1)) occurring in Temperate Eurasia. In non-boreal regions the error reductions for inversions using the GOSAT data are at least three times larger (up to 45 %) than if only surface data are assimilated, a reflection of the greater spatial coverage of GOSAT, with the two exceptions of latitudes >60 degrees associated with a data filter and over Europe where the surface network adequately describes fluxes on our model spatial and temporal grid. We use CarbonTracker and GEOS-Chem XCO2 model output to investigate model error on quantifying proxy GOSAT XCH4 (involving model XCO2) and inferring methane flux estimates from surface mole fraction data and show similar resulting fluxes, with differences reflecting initial differences in the proxy value. Using a series of observing system simulation experiments (OSSEs) we characterize the posterior flux error introduced by non-uniform atmospheric sampling by GOSAT. We show that clear-sky measurements can theoretically reproduce fluxes within 10% of true values, with the exception of tropical regions where, due to a large seasonal cycle in the number of measurements because of clouds and aerosols, fluxes are within 15% of true fluxes. We evaluate our posterior methane fluxes by incorporating them into GEOS-Chem and sampling the model at the location and time of surface CH4 measurements from the AGAGE (Advanced Global Atmospheric Gases Experiment) network and column XCH4 measurements from TCCON (Total Carbon Column Observing Network). The posterior fluxes modestly improve the model agreement with AGAGE and TCCON data relative to prior fluxes, with the correlation coefficients (r(2)) increasing by a mean of 0.04 (range: -0.17 to 0.23) and the biases decreasing by a mean of 0.4 ppb (range: -8.9 to 8.4 ppb). |
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BibTeX:
@article{fraser13a,
author = {Fraser, A. and Palmer, P. I. and Feng, L. and Boesch, H. and Cogan, A. and Parker, R. and Dlugokencky, E. J. and Fraser, P. J. and Krummel, P. B. and Langenfelds, R. L. and O'Doherty, S. and Prinn, R. G. and Steele, L. P. and van der Schoot, M. and Weiss, R. F.},
title = {Estimating regional methane surface fluxes: the relative importance of surface and GOSAT mole fraction measurements},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {11},
pages = {5697--5713},
doi = {https://doi.org/10.5194/acp-13-5697-2013}
}
|
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| Freeman, N.M., Munro, D.R., Sprintall, J., Mazloff, M.R., Purkey, S., Rosso, I., DeRanek, C.A. and Sweeney, C. | The Observed Seasonal Cycle of Macronutrients in Drake Passage: Relationship to Fronts and Utility as a Model Metric | {2019} | JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS Vol. {124}({7}), pp. {4763-4783} |
article | DOI URL |
| Abstract: The Drake Passage Time-series (DPT) is used to quantify the spatial and seasonal variability of historically undersampled, biogeochemically relevant properties across the Drake Passage. From 2004-2017, discrete ship-based observations of surface macronutrients (silicate, nitrate, and phosphate), temperature, and salinity have been collected 5-8 times per year as part of the DPT program. Using the DPT and Antarctic Circumpolar Current (ACC) front locations derived from concurrent expendable bathythermograph data, the distinct physical and biogeochemical characteristics of ACC frontal zones are characterized. Biogeochemical-Argo floats in the region confirm that the near-surface sampling scheme of the DPT robustly captures mixed-layer biogeochemistry. While macronutrient concentrations consistently increase toward the Antarctic continent, their meridional distribution, variability, and biogeochemical gradients are unique across physical ACC fronts, suggesting a combination of physical and biological processes controlling nutrient availability and nutrient front location. The Polar Front is associated with the northern expression of the Silicate Front, marking the biogeographically relevant location between silicate-poor and silicate-rich waters. South of the northern Silicate Front, the silicate-to-nitrate ratio increases, with the sharpest gradient in silicate associated with the Southern ACC Front (i.e., the southern expression of the Silicate Front). Nutrient cycling is an important control on variability in the surface ocean partial pressure of carbon dioxide (pCO(2)). The robust characterization of the spatiotemporal variability of nutrients presented here highlights the utility of biogeochemical time series for diagnosing and potentially reducing biases in modeling Southern Ocean pCO(2) variability, and by inference, air-sea CO2 flux. Plain Language Summary Nutrients fuel phytoplankton communities that are important in the marine food web and global carbon cycling. Understanding modern-day nutrient availability and its physical and biological drivers is critical to accurately predict future climate with models. The Southern Ocean helps regulate climate and is vulnerable to future change, but as one of the least sampled oceans, physical and biogeochemical processes are still not fully understood. This study uses the 13-year Drake Passage Time-series, the longest year-round biogeochemical time series in the Southern Ocean, to quantify nutrient availability and variability on seasonal time scales. Across Drake Passage, temperatures decrease and nutrients increase toward Antarctica, exhibiting sharp gradients at currents and creating conditions favoring distinct phytoplankton groups. Nutrients are used by phytoplankton in summer and regenerated and resupplied by mixing in winter; these processes draw surface ocean carbon down in summer and increase carbon in winter. While nitrate is a necessary nutrient for all phytoplankton, silicate is only required by a single major phytoplankton group. Simultaneous observations of both nutrients allows us to better understand group-specific productivity and, ultimately, its impact on climate. | |||||
BibTeX:
@article{freeman19a,
author = {Freeman, Natalie M. and Munro, David R. and Sprintall, Janet and Mazloff, Matthew R. and Purkey, Sarah and Rosso, Isabella and DeRanek, Carissa A. and Sweeney, Colm},
title = {The Observed Seasonal Cycle of Macronutrients in Drake Passage: Relationship to Fronts and Utility as a Model Metric},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS},
publisher = {AMER GEOPHYSICAL UNION},
year = {2019},
volume = {124},
number = {7},
pages = {4763--4783},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JC015052},
doi = {https://doi.org/10.1029/2019JC015052}
}
|
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| Fu, D., Chen, B., Zhang, H., Wang, J., Black, T.A., Amiro, B.D., Bohrer, G., Bolstad, P., Coulter, R., Rahman, A.F., Dunn, A., McCaughey, J.H., Meyers, T. and Verma, S. | Estimating landscape net ecosystem exchange at high spatial-temporal resolution based on Landsat data, an improved upscaling model framework, and eddy covariance flux measurements | {2014} | REMOTE SENSING OF ENVIRONMENT Vol. {141}, pp. 90-104 |
article | DOI |
| Abstract: More accurate estimation of the carbon dioxide flux depends on the improved scientific understanding of the terrestrial carbon cycle. Remote-sensing-based approaches to continental-scale estimation of net ecosystem exchange (NEE) have been developed but coarse spatial resolution is a source of errors. Here we demonstrate a satellite-based method of estimating NEE using Landsat TM/ETM + data and an upscaling framework. The upscaling framework contains flux-footprint climatology modeling, modified regression tree (MRT) analysis and image fusion. By scaling NEE measured at flux towers to landscape and regional scales, this satellite-based method can improve NEE estimation at high spatial-temporal resolution at the landscape scale relative to methods based on MODIS data with coarser spatial-temporal resolution. This method was applied to sixteen flux sites from the Canadian Carbon Program and AmeriFlux networks located in North America, covering forest, grass, and cropland biomes. Compared to a similar method using MODIS data, our estimation is more effective for diagnosing landscape NEE with the same temporal resolution and higher spatial resolution (30 m versus 1 km) (r(2) = 0.7548 vs. 0.5868, RMSE = 1.3979 vs. 1.7497 g C m-(2) day(-1), average error = 0.8950 vs. 1.0178 g C m(-2) day(-1), relative error = 0.47 vs. 0.54 for fused Landsat and MODIS imagery, respectively). We also compared the regional NEE estimations using Carbon Tracker, our method and eddy-covariance observations. This study demonstrates that the data-driven satellite-based NEE diagnosed model can be used to upscale eddy-flux observations to landscape scales with high spatial-temporal resolutions. (C) 2013 Elsevier Inc. All rights reserved. |
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BibTeX:
@article{fu14a,
author = {Fu, Dongjie and Chen, Baozhang and Zhang, Huifang and Wang, Juan and Black, T. Andy and Amiro, Brian D. and Bohrer, Gil and Bolstad, Paul and Coulter, Richard and Rahman, Abdullah F. and Dunn, Allison and McCaughey, J. Harry and Meyers, Tilden and Verma, Shashi},
title = {Estimating landscape net ecosystem exchange at high spatial-temporal resolution based on Landsat data, an improved upscaling model framework, and eddy covariance flux measurements},
journal = {REMOTE SENSING OF ENVIRONMENT},
year = {2014},
volume = {141},
pages = {90--104},
doi = {https://doi.org/10.1016/j.rse.2013.10.029}
}
|
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| Fu, C., Ma, Z., Ai, L., Guo, W., Wang, S. and Zhang, R. | LAND-ATMOSPHERE INTERACTION IN SEMI-ARID REGIONS: ASIA PERSPECTIVE BASED ON OBSERVATION AND MODELING | 2017 | book | URL | |
| Abstract: Atmospheric chemistry in background areas is strongly influenced by natural vegetation. Boreal coniferous forests are known to produce large quantities of volatile vapours, especially terpenes to the surrounding air 1. These compounds react with OH and O3, and … | |||||
BibTeX:
@book{fu17a,
author = {Congbin Fu and Zhuguo Ma and Likun Ai and Weidong Guo and Shuyu Wang and Renjian Zhang},
title = {LAND-ATMOSPHERE INTERACTION IN SEMI-ARID REGIONS: ASIA PERSPECTIVE BASED ON OBSERVATION AND MODELING},
publisher = {World Scientific Series on Asia-Pacific Weather and Climate},
year = {2017},
url = {https://ileaps.org/sites/default/files/Oral_presentations.pdf}
}
|
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| Fu, Y., Liao, H., Tian, X., Gao, H., Jia, B. and Han, R. | Impact of Prior Terrestrial Carbon Fluxes on Simulations of Atmospheric CO2 Concentrations | 2021 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 126(18) |
article | DOI |
| Abstract: Terrestrial ecosystems have a significant role in shaping the distribution of atmospheric CO2, but it is uncertain how much they affect CO2 concentrations. We assessed the impact of terrestrial fluxes derived from different biosphere models in the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) on atmospheric CO2 estimations based on a global chemical transport model (GEOS-Chem) when these fluxes were applied as prior information. We examined the spatiotemporal uncertainty in terrestrial flux estimations from 15 MsTMIP terrestrial fluxes. We found high uncertainties in the terrestrial fluxes for temperate North America, tropical and temperate South America, southern Africa, Europe and tropical Asia. Sensitivity simulations showed that the annual mean CO2 concentration changed by 6.0-8.0 ppmv with the spread of the terrestrial fluxes. The interannual trend in the terrestrial fluxes could significantly affect the simulated trend of atmospheric CO2 concentrations. As a result of the spread in the prior terrestrial fluxes, large differences in the daily mean CO2 anomalies changed with an interquartile range of -1.0 to +1.0 ppmv and the magnitude of change in the sub-daily CO2 concentrations was in the range 4.0-6.0 ppmv for China, the USA and Europe. Our results suggest an urgent need to increase the reliability of terrestrial flux estimates in CO2 simulations. Surface seasonal CO2 concentrations were simulated to change by +/- 2.0 ppmv in most regions of the world due to the differences in the ensemble mean fluxes, reflecting the impact of the uncertainties in the existing optimized terrestrial fluxes on CO2 simulations. |
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BibTeX:
@article{fu21a,
author = {Fu, Yu and Liao, Hong and Tian, Xiangjun and Gao, Hao and Jia, Binghao and Han, Rui},
title = {Impact of Prior Terrestrial Carbon Fluxes on Simulations of Atmospheric CO2 Concentrations},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2021},
volume = {126},
number = {18},
doi = {https://doi.org/10.1029/2021JD034794}
}
|
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| Gabrys, J. | Sink: the dirt of systems [BibTeX] |
2009 | Environment and Planning D: Society and Space Vol. 27(4), pp. 666-681 |
article | DOI |
BibTeX:
@article{gabrys09a,
author = {Gabrys, Jennifer},
title = {Sink: the dirt of systems},
journal = {Environment and Planning D: Society and Space},
year = {2009},
volume = {27},
number = {4},
pages = {666--681},
doi = {https://doi.org/10.1068/d5708}
}
|
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| Gahlot, S., Shu, S., Jain, A. and Roy, S.B. | Estimating Trends and Variation of Net Biome Productivity in India for 1980--2012 Using a Land Surface Model [BibTeX] |
2017 | Geophysical Research Letters | article | |
BibTeX:
@article{gahlot17a,
author = {S Gahlot and S Shu and AK Jain and S Baidya Roy},
title = {Estimating Trends and Variation of Net Biome Productivity in India for 1980--2012 Using a Land Surface Model},
journal = {Geophysical Research Letters},
year = {2017}
}
|
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| Gately, C.K., Hutyra, L.R., Wing, I.S. and Brondfield, M.N. | A Bottom up Approach to on-Road CO2 Emissions Estimates: Improved Spatial Accuracy and Applications for Regional Planning | {2013} | ENVIRONMENTAL SCIENCE & TECHNOLOGY Vol. {47}({5}), pp. 2423-2430 |
article | DOI |
| Abstract: On-road transportation is responsible for 28% of all U.S. fossil-fuel CO2 emissions. Mapping vehicle emissions at regional scales is challenging due to data limitations. Existing emission inventories use spatial proxies such as population and road density to downscale national or state-level data. Such procedures introduce errors where the proxy variables and actual emissions are weakly correlated, and limit analysis of the relationship between emissions and demographic trends at local scales. We develop an onroad emission inventory product for Massachusetts-based on roadway-level traffic data obtained from the Highway Performance Monitoring System (HPMS). We provide annual estimates of on-road CO2 emissions at a 1 x 1 km grid scale for the years 1980 through 2008. We compared our results with on-road emissions estimates from the Emissions Database for Global Atmospheric Research (EDGAR), with the Vulcan Product, and with estimates derived from state fuel consumption statistics reported by the Federal Highway Administration (FHWA). Our model differs from FHWA estimates by less than 8.5% on average, and is within 596 of Vulcan estimates. We found that EDGAR estimates systematically exceed FHWA by an average of 22.8%. Panel regression analysis of per-mile CO2 emissions on population density at the town scale shows a statistically significant correlation that varies systematically in sign and magnitude as population density increases. Population density has a positive correlation with per-mile CO2 emissions for densities below 2000 persons km(-2), above which increasing density correlates negatively with per-mile emissions. |
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BibTeX:
@article{gately13a,
author = {Gately, Conor K. and Hutyra, Lucy R. and Wing, Ian Sue and Brondfield, Max N.},
title = {A Bottom up Approach to on-Road CO2 Emissions Estimates: Improved Spatial Accuracy and Applications for Regional Planning},
journal = {ENVIRONMENTAL SCIENCE & TECHNOLOGY},
year = {2013},
volume = {47},
number = {5},
pages = {2423--2430},
doi = {https://doi.org/10.1021/es304238v}
}
|
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| Gately, C.K. | Emissions from mobile sources: Improved understanding of the drivers of emissions and their spatial patterns [BibTeX] |
2016 | School: Boston University | phdthesis | URL |
BibTeX:
@phdthesis{gately16a,
author = {Gately, Conor Kennedy},
title = {Emissions from mobile sources: Improved understanding of the drivers of emissions and their spatial patterns},
school = {Boston University},
year = {2016},
url = {http://search.proquest.com/openview/660fb3eced8341af00fe6f17a1aee2f4/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Gately, C.K. and Hutyra, L.R. | Large Uncertainties in Urban-Scale Carbon Emissions | {2017} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {122}({20}), pp. 11242-11260 |
article | DOI |
| Abstract: Accurate estimates of fossil fuel carbon dioxide (FFCO2) emissions are a critical component of local, regional, and global climate agreements. Current global inventories of FFCO2 emissions do not directly quantify emissions at local scales; instead, spatial proxies like population density, nighttime lights, and power plant databases are used to downscale emissions from national totals. We have developed a high-resolution (hourly, 1 km(2)) bottom-up Anthropogenic Carbon Emissions System (ACES) for FFCO2, based on local activity data for the year 2011 across the northeastern U.S. We compare ACES with three widely used global inventories, finding significant differences at regional (20%) and city scales (50-250%). At a spatial resolution of 0.1 degrees, inventories differ by over 100% for half of the grid cells in the domain, with the largest differences in urban areas and oil and gas production regions. Given recent U.S. federal policy pull backs regarding greenhouse gas emissions reductions, inventories like ACES are crucial for U.S. actions, as the impetus for climate leadership has shifted to city and state governments. The development of a robust carbon monitoring system to track carbon fluxes is critical for emissions benchmarking and verification. We show that existing downscaled inventories are not suitable for urban emissions monitoring, as they do not consider important local activity patterns. The ACES methodology is designed for easy updating, making it suitable for emissions monitoring under most city, regional, and state greenhouse gas mitigation initiatives, in particular, for the small-and medium-sized cities that lack the resources to regularly perform their own bottom-up emissions inventories. |
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BibTeX:
@article{gately17a,
author = {Gately, C. K. and Hutyra, L. R.},
title = {Large Uncertainties in Urban-Scale Carbon Emissions},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2017},
volume = {122},
number = {20},
pages = {11242--11260},
doi = {https://doi.org/10.1002/2017JD027359}
}
|
|||||
| Gaubert, B., Stephens, B.B., Basu, S., Chevallier, F., Deng, F., Kort, E.A., Patra, P.K., Peters, W., Roedenbeck, C., Saeki, T., Schimel, D., Van der Laan-Luijkx, I., Wofsy, S. and Yin, Y. | Global atmospheric CO2 inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate | {2019} | BIOGEOSCIENCES Vol. {16}({1}), pp. {117-134} |
article | DOI URL |
| Abstract: We have compared a suite of recent global CO2 atmospheric inversion results to independent airborne observations and to each other, to assess their dependence on differences in northern extratropical (NET) vertical transport and to identify some of the drivers of model spread. We evaluate posterior CO2 concentration profiles against observations from the High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) aircraft campaigns over the mid-Pacific in 2009-2011. Although the models differ in inverse approaches, assimilated observations, prior fluxes, and transport models, their broad latitudinal separation of land fluxes has converged significantly since the Atmospheric Carbon Cycle Inversion Intercomparison (TransCom 3) and the REgional Carbon Cycle Assessment and Processes (RECCAP) projects, with model spread reduced by 80% since TransCom 3 and 70% since RECCAP. Most modeled CO2 fields agree reasonably well with the HIPPO observations, specifically for the annual mean vertical gradients in the Northern Hemisphere. Northern Hemisphere vertical mixing no longer appears to be a dominant driver of northern versus tropical (T) annual flux differences. Our newer suite of models still gives northern extratropical land uptake that is modest relative to previous estimates (Gurney et al., 2002; Peylin et al., 2013) and near-neutral tropical land uptake for 2009-2011. Given estimates of emissions from deforestation, this implies a continued uptake in intact tropical forests that is strong relative to historical estimates (Gurney et al., 2002; Peylin et al., 2013). The results from these models for other time periods (2004-2014, 2001-2004, 1992-1996) and re-evaluation of the TransCom 3 Level 2 and RECCAP results confirm that tropical land carbon fluxes including deforestation have been near neutral for several decades. However, models still have large disagreements on ocean-land partitioning. The fossil fuel (FF) and the atmospheric growth rate terms have been thought to be the best-known terms in the global carbon budget, but we show that they currently limit our ability to assess regional-scale terrestrial fluxes and ocean-land partitioning from the model ensemble. | |||||
BibTeX:
@article{gaubert19a,
author = {Gaubert, Benjamin and Stephens, Britton B. and Basu, Sourish and Chevallier, Frederic and Deng, Feng and Kort, Eric A. and Patra, Prabir K. and Peters, Wouter and Roedenbeck, Christian and Saeki, Tazu and Schimel, David and Van der Laan-Luijkx, Ingrid and Wofsy, Steven and Yin, Yi},
title = {Global atmospheric CO2 inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate},
journal = {BIOGEOSCIENCES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {16},
number = {1},
pages = {117--134},
note = {Query date: 2021-04-02 15:20:04},
url = {https://bg.copernicus.org/articles/16/117/2019/},
doi = {https://doi.org/10.5194/bg-16-117-2019}
}
|
|||||
| Gaudet, B.J., Davis, K.J., Pal, S., Jacobson, A., Schuh, A., Lauvaux, T., Feng, S. and Browell, E. | Regional-scale, sector-specific evaluation of global CO2 inversion models using aircraft data from the ACT-America project | 2021 | Journal of Geophysical Research -- Atmospheres | article | URL |
| Abstract: We use 148 airborne vertical profiles of CO2 for frontal cases from the summer 2016 Atmospheric Carbon and Transport---America (ACT‐America) campaign to evaluate the skill of 10 global CO2 in situ inversion models from the version 7 Orbiting Carbon Observatory--2 … | |||||
BibTeX:
@article{gaudet21a,
author = {B. J. Gaudet and K. J. Davis and S. Pal and A.R. Jacobson and A. Schuh and T. Lauvaux and S. Feng and E.V. Browell},
title = {Regional-scale, sector-specific evaluation of global CO2 inversion models using aircraft data from the ACT-America project},
journal = {Journal of Geophysical Research -- Atmospheres},
year = {2021},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020JD033623}
}
|
|||||
| Geibel, M.C. | Measurement of climate-relevant trace gases via infrared spectroscopy [BibTeX] |
2011 | School: Friedrich-Schiller-Universitat Jena | phdthesis | URL |
BibTeX:
@phdthesis{geibel11a,
author = {Geibel, Marc Christoph},
title = {Measurement of climate-relevant trace gases via infrared spectroscopy},
school = {Friedrich-Schiller-Universitat Jena},
year = {2011},
url = {https://d-nb.info/1016620160/34}
}
|
|||||
| Gennaretti, F., Gea-Izquierdo, G., Boucher, E., Berninger, F., Arseneault, D. and Guiot, J. | Ecophysiological modeling of photosynthesis and carbon allocation to the tree stem in the boreal forest | {2017} | BIOGEOSCIENCES Vol. {14}({21}), pp. 4851-4866 |
article | DOI |
| Abstract: A better understanding of the coupling between photosynthesis and carbon allocation in the boreal forest, together with its associated environmental factors and mechanistic rules, is crucial to accurately predict boreal forest carbon stocks and fluxes, which are significant components of the global carbon budget. Here, we adapted the MAIDEN ecophysiological forest model to consider important processes for boreal tree species, such as nonlinear acclimation of photosynthesis to temperature changes, canopy development as a function of previous-year climate variables influencing bud formation and the temperature dependence of carbon partition in summer. We tested these modifications in the eastern Canadian taiga using black spruce (Picea mariana (Mill.) B.S.P.) gross primary production and ring width data. MAIDEN explains 90% of the observed daily gross primary production variability, 73% of the annual ring width variability and 20-30% of its high-frequency component (i.e., when decadal trends are removed). The positive effect on stem growth due to climate warming over the last several decades is well captured by the model. In addition, we illustrate how we improve the model with each introduced model adaptation and compare the model results with those of linear response functions. Our results demonstrate that MAIDEN simulates robust relationships with the most important climate variables (those detected by classical response-function analysis) and is a powerful tool for understanding how environmental factors interact with black spruce ecophysiol-ogy to influence present-day and future boreal forest carbon fluxes. |
|||||
BibTeX:
@article{gennaretti17a,
author = {Gennaretti, Fabio and Gea-Izquierdo, Guillermo and Boucher, Etienne and Berninger, Frank and Arseneault, Dominique and Guiot, Joel},
title = {Ecophysiological modeling of photosynthesis and carbon allocation to the tree stem in the boreal forest},
journal = {BIOGEOSCIENCES},
year = {2017},
volume = {14},
number = {21},
pages = {4851--4866},
doi = {https://doi.org/10.5194/bg-14-4851-2017}
}
|
|||||
| Georgoulias, A.K., Kourtidis, K.A., Buchwitz, M., Schneising, O. and Burrows, J.P. | A case study on the application of SCIAMACHY satellite methane measurements for regional studies: the Greater Area of the Eastern Mediterranean | {2011} | INTERNATIONAL JOURNAL OF REMOTE SENSING Vol. {32}({3}), pp. 787-813 |
article | DOI |
| Abstract: Many studies have focused on geological formations, such as mud volcanoes, which abound in the Greater Area of the Eastern Mediterranean (GAEM; 25 degrees N-50 degrees N, 5 degrees E-55 degrees E). This geological source is thought to provide a significant portion of the global methane (CH4) emissions. However, studies in the GAEM have focused on specific locations rather than extensive areas, which has led to a gap in our understanding of the spatial and temporal variability of CH4 atmospheric mixing ratios. Here, we present characteristics of methane loading over land in the GAEM using dry air columnar data (XCH4) retrieved from SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Cartography) satellite measurements with the Weighting Function Modified Differential Optical Absorption Spectroscopy (WFM-DOAS) version 1.0 algorithm. We defined methane annual, seasonal and monthly spatial patterns over the area using 2003 and 2004 measurements. The annual mean XCH4 levels over the study area were estimated to be 1761 +/- 27 ppb for 2003 and 1758 +/- 26 ppb for 2004. A seasonal variability with a summer-autumn peak was observed for both 2003 and 2004, August being the month with the highest methane concentrations. The northeastern part of the area exhibits the highest XCH4 values while the high elevation regions defined by the triangle of eastern Turkey, the Persian Gulf and the Caspian Sea and the region of the eastern coast of the Red Sea exhibit the lowest levels. A latitudinal gradient was observed for the area during 2003 and 2004. A comparison of measured XCH4 levels above two of the world's most renowned mud volcano regions situated in the GAEM with anticipated methane columnar concentrations as modelled for eruption cases shows that no mud volcano eruptions were observed from SCIAMACHY during 2003 or 2004. |
|||||
BibTeX:
@article{georgoulias11a,
author = {Georgoulias, A. K. and Kourtidis, K. A. and Buchwitz, M. and Schneising, O. and Burrows, J. P.},
title = {A case study on the application of SCIAMACHY satellite methane measurements for regional studies: the Greater Area of the Eastern Mediterranean},
journal = {INTERNATIONAL JOURNAL OF REMOTE SENSING},
year = {2011},
volume = {32},
number = {3},
pages = {787--813},
doi = {https://doi.org/10.1080/01431161.2010.517791}
}
|
|||||
| Gerbig, C., Dolman, A.J. and Heimann, M. | On observational and modelling strategies targeted at regional carbon exchange over continents | {2009} | BIOGEOSCIENCES Vol. {6}({10}), pp. 1949-1959 |
article | DOI |
| Abstract: Estimating carbon exchange at regional scales is paramount to understanding feedbacks between climate and the carbon cycle, but also to verifying climate change mitigation such as emission reductions and strategies compensating for emissions such as carbon sequestration. This paper discusses evidence for a number of important shortcomings of current generation modelling frameworks designed to provide regional scale budgets from atmospheric observations. Current top-down and bottom-up approaches targeted at deriving consistent regional scale carbon exchange estimates for biospheric and anthropogenic sources and sinks are hampered by a number of issues: we show that top-down constraints using point measurements made from tall towers, although sensitive to larger spatial scales, are however influenced by local areas much more strongly than previously thought. On the other hand, classical bottom-up approaches using process information collected at the local scale, such as from eddy covariance data, need up-scaling and validation on larger scales. We therefore argue for a combination of both approaches, implicitly providing the important local scale information for the top-down constraint, and providing the atmospheric constraint for up-scaling of flux measurements. Combining these data streams necessitates quantifying their respective representation errors, which are discussed. The impact of these findings on future network design is highlighted, and some recommendations are given. |
|||||
BibTeX:
@article{gerbig09a,
author = {Gerbig, C. and Dolman, A. J. and Heimann, M.},
title = {On observational and modelling strategies targeted at regional carbon exchange over continents},
journal = {BIOGEOSCIENCES},
year = {2009},
volume = {6},
number = {10},
pages = {1949--1959},
doi = {https://doi.org/10.5194/bg-6-1949-2009}
}
|
|||||
| Gerken, T., Feng, S., Keller, K., Lauvaux, T., DiGangi, J.P., Choi, Y., Baier, B. and Davis, K.J. | Examining CO2 Model Observation Residuals Using ACT-America Data | 2021 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 126(18) |
article | DOI |
| Abstract: Atmospheric CO2 inversion typically relies on the specification of prior flux and atmospheric model transport errors, which have large uncertainties. Here, we used ACT-America airborne observations to compare CO2 model observation mismatch in the eastern U.S. and during four climatological seasons for the mesoscale WRF(-Chem) and global scale CarbonTracker/TM5 (CT) models. Models used identical surface carbon fluxes, and CT was used as CO2 boundary condition for WRF. Both models showed reasonable agreement with observations, and CO2 residuals follow near symmetric peaked (i.e., non-Gaussian) distribution with near-zero bias of both models (CT: -0.34 +/- 3.12 ppm; WRF: 0.82 +/- 4.37 ppm). We also found large magnitude residuals at the tails of the distribution that contribute considerably to overall bias. Atmospheric boundary-layer biases (1-10 ppm) were much larger than free tropospheric biases (0.5-1 ppm) and were of same magnitude as model-model differences, whereas free tropospheric biases were mostly governed by CO2 background conditions. Results revealed systematic differences in atmospheric transport, most pronounced in the warm and cold sectors of synoptic systems, highlighting the importance of transport for CO2 residuals. While CT could reproduce the principal CO2 dynamics associated with synoptic systems, WRF showed a clearer distinction for CO2 differences across fronts. Variograms were used to quantify spatial correlation of residuals and showed characteristic residual length scales of approximately 100-300 km. Our findings suggest that inclusion of synoptic weather-dependent and non-Gaussian error structure may benefit inversion systems. |
|||||
BibTeX:
@article{gerken21a,
author = {Gerken, Tobias and Feng, Sha and Keller, Klaus and Lauvaux, Thomas and DiGangi, Joshua P. and Choi, Yonghoon and Baier, Bianca and Davis, Kenneth J.},
title = {Examining CO2 Model Observation Residuals Using ACT-America Data},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2021},
volume = {126},
number = {18},
doi = {https://doi.org/10.1029/2020JD034481}
}
|
|||||
| Geyer, N.M. | Time-filtered inverse modeling of land-atmosphere carbon exchange [BibTeX] |
2015 | School: Colorado State University | phdthesis | URL |
BibTeX:
@phdthesis{geyer15a,
author = {Geyer, Nicholas M},
title = {Time-filtered inverse modeling of land-atmosphere carbon exchange},
school = {Colorado State University},
year = {2015},
url = {http://search.proquest.com/openview/e038a9c458ca8f6d6358546eff579bf6/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
|||||
| Gilmanov, T.G., Aires, L., Barcza, Z., Baron, V.S., Belelli, L., Beringer, J., Billesbach, D., Bonal, D., Bradford, J., Ceschia, E., Cook, D., Corradi, C., Frank, A., Gianelle, D., Gimeno, C., Gruenwald, T., Guo, H., Hanan, N., Haszpra, L., Heilman, J., Jacobs, A., Jones, M.B., Johnson, D.A., Kiely, G., Li, S., Magliulo, V., Moors, E., Nagy, Z., Nasyrov, M., Owensby, C., Pinter, K., Pio, C., Reichstein, M., Sanz, M.J., Scott, R., Soussana, J.F., Stoy, P.C., Svejcar, T., Tuba, Z. and Zhou, G. | Productivity, Respiration, and Light-Response Parameters of World Grassland and Agroecosystems Derived From Flux-Tower Measurements | {2010} | RANGELAND ECOLOGY & MANAGEMENT Vol. {63}({1}), pp. 16-39 |
article | DOI |
| Abstract: Grasslands and agroecosystems occupy one-third of the terrestrial area, but their contribution to the global carbon cycle remains uncertain. We used a set of 316 site-years of CO(2) exchange measurements to quantify gross primary productivity, respiration, and light-response parameters of grasslands, shrublands/savanna, wetlands, and cropland ecosystems worldwide. We analyzed data from 72 global flux-tower sites partitioned into gross photosynthesis and ecosystem respiration with the use of the light-response method (Gilmanov, T. G., D. A. Johnson, and N. Z. Saliendra. 2003. Growing season CO(2) fluxes in a sagebrushsteppe ecosystem in Idaho: Bowen ratio/energy balance measurements and modeling. Basic and Applied Ecology 4:167-183) from the RANGEFLUX and WORLDGRASSAGRIFLUX data sets supplemented by 46 sites from the FLUXNET La Thuile data set partitioned with the use of the temperature-response method (Reichstein, M., E. Falge, D. Baldocchi, D. Papale, R. Valentini, M. Aubinet, P. Berbigier, C. Bernhofer, N. Buchmann, M. Falk, T. Gilmanov, A. Granier, T. Grunwald, K. Havrankova, D. Janous, A. Knohl, T. Laurela, A. Lohila, D. Loustau, G. Matteucci, T. Meyers, F. Miglietta, J.M. Ourcival, D. Perrin, J. Pumpanen, S. Rambal, E. Rotenberg, M. Sanz, J. Tenhunen, G. Seufert, F. Vaccari, T. Vesala, and D. Yakir. 2005. On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm. Global Change Biology 11: 1.424-1439). Maximum values of the quantum yield (alpha = 75 mmol.mol(-1)), photosynthetic capacity (A(max) = 3.4 mg CO(2) . m(-2).s-1), gross photosynthesis (P(g,max) = 1.16 g CO(2) . m(-2).d(-1)), and ecological light-use efficiency (epsilon(ecol) = 59 mmol . mol(-1)) of managed grasslands and high-production croplands exceeded those of most forest ecosystems, indicating the potential of nonforest ecosystems for uptake of atmospheric CO(2). Maximum values of gross primary production (8 600 g CO(2) . m(-2).yr(-1)), total ecosystem respiration (7 900 g CO(2) . m(-2).yr(-1)), and net CO(2) exchange (2 400 g CO(2) . m(-2).yr(-1)) were observed for intensively managed grasslands and high-yield crops, and are comparable to or higher than those for forest ecosystems, excluding some tropical forests. On average, 80% of the nonforest sites were apparent sinks for atmospheric CO(2), with mean net uptake of 700 g CO(2) . m(-2).yr(-1) for intensive grasslands and 933 g CO(2) . m(-2).d(-1) for croplands. However, part of these apparent sinks is accumulated in crops and forage, which are carbon pools that are harvested, transported, and decomposed off site. Therefore, although agricultural fields may be predominantly sinks for atmospheric CO(2), this does not imply that they are necessarily increasing their carbon stock. |
|||||
BibTeX:
@article{gilmanov10a,
author = {Gilmanov, Tagir G. and Aires, L. and Barcza, Z. and Baron, V. S. and Belelli, L. and Beringer, J. and Billesbach, D. and Bonal, D. and Bradford, J. and Ceschia, E. and Cook, D. and Corradi, C. and Frank, A. and Gianelle, D. and Gimeno, C. and Gruenwald, T. and Guo, Haiqiang and Hanan, N. and Haszpra, L. and Heilman, J. and Jacobs, A. and Jones, M. B. and Johnson, D. A. and Kiely, G. and Li, Shenggong and Magliulo, V. and Moors, E. and Nagy, Z. and Nasyrov, M. and Owensby, C. and Pinter, K. and Pio, C. and Reichstein, M. and Sanz, M. J. and Scott, R. and Soussana, J. F. and Stoy, P. C. and Svejcar, T. and Tuba, Z. and Zhou, Guangsheng},
title = {Productivity, Respiration, and Light-Response Parameters of World Grassland and Agroecosystems Derived From Flux-Tower Measurements},
journal = {RANGELAND ECOLOGY & MANAGEMENT},
year = {2010},
volume = {63},
number = {1},
pages = {16--39},
doi = {https://doi.org/10.2111/REM-D-09-00072.1}
}
|
|||||
| Glaser, R., Castello-Blindt, P.O. and Yin, J. | Biomimetic Approaches to Reversible CO2 Capture from Air. N-Methylcarbaminic Acid Formation in Rubsico-Inspired Models [BibTeX] |
2013 | New and Future Developments in Catalysis: Activation of Carbon Dioxide, pp. 501-534 | article | URL |
BibTeX:
@article{glaser13a,
author = {Glaser, Rainer and Castello-Blindt, Paula O and Yin, Jian},
title = {Biomimetic Approaches to Reversible CO2 Capture from Air. N-Methylcarbaminic Acid Formation in Rubsico-Inspired Models},
journal = {New and Future Developments in Catalysis: Activation of Carbon Dioxide},
year = {2013},
pages = {501--534},
url = {https://faculty.missouri.edu/ glaserr/vitpub/NMCA_Chapter.pdf}
}
|
|||||
| Gockede, M., Michalak, A.M., Vickers, D., Turner, D.P. and Law, B.E. | Atmospheric inverse modeling to constrain regional-scale CO2 budgets at high spatial and temporal resolution | {2010} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {115} |
article | DOI |
| Abstract: We present an inverse modeling framework designed to constrain CO2 budgets at regional scales. The approach captures atmospheric transport processes in high spatiotemporal resolution by coupling a mesoscale model with Lagrangian Stochastic backward trajectories. Terrestrial biosphere CO2 emissions are generated through a simple diagnostic flux model that splits the net ecosystem exchange into its major components of gross primary productivity and autotrophic and heterotrophic respirations. The modeling framework assimilates state-of-the-art data sets for advected background CO2 and anthropogenic fossil fuel emissions as well as highly resolved remote sensing products. We introduce a Bayesian inversion setup, optimizing a posteriori flux base rates for surface types that are defined through remote sensing information. This strategy significantly reduces the number of parameters to be optimized compared with solving fluxes for each individual grid cell, thus permitting description of the surface in a very high resolution. The model is tested using CO2 concentrations measured in the fall and winter of 2006 at two AmeriFlux sites in Oregon. Because this database does not cover a full seasonal cycle, we focus on conducting model sensitivity tests rather than producing quantitative CO2 flux estimates. Sensitivity tests on the influence of spatial and temporal resolution indicate that optimum results can be obtained using 4 h time steps and grid sizes of 6 km or less. Further tests demonstrate the importance of dividing biome types by ecoregions to capture their different biogeochemical responses to external forcings across climatic gradients. Detailed stand age information was shown to have a positive effect on model performance. |
|||||
BibTeX:
@article{gockede10a,
author = {Gockede, Mathias and Michalak, Anna M. and Vickers, Dean and Turner, David P. and Law, Beverly E.},
title = {Atmospheric inverse modeling to constrain regional-scale CO2 budgets at high spatial and temporal resolution},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2010},
volume = {115},
doi = {https://doi.org/10.1029/2009JD012257}
}
|
|||||
| Gockede, M., Turner, D.P., Michalak, A.M., Vickers, D. and Law, B.E. | Sensitivity of a subregional scale atmospheric inverse CO2 modeling framework to boundary conditions | {2010} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {115} |
article | DOI |
| Abstract: We present an atmospheric inverse modeling framework to constrain terrestrial biosphere CO2 exchange processes at subregional scales. The model is operated at very high spatial and temporal resolution, using the state of Oregon in the northwestern United States as the model domain. The modeling framework includes mesoscale atmospheric simulations coupled to Lagrangian transport, a biosphere flux model that considers, e.g., the effects of drought stress and disturbance on photosynthesis and respiration CO2 fluxes, and a Bayesian optimization approach. This study focuses on the impact of uncertainties in advected background mixing ratios and fossil fuel emissions on simulated flux fields, both taken from external data sets. We found the simulations to be highly sensitive to systematic changes in advected background CO2, while shifts in fossil fuel emissions played a minor role. Correcting for offsets in the background mixing ratios shifted annual CO2 budgets by about 47% and improved the correspondence with the output produced by bottom-up modeling frameworks. Inversion results were robust against shifts in fossil fuel emissions, which is likely a consequence of relatively low emission rates in Oregon. |
|||||
BibTeX:
@article{gockede10b,
author = {Gockede, Mathias and Turner, David P. and Michalak, Anna M. and Vickers, Dean and Law, Beverly E.},
title = {Sensitivity of a subregional scale atmospheric inverse CO2 modeling framework to boundary conditions},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2010},
volume = {115},
doi = {https://doi.org/10.1029/2010JD014443}
}
|
|||||
| Gomes, D., Vicente, L.E., Silva, R., Paula, S., Maçorano, R.P., Victoria, D. and Batistella, M. | Uso de dados MODIS e AIRS para obten¸ cão de parâmetros de corre¸ cão atmosférica [BibTeX] |
2013 | Simpósio Brasileiro de Sensoriamento Remoto Vol. 16, pp. 8019-8026 |
article | URL |
BibTeX:
@article{gomes13a,
author = {Gomes, Daniel and Vicente, Luiz Eduardo and Silva, RFB and Paula, SC and Maçorano, Renan Pfister and Victoria, DC and Batistella, Mateus},
title = {Uso de dados MODIS e AIRS para obten¸ cão de parâmetros de corre¸ cão atmosférica},
journal = {Simpósio Brasileiro de Sensoriamento Remoto},
year = {2013},
volume = {16},
pages = {8019--8026},
url = {https://ainfo.cnptia.embrapa.br/digital/bitstream/item/82762/1/DanielSBSR.pdf}
}
|
|||||
| Gourdji, S.M., Hirsch, A.I., Mueller, K.L., Yadav, V., Andrews, A.E. and Michalak, A.M. | Regional-scale geostatistical inverse modeling of North American CO2 fluxes: a synthetic data study | {2010} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {10}({13}), pp. 6151-6167 |
article | DOI |
| Abstract: A series of synthetic data experiments is performed to investigate the ability of a regional atmospheric inversion to estimate grid-scale CO2 fluxes during the growing season over North America. The inversions are performed within a geostatistical framework without the use of any prior flux estimates or auxiliary variables, in order to focus on the atmospheric constraint provided by the nine towers collecting continuous, calibrated CO2 measurements in 2004. Using synthetic measurements and their associated concentration footprints, flux and model-data mismatch covariance parameters are first optimized, and then fluxes and their uncertainties are estimated at three different temporal resolutions. These temporal resolutions, which include a four-day average, a four-day-average diurnal cycle with 3-hourly increments, and 3-hourly fluxes, are chosen to help assess the impact of temporal aggregation errors on the estimated fluxes and covariance parameters. Estimating fluxes at a temporal resolution that can adjust the diurnal variability is found to be critical both for recovering covariance parameters directly from the atmospheric data, and for inferring accurate ecoregion-scale fluxes. Accounting for both spatial and temporal a priori covariance in the flux distribution is also found to be necessary for recovering accurate a posteriori uncertainty bounds on the estimated fluxes. Overall, the results suggest that even a fairly sparse network of 9 towers collecting continuous CO2 measurements across the continent, used with no auxiliary information or prior estimates of the flux distribution in time or space, can be used to infer relatively accurate monthly ecoregion scale CO2 surface fluxes over North America within estimated uncertainty bounds. Simulated random transport error is shown to decrease the quality of flux estimates in under-constrained areas at the ecoregion scale, although the uncertainty bounds remain realistic. While these synthetic data inversions do not consider all potential issues associated with using actual measurement data, e.g. systematic transport errors or problems with the boundary conditions, they help to highlight the impact of inversion setup choices, and help to provide a baseline set of CO2 fluxes for comparison with estimates from future real-data inversions. |
|||||
BibTeX:
@article{gourdji10a,
author = {Gourdji, S. M. and Hirsch, A. I. and Mueller, K. L. and Yadav, V. and Andrews, A. E. and Michalak, A. M.},
title = {Regional-scale geostatistical inverse modeling of North American CO2 fluxes: a synthetic data study},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2010},
volume = {10},
number = {13},
pages = {6151--6167},
doi = {https://doi.org/10.5194/acp-10-6151-2010}
}
|
|||||
| Gourdji, S.M. | Improved estimates of regional-scale land-atmosphere Carbon dioxide exchange using geostatistical atmospheric inverse models [BibTeX] |
2011 | School: University of Michigan | phdthesis | URL |
BibTeX:
@phdthesis{gourdji11a,
author = {Gourdji, Sharon Muzli},
title = {Improved estimates of regional-scale land-atmosphere Carbon dioxide exchange using geostatistical atmospheric inverse models},
school = {University of Michigan},
year = {2011},
url = {http://search.proquest.com/openview/331603ec402236ba8e528454f7373a97/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
|||||
| Gourdji, S.M., Mueller, K.L., Yadav, V., Huntzinger, D.N., Andrews, A.E., Trudeau, M., Petron, G., Nehrkorn, T., Eluszkiewicz, J., Henderson, J., Wen, D., Lin, J., Fischer, M., Sweeney, C. and Michalak, A.M. | North American CO2 exchange: inter-comparison of modeled estimates with results from a fine-scale atmospheric inversion | {2012} | BIOGEOSCIENCES Vol. {9}({1}), pp. 457-475 |
article | DOI |
| Abstract: Atmospheric inversion models have the potential to quantify CO2 fluxes at regional, sub-continental scales by taking advantage of near-surface CO2 mixing ratio observations collected in areas with high flux variability. This study presents results from a series of regional geostatistical inverse models (GIM) over North America for 2004, and uses them as the basis for an inter-comparison to other inversion studies and estimates from biospheric models collected through the North American Carbon Program Regional and Continental Interim Synthesis. Because the GIM approach does not require explicit prior flux estimates and resolves fluxes at fine spatiotemporal scales (i.e. 1 degrees x 1 degrees, 3-hourly in this study), it avoids temporal and spatial aggregation errors and allows for the recovery of realistic spatial patterns from the atmospheric data relative to previous inversion studies. Results from a GIM inversion using only available atmospheric observations and a fine-scale fossil fuel inventory were used to confirm the quality of the inventory and inversion setup. An inversion additionally including auxiliary variables from the North American Regional Reanalysis found inferred relationships with flux consistent with physiological understanding of the biospheric carbon cycle. Comparison of GIM results with bottom-up biospheric models showed stronger agreement during the growing relative to the dormant season, in part because most of the biospheric models do not fully represent agricultural land-management practices and the fate of both residual biomass and harvested products. Comparison to earlier inversion studies pointed to aggregation errors as a likely source of bias in previous subcontinental scale flux estimates, particularly for inversions that adjust fluxes at the coarsest scales and use atmospheric observations averaged over long periods. Finally, whereas the continental CO2 boundary conditions used in the GIM inversions have a minor impact on spatial patterns, they have a substantial impact on the continental carbon budget, with a difference of 0.8 PgC yr(-1) in the total continental flux resulting from the use of two plausible sets of boundary CO2 mixing ratios. Overall, this inter-comparison study helps to assess the state of the science in estimating regional-scale CO2 fluxes, while pointing towards the path forward for improvements in future top-down and bottom-up modeling efforts. |
|||||
BibTeX:
@article{gourdji12a,
author = {Gourdji, S. M. and Mueller, K. L. and Yadav, V. and Huntzinger, D. N. and Andrews, A. E. and Trudeau, M. and Petron, G. and Nehrkorn, T. and Eluszkiewicz, J. and Henderson, J. and Wen, D. and Lin, J. and Fischer, M. and Sweeney, C. and Michalak, A. M.},
title = {North American CO2 exchange: inter-comparison of modeled estimates with results from a fine-scale atmospheric inversion},
journal = {BIOGEOSCIENCES},
year = {2012},
volume = {9},
number = {1},
pages = {457--475},
doi = {https://doi.org/10.5194/bg-9-457-2012}
}
|
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| Graven, H.D. and Gruber, N. | Continental-scale enrichment of atmospheric (CO2)-C-14 from the nuclear power industry: potential impact on the estimation of fossil fuel-derived CO2 | {2011} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {11}({23}), pp. 12339-12349 |
article | DOI |
| Abstract: The C-14-free fossil carbon added to atmospheric CO2 by combustion dilutes the atmospheric C-14/C ratio (Delta C-14), potentially providing a means to verify fossil CO2 emissions calculated using economic inventories. However, sources of C-14 from nuclear power generation and spent fuel reprocessing can counteract this dilution and may bias C-14/C-based estimates of fossil fuel-derived CO2 if these nuclear influences are not correctly accounted for. Previous studies have examined nuclear influences on local scales, but the potential for continental-scale influences on Delta C-14 has not yet been explored. We estimate annual C-14 emissions from each nuclear site in the world and conduct an Eulerian transport modeling study to investigate the continental-scale, steady-state gradients of Delta C-14 caused by nuclear activities and fossil fuel combustion. Over large regions of Europe, North America and East Asia, nuclear enrichment may offset at least 20% of the fossil fuel dilution in Delta C-14, corresponding to potential biases of more than -0.25 ppm in the CO2 attributed to fossil fuel emissions, larger than the bias from plant and soil respiration in some areas. Model grid cells including high C-14-release reactors or fuel reprocessing sites showed much larger nuclear enrichment, despite the coarse model resolution of 1.8 degrees x 1.8 degrees. The recent growth of nuclear C-14 emissions increased the potential nuclear bias over 1985-2005, suggesting that changing nuclear activities may complicate the use of Delta C-14 observations to identify trends in fossil fuel emissions. The magnitude of the potential nu-clear bias is largely independent of the choice of reference station in the context of continental-scale Eulerian transport and inversion studies, but could potentially be reduced by an appropriate choice of reference station in the context of local-scale assessments. |
|||||
BibTeX:
@article{graven11a,
author = {Graven, H. D. and Gruber, N.},
title = {Continental-scale enrichment of atmospheric (CO2)-C-14 from the nuclear power industry: potential impact on the estimation of fossil fuel-derived CO2},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
volume = {11},
number = {23},
pages = {12339--12349},
doi = {https://doi.org/10.5194/acp-11-12339-2011}
}
|
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| Guan, K. | Hydrological variability on vegetation seasonality, productivity and composition in tropical ecosystems of Africa [BibTeX] |
2013 | School: Princeton University | phdthesis | URL |
BibTeX:
@phdthesis{guan13a,
author = {Guan, Kaiyu},
title = {Hydrological variability on vegetation seasonality, productivity and composition in tropical ecosystems of Africa},
school = {Princeton University},
year = {2013},
url = {http://search.proquest.com/openview/bdb3c89d79b0a9555cf6e3419d6a81d0/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Guan, K., Medvigy, D., Wood, E.F., Caylor, K.K., Li, S. and Jeong, S.-J. | Deriving Vegetation Phenological Time and Trajectory Information Over Africa Using SEVIRI Daily LAI | {2014} | IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Vol. {52}({2}), pp. 1113-1130 |
article | DOI |
| Abstract: Vegetation phenology is closely connected to the terrestrial carbon budget, and interacts with the atmosphere through surface water and energy exchange. A comprehensive and detailed characterization of the spatio-temporal pattern of vegetation phenology can be used to improve the understanding of interactions between vegetation and climate in Africa. This research provides an approach to derive phenology time and trajectory parameters by optimally fitting a double-logistic curve to daily remotely sensed leaf area index (LAI) from the spinning enhanced visible and infrared imager. The proposed algorithm can reconstruct the temporal LAI trajectory based on the optimized parameters with a high accuracy, and provides user-defined phenological timing information (e.g., start/end of the growing season) and trajectory information (e.g., leaf emergence/senescence rate and length) using these fitted parameters. Both single and double growing-season cases have been considered with a spatial classification scheme implemented over Africa. The newly derived vegetation phenology of Africa exhibits emerging spatial patterns in growing season length, asymmetric green-up and green-off length/rate, and distinctive phenological features of cropland and natural vegetation. This approach has the potential to be applied globally, and the derived vegetation phenological information will improve dynamic vegetation modeling and climate prediction. |
|||||
BibTeX:
@article{guan14a,
author = {Guan, Kaiyu and Medvigy, David and Wood, Eric F. and Caylor, Kelly K. and Li, Shi and Jeong, Su-Jong},
title = {Deriving Vegetation Phenological Time and Trajectory Information Over Africa Using SEVIRI Daily LAI},
journal = {IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING},
year = {2014},
volume = {52},
number = {2},
pages = {1113--1130},
doi = {https://doi.org/10.1109/TGRS.2013.2247611}
}
|
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| Guerlet, S., Butz, A., Schepers, D., Basu, S., Hasekamp, O.P., Kuze, A., Yokota, T., Blavier, J.F., Deutscher, N.M., Griffith, D.W.T., Hase, F., Kyro, E., Morino, I., Sherlock, V., Sussmann, R., Galli, A. and Aben, I. | Impact of aerosol and thin cirrus on retrieving and validating XCO2 from GOSAT shortwave infrared measurements | {2013} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {118}({10}), pp. 4887-4905 |
article | DOI |
| Abstract: Inadequate treatment of aerosol scattering can be a significant source of error when retrieving column-averaged dry-air mole fractions of CO2 (XCO2) from space-based measurements of backscattered solar shortwave radiation. We have developed a retrieval algorithm, RemoTeC, that retrieves three aerosol parameters (amount, size, and height) simultaneously with XCO2. Here we evaluate the ability of RemoTeC to account for light path modifications by clouds, subvisual cirrus, and aerosols when retrieving XCO2 from Greenhouse Gases Observing Satellite (GOSAT) Thermal and Near-infrared Sensor for carbon Observation (TANSO)-Fourier Transform Spectrometer (FTS) measurements. We first evaluate a cloud filter based on measurements from the Cloud and Aerosol Imager and a cirrus filter that uses radiances measured by TANSO-FTS in the 2micron spectral region, with strong water absorption. For the cloud-screened scenes, we then evaluate errors due to aerosols. We find that RemoTeC is well capable of accounting for scattering by aerosols for values of aerosol optical thickness at 750nm up to 0.25. While no significant correlation of errors is found with albedo, correlations are found with retrieved aerosol parameters. To further improve the XCO2 accuracy, we propose and evaluate a bias correction scheme. Measurements from 12 ground-based stations of the Total Carbon Column Observing Network (TCCON) are used as a reference in this study. We show that spatial colocation criteria may be relaxed using additional constraints based on modeled XCO2 gradients, to increase the size and diversity of validation data and provide a more robust evaluation of GOSAT retrievals. Global-scale validation of satellite data remains challenging and would be improved by increasing TCCON coverage. |
|||||
BibTeX:
@article{guerlet13a,
author = {Guerlet, S. and Butz, A. and Schepers, D. and Basu, S. and Hasekamp, O. P. and Kuze, A. and Yokota, T. and Blavier, J. -F. and Deutscher, N. M. and Griffith, D. W. T. and Hase, F. and Kyro, E. and Morino, I. and Sherlock, V. and Sussmann, R. and Galli, A. and Aben, I.},
title = {Impact of aerosol and thin cirrus on retrieving and validating XCO2 from GOSAT shortwave infrared measurements},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2013},
volume = {118},
number = {10},
pages = {4887--4905},
doi = {https://doi.org/10.1002/jgrd.50332}
}
|
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| Gunn, K.M., Buda, A.R., Preisendanz, H.E., Cibin, R., Kennedy, C.D. and Veith, T.L. | INTEGRATING DAILY CO2 CONCENTRATIONS IN SWAT-VSA TO EXAMINE CLIMATE CHANGE IMPACTS ON HYDROLOGY IN A KARST WATERSHED | 2021 | TRANSACTIONS OF THE ASABE Vol. 64(4), pp. 1303-1318 |
article | DOI |
| Abstract: Characterizing the effects of climate change on hydrology is important to watershed management. In this study, we used SWAT-VSA to examine the effects of climate change and increasing atmospheric CO2 (CO2) on the water balance of Spring Creek watershed, a mixed land-use karst basin in the Upper Chesapeake Bay watershed. First, we modified the stomatal conductance and leaf area index (LAI) routines of SWAT-VSA's Penman-Monteith evapotranspiration (ET) procedure and enabled the model to accept daily CO2 data. Using downscaled climate projections from nine global climate models (GCMs), we then compared water balance estimations from baseline SWAT-VSA against two modified versions of SWAT-VSA. One SWAT-VSA version integrated daily CO2 levels (SWAT-VSA_CO2), while another version added flexible stomatal conductance and LAI routines (SWAT-VSA_CO2+Plant) to the dynamic CO2 capacity. Under current climate (1985-2015), the three SWAT-VSA models produced generally similar water balance estimations, with 51% of precipitation lost to ET and the remainder converted to runoff (10%), lateral flow (9%), and percolate (30%). For future climate (2020-2065), water balance simulations diverged between baseline SWAT-VSA and the two modified SWAT-VSA models with CO2. Notably, variable stomatal conductance and LAI routines produced no detectable effects beyond that of CO2. For the 2020-2065 period, baseline SWAT-VSA projected ET increases of 0.7 mm year(-1), while SWAT-VSA models with CO2 suggested that annual ET could decline by approximately -0.4 mm year(-1) over the same period. As a result, the two CO2-based SWATVSA models predicted streamflow increases of almost 1.6 mm year(-1) over the 2020-2065 period, which were roughly double the streamflow increases projected by baseline SWAT-VSA. In general, SWAT-VSA models with CO2 effects produced 22.4% more streamflow in 2045-2065 than the SWAT-VSA model without CO2. Results also showed that adding daily CO2 to SWAT-VSA reduced ET in wetter parts of Spring Creek watershed, leading to greater runoff losses from variable source areas compared to baseline SWAT-VSA. Findings from the study highlight the importance of considering increasing atmospheric CO2 concentrations in water balance simulations with SWAT-VSA in order to gain a fuller appreciation of the hydrologic uncertainties with climate change. |
|||||
BibTeX:
@article{gunn21a,
author = {Gunn, Kpoti M. and Buda, Anthony R. and Preisendanz, Heather E. and Cibin, Raj and Kennedy, Casey D. and Veith, Tamie L.},
title = {INTEGRATING DAILY CO2 CONCENTRATIONS IN SWAT-VSA TO EXAMINE CLIMATE CHANGE IMPACTS ON HYDROLOGY IN A KARST WATERSHED},
journal = {TRANSACTIONS OF THE ASABE},
year = {2021},
volume = {64},
number = {4},
pages = {1303-1318},
doi = {https://doi.org/10.13031/trans.13711}
}
|
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| Hakkarainen, J., Ialongo, I., Maksyutov, S. and Crisp, D. | Analysis of Four Years of Global XCO2 Anomalies as Seen by Orbiting Carbon Observatory-2 | {2019} | REMOTE SENSING Vol. {11}({7}) |
article | DOI |
| Abstract: NASA's carbon dioxide mission, Orbiting Carbon Observatory-2, began operating in September 2014. In this paper, we analyze four years (2015-2018) of global (60 degrees S-60 degrees N) XCO2 anomalies and their annual variations and seasonal patterns. We show that the anomaly patterns in the column-averaged CO2 dry air mole fraction, XCO2, are robust and consistent from year-to-year. We evaluate the method by comparing the anomalies to fluxes from anthropogenic, biospheric, and biomass burning and to model-simulated local concentration enhancements. We find that, despite the simplicity of the method, the anomalies describe the spatio-temporal variability of XCO2 (including anthropogenic emissions and seasonal variability related to vegetation and biomass burning) consistently with more complex model-based approaches. We see, for example, that positive anomalies correspond to fossil fuel combustion over the major industrial areas (e.g., China, eastern USA, central Europe, India, and the Highveld region in South Africa), shown as large positive XCO2 enhancements in the model simulations. We also find corresponding positive anomalies and fluxes over biomass burning areas during different fire seasons. On the other hand, the largest negative anomalies correspond to the growing season in the northern middle latitudes, characterized by negative XCO2 enhancements from simulations and high solar-induced chlorophyll fluorescence (SIF) values (indicating the occurrence of photosynthesis). The largest discrepancies between the anomaly patterns and the model-based results are observed in the tropical regions, where OCO-2 shows persistent positive anomalies over every season of every year included in this study. Finally, we demonstrate how XCO2 anomalies enable the detection of anthropogenic signatures for several local scale case studies, both in the Northern and Southern Hemisphere. In particular, we analyze the XCO2 anomalies collocated with the recent TROPOspheric Monitoring Instrument NO2 observations (used as indicator of anthropogenic fossil fuel combustion) over the Highveld region in South Africa. The results highlight the capability of satellite-based observations to monitor natural and man-made CO2 signatures on global scale. | |||||
BibTeX:
@article{hakkarainen19a,
author = {Hakkarainen, Janne and Ialongo, Iolanda and Maksyutov, Shamil and Crisp, David},
title = {Analysis of Four Years of Global XCO2 Anomalies as Seen by Orbiting Carbon Observatory-2},
journal = {REMOTE SENSING},
publisher = {MDPI},
year = {2019},
volume = {11},
number = {7},
doi = {https://doi.org/10.3390/rs11070850}
}
|
|||||
| Halder, S., Tiwari, Y.K., Valsala, V., Sreeush, M.G., Sijikumar, S., Janardanan, R. and Maksyutov, S. | Quantification of Enhancement in Atmospheric CO2 Background Due to Indian Biospheric Fluxes and Fossil Fuel Emissions | 2021 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 126(13) |
article | DOI |
| Abstract: Regional carbon emissions impact global atmospheric carbon dioxide (CO2) background concentrations. This study quantified the enhancement in the atmospheric CO2 mole fractions due to biospheric and fossil fuel fluxes from India. Sensitivity experiments using model simulations were conducted, allowing CO2 enhancement due to biospheric and fossil fuel fluxes from India to diffuse into the global atmospheric background. The areal extent of column-averaged enhancement of 0.2 ppm and above due to Indian fluxes are spread over a larger area covering the Indian subcontinent, neighboring Asian regions, and the north Indian Ocean in all four seasons. The boundary layer CO2 enhancement due to biospheric fluxes (fossil fuel fluxes) have a maximum range of -2.6 to +1.4 ppm (1.8-2.0 ppm) most time of the year. At higher altitude, the amplitudes of enhancement are reduced from 1.8 to 0.6 ppm as we go up from 850 to 500 hPa due to diffusion by prevailing atmospheric dynamics and convection. With the information of the areal extent of >0.2 ppm CO2 enhancement due to Indian fluxes, we have evaluated the representativeness of satellite observations (GOSAT and OCO-2) in capturing those enhancements. Both the satellite coverage show a similar number of observations (0.1 per day) during all seasons except for June to August, wherein the cloud screening eliminates almost all the satellite data over the region. Within this areal extent, the satellite XCO2 shows average anomalies of nearly 2.0 ppm; it is a valuable piece of information because it is well above the retrieval uncertainty, yet capturing the potential enhancement due to fluxes from India. The study implies that the regions of enhancement greater than 0.2 ppm can be considered locations for surface observations representing Indian fluxes. Similarly, the region with enhancement greater than one ppm could be covered by satellites/airborne observations to discern enhancement in the atmospheric CO2 mole fractions due to Indian fluxes. Plain Language Summary This study calculates the seasonal enhancement of the atmospheric CO2 concentration (in ppm) due to biospheric fluxes and fossil fuel emissions from India. The regional fluxes of fossil fuel and biospheric activities contribute to the global atmospheric CO2 within a few ppm. Using a global atmospheric tracer transport model and regional fluxes, we show that the enhancement of the atmospheric CO2 due to India's biospheric fluxes and fossil fuel emission spread over a large extent over India and surrounding regions. A tangible value of 1.8 ppm and above can be found in most parts of India and its surrounding regions during significant seasons. The areal extent grows from the boundary layer to the upper atmosphere due to corresponding atmospheric mixing and dynamics. On the surface, the enhancement due to biospheric fluxes is about -2.6 to +1.4 ppm in all four seasons, whereas the enhancement due to fossil fuel shows about 1.8-2 ppm. The extent of discernible enhancement in the global atmospheric background due to Indian fluxes helps us understand the optimum location where all observational efforts should be made to sample Indian emission scenarios from global backgrounds. This study also points out the capability in observing the enhancement of XCO2 by the satellite over India and its surroundings. Satellite observations are crucial where the observations of atmospheric CO2 are limited to constrain the surface fluxes in the inverse modeling study. Satellite measurements can capture the enhancement except June to August when the observations are screened out for cloud contamination. Therefore, surface observations are necessary to capture the enhancement of Indian emissions in the global atmospheric CO2 background in all seasons. Key Points Indian carbon fluxes significantly contribute to the CO2 concentrations as large as +/- 2.0 ppm over India and neighboring regions throughout the year at surface level (i.e., 975 hPa) Satellites are capable of representing the XCO2 anomalies up to +/- 2.0 ppm over corresponding regions; however, they have no data coverage during rainy seasons The study recommends both ground-based and satellite/aircraft measurements of CO2 be employed to observe the larger area of Indian CO2 enhancements |
|||||
BibTeX:
@article{halder21a,
author = {Halder, Santanu and Tiwari, Yogesh K. and Valsala, Vinu and Sreeush, M. G. and Sijikumar, S. and Janardanan, Rajesh and Maksyutov, Shamil},
title = {Quantification of Enhancement in Atmospheric CO2 Background Due to Indian Biospheric Fluxes and Fossil Fuel Emissions},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2021},
volume = {126},
number = {13},
doi = {https://doi.org/10.1029/2021JD034545}
}
|
|||||
| Halloran, P.R. | Does atmospheric CO2 seasonality play an important role in governing the air-sea flux of CO2? | {2012} | BIOGEOSCIENCES Vol. {9}({6}), pp. 2311-2323 |
article | DOI |
| Abstract: The amplitude, phase, and form of the seasonal cycle of atmospheric CO2 concentrations varies on many time and space scales (Peters et al., 2007). Intra-annual CO2 variation is primarily driven by seasonal uptake and release of CO2 by the terrestrial biosphere (Machta et al., 1977; Buchwitz et al., 2007), with a small (Cadule et al., 2010; Heimann et al., 1998), but potentially changing (Gorgues et al., 2010) contribution from the ocean. Variability in the magnitude, spatial distribution, and seasonal drivers of terrestrial net primary productivity (NPP) will be induced by, amongst other factors, anthropogenic CO2 release (Keeling et al., 1996), land-use change (Zimov et al., 1999) and planetary orbital variability, and will lead to changes in CO2atm seasonality. Despite CO2atm seasonality being a dynamic and prominent feature of the Earth System, its potential to drive changes in the air-sea flux of CO2 has not previously (to the best of my knowledge) been explored. It is important that we investigate the impact of CO2atm seasonality change, and the potential for carbon-cycle feedbacks to operate through the modification of the CO2atm seasonal cycle, because the decision had been made to prescribe CO2atm concentrations (rather than emissions) within model simulations for the fifth IPCC climate assessment (Taylor et al., 2009). In this study I undertake ocean-model simulations within which different magnitude CO2atm seasonal cycles are prescribed. These simulations allow me to examine the effect of a change in CO2atm seasonal cycle magnitude on the air-sea CO2 flux. I then use an offline model to isolate the drivers of the identified air-sea CO2 flux change, and propose mechanisms by which this change may come about. Three mechanisms are identified by which co-variability of the seasonal cycles in atmospheric CO2 concentration, and seasonality in sea-ice extent, wind-speed and ocean temperature, could potentially lead to changes in the air-sea flux of CO2 at mid-to-high latitudes. The sea-ice driven mechanism responds to an increase in CO2atm seasonality by pumping CO2 into the ocean, the wind-speed and solubility-driven mechanisms, by releasing CO2 from the ocean (in a relative sense). The relative importance of the mechanisms will be determined by, amongst other variables, the seasonal extent of sea-ice. To capture the described feedbacks within earth system models, CO2atm concentrations must be allowed to evolve freely, forced only by anthropogenic emissions rather than prescribed CO2atm concentrations; however, time-integrated ocean simulations imply that the cumulative net air-sea flux could be at most equivalent to a few ppm CO2atm. The findings presented here suggest that, at least under pre-industrial conditions, the prescription of CO2atm concentrations rather than emissions within simulations will have little impact on the marine anthropogenic CO2 sink. |
|||||
BibTeX:
@article{halloran12a,
author = {Halloran, P. R.},
title = {Does atmospheric CO2 seasonality play an important role in governing the air-sea flux of CO2?},
journal = {BIOGEOSCIENCES},
year = {2012},
volume = {9},
number = {6},
pages = {2311--2323},
doi = {https://doi.org/10.5194/bg-9-2311-2012}
}
|
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| Hari, M. and Tyagi, B. | Terrestrial carbon cycle: tipping edge of climate change between the atmosphere and biosphere ecosystems | 2022 | ENVIRONMENTAL SCIENCE-ATMOSPHERES Vol. 2(5), pp. 867-890 |
article | DOI |
| Abstract: Owing to its tendency to couple with multiple elements, carbon forms complex molecules, which is the basic chemistry of life. Given that the climate system is inextricably coupled with the biosphere, understanding the terrestrial mechanistic pathway of carbon is critical in the transformation of the augmenting atmospheric carbon dioxide (CO2) in future. Although the global terrestrial carbon sink reduces the accumulation of atmospheric CO2, which is contingent on the climate and ecosystem, the underlying key biophysical function that controls the ecosystem-carbon-climate responses and their feedback is uncertain. Accordingly, numerous unprecedented multi-scale studies have highlighted the dynamics of terrestrial carbon by strategically employing in situ, earth observation and process-based models; however, to date, the driving force for its dynamics remains unclassified. Besides, the significant variability in carbon is related to the large uncertainties from changes in land use, unambiguously increasing the regional carbon source from the seasonal to interannual scale but without long-term positive or negative feedback. Accordingly, in this review, we attempt to present a holistic understanding of the terrestrial carbon cycle by addressing its nature and different key drivers. The heterogenetic data platforms that reliably address the terrestrial carbon sink and its source dynamics are discussed in detail to demonstrate the potential of systematic quantification. Moreover, we summarize the complexity of carbon-climate feedbacks and their associates, extending the pathway for understanding the recent terrestrial carbon allocation, where India's environment is highlighted. This comprehensive review can be valuable to the research community in understanding the importance of the present and future carbon-climate feedback. |
|||||
BibTeX:
@article{hari22a,
author = {Hari, Manoj and Tyagi, Bhishma},
title = {Terrestrial carbon cycle: tipping edge of climate change between the atmosphere and biosphere ecosystems},
journal = {ENVIRONMENTAL SCIENCE-ATMOSPHERES},
year = {2022},
volume = {2},
number = {5},
pages = {867-890},
doi = {https://doi.org/10.1039/d1ea00102g}
}
|
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| Haszpra, L., Ramonet, M., Schmidt, M., Barcza, Z., Patkai, Z., Tarczay, K., Yver, C., Tarniewicz, J. and Ciais, P. | Variation of CO2 mole fraction in the lower free troposphere, in the boundary layer and at the surface | {2012} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {12}({18}), pp. 8865-8875 |
article | DOI |
| Abstract: Eight years of occasional flask air sampling and 3 years of frequent in situ measurements of carbon dioxide (CO2) vertical profiles on board of a small aircraft, over a tall tower greenhouse gases monitoring site in Hungary are used for the analysis of the variations of vertical profile of CO2 mole fraction. Using the airborne vertical profiles and the measurements along the 115 m tall tower it is shown that the measurements at the top of the tower estimate the mean boundary layer CO2 mole fraction during the mid-afternoon fairly well, with an underestimation of 0.27-0.85 mu mol mol(-1) in summer, and an overestimation of 0.66-1.83 mu mol mol(-1) in winter. The seasonal cycle of CO2 mole fraction is damped with elevation. While the amplitude of the seasonal cycle is 28.5 mu mol mol(-1) at 10 m above the ground, it is only 10.7 mu mol mol(-1) in the layer of 2500-3000 m corresponding to the lower free atmosphere above the well-mixed boundary layer. The maximum mole fraction in the layer of 2500-3000 m can be observed around 25 March on average, two weeks ahead of that of the marine boundary layer reference (GLOBALVIEW). By contrast, close to the ground, the maximum CO2 mole fraction is observed late December, early January. The specific seasonal behavior is attributed to the climatology of vertical mixing of the atmosphere in the Carpathian Basin. |
|||||
BibTeX:
@article{haszpra12a,
author = {Haszpra, L. and Ramonet, M. and Schmidt, M. and Barcza, Z. and Patkai, Zs and Tarczay, K. and Yver, C. and Tarniewicz, J. and Ciais, P.},
title = {Variation of CO2 mole fraction in the lower free troposphere, in the boundary layer and at the surface},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2012},
volume = {12},
number = {18},
pages = {8865--8875},
doi = {https://doi.org/10.5194/acp-12-8865-2012}
}
|
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| Hayashida, S., Ono, A., Yoshizaki, S., Frankenberg, C., Takeuchi, W. and Yan, X. | Methane concentrations over Monsoon Asia as observed by SCIAMACHY: Signals of methane emission from rice cultivation | {2013} | REMOTE SENSING OF ENVIRONMENT Vol. {139}, pp. 246-256 |
article | DOI |
| Abstract: We have analyzed the column-averaged CH4 concentration (xCH(4)) using scanning imaging absorption spectrometer for atmospheric chartography (SCIAMACHY) and compared the data with the bottom-up emission inventory data sets and other satellite-derived indices such as the land-surface water coverge (LSWC) and the normalized difference vegetation index (NDVI). The geographical distribution of high CH4 values corresponds to strong emissions from regions where rice is cultivated, as indicated in the inventory maps. The Pearson's correlation coefficients (r) between xCH(4) and the rice emission inventory data are observed to be greater than similar to 0.6 over typical rice fields, with outstanding r-values of similar to 0.8 in the Ganges Basin, Myanmar, and Thailand. This suggests that the emission of CH4 from rice cultivation mainly controls the seasonality of the CH4 concentration over such regions. The correlation between xCH(4) and LSWC and NDVI is also as large as 0.6. In Southeast Asia, the r-values of xCH4 with bottom-up inventory data that includes all categories are not as high as those with the emission, as estimated from the rice category only. This is indicative of the relative importance of rice emissions among all other emission categories in Southeast Asia. (C) 2013 Elsevier Inc. All rights reserved. |
|||||
BibTeX:
@article{hayashida13a,
author = {Hayashida, S. and Ono, A. and Yoshizaki, S. and Frankenberg, C. and Takeuchi, W. and Yan, X.},
title = {Methane concentrations over Monsoon Asia as observed by SCIAMACHY: Signals of methane emission from rice cultivation},
journal = {REMOTE SENSING OF ENVIRONMENT},
year = {2013},
volume = {139},
pages = {246--256},
doi = {https://doi.org/10.1016/j.rse.2013.08.008}
}
|
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| Hayes, D.J., Turner, D.P., Stinson, G., McGuire, A.D., Wei, Y., West, T.O., Heath, L.S., Dejong, B., McConkey, B.G., Birdsey, R.A., Kurz, W.A., Jacobson, A.R., Huntzinger, D.N., Pan, Y., Mac Post, W. and Cook, R.B. | Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data | {2012} | GLOBAL CHANGE BIOLOGY Vol. {18}({4}), pp. 1282-1299 |
article | DOI |
| Abstract: We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000-2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a -327 similar to +/-similar to 252 similar to TgC similar to yr-1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (-248 similar to TgC similar to yr-1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (-297 similar to TgC similar to yr-1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 similar to TgC similar to yr-1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated to be a small net source (+18 similar to TgC similar to yr-1) due to land use change between 1993 and 2002. We compare these inventory-based estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is -511 similar to TgC similar to yr-1 and -931 similar to TgC similar to yr-1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional -239 similar to TgC similar to yr-1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches. |
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BibTeX:
@article{hayes12a,
author = {Hayes, Daniel J. and Turner, David P. and Stinson, Graham and McGuire, A. David and Wei, Yaxing and West, Tristram O. and Heath, Linda S. and Dejong, Bernardus and McConkey, Brian G. and Birdsey, Richard A. and Kurz, Werner A. and Jacobson, Andrew R. and Huntzinger, Deborah N. and Pan, Yude and Mac Post, W. and Cook, Robert B.},
title = {Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2012},
volume = {18},
number = {4},
pages = {1282--1299},
doi = {https://doi.org/10.1111/j.1365-2486.2011.02627.x}
}
|
|||||
| Hayes, D. and Turner, D. | The need for ``apples‐to‐apples'' comparisons of carbon dioxide source and sink estimates [BibTeX] |
2012 | Eos, Transactions American Geophysical Union Vol. 93(41), pp. 404-405 |
article | DOI |
BibTeX:
@article{hayes12b,
author = {Hayes, Daniel and Turner, David},
title = {The need for ``apples‐to‐apples'' comparisons of carbon dioxide source and sink estimates},
journal = {Eos, Transactions American Geophysical Union},
year = {2012},
volume = {93},
number = {41},
pages = {404--405},
doi = {https://doi.org/10.1029/2012EO410007/full}
}
|
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| Hazan, L., Tarniewicz, J., Ramonet, M., Laurent, O. and Abbaris, A. | Automatic processing of atmospheric CO2 and CH4 mole fractions at the ICOS Atmosphere Thematic Centre | {2016} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {9}({9}), pp. 4719-4736 |
article | DOI |
| Abstract: The Integrated Carbon Observation System Atmosphere Thematic Centre (ICOS ATC) automatically processes atmospheric greenhouse gases mole fractions of data coming from sites of the ICOS network. Daily transferred raw data files are automatically processed and archived. Data are stored in the ICOS atmospheric database, the backbone of the system, which has been developed with an emphasis on the traceability of the data processing. Many data products, updated daily, explore the data through different angles to support the quality control of the dataset performed by the principal operators in charge of the instruments. The automatic processing includes calibration and water vapor corrections as described in the paper. The mole fractions calculated in near-real time (NRT) are automatically revaluated as soon as a new instrument calibration is processed or when the station supervisors perform quality control. By analyzing data from 11 sites, we determined that the average calibration corrections are equal to 1.7 +/- 0.3 mu mol mol(-1) for CO2 and 2.8 +/- 3 nmol mol(-1) for CH4. These biases are important to correct to avoid artificial gradients between stations that could lead to error in flux estimates when using atmospheric inversion techniques. We also calculated that the average drift between two successive calibrations separated by 15 days amounts to +/- 0.05 mu mol mol(-1) and +/- 0.7 nmol mol(-1) for CO2 and CH4, respectively. Outliers are generally due to errors in the instrument configuration and can be readily detected thanks to the data products provided by the ATC. Several developments are still ongoing to improve the processing, including automated spike detection and calculation of time-varying uncertainties. |
|||||
BibTeX:
@article{hazan16a,
author = {Hazan, Lynn and Tarniewicz, Jerome and Ramonet, Michel and Laurent, Olivier and Abbaris, Amara},
title = {Automatic processing of atmospheric CO2 and CH4 mole fractions at the ICOS Atmosphere Thematic Centre},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2016},
volume = {9},
number = {9},
pages = {4719--4736},
doi = {https://doi.org/10.5194/amt-9-4719-2016}
}
|
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| He, Z., Zeng, Z.-C., Lei, L., Bie, N. and Yang, S. | A Data-Driven Assessment of Biosphere-Atmosphere Interaction Impact on Seasonal Cycle Patterns of XCO2 Using GOSAT and MODIS Observations | {2017} | REMOTE SENSING Vol. {9}({3}) |
article | DOI |
| Abstract: Using measurements of the column-averaged CO2 dry air mole fraction (XCO2) from GOSAT and biosphere parameters, including normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), leaf area index (LAI), gross primary production (GPP), and land surface temperature (LST) from MODIS, this study proposes a data-driven approach to assess the impacts of terrestrial biosphere activities on the seasonal cycle pattern of XCO2. A unique global land mapping dataset of XCO2 with a resolution of 1 degrees by 1 degrees in space, and three days in time, from June 2009 to May 2014, which facilitates the assessment at a fine scale, is first produced from GOSAT XCO2 retrievals. We then conduct a statistical fitting method to obtain the global map of seasonal cycle amplitudes (SCA) of XCO2 and NDVI, and implement correlation analyses of seasonal variation between XCO2 and the vegetation parameters. As a result, the spatial distribution of XCO2 SCA decreases globally with latitude from north to south, which is in good agreement with that of simulated XCO2 from CarbonTracker. The spatial pattern of XCO2 SCA corresponds well to the vegetation seasonal activity revealed by NDVI, with a strong correlation coefficient of 0.74 in the northern hemisphere (NH). Some hotspots in the subtropical areas, including Northern India (with SCA of 8.68 +/- 0.49 ppm on average) and Central Africa (with SCA of 8.33 +/- 0.25 ppm on average), shown by satellite measurements, but missed by model simulations, demonstrate the advantage of satellites in observing the biosphere-atmosphere interactions at local scales. Results from correlation analyses between XCO2 and NDVI, EVI, LAI, or GPP show a consistent spatial distribution, and NDVI and EVI have stronger negative correlations over all latitudes. This may suggest that NDVI and EVI can be better vegetation parameters in characterizing the seasonal variations of XCO2 and its driving terrestrial biosphere activities. We, furthermore, present the global distribution of phase lags of XCO2 compared to NDVI in seasonal variation, which, to our knowledge, is the first such map derived from a completely data-driven approach using satellite observations. The impact of retrieval error of GOSAT data on the mapping data, especially over high-latitude areas, is further discussed. Results from this study provide reference for better understanding the distribution of the strength of carbon sink by terrestrial ecosystems and utilizing remote sensing data in assessing the impact of biosphere-atmosphere interactions on the seasonal cycle pattern of atmospheric CO2 columns. |
|||||
BibTeX:
@article{he17a,
author = {He, Zhonghua and Zeng, Zhao-Cheng and Lei, Liping and Bie, Nian and Yang, Shaoyuan},
title = {A Data-Driven Assessment of Biosphere-Atmosphere Interaction Impact on Seasonal Cycle Patterns of XCO2 Using GOSAT and MODIS Observations},
journal = {REMOTE SENSING},
year = {2017},
volume = {9},
number = {3},
doi = {https://doi.org/10.3390/rs9030251}
}
|
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| He, Z., Lei, L., Welp, L.R., Zeng, Z.-C., Bie, N., Yang, S. and Liu, L. | Detection of Spatiotemporal Extreme Changes in Atmospheric CO2 Concentration Based on Satellite Observations [BibTeX] |
2018 | Remote Sensing Vol. 10 |
article | URL |
BibTeX:
@article{he18a,
author = {Zhonghua He and Liping Lei and Lisa R. Welp and Zhao-Cheng Zeng and Nian Bie and Shaoyuan Yang and Liangyun Liu},
title = {Detection of Spatiotemporal Extreme Changes in Atmospheric CO2 Concentration Based on Satellite Observations},
journal = {Remote Sensing},
year = {2018},
volume = {10},
url = {https://www.mdpi.com/2072-4292/10/6/839}
}
|
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| He, W., Ju, W., Schwaim, C.R., Sippel, S., Wu, X., He, Q., Song, L., Zhang, C., Li, J., Sitch, S., Viovy, N., Friedlingstein, P. and Jain, A.K. | Large-Scale Droughts Responsible for Dramatic Reductions of Terrestrial Net Carbon uptake Over North America in 2011 and 2012 | {2018} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {123}({7}), pp. {2053-2071} |
article | DOI |
| Abstract: Recently, severe droughts that occurred in North America are likely to have impacted its terrestrial carbon sink. However, process-based understanding of how meteorological conditions prior to the onset of drought, for instance warm or cold springs, affect drought-induced carbon cycle effects remains scarce. Here we assess and compare the response of terrestrial carbon fluxes to summer droughts in 2011 and 2012 characterized by contrasting spring conditions. The analysis is based on a comprehensive ensemble of carbon cycle models, including FLUXCOM, TRENDY v5, SiBCASA, CarbonTracker Europe, and CarbonTracker, and emerging Earth observations. In 2011, large reductions of net ecosystem production (NEP; -0.24 +/- 0.17 Pg C/year) are due to decreased gross primary production (-0.17 +/- 0.18 Pg C/year) and slightly increased ecosystem respiration (+0.07 +/- 0.17 Pg C/year). Conversely, in 2012, NEP reductions (-0.17 +/- 0.25 Pg C/year) are attributed to a larger increase of ecosystem respiration (+0.48 +/- 0.27 Pg C/year) than gross primary production (+0.31 +/- 0.29 Pg C/year), induced predominantly by an extra warmer spring prior to summer drought. Two temperate ecoregions crops/agriculture and the grass/shrubs contribute largest to these reductions and also dominate the interannual variations of NEP during 2007-2014. Moreover, the warming spring compensated largely the negative carbon anomaly due to summer drought, consistent with earlier studies; however, the compensation occurred only in some specific ecoregions. Overall, our analysis offers a refined view on recent carbon cycle variability and extremes in North America. It corroborates earlier results but also highlights differences with respect to ecoregion-specific carbon cycle responses to drought and heat. |
|||||
BibTeX:
@article{he18b,
author = {He, Wei and Ju, Weimin and Schwaim, Christopher R. and Sippel, Sebastian and Wu, Xiaocui and He, Qiaoning and Song, Lian and Zhang, Chunhua and Li, Jing and Sitch, Stephen and Viovy, Nicolas and Friedlingstein, Pierre and Jain, Atul K.},
title = {Large-Scale Droughts Responsible for Dramatic Reductions of Terrestrial Net Carbon uptake Over North America in 2011 and 2012},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2018},
volume = {123},
number = {7},
pages = {2053-2071},
doi = {https://doi.org/10.1029/2018JG004520}
}
|
|||||
| He, W., van der Velde, I.R., Andrews, A.E., Sweeney, C., Miller, J., Tans, P., van der Laan-Luijkx, I.T., Nehrkorn, T., Mountain, M., Ju, W., Peters, W. and Chen, H. | CTDAS-Lagrange v1. 0: A high-resolution data assimilation system for regional carbon dioxide observations [BibTeX] |
2018 | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. 11, pp. 3515-3536 |
article | URL |
BibTeX:
@article{he18c,
author = {Wei He and Ivar R. van der Velde and Arlyn E. Andrews and Colm Sweeney and John Miller and Pieter Tans and Ingrid T. van der Laan-Luijkx and Thomas Nehrkorn and Marikate Mountain and Weimin Ju and Wouter Peters and Huilin Chen},
title = {CTDAS-Lagrange v1. 0: A high-resolution data assimilation system for regional carbon dioxide observations},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2018},
volume = {11},
pages = {3515-3536},
url = {https://www.geosci-model-dev.net/11/3515/2018/gmd-11-3515-2018.pdf}
}
|
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| He, L., Magney, T., Dutta, D., Yin, Y., Kohler, P., Grossmann, K., Stutz, J., Dold, C., Hatfield, J., Guan, K., Peng, B. and Frankenberg, C. | From the Ground to Space: Using Solar-Induced Chlorophyll Fluorescence to Estimate Crop Productivity | {2020} | GEOPHYSICAL RESEARCH LETTERS Vol. {47}({7}) |
article | DOI URL |
| Abstract: Timely and accurate monitoring of crops is essential for food security. Here, we examine how well solar-induced chlorophyll fluorescence (SIF) can inform crop productivity across the United States. Based on tower-level observations and process-based modeling, we find highly linear gross primary production (GPP):SIF relationships for C4 crops, while C3 crops show some saturation of GPP at high light when SIF continues to increase. C4 crops yield higher GPP:SIF ratios (30-50%) primarily because SIF is most sensitive to the light reactions (does not account for photorespiration). Scaling to the satellite, we compare SIF from the TROPOspheric Monitoring Instrument (TROPOMI) against tower-derived GPP and county-level crop statistics. Temporally, TROPOMI SIF strongly agrees with GPP observations upscaled across a corn and soybean dominated cropland (R-2 = 0.89). Spatially, county-level TROPOMI SIF correlates with crop productivity (R-2 = 0.72; 0.86 when accounting for planted area and C3/C4 contributions), highlighting the potential of SIF for reliable crop monitoring. Plain Language Summary Crop monitoring is essential for ensuring food security, but reliable, instantaneous production estimates at the global scale are lacking. The monitoring of crop production in a changing climate is of paramount importance to sustainable food security. Accurate estimates of crop production are dependent on adequately quantifying crop photosynthesis. Our paper demonstrates that solar-induced chlorophyll fluorescence (SIF), an emission of red to far-red light from chlorophyll is highly correlated with crop photosynthesis. We show that a new high spatial resolution satellite SIF data set is highly correlated with crop productivity in the United States, which is benchmarked by the United States Department of Agriculture county-level crop statistics. These results will improve the understanding of crop production and carbon flux over agricultural lands, as well as provide an accurate, large-scale, and timely monitoring method for global crop production estimates. | |||||
BibTeX:
@article{he20a,
author = {He, Liyin and Magney, Troy and Dutta, Debsunder and Yin, Yi and Kohler, Philipp and Grossmann, Katja and Stutz, Jochen and Dold, Christian and Hatfield, Jerry and Guan, Kaiyu and Peng, Bin and Frankenberg, Christian},
title = {From the Ground to Space: Using Solar-Induced Chlorophyll Fluorescence to Estimate Crop Productivity},
journal = {GEOPHYSICAL RESEARCH LETTERS},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {47},
number = {7},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL087474},
doi = {https://doi.org/10.1029/2020GL087474}
}
|
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| He, Z., Lei, L., Zeng, Z.-C., Sheng, M. and Welp, L.R. | Evidence of Carbon Uptake Associated with Vegetation Greening Trends in Eastern China | {2020} | REMOTE SENSING Vol. {12}({4}) |
article | DOI |
| Abstract: Persistent and widespread increase of vegetation cover, identified as greening, has been observed in areas of the planet over late 20th century and early 21st century by satellite-derived vegetation indices. It is difficult to verify whether these regions are net carbon sinks or sources by studying vegetation indices alone. In this study, we investigate greening trends in Eastern China (EC) and corresponding trends in atmospheric CO2 concentrations. We used multiple vegetation indices including NDVI and EVI to characterize changes in vegetation activity over EC from 2003 to 2016. Gap-filled time series of column-averaged CO2 dry air mole fraction (XCO2) from January 2003 to May 2016, based on observations from SCIAMACHY, GOSAT, and OCO-2 satellites, were used to calculate XCO2 changes during growing season for 13 years. We derived a relationship between XCO2 and surface net CO2 fluxes from two inversion model simulations, CarbonTracker and Monitoring Atmospheric Composition and Climate (MACC), and used those relationships to estimate the biospheric CO2 flux enhancement based on satellite observed XCO2 changes. We observed significant growing period (GP) greening trends in NDVI and EVI related to cropland intensification and forest growth in the region. After removing the influence of large urban center CO2 emissions, we estimated an enhanced XCO2 drawdown during the GP of -0.070 to -0.084 ppm yr(-1). Increased carbon uptake during the GP was estimated to be 28.41 to 46.04 Tg C, mainly from land management, which could offset about 2-3% of EC's annual fossil fuel emissions. These results show the potential of using multi-satellite observed XCO2 to estimate carbon fluxes from the regional biosphere, which could be used to verify natural sinks included as national contributions of greenhouse gas emissions reduction in international climate change agreements like the UNFCC Paris Accord. | |||||
BibTeX:
@article{he20b,
author = {He, Zhonghua and Lei, Liping and Zeng, Zhao-Cheng and Sheng, Mengya and Welp, Lisa R.},
title = {Evidence of Carbon Uptake Associated with Vegetation Greening Trends in Eastern China},
journal = {REMOTE SENSING},
publisher = {MDPI},
year = {2020},
volume = {12},
number = {4},
doi = {https://doi.org/10.3390/rs12040718}
}
|
|||||
| He, Z., Lei, L., Zhang, Y., Sheng, M., Wu, C., Li, L., Zeng, Z.-C. and We, L.R. | Spatio-Temporal Mapping of Multi-Satellite Observed Column Atmospheric CO2 Using Precision-Weighted Kriging Method | {2020} | REMOTE SENSING Vol. {12}({3}) |
article | DOI |
| Abstract: Column-averaged dry air mole fraction of atmospheric CO2 (XCO2), obtained by multiple satellite observations since 2003 such as ENVISAT/SCIAMACHY, GOSAT, and OCO-2 satellite, is valuable for understanding the spatio-temporal variations of atmospheric CO2 concentrations which are related to carbon uptake and emissions. In order to construct long-term spatio-temporal continuous XCO2 from multiple satellites with different temporal and spatial periods of observations, we developed a precision-weighted spatio-temporal kriging method for integrating and mapping multi-satellite observed XCO2. The approach integrated XCO2 from different sensors considering differences in vertical sensitivity, overpass time, the field of view, repeat cycle and measurement precision. We produced globally mapped XCO2 (GM-XCO2) with spatial/temporal resolution of 1 x 1 degree every eight days from 2003 to 2016 with corresponding data precision and interpolation uncertainty in each grid. The predicted GM-XCO2 precision improved in most grids compared with conventional spatio-temporal kriging results, especially during the satellites overlapping period (0.3-0.5 ppm). The method showed good reliability with R-2 of 0.97 from cross-validation. GM-XCO2 showed good accuracy with a standard deviation of bias from total carbon column observing network (TCCON) measurements of 1.05 ppm. This method has potential applications for integrating and mapping XCO2 or other similar datasets observed from multiple satellite sensors. The resulting GM-XCO2 product may be also used in different carbon cycle research applications with different precision requirements. | |||||
BibTeX:
@article{he20c,
author = {He, Zhonghua and Lei, Liping and Zhang, Yuhui and Sheng, Mengya and Wu, Changjiang and Li, Liang and Zeng, Zhao-Cheng and We, Lisa R.},
title = {Spatio-Temporal Mapping of Multi-Satellite Observed Column Atmospheric CO2 Using Precision-Weighted Kriging Method},
journal = {REMOTE SENSING},
publisher = {MDPI},
year = {2020},
volume = {12},
number = {3},
doi = {https://doi.org/10.3390/rs12030576}
}
|
|||||
| He, W., Jiang, F., Wu, M., Ju, W., Scholze, M., Chen, J.M., Byrne, B., Liu, J., Wang, H., Wang, J., Wang, S., Zhou, Y., Zhang, C., Nguyen, N.T., Shen, Y. and Chen, Z. | China's Terrestrial Carbon Sink Over 2010-2015 Constrained by Satellite Observations of Atmospheric CO2 and Land Surface Variables | 2022 | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. 127(2) |
article | DOI |
| Abstract: The magnitude and distribution of China's terrestrial carbon sink remain uncertain due to insufficient constraints at large scales, whereby satellite data offer great potential for reducing the uncertainty. Here, we present two carbon sink estimates for China constrained either by satellite CO2 column concentrations (XCO2) within the Global Carbon Assimilation System or by remotely sensed soil moisture and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) in addition to in situ CO2 observations within the Carbon Cycle Data Assimilation System. They point to a moderate size of carbon sinks of 0.34 +/- 0.14 (mean +/- unc.) and 0.43 +/- 0.09 PgC/yr during 2010-2015, which are supported by an inventory-based estimate for forest and soil carbon sink (0.26 PgC/yr) and fall in the range of contemporary ensemble atmospheric inversions (0.25-0.48 PgC/yr). They also agree reasonably well on interannual variations, which reflect the carbon sink anomalies induced by regional droughts in southwest China. Furthermore, their spatial distributions are broadly consistent that of the forest inventory-based estimate, indicating that the largest carbon sinks locate in central and eastern China. Their estimates for forest carbon sink coincide fairly well with the inventory-based estimate across different regions, especially when aggregated to the north and south of China. Although enhanced recently by afforestation, China's carbon sink was also significantly weakened by regional droughts, which were often not fully represented in previous in situ CO2-based inversions due to insufficient observations. Our results suggest that satellite-based atmospheric CO2 and land surface observations are vital in characterizing terrestrial net carbon fluxes at regional scales. |
|||||
BibTeX:
@article{he22a,
author = {He, Wei and Jiang, Fei and Wu, Mousong and Ju, Weimin and Scholze, Marko and Chen, Jing M. and Byrne, Brendan and Liu, Junjie and Wang, Hengmao and Wang, Jun and Wang, Songhan and Zhou, Yanlian and Zhang, Chunhua and Ngoc Tu Nguyen and Shen, Yang and Chen, Zhi},
title = {China's Terrestrial Carbon Sink Over 2010-2015 Constrained by Satellite Observations of Atmospheric CO2 and Land Surface Variables},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2022},
volume = {127},
number = {2},
doi = {https://doi.org/10.1029/2021JG006644}
}
|
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| Helbig, M., Chasmer, L.E., Desai, A.R., Kljun, N., Quinton, W.L. and Sonnentag, O. | Direct and indirect climate change effects on carbon dioxide fluxes in a thawing boreal forest-wetland landscape | {2017} | GLOBAL CHANGE BIOLOGY Vol. {23}({8}), pp. 3231-3248 |
article | DOI |
| Abstract: In the sporadic permafrost zone of northwestern Canada, boreal forest carbon dioxide (CO2) fluxes will be altered directly by climate change through changing meteorological forcing and indirectly through changes in landscape functioning associated with thaw-induced collapse-scar bog (` wetland') expansion. However, their combined effect on landscape-scale net ecosystem CO2 exchange (NEELAND), resulting from changing gross primary productivity (GPP) and ecosystem respiration (ER), remains unknown. Here, we quantify indirect land cover change impacts on NEELAND and direct climate change impacts on modeled temperature-and light-limited NEELAND of a boreal forestwetland landscape. Using nested eddy covariance flux towers, we find both GPP and ER to be larger at the landscape compared to the wetland level. However, annual NEELAND (-20 g C m(-2)) and wetland NEE (-24 g C m(-2)) were similar, suggesting negligible wetland expansion effects on NEELAND. In contrast, we find non-negligible direct climate change impacts when modeling NEELAND using projected air temperature and incoming shortwave radiation. At the end of the 21st century, modeled GPP mainly increases in spring and fall due to reduced temperature limitation, but becomes more frequently light-limited in fall. In a warmer climate, ER increases year-round in the absence of moisture stress resulting in net CO2 uptake increases in the shoulder seasons and decreases during the summer. Annually, landscape net CO2 uptake is projected to decline by 25 +/- 14 g C m(-2) for a moderate and 103 +/- 38 g C m(-2) for a high warming scenario, potentially reversing recently observed positive net CO2 uptake trends across the boreal biome. Thus, even without moisture stress, net CO2 uptake of boreal forest-wetland landscapes may decline, and ultimately, these landscapes may turn into net CO2 sources under continued anthropogenic CO2 emissions. We conclude that NEELAND changes are more likely to be driven by direct climate change rather than by indirect land cover change impacts. |
|||||
BibTeX:
@article{helbig17a,
author = {Helbig, Manuel and Chasmer, Laura E. and Desai, Ankur R. and Kljun, Natascha and Quinton, William L. and Sonnentag, Oliver},
title = {Direct and indirect climate change effects on carbon dioxide fluxes in a thawing boreal forest-wetland landscape},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2017},
volume = {23},
number = {8},
pages = {3231--3248},
doi = {https://doi.org/10.1111/gcb.13638}
}
|
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| Hernandez-Carrasco, I., Sudre, J., Garcon, V., Yahia, H., Garbe, C., Paulmier, A., Dewitte, B., Illig, S., Dadou, I., Gonzalez-Davila, M. and Santana-Casiano, J.M. | Reconstruction of super-resolution ocean pCO(2) and air-sea fluxes of CO2 from satellite imagery in the southeastern Atlantic | {2015} | BIOGEOSCIENCES Vol. {12}({17}), pp. 5229-5245 |
article | DOI |
| Abstract: An accurate quantification of the role of the ocean as source/sink of greenhouse gases (GHGs) requires to access the high-resolution of the GHG air-sea flux at the interface. In this paper we present a novel method to reconstruct maps of surface ocean partial pressure of CO2 (pCO(2)) and air-sea CO2 fluxes at super resolution (4 km, i.e., 1/32 degrees at these latitudes) using sea surface temperature (SST) and ocean color (OC) data at this resolution, and CarbonTracker CO2 fluxes data at low resolution (110 km). Inference of super-resolution pCO(2) and air-sea CO2 fluxes is performed using novel nonlinear signal processing methodologies that prove efficient in the context of oceanography. The theoretical background comes from the microcanonical multi-fractal formalism which unlocks the geometrical determination of cascading properties of physical intensive variables. As a consequence, a multi-resolution analysis performed on the signal of the so-called singularity exponents allows for the correct and near optimal cross-scale inference of GHG fluxes, as the inference suits the geometric realization of the cascade. We apply such a methodology to the study offshore of the Benguela area. The inferred representation of oceanic partial pressure of CO2 improves and enhances the description provided by CarbonTracker, capturing the small-scale variability. We examine different combinations of ocean color and sea surface temperature products in order to increase the number of valid points and the quality of the inferred pCO(2) field. The methodology is validated using in situ measurements by means of statistical errors. We find that mean absolute and relative errors in the inferred values of pCO(2) with respect to in situ measurements are smaller than for CarbonTracker. |
|||||
BibTeX:
@article{hernandez-carrasco15a,
author = {Hernandez-Carrasco, I. and Sudre, J. and Garcon, V. and Yahia, H. and Garbe, C. and Paulmier, A. and Dewitte, B. and Illig, S. and Dadou, I. and Gonzalez-Davila, M. and Santana-Casiano, J. M.},
title = {Reconstruction of super-resolution ocean pCO(2) and air-sea fluxes of CO2 from satellite imagery in the southeastern Atlantic},
journal = {BIOGEOSCIENCES},
year = {2015},
volume = {12},
number = {17},
pages = {5229--5245},
doi = {https://doi.org/10.5194/bg-12-5229-2015}
}
|
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| Hernandez-Carrasco, I., Garcon, V., Sudre, J., Garbe, C. and Yahia, H. | Increasing the Resolution of Ocean pCO(2) Maps in the South Eastern Atlantic Ocean Merging Multifractal Satellite-Derived Ocean Variables | {2018} | IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Vol. {56}({11}), pp. {6596-6610} |
article | DOI |
| Abstract: A new methodology has been developed in order to improve the description of the spatial and temporal variability of not well-resolved oceanic variables from other well-observed high-resolution oceanic variables. The method is based on the cross-scale inference of information, incorporating the common features of different multifractal high-resolution variables into a coarser one. An exercise of validation of the methodology has been performed based on the outputs of coupled physical-biogeochemical Regional Ocean Modeling System adapted to the eastern boundary upwelling systems at two spatial resolutions. Once the algorithm has been proved to he effective in increasing the spatial resolution of modeled partial pressure of CO2 at the surface ocean (pCO(2)), we have investigated the capability of our methodology when it is applied to remote sensing data, focusing on the improvement of the temporal description. In this regard, we have inferred daily pCO(2) maps at high resolution (4 km, i.e., 1/24 degrees) fusing monthly pCO(2) data at low resolution (100 kin, i.e., 1 degrees) with the small-scale features contained in daily high-resolution maps of satellite sea surface temperature and Chlorophyll-a. The algorithm has been applied to the South Eastern Atlantic Ocean opening the possibility to obtain an accurate quantification of the CO2 fluxes in relevant coastal regions, such as the eastern boundary upwelling systems. Outputs of our algorithm have been compared with in situ measurements, showing that daily maps inferred from monthly products are in average 6 mu atm closer to the in situ values than the original coarser monthly maps. Furthermore, values of pCO(2) have been improved in points close to the coast with respect to the original input data. |
|||||
BibTeX:
@article{hernandez-carrasco18a,
author = {Hernandez-Carrasco, Ismael and Garcon, Veronique and Sudre, Joel and Garbe, Christoph and Yahia, Hussein},
title = {Increasing the Resolution of Ocean pCO(2) Maps in the South Eastern Atlantic Ocean Merging Multifractal Satellite-Derived Ocean Variables},
journal = {IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING},
year = {2018},
volume = {56},
number = {11},
pages = {6596-6610},
doi = {https://doi.org/10.1109/TGRS.2018.2840526}
}
|
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| Hewitt, A.J. | Investigating land-air carbon fluxes using a Lagrangian model and satellite retrieved carbon dioxide | 2010 | School: University of Leicester | phdthesis | URL |
| Abstract: The existing generation of satellite instruments (such as SCIAMACHY and AIRS) has allowed the retrieval of atmospheric mixing ratios of carbon dioxide. The feasibility of using these and later satellites (OCO-like or GOSAT) to investigate carbon fluxes between the … | |||||
BibTeX:
@phdthesis{hewitt10a,
author = {Alan James Hewitt},
title = {Investigating land-air carbon fluxes using a Lagrangian model and satellite retrieved carbon dioxide},
school = {University of Leicester},
year = {2010},
url = {https://leicester.figshare.com/articles/thesis/Investigating_land-air_carbon_fluxes_using_a_Lagrangian_model_and_satellite_retrieved_carbon_dioxide/10098698/1}
}
|
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| Heymann, J., Schneising, O., Reuter, M., Buchwitz, M., Rozanov, V.V., Velazco, V.A., Bovensmann, H. and Burrows, J.P. | SCIAMACHY WFM-DOAS XCO2: comparison with CarbonTracker XCO2 focusing on aerosols and thin clouds | {2012} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {5}({8}), pp. 1935-1952 |
article | DOI |
| Abstract: Carbon dioxide (CO2) is the most important greenhouse gas whose atmospheric loading has been significantly increased by anthropogenic activity leading to global warming. Accurate measurements and models are needed in order to reliably predict our future climate. This, however, has challenging requirements. Errors in measurements and models need to be identified and minimised. In this context, we present a comparison between satellite-derived column-averaged dry air mole fractions of CO2, denoted XCO2, retrieved from SCIAMACHY/ENVISAT using the WFM-DOAS (weighting function modified differential optical absorption spectroscopy) algorithm, and output from NOAA's global CO2 modelling and assimilation system CarbonTracker. We investigate to what extent differences between these two data sets are influenced by systematic retrieval errors due to aerosols and unaccounted clouds. We analyse seven years of SCIAMACHY WFM-DOAS version 2.1 retrievals (WFMDv2.1) using CarbonTracker version 2010. We investigate to what extent the difference between SCIAMACHY and CarbonTracker XCO2 are temporally and spatially correlated with global aerosol and cloud data sets. For this purpose, we use a global aerosol data set generated within the European GEMS project, which is based on assimilated MODIS satellite data. For clouds, we use a data set derived from CALIOP/CALIPSO. We find significant correlations of the SCIAMACHY minus CarbonTracker XCO2 difference with thin clouds over the Southern Hemisphere. The maximum temporal correlation we find for Darwin, Australia (r(2) = 54%). Large temporal correlations with thin clouds are also observed over other regions of the Southern Hemisphere (e. g. 43% for South America and 31% for South Africa). Over the Northern Hemisphere the temporal correlations are typically much lower. An exception is India, where large temporal correlations with clouds and aerosols have also been found. For all other regions the temporal correlations with aerosol are typically low. For the spatial correlations the picture is less clear. They are typically low for both aerosols and clouds, but depending on region and season, they may exceed 30% (the maximum value of 46% has been found for Darwin during September to November). Overall we find that the presence of thin clouds can potentially explain a significant fraction of the difference between SCIAMACHY WFMDv2.1 XCO2 and CarbonTracker over the Southern Hemisphere. Aerosols appear to be less of a problem. Our study indicates that the quality of the satellite derived XCO2 will significantly benefit from a reduction of scattering related retrieval errors at least for the Southern Hemisphere. |
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BibTeX:
@article{heymann12a,
author = {Heymann, J. and Schneising, O. and Reuter, M. and Buchwitz, M. and Rozanov, V. V. and Velazco, V. A. and Bovensmann, H. and Burrows, J. P.},
title = {SCIAMACHY WFM-DOAS XCO2: comparison with CarbonTracker XCO2 focusing on aerosols and thin clouds},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2012},
volume = {5},
number = {8},
pages = {1935--1952},
doi = {https://doi.org/10.5194/amt-5-1935-2012}
}
|
|||||
| Heymann, J., Bovensmann, H., Buchwitz, M., Burrows, J.P., Deutscher, N.M., Notholt, J., Rettinger, M., Reuter, M., Schneising, O., Sussmann, R. and Warneke, T. | SCIAMACHY WFM-DOAS XCO2: reduction of scattering related errors | {2012} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {5}({10}), pp. 2375-2390 |
article | DOI |
| Abstract: Global observations of column-averaged dry air mole fractions of carbon dioxide (CO2), denoted by XCO2, retrieved from SCIAMACHY on-board ENVISAT can provide important and missing global information on the distribution and magnitude of regional CO2 surface fluxes. This application has challenging precision and accuracy requirements. In a previous publication (Heymann et al., 2012), it has been shown by analysing seven years of SCIAMACHY WFM-DOAS XCO2 (WFMDv2.1) that unaccounted thin cirrus clouds can result in significant errors. In order to enhance the quality of the SCIAMACHY XCO2 data product, we have developed a new version of the retrieval algorithm (WFMDv2.2), which is described in this manuscript. It is based on an improved cloud filtering and correction method using the 1.4 mu m strong water vapour absorption and 0.76 mu m O-2-A bands. The new algorithm has been used to generate a SCIAMACHY XCO2 data set covering the years 2003-2009. The new XCO2 data set has been validated using ground-based observations from the Total Carbon Column Observing Network (TCCON). The validation shows a significant improvement of the new product (v2.2) in comparison to the previous product (v2.1). For example, the standard deviation of the difference to TCCON at Darwin, Australia, has been reduced from 4 ppm to 2 ppm. The monthly regional-scale scatter of the data (defined as the mean intra-monthly standard deviation of all quality filtered XCO2 retrievals within a radius of 350 km around various locations) has also been reduced, typically by a factor of about 1.5. Overall, the validation of the new WFMDv2.2 XCO2 data product can be summarised by a single measurement precision of 3.8 ppm, an estimated regional-scale (radius of 500 km) precision of monthly averages of 1.6 ppm and an estimated regional-scale relative accuracy of 0.8 ppm. In addition to the comparison with the limited number of TCCON sites, we also present a comparison with NOAA's global CO2 modelling and assimilation system Carbon-Tracker. This comparison also shows significant improvements especially over the Southern Hemisphere. |
|||||
BibTeX:
@article{heymann12b,
author = {Heymann, J. and Bovensmann, H. and Buchwitz, M. and Burrows, J. P. and Deutscher, N. M. and Notholt, J. and Rettinger, M. and Reuter, M. and Schneising, O. and Sussmann, R. and Warneke, T.},
title = {SCIAMACHY WFM-DOAS XCO2: reduction of scattering related errors},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2012},
volume = {5},
number = {10},
pages = {2375--2390},
doi = {https://doi.org/10.5194/amt-5-2375-2012}
}
|
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| Heymann, J. | Satellite measurements of carbon dioxide: impact and consideration of atmospheric scattering on the data retrieval and interpretation [BibTeX] |
2013 | School: Universität Bremen | phdthesis | URL |
BibTeX:
@phdthesis{heymann13a,
author = {Heymann, Jens},
title = {Satellite measurements of carbon dioxide: impact and consideration of atmospheric scattering on the data retrieval and interpretation},
school = {Universität Bremen},
year = {2013},
url = {https://d-nb.info/1072047985/34}
}
|
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| Heymann, J., Reuter, M., Hilker, M., Buchwitz, M., Schneising, O., Bovensmann, H., Burrows, J.P., Kuze, A., Suto, H., Deutscher, N.M., Dubey, M.K., Griffith, D.W.T., Hase, F., Kawakami, S., Kivi, R., Morino, I., Petri, C., Roehl, C., Schneider, M., Sherlock, V., Sussmann, R., Velazco, V.A., Warneke, T. and Wunch, D. | Consistent satellite XCO2 retrievals from SCIAMACHY and GOSAT using the BESD algorithm | {2015} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {8}({7}), pp. 2961-2980 |
article | DOI |
| Abstract: Consistent and accurate long-term data sets of global atmospheric concentrations of carbon dioxide (CO2) are required for carbon cycle and climate-related research. However, global data sets based on satellite observations may suffer from inconsistencies originating from the use of products derived from different satellites as needed to cover a long enough time period. One reason for inconsistencies can be the use of different retrieval algorithms. We address this potential issue by applying the same algorithm, the Bremen Optimal Estimation DOAS (BESD) algorithm, to different satellite instruments, SCIAMACHY on-board ENVISAT (March 2002-April 2012) and TANSO-FTS onboard GOSAT (launched in January 2009), to retrieve XCO2, the column-averaged dry-air mole fraction of CO2. BESD has been initially developed for SCIAMACHY XCO2 retrievals. Here, we present the first detailed assessment of the new GOSAT BESD XCO2 product. GOSAT BESD XCO2 is a product generated and delivered to the MACC project for assimilation into ECMWF's Integrated Forecasting System. We describe the modifications of the BESD algorithm needed in order to retrieve XCO2 from GOSAT and present de-tailed comparisons with ground-based observations of XCO2 from the Total Carbon Column Observing Network (TCCON). We discuss detailed comparison results between all three XCO2 data sets (SCIAMACHY, GOSAT and TCCON). The comparison results demonstrate the good consistency between SCIAMACHY and GOSAT XCO2. For example, we found a mean difference for daily averages of -0.60 +/- 1.56 ppm (mean difference +/- standard deviation) for GOSAT-SCIAMACHY (linear correlation coefficient r = 0.82), -0.34 +/- 1.37 ppm (r = 0.86) for GOSAT-TCCON and 0.10 +/- 1.79 ppm (r = 0.75) for SCIAMACHY-TCCON. The remaining differences between GOSAT and SCIAMACHY are likely due to non-perfect collocation (+/- 2 h, 10 degrees x 10 degrees around TCCON sites), i.e. the observed air masses are not exactly identical but likely also due to a still non-perfect BESD retrieval algorithm, which will be continuously improved in the future. Our overarching goal is to generate a satellite-derived XCO2 data set appropriate for climate and carbon cycle research covering the longest possible time period. We therefore also plan to extend the existing SCIAMACHY and GOSAT data set discussed here by also using data from other missions (e.g. OCO-2, GOSAT-2, CarbonSat) in the future. |
|||||
BibTeX:
@article{heymann15a,
author = {Heymann, J. and Reuter, M. and Hilker, M. and Buchwitz, M. and Schneising, O. and Bovensmann, H. and Burrows, J. P. and Kuze, A. and Suto, H. and Deutscher, N. M. and Dubey, M. K. and Griffith, D. W. T. and Hase, F. and Kawakami, S. and Kivi, R. and Morino, I. and Petri, C. and Roehl, C. and Schneider, M. and Sherlock, V. and Sussmann, R. and Velazco, V. A. and Warneke, T. and Wunch, D.},
title = {Consistent satellite XCO2 retrievals from SCIAMACHY and GOSAT using the BESD algorithm},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2015},
volume = {8},
number = {7},
pages = {2961--2980},
doi = {https://doi.org/10.5194/amt-8-2961-2015}
}
|
|||||
| Heymann, J., Reuter, M., Buchwitz, M., Schneising, O., Bovensmann, H., Burrows, J.P., Massart, S., Kaiser, J.W. and Crisp, D. | CO2 emission of Indonesian fires in 2015 estimated from satellite-derived atmospheric CO2 concentrations | {2017} | GEOPHYSICAL RESEARCH LETTERS Vol. {44}({3}), pp. 1537-1544 |
article | DOI |
| Abstract: Indonesia experienced an exceptional number of fires in 2015 as a result of droughts related to the recent El Nio event and human activities. These fires released large amounts of carbon dioxide (CO2) into the atmosphere. Emission databases such as the Global Fire Assimilation System version 1.2 and the Global Fire Emission Database version 4s estimated the CO2 emission to be approximately 1100 MtCO(2) in the time period from July to November 2015. This emission was indirectly estimated by using parameters like burned area, fire radiative power, and emission factors. In the study presented in this paper, we estimate the Indonesian fire CO2 emission by using the column-averaged dry air mole fraction of CO2, XCO2, derived from measurements of the Orbiting Carbon Observatory-2 satellite mission. The estimated CO2 emission is 748 +/- 209 MtCO(2), which is about 30% lower than provided by the emission databases. |
|||||
BibTeX:
@article{heymann17a,
author = {Heymann, J. and Reuter, M. and Buchwitz, M. and Schneising, O. and Bovensmann, H. and Burrows, J. P. and Massart, S. and Kaiser, J. W. and Crisp, D.},
title = {CO2 emission of Indonesian fires in 2015 estimated from satellite-derived atmospheric CO2 concentrations},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2017},
volume = {44},
number = {3},
pages = {1537--1544},
doi = {https://doi.org/10.1002/2016GL072042}
}
|
|||||
| Hilton, T.W. | Spatial structure in North American terrestrial biological carbon fluxes and flux model errors evaluated with a simple land surface model [BibTeX] |
2011 | School: The Pennsylvania State University | phdthesis | URL |
BibTeX:
@phdthesis{hilton11a,
author = {Hilton, Timothy William},
title = {Spatial structure in North American terrestrial biological carbon fluxes and flux model errors evaluated with a simple land surface model},
school = {The Pennsylvania State University},
year = {2011},
url = {http://search.proquest.com/openview/ad1f013a7f8d52fe468d7ba861602aa1/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Hilton, T.W., Davis, K.J., Keller, K. and Urban, N.M. | Improving North American terrestrial CO2 flux diagnosis using spatial structure in land surface model residuals | {2013} | BIOGEOSCIENCES Vol. {10}({7}), pp. 4607-4625 |
article | DOI |
| Abstract: We evaluate spatial structure in North American CO2 flux observations using a simple diagnostic land surface model. The vegetation photosynthesis respiration model (VPRM) calculates net ecosystem exchange (NEE) using locally observed temperature and photosynthetically active radiation (PAR) along with satellite-derived phenology and moisture. We use observed NEE from a group of 65 North American eddy covariance tower sites spanning North America to estimate VPRM parameters for these sites. We investigate spatial coherence in regional CO2 fluxes at several different time scales by using geostatistical methods to examine the spatial structure of model-data residuals. We find that persistent spatial structure does exist in the model-data residuals at a length scale of approximately 400 km (median 402 km, mean 712 km, standard deviation 931 km). This spatial structure defines a flux-tower-based VPRM residual covariance matrix. The residual covariance matrix is useful in constructing prior fluxes for atmospheric CO2 concentration inversion calculations, as well as for constructing a VPRM North American CO2 flux map optimized to eddy covariance observations. Finally (and secondarily), the estimated VPRM parameter values do not separate clearly by plant functional type (PFT). This calls into question whether PFTs can successfully partition ecosystems' fundamental ecological drivers when the viewing lens is a simple model. |
|||||
BibTeX:
@article{hilton13a,
author = {Hilton, T. W. and Davis, K. J. and Keller, K. and Urban, N. M.},
title = {Improving North American terrestrial CO2 flux diagnosis using spatial structure in land surface model residuals},
journal = {BIOGEOSCIENCES},
year = {2013},
volume = {10},
number = {7},
pages = {4607--4625},
doi = {https://doi.org/10.5194/bg-10-4607-2013}
}
|
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| Hilton, T.W., Davis, K.J. and Keller, K. | Evaluating terrestrial CO2 flux diagnoses and uncertainties from a simple land surface model and its residuals | {2014} | BIOGEOSCIENCES Vol. {11}({2}), pp. 217-235 |
article | DOI |
| Abstract: Global terrestrial atmosphere-ecosystem carbon dioxide fluxes are well constrained by the concentration and isotopic composition of atmospheric carbon dioxide. In contrast, considerable uncertainty persists surrounding regional contributions to the net global flux as well as the impacts of atmospheric and biological processes that drive the net flux. These uncertainties severely limit our ability to make confident predictions of future terrestrial biological carbon fluxes. Here we use a simple light-use efficiency land surface model (the Vegetation Photosynthesis Respiration Model, VPRM) driven by remotely sensed temperature, moisture, and phenology to diagnose North American gross ecosystem exchange (GEE), ecosystem respiration, and net ecosystem exchange (NEE) for the period 2001 to 2006. We optimize VPRM parameters to eddy covariance (EC) NEE observations from 65 North American FluxNet sites. We use a separate set of 27 cross-validation FluxNet sites to evaluate a range of spatial and temporal resolutions for parameter estimation. With these results we demonstrate that different spatial and temporal groupings of EC sites for parameter estimation achieve similar sum of squared residuals values through radically different spatial patterns of NEE. We also derive a regression model to estimate observed VPRM errors as a function of VPRM NEE, temperature, and precipitation. Because this estimate is based on model-observation residuals it is comprehensive of all the error sources present in modeled fluxes. We find that 1 km interannual variability in VPRM NEE is of similar magnitude to estimated 1 km VPRM NEE errors. |
|||||
BibTeX:
@article{hilton14a,
author = {Hilton, T. W. and Davis, K. J. and Keller, K.},
title = {Evaluating terrestrial CO2 flux diagnoses and uncertainties from a simple land surface model and its residuals},
journal = {BIOGEOSCIENCES},
year = {2014},
volume = {11},
number = {2},
pages = {217--235},
doi = {https://doi.org/10.5194/bg-11-217-2014}
}
|
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| Hiyama, T., Ueyama, M., Kotani, A., Iwata, H., Nakai, T., Okamura, M., Ohta, T., Harazono, Y., Petrov, R.E. and Maximov, T.C. | Lessons learned from more than a decade of greenhouse gas flux measurements at boreal forests in eastern Siberia and interior Alaska | 2020 | Polar Science | article | URL |
| Abstract: We summarized our recently-published papers on greenhouse gas exchanges at two important boreal regions underlain by permafrost: eastern Siberia and interior Alaska. Relevant literatures were also referred to, and future research directions on the high-latitude … | |||||
BibTeX:
@article{hiyama20a,
author = {Tetsuya Hiyama and Masahito Ueyama and Ayumi Kotani and Hiroki Iwata and Taro Nakai and Mikita Okamura and Takeshi Ohta and Yoshinobu Harazono and Roman E. Petrov and Trofim C. Maximov},
title = {Lessons learned from more than a decade of greenhouse gas flux measurements at boreal forests in eastern Siberia and interior Alaska},
journal = {Polar Science},
year = {2020},
url = {https://www.sciencedirect.com/science/article/pii/S1873965220301250}
}
|
|||||
| Hiyama, T., Ueyama, M., Kotani, A., Iwata, H., Nakai, T., Okamura, M., Ohta, T., Harazono, Y., Petrov, R.E. and Maximov, T.C. | Lessons learned from more than a decade of greenhouse gas flux measurements at boreal forests in eastern Siberia and interior Alaska | 2021 | POLAR SCIENCE Vol. 27 |
article | DOI |
| Abstract: We summarized our recently-published papers on greenhouse gas exchanges at two important boreal regions underlain by permafrost: eastern Siberia and interior Alaska. Relevant literatures were also referred to, and future research directions on the high-latitude terrestrial processes were suggested. Long-term monitoring of CO2 fluxes at the boreal forests revealed that anomalous weather and disturbances changed the CO2 balance. More than a decade is required to return to a CO2 sink at burned forests in interior Alaska. Anomalous high precipitation altered the forest structure in eastern Siberia, shifting the overstory/understory contributions to the CO2 balance. The CH4 emissions were higher in the two boreal forests than in the other boreal forests. Upscaling the in-situ observations and comparisons with top-down approaches revealed considerable inconsistencies exist among the approaches. We recommend the following directions in future research. First, long-term monitoring is indispensable to detect the effect of climate change on ecosystems. Second, disturbance impacts, including fire, thermokarst, and wet spells, need to be quantified. Third, further observations are necessary for constraining CH4 exchange models. Finally, reconciling top-down and bottom-up approaches is required to reduce uncertainty. Prompt sharing of observed data and model products is crucial to improve our understanding of high-latitude processes. |
|||||
BibTeX:
@article{hiyama21a,
author = {Hiyama, Tetsuya and Ueyama, Masahito and Kotani, Ayumi and Iwata, Hiroki and Nakai, Taro and Okamura, Mikita and Ohta, Takeshi and Harazono, Yoshinobu and Petrov, Roman E. and Maximov, Trofim C.},
title = {Lessons learned from more than a decade of greenhouse gas flux measurements at boreal forests in eastern Siberia and interior Alaska},
journal = {POLAR SCIENCE},
year = {2021},
volume = {27},
doi = {https://doi.org/10.1016/j.polar.2020.100607}
}
|
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| Ho, D.T. and Schanze, J.J. | Precipitation-Induced Reduction in Surface Ocean pCO(2): Observations From the Eastern Tropical Pacific Ocean | {2020} | GEOPHYSICAL RESEARCH LETTERS Vol. {47}({15}) |
article | DOI |
| Abstract: Determining air-sea CO2 fluxes using pCO(2) disequilibrium requires knowing the gas transfer velocity and air-sea pCO(2) difference. Most pCO(2) measurements are made from ships, whose uncontaminated seawater intakes are located at >5-m depth to prevent ingestion of air. However, there could be bias in determinations of CO2 fluxes if there is disagreement between pCO(2) measurements at the surface and 5 m. Seawater measurements made at the near surface and 5 m in the eastern Equatorial Pacific Ocean show that precipitation can dilute surface seawater salinity and lower the pCO(2) and dissolved inorganic carbon and raise pH of the same water, and that these changes in ocean chemistry are largely missed by measurements at 5 m. This finding implies that estimates of ocean CO2 uptake might be underestimated, since rain will lower surface ocean pCO(2) in both source and sink regions and, hence, increase uptake in sink regions and decrease outgassing in source regions. | |||||
BibTeX:
@article{ho20a,
author = {Ho, David T. and Schanze, Julian J.},
title = {Precipitation-Induced Reduction in Surface Ocean pCO(2): Observations From the Eastern Tropical Pacific Ocean},
journal = {GEOPHYSICAL RESEARCH LETTERS},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {47},
number = {15},
doi = {https://doi.org/10.1029/2020GL088252}
}
|
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| Honeycutt, W.T., Kim, T., Ley, M.T. and Materer, N.F. | Sensor array for wireless remote monitoring of carbon dioxide and methane near carbon sequestration and oil recovery sites | {2021} | RSC ADVANCES Vol. {11}({12}), pp. {6972-6984} |
article | DOI |
| Abstract: Carbon sequestration and enhanced oil recovery are two important geochemical applications currently deployed using carbon dioxide (CO2), a prevalent greenhouse gas. Despite the push to find ways to use and store excess CO2, the development of a large-area monitoring system is lacking. For these applications, there is little literature reporting the development and testing of sensor systems capable of operating in remote areas without maintenance and having significantly low cost to allow their deployment across a large land area. This paper presents the design and validation of a low-cost solar-power distributed sensing architecture using a wireless mesh network integrated, at selective nodes, into a cellular network. This combination allows an ``internet of things'' approach in remote locations and the integration of a large number of sensor units to monitor CO2 and methane (CH4). This system will allow efficient large area monitoring of both rare catastrophic leaks along with the common micro-seepage of greenhouse gas near carbon sequestration and oil recovery sites. The deployment and testing of the sensor system was performed in an open field at Oklahoma State University. The two-tear network functionality and robustness were determined from a multi-year field study. The reliability of the system was benchmarked by correlating the measured temperature, pressure, and humidity measurement by the network of devices to existing weather data. The CO2 and CH4 gas concentration tracked their expected daily and seasonal cycles. This multi-year field study established that this system can operate in remote areas with minimal human interactions. | |||||
BibTeX:
@article{honeycutt21a,
author = {Honeycutt, Wesley T. and Kim, Taehwan and Ley, M. Tyler and Materer, Nicholas F.},
title = {Sensor array for wireless remote monitoring of carbon dioxide and methane near carbon sequestration and oil recovery sites},
journal = {RSC ADVANCES},
publisher = {ROYAL SOC CHEMISTRY},
year = {2021},
volume = {11},
number = {12},
pages = {6972--6984},
doi = {https://doi.org/10.1039/d0ra08593f}
}
|
|||||
| Houweling, S., Aben, I., Breon, F.-M., Chevallier, F., Deutscher, N., Engelen, R., Gerbig, C., Griffith, D., Hungershoefer, K., Macatangay, R., Marshall, J., Notholt, J., Peters, W. and Serrar, S. | The importance of transport model uncertainties for the estimation of CO2 sources and sinks using satellite measurements | {2010} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {10}({20}), pp. 9981-9992 |
article | DOI |
| Abstract: This study presents a synthetic model intercomparison to investigate the importance of transport model errors for estimating the sources and sinks of CO2 using satellite measurements. The experiments were designed for testing the potential performance of the proposed CO2 lidar A-SCOPE, but also apply to other space borne missions that monitor total column CO2. The participating transport models IFS, LMDZ, TM3, and TM5 were run in forward and inverse mode using common a priori CO2 fluxes and initial concentrations. Forward simulations of column averaged CO2 (xCO(2)) mixing ratios vary between the models by sigma = 0.5 ppm over the continents and sigma = 0.27 ppm over the oceans. Despite the fact that the models agree on average on the sub-ppm level, these modest differences nevertheless lead to significant discrepancies in the inverted fluxes of 0.1 PgC/yr per 10(6) km(2) over land and 0.03 PgC/yr per 10(6) km(2) over the ocean. These transport model induced flux uncertainties exceed the target requirement that was formulated for the A-SCOPE mission of 0.02 PgC/yr per 10(6) km(2), and could also limit the overall performance of other CO2 missions such as GOSAT. A variable, but overall encouraging agreement is found in comparison with FTS measurements at Park Falls, Darwin, Spitsbergen, and Bremen, although systematic differences are found exceeding the 0.5 ppm level. Because of this, our estimate of the impact of transport model uncerainty is likely to be conservative. It is concluded that to make use of the remote sensing technique for quantifying the sources and sinks of CO2 not only requires highly accurate satellite instruments, but also puts stringent requirements on the performance of atmospheric transport models. Improving the accuracy of these models should receive high priority, which calls for a closer collaboration between experts in atmospheric dynamics and tracer transport. |
|||||
BibTeX:
@article{houweling10a,
author = {Houweling, S. and Aben, I. and Breon, F-M and Chevallier, F. and Deutscher, N. and Engelen, R. and Gerbig, C. and Griffith, D. and Hungershoefer, K. and Macatangay, R. and Marshall, J. and Notholt, J. and Peters, W. and Serrar, S.},
title = {The importance of transport model uncertainties for the estimation of CO2 sources and sinks using satellite measurements},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2010},
volume = {10},
number = {20},
pages = {9981--9992},
doi = {https://doi.org/10.5194/acp-10-9981-2010}
}
|
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| Houweling, S., Krol, M., Bergamaschi, P., Frankenberg, C., Dlugokencky, E.J., Morino, I., Notholt, J., Sherlock, V., Wunch, D., Beck, V., Gerbig, C., Chen, H., Kort, E.A., Rockmann, T. and Aben, I. | A multi-year methane inversion using SCIAMACHY, accounting for systematic errors using TCCON measurements | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({8}), pp. 3991-4012 |
article | DOI |
| Abstract: This study investigates the use of total column CH4 (XCH4) retrievals from the SCIAMACHY satellite instrument for quantifying large-scale emissions of methane. A unique data set from SCIAMACHY is available spanning almost a decade of measurements, covering a period when the global CH4 growth rate showed a marked transition from stable to increasing mixing ratios. The TM5 4DVAR inverse modelling system has been used to infer CH4 emissions from a combination of satellite and surface measurements for the period 2003-2010. In contrast to earlier inverse modelling studies, the SCIAMACHY retrievals have been corrected for systematic errors using the TCCON network of ground-based Fourier transform spectrometers. The aim is to further investigate the role of bias correction of satellite data in inversions. Methods for bias correction are discussed, and the sensitivity of the optimized emissions to alternative bias correction functions is quantified. It is found that the use of SCIAMACHY retrievals in TM5 4DVAR increases the estimated inter-annual variability of large-scale fluxes by 22% compared with the use of only surface observations. The difference in global methane emissions between 2-year periods before and after July 2006 is estimated at 27-35 Tg yr(-1). The use of SCIAMACHY retrievals causes a shift in the emissions from the extra-tropics to the tropics of 50 +/- 25 Tg yr(-1). The large uncertainty in this value arises from the uncertainty in the bias correction functions. Using measurements from the HIPPO and BARCA aircraft campaigns, we show that systematic errors in the SCIAMACHY measurements are a main factor limiting the performance of the inversions. To further constrain tropical emissions of methane using current and future satellite missions, extended validation capabilities in the tropics are of critical importance. |
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BibTeX:
@article{houweling14a,
author = {Houweling, S. and Krol, M. and Bergamaschi, P. and Frankenberg, C. and Dlugokencky, E. J. and Morino, I. and Notholt, J. and Sherlock, V. and Wunch, D. and Beck, V. and Gerbig, C. and Chen, H. and Kort, E. A. and Rockmann, T. and Aben, I.},
title = {A multi-year methane inversion using SCIAMACHY, accounting for systematic errors using TCCON measurements},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {8},
pages = {3991--4012},
doi = {https://doi.org/10.5194/acp-14-3991-2014}
}
|
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| Houweling, S., Bergamaschi, P., Chevallier, F., Heimann, M., Kaminski, T., Krol, M., Michalak, A.M. and Patra, P. | Global inverse modeling of CH4 sources and sinks: an overview of methods | {2017} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {17}({1}), pp. 235-256 |
article | DOI |
| Abstract: The aim of this paper is to present an overview of inverse modeling methods that have been developed over the years for estimating the global sources and sinks of CH4. It provides insight into how techniques and estimates have evolved over time and what the remaining shortcomings are. As such, it serves a didactical purpose of introducing apprentices to the field, but it also takes stock of developments so far and reflects on promising new directions. The main focus is on methodological aspects that are particularly relevant for CH4, such as its atmospheric oxidation, the use of methane isotopologues, and specific challenges in atmospheric transport modeling of CH4. The use of satellite retrievals receives special attention as it is an active field of methodological development, with special requirements on the sampling of the model and the treatment of data uncertainty. Regional scale flux estimation and attribution is still a grand challenge, which calls for new methods capable of combining information from multiple data streams of different measured parameters. A process model representation of sources and sinks in atmospheric transport inversion schemes allows the integrated use of such data. These new developments are needed not only to improve our understanding of the main processes driving the observed global trend but also to support international efforts to reduce greenhouse gas emissions. |
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BibTeX:
@article{houweling17a,
author = {Houweling, Sander and Bergamaschi, Peter and Chevallier, Frederic and Heimann, Martin and Kaminski, Thomas and Krol, Maarten and Michalak, Anna M. and Patra, Prabir},
title = {Global inverse modeling of CH4 sources and sinks: an overview of methods},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2017},
volume = {17},
number = {1},
pages = {235--256},
doi = {https://doi.org/10.5194/acp-17-235-2017}
}
|
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| Howe, S. | Model Validation and Estimation of the Complete Carbon Cycle in the Northeastern United States | 2019 | School: University of Maryland | phdthesis | URL |
| Abstract: To obtain accurate greenhouse gas emissions estimates, it is important to understand the influence of the biosphere on atmospheric carbon dioxide (CO2). This is difficult as observations are sparse over large spatial domains. The Northeastern United States is an … | |||||
BibTeX:
@phdthesis{howe19a,
author = {Shaun Howe},
title = {Model Validation and Estimation of the Complete Carbon Cycle in the Northeastern United States},
school = {University of Maryland},
year = {2019},
url = {https://aosc.umd.edu/sites/default/files/dissertations-theses/Shaun%20Howe-Thesis-2019.pdf}
}
|
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| Hsueh, D. | New York City's Metropolitan Dome: past and present CO2 concentration patterns from an urban to rural gradient [BibTeX] |
2009 | School: Columbia University, New York | mastersthesis | |
BibTeX:
@mastersthesis{hsueh09a,
author = {Hsueh, Diana},
title = {New York City's Metropolitan Dome: past and present CO2 concentration patterns from an urban to rural gradient},
school = {Columbia University, New York},
year = {2009}
}
|
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| Hsueh, Y.-H., Li, K.-F., Lin, L.-C., Bhattacharya, S.K., Laskar, A.H. and Liang, M.-C. | East Asian CO2 level change caused by Pacific Decadal Oscillation | 2021 | REMOTE SENSING OF ENVIRONMENT Vol. 264 |
article | DOI |
| Abstract: Accurate projection of CO2 concentration in time and space remains challenging because of complex interplay between anthropogenic emissions, biospheric responses, and climatic variabilities. While the increase of atmospheric CO2 concentration is due primarily to fossil fuel burning, natural climate variabilities are known to introduce intermittent changes in the global CO2 growth rates. Thus, understanding the correlation of climate and carbon cycling systems is important in assessing the anthropogenic and natural impacts. Here, we report decadal CO2 variabilities in western Pacific based on data from several ground-based stations in the region and Atmospheric Infrared Sounder (AIRS). In addition to the well-established El Nino-Southern Oscillation (ENSO), there exists a decadal changing CO2 trend in the datasets mentioned above. Analysis of ground-based CO2 measurements in northern Taiwan shows a decadal signal at amplitudes of -5 ppm. In contrast, AIRS shows a similar trend but at a reduced amplitude of -1 ppm. We attribute the decadal signal to dynamical factors related to the Pacific Decadal Oscillation (PDO). This decadal signal, however, is not reproduced by the state-of-the-art data assimilation system, CarbonTacker, suggesting a gap in our knowledge of the modulation of carbon cycling systems and climate. |
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BibTeX:
@article{hsueh21a,
author = {Hsueh, Yu-Hsin and Li, King-Fai and Lin, Li-Ching and Bhattacharya, Sourendra Kumar and Laskar, Amzad H. and Liang, Mao-Chang},
title = {East Asian CO2 level change caused by Pacific Decadal Oscillation},
journal = {REMOTE SENSING OF ENVIRONMENT},
year = {2021},
volume = {264},
doi = {https://doi.org/10.1016/j.rse.2021.112624}
}
|
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| Hu, L., Montzka, S.A., Miller, J.B., Andrews, A.E., Lehman, S.J., Miller, B.R., Thoning, K., Sweeney, C., Chen, H., Godwin, D.S., Masarie, K., Bruhwiler, L., Fischer, M.L., Biraud, S.C., Torn, M.S., Mountain, M., Nehrkorn, T., Eluszkiewicz, J., Miller, S., Draxler, R.R., Stein, A.F., Hall, B.D., Elkins, J.W. and Tans, P.P. | US emissions of HFC-134a derived for 2008-2012 from an extensive flask-air sampling network | {2015} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {120}({2}), pp. 801-825 |
article | DOI |
| Abstract: U.S. national and regional emissions of HFC-134a are derived for 2008-2012 based on atmospheric observations from ground and aircraft sites across the U.S. and a newly developed regional inverse model. Synthetic data experiments were first conducted to optimize the model assimilation design and to assess model-data mismatch errors and prior flux error covariances computed using a maximum likelihood estimation technique. The synthetic data experiments also tested the sensitivity of derived national and regional emissions to a range of assumed prior emissions, with the goal of designing a system that was minimally reliant on the prior. We then explored the influence of additional sources of error in inversions with actual observations, such as those associated with background mole fractions and transport uncertainties. Estimated emissions of HFC-134a range from 52 to 61 Gg yr(-1) for the contiguous U.S. during 2008-2012 for inversions using air transport from Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model driven by the 12km resolution meteorogical data from North American Mesoscale Forecast System (NAM12) and all tested combinations of prior emissions and background mole fractions. Estimated emissions for 2008-2010 were 20% lower when specifying alternative transport from Stochastic Time-Inverted Lagrangian Transport (STILT) model driven by the Weather Research and Forecasting (WRF) meteorology. Our estimates (for HYSPLIT-NAM12) are consistent with annual emissions reported by U.S. Environmental Protection Agency for the full study interval. The results suggest a 10-20% drop in U.S. national HFC-134a emission in 2009 coincident with a reduction in transportation-related fossil fuel CO2 emissions, perhaps related to the economic recession. All inversions show seasonal variation in national HFC-134a emissions in all years, with summer emissions greater than winter emissions by 20-50%. |
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BibTeX:
@article{hu15a,
author = {Hu, Lei and Montzka, Stephen A. and Miller, John B. and Andrews, Aryln E. and Lehman, Scott J. and Miller, Benjamin R. and Thoning, Kirk and Sweeney, Colm and Chen, Huilin and Godwin, David S. and Masarie, Kenneth and Bruhwiler, Lori and Fischer, Marc L. and Biraud, Sebastien C. and Torn, Margaret S. and Mountain, Marikate and Nehrkorn, Thomas and Eluszkiewicz, Janusz and Miller, Scot and Draxler, Roland R. and Stein, Ariel F. and Hall, Bradley D. and Elkins, James W. and Tans, Pieter P.},
title = {US emissions of HFC-134a derived for 2008-2012 from an extensive flask-air sampling network},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2015},
volume = {120},
number = {2},
pages = {801--825},
doi = {https://doi.org/10.1002/2014JD022617}
}
|
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| Hu, C., Griffis, T.J., Lee, X., Millet, D.B., Chen, Z., Baker, J.M. and Xiao, K. | Top-Down Constraints on Anthropogenic CO2 Emissions Within an Agricultural-Urban Landscape | {2018} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {123}({9}), pp. {4674-4694} |
article | DOI |
| Abstract: Anthropogenic carbon dioxide (CO2) emissions dominate the atmospheric greenhouse gas radiative forcing budget. However, these emissions are poorly constrained at the regional (10(2)-10(6)km(2)) and seasonal scales. Here we use a combination of tall tower CO2 mixing ratio and carbon isotope ratio observations and inverse modeling techniques to constrain anthropogenic CO2 emissions within a highly heterogeneous agricultural landscape near Saint Paul, Minnesota, in the Upper Midwestern United States. The analyses indicate that anthropogenic emissions contributed 6.6, 6.8, and 7.4mol/mol annual CO2 enhancements (i.e., departures from the background values) in 2008, 2009, and 2010, respectively. Oil refinery, the energy industry (power and heat generation), and residential emissions (home heating and cooking) contributed 2.9 (42.5%), 1.4 (19.8%), and 1.1mol/mol (15.8%) of the total anthropogenic enhancement over the 3-year period according to a priori inventories. The total anthropogenic signal was further partitioned into CO2 emissions derived from fuel oil, natural gas, coal, gasoline, and diesel consumption using inverse modeling and carbon isotope ratio analyses. The results indicate that fuel oil and natural gas consumption accounted for 52.5% of the anthropogenic CO2 sources in winter. Here the a posteriori CO2 emission from natural gas was 79.04.1% (a priori 20.0%) and accounted for 63% of the total CO2 enhancement including both biological and anthropogenic sources. The a posteriori CO2 emission from fuel oil was 8.43.8% (a priori 32.5%)suggesting a more important role of residential heating in winter. The modeled carbon isotope ratio of the CO2 source (delta C-13(s), -29.3 +/- 0.4%) was relatively more enriched in C-13-CO2 compared to that derived from Miller-Tans plot analyses (-35.5 parts per thousand to -34.8 parts per thousand), supporting that natural gas consumption was underestimated for this region. |
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BibTeX:
@article{hu18a,
author = {Hu, Cheng and Griffis, Timothy J. and Lee, Xuhui and Millet, Dylan B. and Chen, Zichong and Baker, John M. and Xiao, Ke},
title = {Top-Down Constraints on Anthropogenic CO2 Emissions Within an Agricultural-Urban Landscape},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2018},
volume = {123},
number = {9},
pages = {4674-4694},
doi = {https://doi.org/10.1029/2017JD027881}
}
|
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| Hu, H., Landgraf, J., Detmers, R., Borsdorff, T., de Brugh, J.A., Aben, I., Butz, A. and Hasekamp, O. | Toward Global Mapping of Methane With TROPOMI: First Results and Intersatellite Comparison to GOSAT | {2018} | GEOPHYSICAL RESEARCH LETTERS Vol. {45}({8}), pp. {3682-3689} |
article | DOI |
| Abstract: The TROPOspheric Monitoring Instrument (TROPOMI), launched on 13 October 2017, aboard the Sentinel-5 Precursor satellite, measures reflected sunlight in the ultraviolet, visible, near-infrared, and shortwave infrared spectral range. It enables daily global mapping of key atmospheric species for monitoring air quality and climate. We present the first methane observations from November and December 2017, using TROPOMI radiance measurements in the shortwave infrared band around 2.3 mu m. We compare our results with the methane product obtained from the Greenhouse gases Observing SAT-ellite (GOSAT). Although different spectral ranges and retrieval methods are used, we find excellent agreement between the methane products acquired from the two satellites with a mean difference of 13.6 ppb, standard deviation of 19.6 ppb, and Pearson's correlation coefficient of 0.95. Our preliminary results capture the latitudinal gradient and show expected regional enhancements, for example, in the African Sudd wetlands, with much more detail than has been observed before. Plain Language Summary Methane is the second most important anthropogenic greenhouse gas. Improved knowledge about methane variations and detection of localized sources is of great importance for scientists, policy makers, and private companies. One of the goals of the recently launched European Space Agency Sentinel-5 Precursor satellite, with on board the cutting-edge TROPOspheric Monitoring Instrument (TROPOMI), is to measure methane with an unprecedented combination of accuracy, spatial coverage, and resolution. This work presents the first TROPOMI methane measurements and shows that these are in excellent agreement with methane measurements from the validated Japanese Greenhouse gases Observing SATellite satellite. |
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BibTeX:
@article{hu18b,
author = {Hu, Haili and Landgraf, Jochen and Detmers, Rob and Borsdorff, Tobias and de Brugh, Joost Aan and Aben, Ilse and Butz, Andre and Hasekamp, Otto},
title = {Toward Global Mapping of Methane With TROPOMI: First Results and Intersatellite Comparison to GOSAT},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2018},
volume = {45},
number = {8},
pages = {3682-3689},
doi = {https://doi.org/10.1002/2018GL077259}
}
|
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| Hu, C., Liu, S., Wang, Y., Zhang, M., Xiao, W., Wang, W. and Xu, J. | Anthropogenic CO2 emissions from a megacity in the Yangtze River Delta of China | {2018} | ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH Vol. {25}({23, SI}), pp. {23157-23169} |
article | DOI |
| Abstract: Anthropogenic CO2 emissions from cities represent a major source contributing to the global atmospheric CO2 burden. Here, we examined the enhancement of atmospheric CO2 mixing ratios by anthropogenic emissions within the Yangtze River Delta (YRD), China, one of the world's most densely populated regions (population greater than 150 million). Tower measurements of CO2 mixing ratios were conducted from March 2013 to August 2015 and were combined with numerical source footprint modeling to help constrain the anthropogenic CO2 emissions. We simulated the CO2 enhancements (i.e., fluctuations superimposed on background values) for winter season (December, January, and February). Overall, we observed mean diurnal variation of CO2 enhancement of 23.5 similar to 49.7 mu mol mol(-1), 21.4 similar to 52.4 mu mol mol(-1), 28.1 similar to 55.4 mu mol mol(-1), and 29.5 similar to 42.4 mu mol mol(-1) in spring, summer, autumn, and winter, respectively. These enhancements were much larger than previously reported values for other countries. The diurnal CO2 enhancements reported here showed strong similarity for all 3 years of the study. Results from source footprint modeling indicated that our tower observations adequately represent emissions from the broader YRD area. Here, the east of Anhui and the west of Jiangsu province contributed significantly more to the anthropogenic CO2 enhancement compared to the other sectors of YRD. The average anthropogenic CO2 emission in 2014 was 0.162 (+/- 0.005) mg m(-2) s(-1) and was 7 +/- 3% higher than 2010 for the YRD. Overall, our emission estimates were significantly smaller (9.5%) than those estimated (0.179 mg m(-2) s(-1)) from the EDGAR emission database. |
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BibTeX:
@article{hu18c,
author = {Hu, Cheng and Liu, Shoudong and Wang, Yongwei and Zhang, Mi and Xiao, Wei and Wang, Wei and Xu, Jiaping},
title = {Anthropogenic CO2 emissions from a megacity in the Yangtze River Delta of China},
journal = {ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH},
year = {2018},
volume = {25},
number = {23, SI},
pages = {23157-23169},
doi = {https://doi.org/10.1007/s11356-018-2325-3}
}
|
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| Hu, C., Griffis, T.J., Liu, S., Xiao, W., Hu, N., Huang, W., Yang, D. and Lee, X. | Anthropogenic Methane Emission and Its Partitioning for the Yangtze River Delta Region of China | {2019} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {124}({5}), pp. {1148-1170} |
article | DOI URL |
| Abstract: Urban areas are global methane (CH4) hotspots. Yet large uncertainties still remain for the CH4 budget of these domains. The Yangtze River Delta (YRD), China, is one of the world's most densely populated regions where a large number of cities are located. To estimate anthropogenic CH4 emissions in YRD, we conducted simultaneous atmospheric CH4 and CO2 mixing ratio measurements from June 2010 to April 2011. By combining these measurements with the Weather Research and Forecasting and Stochastic Time-Inverted Lagrangian Transport models and a priori Emission Database for Global Atmospheric Research emission inventories, we applied three top-down approaches to constrain anthropogenic CH4 emissions. These three approaches included multiplicative scaling factors, flux ratio, and scale factor Bayesian inversion. The posteriori CH4 flux density estimated from the three approaches showed high consistency and were 36.32 (9.17), 35.66 (2.92), and 36.03(14.25) nmolm(-2)s(-1), respectively, for the duration of the study period (November 2010 to April 2011). The total annual anthropogenic CH4 emission was 6.52(1.59) Tg for the YRD region based on the average of these three approaches. Our emission estimates were 30.2(+/- 17.6)%, 31.5 (+/- 5.6)%, and 30.8 (+/- 27.4)% lower than the a priori Emission Database for Global Atmospheric Research v432 emission inventory estimate. The scale factor Bayesian inversion results indicate that the overestimate was mainly caused by two source categories including fuel exploitation and agricultural soil emissions (rice cultivation). The posteriori flux densities for agricultural soil and fuel exploitation were 10.68 and 6.34nmolm(-2)s(-1), respectively, and were 47.8% and 29.2% lower than the a priori inventory. Agricultural soil was the largest source contribution and accounted for 29.6% of the YRD CH4 budget during the study period. | |||||
BibTeX:
@article{hu19a,
author = {Hu, Cheng and Griffis, Timothy J. and Liu, Shoudong and Xiao, Wei and Hu, Ning and Huang, Wenjing and Yang, Dong and Lee, Xuhui},
title = {Anthropogenic Methane Emission and Its Partitioning for the Yangtze River Delta Region of China},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2019},
volume = {124},
number = {5},
pages = {1148--1170},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JG004850},
doi = {https://doi.org/10.1029/2018JG004850}
}
|
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| Hu, L., Andrews, A.E., Thoning, K.W., Sweeney, C., Miller, J.B., Michalak, A.M., Dlugokencky, E., Tans, P.P., Shiga, Y.P., Mountain, M., Nehrkorn, T., Montzka, S.A., McKain, K., Kofler, J., Trudeau, M., Michel, S.E., Biraud, S.C., Fischer, M.L., Worthy, D.E.J., Vaughn, B.H., White, J.W.C., Yadav, V., Basu, S. and van der Velde, I.R. | Enhanced North American carbon uptake associated with El Nino | {2019} | SCIENCE ADVANCES Vol. {5}({6}) |
article | DOI URL |
| Abstract: Long-term atmospheric CO2 mole fraction and delta(CO2)-C-13 observations over North America document persistent responses to the El Nino-Southern Oscillation. We estimate these responses corresponded to 0.61 (0.45 to 0.79) PgC year(-1) more North American carbon uptake during El Nino than during La Nina between 2007 and 2015, partially offsetting increases of net tropical biosphere-to-atmosphere carbon flux around El Nino. Anomalies in derived North American net ecosystem exchange (NEE) display strong but opposite correlations with surface air temperature between seasons, while their correlation with water availability was more constant throughout the year, such that water availability is the dominant control on annual NEE variability over North America. These results suggest that increased water availability and favorable temperature conditions (warmer spring and cooler summer) caused enhanced carbon uptake over North America near and during El Nino. | |||||
BibTeX:
@article{hu19b,
author = {Hu, Lei and Andrews, Arlyn E. and Thoning, Kirk W. and Sweeney, Colm and Miller, John B. and Michalak, Anna M. and Dlugokencky, Ed and Tans, Pieter P. and Shiga, Yoichi P. and Mountain, Marikate and Nehrkorn, Thomas and Montzka, Stephen A. and McKain, Kathryn and Kofler, Jonathan and Trudeau, Michael and Michel, Sylvia E. and Biraud, Sebastien C. and Fischer, Marc L. and Worthy, Doug E. J. and Vaughn, Bruce H. and White, James W. C. and Yadav, Vineet and Basu, Sourish and van der Velde, Ivar R.},
title = {Enhanced North American carbon uptake associated with El Nino},
journal = {SCIENCE ADVANCES},
publisher = {AMER ASSOC ADVANCEMENT SCIENCE},
year = {2019},
volume = {5},
number = {6},
note = {Query date: 2021-04-02 15:20:04},
url = {https://advances.sciencemag.org/content/5/6/eaaw0076?intcmp=trendmd-adv},
doi = {https://doi.org/10.1126/sciadv.aaw0076}
}
|
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| Hu, X.-M., Crowell, S., Wang, Q., Zhang, Y., Davis, K.J., Xue, M., Xiao, X., Moore, B., Wu, X., Choi, Y. and DiGangi, J.P. | Dynamical Downscaling of CO2 in 2016 Over the Contiguous United States Using WRF-VPRM, a Weather-Biosphere-Online-Coupled Model | {2020} | JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS Vol. {12}({4}) |
article | DOI URL |
| Abstract: Ecosystem function (particularly CO2 fluxes and the subsequent atmospheric transport), synoptic-scale weather (e.g., midlatitude cyclones), and interactions between ecosystems and the atmosphere can be investigated using a weather-biosphere-online-coupled model. The Vegetation Photosynthesis and Respiration Model (VPRM) was coupled with the Weather Research and Forecasting (WRF) model in 2008 to simulate ``weather-aware'' biospheric CO2 fluxes and subsequent transport and dispersion. The ability of the coupled WRF-VPRM modeling system to simulate the CO2 structures within midlatitude cyclones, however, has not been evaluated due to the lack of data within these weather systems. In this study, VPRM parameters previously calibrated off-line using eddy covariance tower data over North America are implemented into WRF-VPRM. The updated WRF-VPRM is then used to simulate spatiotemporal variations of CO2 over the contiguous United States at a horizontal grid spacing of 12 km for 2016 using an optimized downscaling configuration. The downscaled fields are evaluated using remotely sensed data from the Orbiting Carbon Observatory-2, Total Carbon Column Observing Network, and in situ aircraft measurements from Atmospheric Carbon and Transport-America missions. Evaluations show that WRF-VPRM captures the monthly variation of column-averaged CO2 concentrations (XCO2) and episodic variations associated with frontal passages. The downscaling also successfully captures the horizontal CO2 gradients across fronts and vertical CO2 contrast between the boundary layer and the free troposphere. WRF-VPRM modeling results indicate that from May to September, biogenic fluxes dominate variability in XCO2 over most of the contiguous United States, except over a few metropolitan areas such as Los Angeles. | |||||
BibTeX:
@article{hu20a,
author = {Hu, Xiao-Ming and Crowell, Sean and Wang, Qingyu and Zhang, Yao and Davis, Kenneth J. and Xue, Ming and Xiao, Xiangming and Moore, Berrien and Wu, Xiaocui and Choi, Yonghoon and DiGangi, Joshua P.},
title = {Dynamical Downscaling of CO2 in 2016 Over the Contiguous United States Using WRF-VPRM, a Weather-Biosphere-Online-Coupled Model},
journal = {JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {12},
number = {4},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019MS001875},
doi = {https://doi.org/10.1029/2019MS001875}
}
|
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| Hu, X.-M., Hu, J., Gao, L., Cai, C., Jiang, Y., Xue, M., Zhao, T. and Crowell, S.M.R. | Multisensor and Multimodel Monitoring and Investigation of a Wintertime Air Pollution Event Ahead of a Cold Front Over Eastern China | 2021 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 126(10) |
article | DOI |
| Abstract: Given the limitations in pollutant measurements (e.g., coverage, observation errors) and air quality model uncertainties (e.g., with parameterizations and emissions), a multisensor and multimodel approach offers additional benefits compared to a single-instrument and deterministic approach for monitoring, investigating, and predicting air pollution events. In this study, we use multisensors (including the spaceborne MODIS, OCO-2, AIRS, and OMPS instruments as well as surface instruments) and multimodels (including WRF-Chem and WRF-CO2) to investigate a severe air pollution event on December 9, 2016 over eastern China. During this episode, a strong cold front moved southward. At the leading edge of the front, WRF-CO2 simulates an enhanced XCO2 belt while WRF-Chem simulates a belt of high PM2.5 concentration. The XCO2 and PM2.5 belts are generally colocated, due to coemission of CO2 and pollutants (or their precursors). Satellite observations including MODIS AOD, OCO-2 XCO2, OMPS NO2, AIRS CO, and surface data confirm the simulated pollution and XCO2 belts. Later on, the front became distorted due to terrain blocking and mountain channel flows. Both observations and simulations show that the channel winds between Mountains Dabie and Huang transport the haze plume into Jiangxi province, enhancing pollution in the region. It is concluded that the multisensor (including space-based and ground-based instruments) and multimodel (e.g., WRF-CO2, WRF-Chem) approach can be used to collectively monitor and investigate air pollution events, given that emissions of the involved species have generally similar spatial distributions. |
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BibTeX:
@article{hu21a,
author = {Hu, Xiao-Ming and Hu, Jun and Gao, Lan and Cai, Changjie and Jiang, Yujun and Xue, Ming and Zhao, Tianliang and Crowell, Sean M. R.},
title = {Multisensor and Multimodel Monitoring and Investigation of a Wintertime Air Pollution Event Ahead of a Cold Front Over Eastern China},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2021},
volume = {126},
number = {10},
doi = {https://doi.org/10.1029/2020JD033538}
}
|
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| Hu, X.-M., Gourdji, S.M., Davis, K.J., Wang, Q., Zhang, Y., Xue, M., Feng, S., Moore, B. and Crowell, S.M.R. | Implementation of Improved Parameterization of Terrestrial Flux in WRF-VPRM Improves the Simulation of Nighttime CO2 Peaks and a Daytime CO2 Band Ahead of a Cold Front | 2021 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 126(10) |
article | DOI |
| Abstract: Enhanced CO2 mole fraction bands were often observed immediately ahead of cold front during the Atmospheric Carbon and Transport (ACT)-America mission and their formation mechanism is undetermined. Improved understanding and correct simulation of these CO2 bands are needed for unbiased inverse CO2 flux estimation. Such CO2 bands are hypothesized to be related to nighttime CO2 respiration and investigated in this study using WRF-VPRM, a weather-biosphere-online-coupled model, in which the biogenic fluxes are handled by the Vegetation Photosynthesis and Respiration Model (VPRM). While the default VPRM satisfactorily parameterizes gross ecosystem exchange, its treatment of terrestrial respiration as a linear function of temperature was inadequate as respiration is a nonlinear function of temperature and also depends on the amount of biomass and soil wetness. An improved ecosystem respiration parameterization including enhanced vegetation index, a water stress factor, and a quadratic temperature dependence is incorporated into WRF-VPRM and evaluated in a year-long simulation before applied to the investigation of the frontal CO2 band on August 4, 2016. The evaluation shows that the modified WRF-VPRM increases ecosystem respiration during the growing season, and improves model skill in reproducing nighttime near-surface CO2 peaks. A nested-domain WRF-VPRM simulation is able to capture the main characteristics of the August 4 CO2 band and informs its formation mechanism. Nighttime terrestrial respiration leads to accumulation of near-surface CO2 in the region. As the cold front carrying low-CO2 air moves southeastward, and strong photosynthesis depletes CO2 further southeast of the front, a CO2 band develops immediately ahead of the front. |
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BibTeX:
@article{hu21b,
author = {Hu, Xiao-Ming and Gourdji, Sharon M. and Davis, Kenneth J. and Wang, Qingyu and Zhang, Yao and Xue, Ming and Feng, Sha and Moore, Berrien and Crowell, Sean M. R.},
title = {Implementation of Improved Parameterization of Terrestrial Flux in WRF-VPRM Improves the Simulation of Nighttime CO2 Peaks and a Daytime CO2 Band Ahead of a Cold Front},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2021},
volume = {126},
number = {10},
doi = {https://doi.org/10.1029/2020JD034362}
}
|
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| Hu, C., Xu, J., Liu, C., Chen, Y., Yang, D., Huang, W., Deng, L., Liu, S., Griffis, T.J. and Lee, X. | Anthropogenic and natural controls on atmospheric delta C-13-CO2 variations in the Yangtze River delta: insights from a carbon isotope modeling framework | 2021 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 21(13), pp. 10015-10037 |
article | DOI |
| Abstract: The atmospheric carbon dioxide (CO2) mixing ratio and its carbon isotope (delta C-13-CO2) composition contain important CO2 sink and source information spanning from ecosystem to global scales. The observation and simulation for both CO2 and delta C-13-CO2 can be used to constrain regional emissions and better understand the anthropogenic and natural mechanisms that control delta C-13-CO2 variations. Such work remains rare for urban environments, especially megacities. Here, we used near-continuous CO2 and delta C-13-CO2 measurements, from September 2013 to August 2015, and inverse modeling to constrain the CO2 budget and investigate the main factors that dominated delta C-13-CO2 variations for the Yangtze River delta (YRD) region, one of the largest anthropogenic CO2 hotspots and densely populated regions in China. We used the WRF-STILT model framework with category-specified EDGAR v4.3.2 CO2 inventories to simulate hourly CO2 mixing ratios and delta C-13-CO2, evaluated these simulations with observations, and constrained the total anthropogenic CO2 emission. We show that (1) top-down and bottom-up estimates of anthropogenic CO2 emissions agreed well (bias < 6 %) on an annual basis, (2) the WRF-STILT model can generally reproduce the observed diel and seasonal atmospheric delta C-13-CO2 variations, and (3) anthropogenic CO2 emissions played a much larger role than ecosystems in controlling the delta C-13-CO2 seasonality. When excluding ecosystem respiration and photosynthetic discrimination in the YRD area, delta C-13-CO2 seasonality increased from 1.53% to 1.66 %. (4) Atmospheric transport processes in summer amplified the cement CO2 enhancement proportions in the YRD area, which dominated monthly delta(s) (the mixture of delta C-13-CO2 from all regional end-members) variations. These findings show that the combination of long-term atmospheric carbon isotope observations and inverse modeling can provide a powerful constraint on the carbon cycle of these complex megacities. |
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BibTeX:
@article{hu21c,
author = {Hu, Cheng and Xu, Jiaping and Liu, Cheng and Chen, Yan and Yang, Dong and Huang, Wenjing and Deng, Lichen and Liu, Shoudong and Griffis, Timothy J. and Lee, Xuhui},
title = {Anthropogenic and natural controls on atmospheric delta C-13-CO2 variations in the Yangtze River delta: insights from a carbon isotope modeling framework},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2021},
volume = {21},
number = {13},
pages = {10015-10037},
doi = {https://doi.org/10.5194/acp-21-10015-2021}
}
|
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| Hu, C., Liu, C., Hu, N., Hong, J. and Ai, X. | Government environmental control measures on CO2 emission during the 2014 Youth Olympic Games in Nanjing: Perspectives from a top-down approach | 2022 | JOURNAL OF ENVIRONMENTAL SCIENCES Vol. 113, pp. 165-178 |
article | DOI |
| Abstract: Strict air pollution control measures were conducted during the Youth Olympic Games (YOG) period at Nanjing city and surrounding areas in August 2014. This event provides a unique chance to evaluate the effect of government control measures on regional atmospheric pollution and greenhouse gas emissions. Many previous studies have observed significant reductions of atmospheric pollution species and improvement in air quality, while no study has quantified its synergism on anthropogenic CO2 emissions, which can be co-reduced with air pollutants. To better understand to what extent these pollution control measures have reduced anthropogenic CO2 emissions, we conducted atmospheric CO2 measurements at the suburban site in Nanjing city from 1st July to 30th September 2014 and 1st August to 31st August 2015, obvious decrease in atmospheric CO2 was observed between YOG and the rest period. By coupling the a priori emission inventory with atmospheric transport model, we applied the scale factor Bayesian inversion approach to derive the posteriori CO2 emissions in YOG period and regular period. Results indicate CO2 emissions from power industry decreased by 45%, and other categories also decreased by 16% for manufacturing combusting, and 37% for non-metallic mineral production. Monthly total anthropogenic CO2 emissions were 9.8 (+/- 3.6) x 10(9) kg/month CO2 for regular period and decreased to 6.2 (+/- 1.9) x 10(9) kg/month during the YOG period in Nanjing city, with a 36.7% reduction. When scaling up to whole Jiangsu Province, anthropogenic CO2 emissions were 7.1 (+/- 2.4) x 10(10) kg/month CO2 for regular period and decreased to 4.4 (+/- 1.2) x 10(10) kg/month CO2 during the YOG period, yielding a 38.0% reduction. (C) 2021 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. |
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BibTeX:
@article{hu22a,
author = {Hu, Cheng and Liu, Cheng and Hu, Ning and Hong, Jun and Ai, Xinyue},
title = {Government environmental control measures on CO2 emission during the 2014 Youth Olympic Games in Nanjing: Perspectives from a top-down approach},
journal = {JOURNAL OF ENVIRONMENTAL SCIENCES},
year = {2022},
volume = {113},
pages = {165-178},
doi = {https://doi.org/10.1016/j.jes.2021.04.016}
}
|
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| Huang, W.-J., Kao, K.-J., Lin, Y.-S., Chen, C.-T.A. and Liu, J.T. | Daily to weekly impacts of mixing and biological activity on carbonate dynamics in a large river-dominated shelf | {2020} | ESTUARINE COASTAL AND SHELF SCIENCE Vol. {245} |
article | DOI URL |
| Abstract: Large eutrophic river plumes can lead to hypoxic near-bottom water during summer. However, how the carbonate system in this stratified water column varies at a daily-to-weekly scale is still unclear. At the end of the first severe El Nino Southern Oscillation event in the 21st century during 2015/2016, high temperature, high salinity water was observed in the middle of the Pearl River plume on the northern South China Sea shelf over 6 d (July 24-29, 2016). We deployed a sensor pack (conductivity, temperature, pressure, and dissolved oxygen [DO]) along the water column each hour and took discrete samples, including total alkalinity and dissolved inorganic carbon every 3 h, to calculate pH. We observe a pH reduction rate of 0.011 pH unit. d(-1) and an oxygen consumption rate of 4.4 mu mol kg(-1).d(-1) in the near-bottom water. The temporal variations in calculated net community production rate and excess DO (measured DO - saturated DO) implies the switch in the dominance of net respiration to net photosynthesis in the near-surface water during this mixing event. We suggest that both net photosynthesis and net respiration were in the water with oversaturated DO on a short-term scale. The pH reduction and oxygen consumption rates in this study could help to estimate the level of coastal acidification and hypoxia better. | |||||
BibTeX:
@article{huang20a,
author = {Huang, Wei-Jen and Kao, Kai-Jung and Lin, Yu-Shih and Chen, Chen-Tung Arthur and Liu, James T.},
title = {Daily to weekly impacts of mixing and biological activity on carbonate dynamics in a large river-dominated shelf},
journal = {ESTUARINE COASTAL AND SHELF SCIENCE},
publisher = {ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD},
year = {2020},
volume = {245},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S0272771419309084},
doi = {https://doi.org/10.1016/j.ecss.2020.106914}
}
|
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| Humpage, N., Boesch, H., Palmer, P.I., Vick, A., Parr-Burman, P., Wells, M., Pearson, D., Strachan, J. and Bezawada, N. | GreenHouse gas Observations of the Stratosphere and Troposphere (GHOST): an airborne shortwave-infrared spectrometer for remote sensing of greenhouse gases | {2018} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {11}({9}), pp. {5199-5222} |
article | DOI |
| Abstract: GHOST is a novel, compact shortwave-infrared grating spectrometer, designed for remote sensing of tropospheric columns of greenhouse gases (GHGs) from an airborne platform. It observes solar radiation at medium to high spectral resolution (better than 0.3 nm), which has been reflected by the Earth's surface using similar methods to those used by polar-orbiting satellites such as the JAXA GOSAT mission, NASA's OCO-2, and the Copernicus Sentinel-5 Precursor. By using an original design comprising optical fibre inputs along with a single diffraction grating and detector array, GHOST is able to observe CO2 absorption bands centred around 1.61 and 2.06 mu m (the same wavelength regions used by OCO-2 and GOSAT) whilst simultaneously measuring CH4 absorption at 1.65 mu m (also observed by GOSAT) and CH4 and CO at 2.30 mu m (observed by Sentinel-5P). With emissions expected to become more concentrated towards city sources as the global population residing in urban areas increases, there emerges a clear requirement to bridge the spatial scale gap between small-scale urban emission sources and global-scale GHG variations. In addition to the benefits achieved in spatial coverage through being able to remotely sense GHG tropospheric columns from an aircraft, the overlapping spectral ranges and comparable spectral resolutions mean that GHOST has unique potential for providing validation opportunities for these platforms, particularly over the ocean, where ground-based validation measurements are not available. In this paper we provide an overview of the GHOST instrument, calibration, and data processing, demonstrating the instrument's performance and suitability for GHG remote sensing. We also report on the first GHG observations made by GHOST during its maiden science flights on board the NASA Global Hawk unmanned aerial vehicle, which took place over the eastern Pacific Ocean in March 2015 as part of the CAST/ATTREX joint Global Hawk flight campaign. |
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BibTeX:
@article{humpage18a,
author = {Humpage, Neil and Boesch, Hartmut and Palmer, Paul I. and Vick, Andy and Parr-Burman, Phil and Wells, Martyn and Pearson, David and Strachan, Jonathan and Bezawada, Naidu},
title = {GreenHouse gas Observations of the Stratosphere and Troposphere (GHOST): an airborne shortwave-infrared spectrometer for remote sensing of greenhouse gases},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2018},
volume = {11},
number = {9},
pages = {5199-5222},
doi = {https://doi.org/10.5194/amt-11-5199-2018}
}
|
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| Hungershoefer, K., Breon, F.M., Peylin, P., Chevallier, F., Rayner, P., Klonecki, A., Houweling, S. and Marshall, J. | Evaluation of various observing systems for the global monitoring of CO2 surface fluxes | {2010} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {10}({21}), pp. 10503-10520 |
article | DOI |
| Abstract: In the context of rising greenhouse gas concentrations, and the potential feedbacks between climate and the carbon cycle, there is an urgent need to monitor the exchanges of carbon between the atmosphere and both the ocean and the land surfaces. In the so-called top-down approach, the surface fluxes of CO2 are inverted from the observed spatial and temporal concentration gradients. The concentrations of CO2 are measured in-situ at a number of surface stations unevenly distributed over the Earth while several satellite missions may be used to provide a dense and better-distributed set of observations to complement this network. In this paper, we compare the ability of different CO2 concentration observing systems to constrain surface fluxes. The various systems are based on realistic scenarios of sampling and precision for satellite and in-situ measurements. It is shown that satellite measurements based on the differential absorption technique (such as those of SCIAMACHY, GOSAT or OCO) provide more information than the thermal infrared observations (such as those of AIRS or IASI). The OCO observations will provide significantly better information than those of GOSAT. A CO2 monitoring mission based on an active (lidar) technique could potentially provide an even better constraint. This constraint can also be realized with the very dense surface network that could be built with the same funding as that of the active satellite mission. Despite the large uncertainty reductions on the surface fluxes that may be expected from these various observing systems, these reductions are still insufficient to reach the highly demanding requirements for the monitoring of anthropogenic emissions of CO2 or the oceanic fluxes at a spatial scale smaller than that of oceanic basins. The scientific objective of these observing system should therefore focus on the fluxes linked to vegetation and land ecosystem dynamics. |
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BibTeX:
@article{hungershoefer10a,
author = {Hungershoefer, K. and Breon, F. -M. and Peylin, P. and Chevallier, F. and Rayner, P. and Klonecki, A. and Houweling, S. and Marshall, J.},
title = {Evaluation of various observing systems for the global monitoring of CO2 surface fluxes},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2010},
volume = {10},
number = {21},
pages = {10503--10520},
doi = {https://doi.org/10.5194/acp-10-10503-2010}
}
|
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| Huntzinger, D.N., Gourdji, S.M., Mueller, K.L. and Michalak, A.M. | The utility of continuous atmospheric measurements for identifying biospheric CO2 flux variability | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: Motivated by the need to improve the modeling of land-atmosphere carbon exchange, this study examines the extent to which continuous atmospheric carbon dioxide (CO2) observations can be used to evaluate flux variability at regional scales. The net ecosystem exchange estimates of four terrestrial biospheric models (TBMs) are used to represent plausible scenarios of surface flux distributions, which are compared in terms of their resulting atmospheric signals. The analysis focuses on North America using the nine towers of the continuous observation network that were operational in 2004. Four test cases are designed to isolate the influence on the atmospheric observations of (1) overall flux differences, (2) magnitude differences in flux across large regions, (3) differences in the flux patterns within ecoregions, and (4) flux variability in the near and far field of observation locations. The CO2 signals generated from the different representations of surface flux distribution are compared using a Chi-square test of variance. Differences found to be significant are driven primarily by differences in flux magnitude over large scales, and the fine-scale (primarily temporal) variability of fluxes within the near field of observation locations. Differences in the spatial distribution of fluxes within individual ecoregions, on the other hand, do not translate into significant differences in the observed signals at the towers. Thus, given the types of variation in flux represented by the four TBMs, the atmospheric data may be most informative in the evaluation of aggregated fluxes over large spatial scales (e. g., ecoregions), as well as in the improvement of how the diurnal cycle of fluxes is represented in TBMs, particularly in areas close to tower locations. |
|||||
BibTeX:
@article{huntzinger11a,
author = {Huntzinger, Deborah N. and Gourdji, Sharon M. and Mueller, Kimberly L. and Michalak, Anna M.},
title = {The utility of continuous atmospheric measurements for identifying biospheric CO2 flux variability},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2010JD015048}
}
|
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| Huntzinger, D.N., Gourdji, S.M., Mueller, K.L. and Michalak, A.M. | A systematic approach for comparing modeled biospheric carbon fluxes across regional scales | {2011} | BIOGEOSCIENCES Vol. {8}({6}), pp. 1579-1593 |
article | DOI |
| Abstract: Given the large differences between biospheric model estimates of regional carbon exchange, there is a need to understand and reconcile the predicted spatial variability of fluxes across models. This paper presents a set of quantitative tools that can be applied to systematically compare flux estimates despite the inherent differences in model formulation. The presented methods include variogram analysis, variable selection, and geostatistical regression. These methods are evaluated in terms of their ability to assess and identify differences in spatial variability in flux estimates across North America among a small subset of models, as well as differences in the environmental drivers that best explain the spatial variability of predicted fluxes. The examined models are the Simple Biosphere (SiB 3.0), Carnegie Ames Stanford Approach (CASA), and CASA coupled with the Global Fire Emissions Database (CASA GFEDv2), and the analyses are performed on model-predicted net ecosystem exchange, gross primary production, and ecosystem respiration. Variogram analysis reveals consistent seasonal differences in spatial variability among modeled fluxes at a 1 degrees x 1 degrees spatial resolution. However, significant differences are observed in the overall magnitude of the carbon flux spatial variability across models, in both net ecosystem exchange and component fluxes. Results of the variable selection and geostatistical regression analyses suggest fundamental differences between the models in terms of the factors that explain the spatial variability of predicted flux. For example, carbon flux is more strongly correlated with percent land cover in CASA GFEDv2 than in SiB or CASA. Some of the differences in spatial patterns of estimated flux can be linked back to differences in model formulation, and would have been difficult to identify simply by comparing net fluxes between models. Overall, the systematic approach presented here provides a set of tools for comparing predicted grid-scale fluxes across models, a task that has historically been difficult unless standardized forcing data were prescribed, or a detailed sensitivity analysis performed. |
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BibTeX:
@article{huntzinger11b,
author = {Huntzinger, D. N. and Gourdji, S. M. and Mueller, K. L. and Michalak, A. M.},
title = {A systematic approach for comparing modeled biospheric carbon fluxes across regional scales},
journal = {BIOGEOSCIENCES},
year = {2011},
volume = {8},
number = {6},
pages = {1579--1593},
doi = {https://doi.org/10.5194/bg-8-1579-2011}
}
|
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| Hutjes, R.W.A., Vellinga, U.S., Gioli, B. and Miglietta, F. | Dis-aggregation of airborne flux measurements using footprint analysis | {2010} | AGRICULTURAL AND FOREST METEOROLOGY Vol. {150}({7-8}), pp. 966-983 |
article | DOI |
| Abstract: Aircraft measurements of turbulent fluxes are generally being made with the objective to obtain an estimate of regional exchanges between land surface and atmosphere, to investigate the spatial variability of these fluxes, but also to learn something about the fluxes from some or all of the land cover types that make up the landscape. In this study we develop a method addressing this last objective, an approach to disentangle blended fluxes from a landscape into the component fluxes emanating from the various land cover classes making up that landscape. The method relies on using a footprint model to determine which part of the landscape the airborne flux observation refers to, using a high resolution land cover map to determine the fractional covers of the various land cover classes within that footprint, and finally using multiple linear regression on many such flux/fractional cover data records to estimate the component fluxes. The method is developed in the context of three case studies of increasing complexity and the analysis covers three scalar fluxes: sensible and latent heat fluxes and carbon dioxide flux, as well as the momentum flux. A basic assumption under the dis-aggregation method is that the composite flux, i.e. the landscape flux, is a linear average of the component fluxes, i.e. the fluxes from the various land elements. We test and justify this assumption by comparing linear averages of component fluxes in simple `binary landscapes', weighted by their relative area, with directly aircraft observed fluxes. In all case studies dis-aggregation of mixed values for fluxes from heterogeneous areas into component land cover class specific fluxes is feasible using robust least squares regression, both in simple binary `landscapes' and in more complex cases. Both the differences between land cover classes and the differences between synoptic conditions can be resolved, for those land cover classes that make up sufficiently large fractions of the landscape. The regression F-statistic and the closely associated p-values are good indicators for this latter prerequisite and for other sources of uncertainty in the dis-aggregated flux estimates that render it meaningful or not. An analysis of the effect of various sources of errors in input data, footprint estimates and of skewed land cover class distributions is presented. A validation of flux estimates obtained through the dis-aggregation method against independent ground data proved satisfactorily. Recommendations for the use of the method are given as are suggestions for further development. (C) 2010 Elsevier B.V. All rights reserved. |
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BibTeX:
@article{hutjes10a,
author = {Hutjes, R. W. A. and Vellinga, U. S. and Gioli, B. and Miglietta, F.},
title = {Dis-aggregation of airborne flux measurements using footprint analysis},
journal = {AGRICULTURAL AND FOREST METEOROLOGY},
year = {2010},
volume = {150},
number = {7-8},
pages = {966--983},
doi = {https://doi.org/10.1016/j.agrformet.2010.03.004}
}
|
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| Hutjes, R., Bosveld, F., Dolman, A., Houweling, S., Peters, W., Meesters, A., Moene, A., Neubert, R., KleinBaltink, H., Unal, C. and others | Titel rapport AN ASSESSMENT OF THE POTENTIAL FOR ATMOSPHERIC EMISSION VERIFICATION IN THE NETHERLANDS [BibTeX] |
2012 | School: Wageningen University and Research Centre | techreport | URL |
BibTeX:
@techreport{hutjes12a,
author = {Hutjes, RWA and Bosveld, FC and Dolman, AJ and Houweling, S and Peters, W and Meesters, AGCA and Moene, A and Neubert, REM and KleinBaltink, H and Unal, CMH and others},
title = {Titel rapport AN ASSESSMENT OF THE POTENTIAL FOR ATMOSPHERIC EMISSION VERIFICATION IN THE NETHERLANDS},
school = {Wageningen University and Research Centre},
year = {2012},
url = {https://www.researchgate.net/profile/Ronald_Hutjes/publication/283419017_An_assessment_of_the_potential_for_atmospheric_emission_verification_in_The_Netherlands/links/5640741a08ae34e98c4e8221/An-assessment-of-the-potential-for-atmospheric-emission-verification-in-The-Netherlands.pdf}
}
|
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| Isaac, L.I.D., Lauvaux, T., Davis, K.J., Miles, N.L., Richardson, S.J., Jacobson, A.R. and Andrews, A.E. | Model-data comparison of MCI field campaign atmospheric CO2 mole fractions | {2014} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {119}({17}) |
article | DOI |
| Abstract: Atmospheric transport model errors are a major contributor to uncertainty in CO2 inverse flux estimates. Our study compares CO2 mole fraction observations from the North American Carbon Program Mid-Continental Intensive (MCI) field campaign and modeled mole fractions from two atmospheric transport models: the global Transport Model 5 from NOAA's CarbonTracker system and the mesoscale Weather Research and Forecasting model. Both models are coupled to identical CO2 fluxes and lateral boundary conditions from CarbonTracker (CT2009 release). Statistical analyses were performed for two periods of 2007 using observed daily daytime average mole fractions of CO2 to test the ability of these models to reproduce the observations and to infer possible causes of the discrepancies. TM5-CT2009 overestimates midsummer planetary boundary layer CO2 for sites in the U. S. corn belt by 10 ppm. Weather Research and Forecasting (WRF)-CT2009 estimates diverge from the observations with similar magnitudes, but the signs of the differences vary from site to site. The modeled mole fractions are highly correlated with the observed seasonal cycle (r >= 0.7) but less correlated in the growing season, where weather-related changes in CO2 dominate the observed variability. Spatial correlations in residuals from TM5-CT2009 are higher than WRF-CT2009 perhaps due to TM5's coarse horizontal resolution and shallow vertical mixing. Vertical mixing appears to have influenced CO2 residuals from both models. TM5-CT2009 has relatively weak vertical mixing near the surface limiting the connection between local CO2 surface fluxes and boundary layer. WRF-CT2009 has stronger vertical mixing that may increase the connections between local surface fluxes and the boundary layer. |
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BibTeX:
@article{isaac14a,
author = {Isaac, Liza I. Diaz and Lauvaux, Thomas and Davis, Kenneth J. and Miles, Natasha L. and Richardson, Scott J. and Jacobson, Andrew R. and Andrews, Arlyn E.},
title = {Model-data comparison of MCI field campaign atmospheric CO2 mole fractions},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2014},
volume = {119},
number = {17},
doi = {https://doi.org/10.1002/2014JD021593}
}
|
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| Ishidoya, S., Aoki, S., Goto, D., Nakazawa, T., Taguchi, S. and Patra, P.K. | Time and space variations of the O-2/N-2 ratio in the troposphere over Japan and estimation of the global CO2 budget for the period 2000-2010 | {2012} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {64} |
article | DOI |
| Abstract: Systematic measurements of the atmospheric O-2/N-2 ratio have been made using aircraft and ground-based stations in Japan since 1999. The observed seasonal cycles of the O-2/N-2 ratio and atmospheric potential oxygen (APO) vary almost in opposite phase to that of the CO2 concentration at all altitudes, and their amplitudes and phases are generally reduced and delayed, respectively, with increasing altitude. Simulations of APO using two atmospheric transport models reproduce general features of the observed seasonal cycle, but both models fail to reproduce the phase at an altitude ranging from 8 km to the tropopause. By analysing the observed secular trends of APO and CO2 concentration, and assuming a global net oceanic O-2 outgassing of 0.2 +/- 0.5 GtC yr(-1), we estimate global average terrestrial biospheric and oceanic CO2 uptake for the period 2000-2010 to be 1.0 +/- 0.8 and 2.5 +/- 0.7 GtC yr(-1), respectively. |
|||||
BibTeX:
@article{ishidoya12a,
author = {Ishidoya, Shigeyuki and Aoki, Shuji and Goto, Daisuke and Nakazawa, Takakiyo and Taguchi, Shoichi and Patra, Prabir K.},
title = {Time and space variations of the O-2/N-2 ratio in the troposphere over Japan and estimation of the global CO2 budget for the period 2000-2010},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2012},
volume = {64},
doi = {https://doi.org/10.3402/tellusb.v64i0.18964}
}
|
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| Ishii, M., Feely, R.A., Rodgers, K.B., Park, G.H., Wanninkhof, R., Sasano, D., Sugimoto, H., Cosca, C.E., Nakaoka, S., Telszewski, M., Nojiri, Y., Fletcher, S.E.M., Niwa, Y., Patra, P.K., Valsala, V., Nakano, H., Lima, I., Doney, S.C., Buitenhuis, E.T., Aumont, O., Dunne, J.P., Lenton, A. and Takahashi, T. | Air-sea CO2 flux in the Pacific Ocean for the period 1990-2009 | {2014} | BIOGEOSCIENCES Vol. {11}({3}), pp. 709-734 |
article | DOI |
| Abstract: Air-sea CO2 fluxes over the Pacific Ocean are known to be characterized by coherent large-scale structures that reflect not only ocean subduction and upwelling patterns, but also the combined effects of wind-driven gas exchange and biology. On the largest scales, a large net CO2 influx into the extratropics is associated with a robust seasonal cycle, and a large net CO2 efflux from the tropics is associated with substantial interannual variability. In this work, we have synthesized estimates of the net air-sea CO2 flux from a variety of products, drawing upon a variety of approaches in three sub-basins of the Pacific Ocean, i. e., the North Pacific extratropics (18-66 degrees N), the tropical Pacific (18 degrees S-18 degrees N), and the South Pacific extratropics (44.5-18 degrees S). These approaches include those based on the measurements of CO2 partial pressure in surface seawater (pCO(2)sw), inversions of ocean-interior CO2 data, forward ocean biogeochemistry models embedded in the ocean general circulation models (OBGCMs), a model with assimilation of pCO(2)sw data, and inversions of atmospheric CO2 measurements. Long-term means, interannual variations and mean seasonal variations of the regionally integrated fluxes were compared in each of the sub-basins over the last two decades, spanning the period from 1990 through 2009. A simple average of the long-term mean fluxes obtained with surface water pCO(2) diagnostics and those obtained with ocean-interior CO2 inversions are -0.47 +/- 0.13 Pg Cyr(-1) in the North Pacific extratropics, +/- 0.44 +/- 0.14 Pg Cyr(-1) in the tropical Pacific, and -0.37 +/- 0.08 Pg C yr(-1) in the South Pacific extratropics, where positive fluxes are into the atmosphere. This suggests that approximately half of the CO2 taken up over the North and South Pacific extratropics is released back to the atmosphere from the tropical Pacific. These estimates of the regional fluxes are also supported by the estimates from OBGCMs after adding the riverine CO2 flux, i.e., -0.49 +/- 0.02 Pg Cyr(-1) in the North Pacific extratropics, +0.41 +/- 0.05 Pg Cyr(-1) in the tropical Pacific, and -0.39 +/- 0.11 Pg Cyr(-1) in the South Pacific extratropics. The estimates from the atmospheric CO2 inversions show large variations amongst different inversion systems, but their median fluxes are consistent with the estimates from climatological pCO(2)sw data and pCO(2)sw diagnostics. In the South Pacific extratropics, where CO2 variations in the surface and ocean interior are severely undersampled, the difference in the air-sea CO2 flux estimates between the diagnostic models and ocean-interior CO2 inversions is larger (0.18 Pg Cyr(-1)). The range of estimates from forward OBGCMs is also large (-0.19 to -0.72 Pg Cyr(-1)). Regarding interannual variability of air-sea CO2 fluxes, positive and negative anomalies are evident in the tropical Pacific during the cold and warm events of the El Nino-Southern Oscillation in the estimates from pCO(2)sw diagnostic models and from OBGCMs. They are consistent in phase with the Southern Oscillation Index, but the peak-to-peak amplitudes tend to be higher in OBGCMs (0.40 +/- 0.09 Pg Cyr(-1)) than in the diagnostic models (0.27 +/- 0.07 Pg Cyr(-1)). |
|||||
BibTeX:
@article{ishii14a,
author = {Ishii, M. and Feely, R. A. and Rodgers, K. B. and Park, G. -H. and Wanninkhof, R. and Sasano, D. and Sugimoto, H. and Cosca, C. E. and Nakaoka, S. and Telszewski, M. and Nojiri, Y. and Fletcher, S. E. Mikaloff and Niwa, Y. and Patra, P. K. and Valsala, V. and Nakano, H. and Lima, I. and Doney, S. C. and Buitenhuis, E. T. and Aumont, O. and Dunne, J. P. and Lenton, A. and Takahashi, T.},
title = {Air-sea CO2 flux in the Pacific Ocean for the period 1990-2009},
journal = {BIOGEOSCIENCES},
year = {2014},
volume = {11},
number = {3},
pages = {709--734},
doi = {https://doi.org/10.5194/bg-11-709-2014}
}
|
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| Ito, A. | Decadal Variability in the Terrestrial Carbon Budget Caused by the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation | {2011} | JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN Vol. {89}({5}), pp. 441-454 |
article | DOI |
| Abstract: The terrestrial carbon dioxide (CO2) budget interacts with the Earth's climate system on diurnal to centennial and longer time scales, making it critical for climatic prediction and stabilization. Atmospheric observations and global syntheses of CO2 data indicate that the terrestrial biosphere is one the major sources of interannual variability, but the underlying mechanisms operating on different time-scales and the potential impacts of this on future projections remain unclear. Here it is shown that the El Nino and Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO) regime affect temporal variability in the terrestrial carbon budget with different time scales. The terrestrial carbon budget, estimated using a process-based model (VISIT) for the period 1910-2005, was correlated with the indices of PDO, AMO, and ENSO with various smoothing periods and lag lengths. ENSO showed the highest short-term correlation, corresponding to interannual terrestrial variability, whereas PDO and AMO had higher correlations at the decadal time scale. Such correlations with the meteorological regimes occurred heterogeneously over the land surface. Tin; study suggests that long-term monitoring is needed to elucidate the temporal variability, and that decadal predictability of climate and terrestrial models should be improved further. |
|||||
BibTeX:
@article{ito11a,
author = {Ito, Akihiko},
title = {Decadal Variability in the Terrestrial Carbon Budget Caused by the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation},
journal = {JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN},
year = {2011},
volume = {89},
number = {5},
pages = {441--454},
doi = {https://doi.org/10.2151/jmsj.2011-503}
}
|
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| Ito, A. | Disequilibrium of terrestrial ecosystem CO2 budget caused by disturbance-induced emissions and non-CO2 carbon export flows: a global model assessment | {2019} | EARTH SYSTEM DYNAMICS Vol. {10}({4}), pp. {685-709} |
article | DOI |
| Abstract: The global carbon budget of terrestrial ecosystems is chiefly determined by major flows of carbon dioxide (CO2) such as photosynthesis and respiration, but various minor flows exert considerable influence in determining carbon stocks and their turnover. This study assessed the effects of eight minor carbon flows on the terrestrial carbon budget using a process-based model, the Vegetation Integrative SImulator for Trace gases (VISIT), which included non-CO2 carbon flows, such as methane and biogenic volatile organic compound (BVOC) emissions and subsurface carbon exports and disturbances such as biomass burning, land-use changes, and harvest activities. The range of model-associated uncertainty was evaluated through parameter-ensemble simulations and the results were compared with corresponding observational and modeling studies. In the historical period of 1901-2016, the VISIT simulation indicated that the minor flows substantially influenced terrestrial carbon stocks, flows, and budgets. The simulations estimated mean net ecosystem production in 2000-2009 as 3.21 +/- 1.1 Pg C yr(-1) without minor flows and 6.85 +/- 0.9 Pg C yr(-1) with minor flows. Including minor carbon flows yielded an estimated net biome production of 1.62 +/- 1.0 Pg C yr(-1) in the same period. Biomass burning, wood harvest, export of organic carbon by water erosion, and BVOC emissions had impacts on the global terrestrial carbon budget amounting to around 1 Pg C yr(-1) with specific interannual variabilities. After including the minor flows, ecosystem carbon storage was suppressed by about 440 Pg C, and its mean residence time was shortened by about 2.4 years. The minor flows occur heterogeneously over the land, such that BVOC emission, subsurface export, and wood harvest occur mainly in the tropics, and biomass burning occurs extensively in boreal forests. They also differ in their decadal trends, due to differences in their driving factors. Aggregating the simulation results by land-cover type, cropland fraction, and annual precipitation yielded more insight into the contributions of these minor flows to the terrestrial carbon budget. Considering their substantial and unique roles, these minor flows should be taken into account in the global carbon budget in an integrated manner. | |||||
BibTeX:
@article{ito19a,
author = {Ito, Akihiko},
title = {Disequilibrium of terrestrial ecosystem CO2 budget caused by disturbance-induced emissions and non-CO2 carbon export flows: a global model assessment},
journal = {EARTH SYSTEM DYNAMICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {10},
number = {4},
pages = {685--709},
doi = {https://doi.org/10.5194/esd-10-685-2019}
}
|
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| Ito, G., Romanou, A., Kiang, N.Y., Faluvegi, G., Aleinov, I., Ruedy, R., Russell, G., Lerner, P., Kelley, M. and Lo, K. | Global Carbon Cycle and Climate Feedbacks in the NASA GISS ModelE2.1 | {2020} | JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS Vol. {12}({10}) |
article | DOI URL |
| Abstract: We present results from the NASA GISS ModelE2.1-G-CC Earth System Model with coupled climate-carbon cycle simulations that were submitted to the sixth phase of the Coupled Model Intercomparison Project (CMIP6) Coupled Climate-Carbon Cycle MIP (C4MIP). Atmospheric CO2 concentration and carbon budgets for the land and ocean in the historical simulations were generally consistent with observations. Low simulated atmospheric CO2 concentrations during 1850-1950 were due to excess uptake from prescribed land cover change, which erroneously replaced arid shrublands with higher biomass crops, and assumed high 2004 LAI values in vegetated lands throughout the historical simulation. At the end of the historical period, slightly higher simulated CO2 than observed resulted from the land being an insufficient net carbon sink, despite the net effect of CO2 fertilization and warming-induced increases to leaf photosynthetic capacity. The global ocean carbon uptake agreed well with the observations with the largest discrepancies in the low latitudes. Future climate projection at 2091-2100 agreed with CMIP5 models in the northward shift, of temperate deciduous forest climate and expansion across Eurasia along 60 degrees N latitude, and dramatic regional biome shifts from drying and warming in continental Europe. Carbon feedback parameters were largely similar to the CMIP5 model ensemble. For our model, the variation of land feedback parameters within the uncertainty arises from the fertilization feedback being less sensitive due to lack of increased vegetation growth, and the comparably more negative ocean carbon-climate feedback is due to the large slowdown of the Atlantic overturning circulation. | |||||
BibTeX:
@article{ito20a,
author = {Ito, Gen and Romanou, Anastasia and Kiang, Nancy Y. and Faluvegi, Gregory and Aleinov, Igor and Ruedy, Reto and Russell, Gary and Lerner, Paul and Kelley, Maxwell and Lo, Ken},
title = {Global Carbon Cycle and Climate Feedbacks in the NASA GISS ModelE2.1},
journal = {JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {12},
number = {10},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019MS002030},
doi = {https://doi.org/10.1029/2019MS002030}
}
|
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| Jacob, D.J., Turner, A.J., Maasakkers, J.D., Sheng, J., Sun, K., Liu, X., Chance, K., Aben, I., McKeever, J. and Frankenberg, C. | Satellite observations of atmospheric methane and their value for quantifying methane emissions | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({22}), pp. 14371-14396 |
article | DOI |
| Abstract: Methane is a greenhouse gas emitted by a range of natural and anthropogenic sources. Atmospheric methane has been measured continuously from space since 2003, and new instruments are planned for launch in the near future that will greatly expand the capabilities of space-based observations. We review the value of current, future, and proposed satellite observations to better quantify and understand methane emissions through inverse analyses, from the global scale down to the scale of point sources and in combination with suborbital (surface and aircraft) data. Current global observations from Greenhouse Gases Observing Satellite (GOSAT) are of high quality but have sparse spatial coverage. They can quantify methane emissions on a regional scale (100-1000 km) through multiyear averaging. The Tropospheric Monitoring Instrument (TROPOMI), to be launched in 2017, is expected to quantify daily emissions on the regional scale and will also effectively detect large point sources. A different observing strategy by GHGSat (launched in June 2016) is to target limited viewing domains with very fine pixel resolution in order to detect a wide range of methane point sources. Geostationary observation of methane, still in the proposal stage, will have the unique capability of mapping source regions with high resolution, detecting transient ``super-emitter'' point sources and resolving diurnal variation of emissions from sources such as wetlands and manure. Exploiting these rapidly expanding satellite measurement capabilities to quantify methane emissions requires a parallel effort to construct high-quality spatially and sectorally resolved emission inventories. Partnership between top-down inverse analyses of atmospheric data and bottom-up construction of emission inventories is crucial to better understanding methane emission processes and subsequently informing climate policy. |
|||||
BibTeX:
@article{jacob16a,
author = {Jacob, Daniel J. and Turner, Alexander J. and Maasakkers, Joannes D. and Sheng, Jianxiong and Sun, Kang and Liu, Xiong and Chance, Kelly and Aben, Ilse and McKeever, Jason and Frankenberg, Christian},
title = {Satellite observations of atmospheric methane and their value for quantifying methane emissions},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {22},
pages = {14371--14396},
doi = {https://doi.org/10.5194/acp-16-14371-2016}
}
|
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| Jamroensan, A. | Improving bottom-up and top-down estimates of carbon fluxes in the Midwestern USA [BibTeX] |
2013 | School: The University of Iowa | phdthesis | URL |
BibTeX:
@phdthesis{jamroensan13a,
author = {Jamroensan, Aditsuda},
title = {Improving bottom-up and top-down estimates of carbon fluxes in the Midwestern USA},
school = {The University of Iowa},
year = {2013},
url = {http://search.proquest.com/openview/0101c608a315817af6e44eee3c2c3053/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Jiang, F., Wang, H.W., Chen, J.M., Zhou, L.X., Ju, W.M., Ding, A.J., Liu, L.X. and Peters, W. | Nested atmospheric inversion for the terrestrial carbon sources and sinks in China | {2013} | BIOGEOSCIENCES Vol. {10}({8}), pp. 5311-5324 |
article | DOI |
| Abstract: In this study, we establish a nested atmospheric inversion system with a focus on China using the Bayesian method. The global surface is separated into 43 regions based on the 22 TransCom large regions, with 13 small regions in China. Monthly CO2 concentrations from 130 GlobalView sites and 3 additional China sites are used in this system. The core component of this system is an atmospheric transport matrix, which is created using the TM5 model with a horizontal resolution of 3 degrees x 2 degrees. The net carbon fluxes over the 43 global land and ocean regions are inverted for the period from 2002 to 2008. The inverted global terrestrial carbon sinks mainly occur in boreal Asia, South and Southeast Asia, eastern America and southern South America. Most China areas appear to be carbon sinks, with strongest carbon sinks located in Northeast China. From 2002 to 2008, the global terrestrial carbon sink has an increasing trend, with the lowest carbon sink in 2002. The inter-annual variation (IAV) of the land sinks shows remarkable correlation with the El Nino Southern Oscillation (ENSO). The terrestrial carbon sinks in China also show an increasing trend. However, the IAV in China is not the same as that of the globe. There is relatively stronger land sink in 2002, lowest sink in 2006, and strongest sink in 2007 in China. This IAV could be reasonably explained with the IAVs of temperature and precipitation in China. The mean global and China terrestrial carbon sinks over the period 2002-2008 are -3.20 +/- 0.63 and -0.28 +/- 0.18 PgC yr(-1), respectively. Considering the carbon emissions in the form of reactive biogenic volatile organic compounds (BVOCs) and from the import of wood and food, we further estimate that China's land sink is about -0.31 PgC yr(-1). |
|||||
BibTeX:
@article{jiang13a,
author = {Jiang, F. and Wang, H. W. and Chen, J. M. and Zhou, L. X. and Ju, W. M. and Ding, A. J. and Liu, L. X. and Peters, W.},
title = {Nested atmospheric inversion for the terrestrial carbon sources and sinks in China},
journal = {BIOGEOSCIENCES},
year = {2013},
volume = {10},
number = {8},
pages = {5311--5324},
doi = {https://doi.org/10.5194/bg-10-5311-2013}
}
|
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| Jiang, F., Chen, J.M., Zhou, L., Ju, W., Zhang, H., Machida, T., Ciais, P., Peters, W., Wang, H., Chen, B., Liu, L., Zhang, C., Matsueda, H. and Sawa, Y. | A comprehensive estimate of recent carbon sinks in China using both top-down and bottom-up approaches | {2016} | SCIENTIFIC REPORTS Vol. {6} |
article | DOI |
| Abstract: Atmospheric inversions use measurements of atmospheric CO2 gradients to constrain regional surface fluxes. Current inversions indicate a net terrestrial CO2 sink in China between 0.16 and 0.35 PgC/yr. The uncertainty of these estimates is as large as the mean because the atmospheric network historically contained only one high altitude station in China. Here, we revisit the calculation of the terrestrial CO2 flux in China, excluding emissions from fossil fuel burning and cement production, by using two inversions with three new CO2 monitoring stations in China as well as aircraft observations over Asia. We estimate a net terrestrial CO2 uptake of 0.39-0.51 PgC/yr with a mean of 0.45 PgC/yr in 2006-2009. After considering the lateral transport of carbon in air and water and international trade, the annual mean carbon sink is adjusted to 0.35 PgC/yr. To evaluate this top-down estimate, we constructed an independent bottom-up estimate based on ecosystem data, and giving a net land sink of 0.33 PgC/yr. This demonstrates closure between the top-down and bottom-up estimates. Both top-down and bottom-up estimates give a higher carbon sink than previous estimates made for the 1980s and 1990s, suggesting a trend towards increased uptake by land ecosystems in China. |
|||||
BibTeX:
@article{jiang16a,
author = {Jiang, Fei and Chen, Jing M. and Zhou, Lingxi and Ju, Weimin and Zhang, Huifang and Machida, Toshinobu and Ciais, Philippe and Peters, Wouter and Wang, Hengmao and Chen, Baozhang and Liu, Lixin and Zhang, Chunhua and Matsueda, Hidekazu and Sawa, Yousuke},
title = {A comprehensive estimate of recent carbon sinks in China using both top-down and bottom-up approaches},
journal = {SCIENTIFIC REPORTS},
year = {2016},
volume = {6},
doi = {https://doi.org/10.1038/srep22130}
}
|
|||||
| Jiang, X., Crisp, D., Olsen, E.T., Kulawik, S.S., Miller, C.E., Pagano, T.S., Liang, M. and Yung, Y.L. | CO2 annual and semiannual cycles from multiple satellite retrievals and models [BibTeX] |
2016 | Earth and Space Science Vol. 3(2), pp. 78-87 |
article | DOI |
BibTeX:
@article{jiang16b,
author = {Jiang, Xun and Crisp, David and Olsen, Edward T and Kulawik, Susan S and Miller, Charles E and Pagano, Thomas S and Liang, Maochang and Yung, Yuk L},
title = {CO2 annual and semiannual cycles from multiple satellite retrievals and models},
journal = {Earth and Space Science},
year = {2016},
volume = {3},
number = {2},
pages = {78--87},
doi = {https://doi.org/10.1002/2014EA000045/full}
}
|
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| Jiang, F., Wang, H., Chen, J.M., Ju, W., Tian, X., Feng, S., Li, G., Chen, Z., Zhang, S., Lu, X., Liu, J., Wang, H., Wang, J., He, W. and Wu, M. | Regional CO2 fluxes from 2010 to 2015 inferred from GOSAT XCO2 retrievals using a new version of the Global Carbon Assimilation System | {2021} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {21}({3}), pp. {1963-1985} |
article | DOI URL |
| Abstract: Satellite retrievals of the column-averaged dry air mole fractions of CO2 (XCO2) could help to improve carbon flux estimation due to their good spatial coverage. In this study, in order to assimilate the GOSAT (Greenhouse Gases Observing Satellite) XCO2 retrievals, the Global Carbon Assimilation System (GCAS) is upgraded with new assimilation algorithms, procedures, a localization scheme, and a higher assimilation parameter resolution. This upgraded system is referred to as GCASv2. Based on this new system, the global terrestrial ecosystem (BIO) and ocean (OCN) carbon fluxes from 1 May 2009 to 31 December 2015 are constrained using the GOSAT ACOS (Atmospheric CO2 Observations from Space) XCO2 retrievals (Version 7.3). The posterior carbon fluxes from 2010 to 2015 are independently evaluated using CO2 observations from 52 surface flask sites. The results show that the posterior carbon fluxes could significantly improve the modeling of atmospheric CO2 concentrations, with global mean bias decreases from a prior value of 1.6 +/- 1.8 ppm to -0.5 +/- 1.8 ppm. The uncertainty reduction (UR) of the global BIO flux is 17 %, and the highest monthly regional UR could reach 51 %. Globally, the mean annual BIO and OCN carbon sinks and their interannual variations inferred in this study are very close to the estimates of CarbonTracker 2017 (CT2017) during the study period, and the inferred mean atmospheric CO2 growth rate and its interannual changes are also very close to the observations. Regionally, over the northern lands, the strongest carbon sinks are seen in temperate North America, followed by Europe, boreal Asia, and temperate Asia; in the tropics, there are strong sinks in tropical South America and tropical Asia, but a very weak sink in Africa. This pattern is significantly different from the estimates of CT2017, but the estimated carbon sinks for each continent and some key regions like boreal Asia and the Amazon are comparable or within the range of previous bottom-up estimates. The inversion also changes the interannual variations in carbon fluxes in most TransCom land regions, which have a better relationship with the changes in severe drought area (SDA) or leaf area index (LAI), or are more consistent with previous estimates for the impact of drought. These results suggest that the GCASv2 system works well with the GOSAT XCO2 retrievals and shows good performance with respect to estimating the sur- face carbon fluxes; meanwhile, our results also indicate that the GOSAT XCO2 retrievals could help to better understand the interannual variations in regional carbon fluxes. | |||||
BibTeX:
@article{jiang21a,
author = {Jiang, Fei and Wang, Hengmao and Chen, Jing M. and Ju, Weimin and Tian, Xiangjun and Feng, Shuzhuang and Li, Guicai and Chen, Zhuoqi and Zhang, Shupeng and Lu, Xuehe and Liu, Jane and Wang, Haikun and Wang, Jun and He, Wei and Wu, Mousong},
title = {Regional CO2 fluxes from 2010 to 2015 inferred from GOSAT XCO2 retrievals using a new version of the Global Carbon Assimilation System},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2021},
volume = {21},
number = {3},
pages = {1963--1985},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/21/1963/2021/acp-21-1963-2021.html},
doi = {https://doi.org/10.5194/acp-21-1963-2021}
}
|
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| Jiang, F., He, W., Ju, W., Wang, H., Wu, M., Wang, J., Feng, S., Zhang, L. and Chen, J.M. | The status of carbon neutrality of the world's top 5 CO2 emitters as seen by carbon satellites | 2022 | FUNDAMENTAL RESEARCH Vol. 2(3), pp. 357-366 |
article | DOI |
| Abstract: China, the Unite States (US), the European Union (EU), India, and Russia are the world's top 5 fossil fuel and cement CO2 (FFC) emitting countries or regions (CRs). It is very important to understand their status of carbon neutrality, and to monitor their future changes of net carbon fluxes (NCFs). In this study, we implemented a well-established global carbon assimilation system (GCAS, Version 2) to infer global surface carbon fluxes from May 2009 to December 2019 using both GOSAT and OCO-2 XCO2 retrievals. The reductions of flux uncertainty and XCO2 bias, and the evaluation of posterior flux show that GCAS has comparable and good performance in the 5 CRs. The results suggest that Russia has achieved carbon neutrality, but the other 4 are still far from being carbon neutral, especially China. The mean annual NCFs in China, the US, the EU, India, and Russia are 2.33 +/- 0.29, 0.82 +/- 0.20, 0.42 +/- 0.16, 0.50 +/- 0.12, and -0.33 +/- 0.23 PgC yr(-1), respectively. From 2010 to 2019, the NCFs showed an increasing trend in the US and India, a slight downward trend after 2013 in China, and were stable in the EU. The changes of land sinks in China and the US might be the main reason for their trends. India's trend was mainly due to the increase of FFC emission. The relative contributions of NCFs to the global land net carbon emission of China and the EU have decreased, while those of the US and India have increased, implying the US and India must take more active measures to control carbon emissions or increase their sinks. This study indicates that satellite XCO2 could be successfully used to monitor the changes of regional NCFs, which is of great significance for major countries to achieve greenhouse gas control goals. |
|||||
BibTeX:
@article{jiang22a,
author = {Jiang, Fei and He, Wei and Ju, Weimin and Wang, Hengmao and Wu, Mousong and Wang, Jun and Feng, Shuzhuang and Zhang, Lingyu and Chen, Jing M.},
title = {The status of carbon neutrality of the world's top 5 CO2 emitters as seen by carbon satellites},
journal = {FUNDAMENTAL RESEARCH},
year = {2022},
volume = {2},
number = {3},
pages = {357-366},
doi = {https://doi.org/10.1016/j.fmre.2022.02.001}
}
|
|||||
| Jin, C., Xue, Y., Jiang, X., Zhao, L., Yuan, T., Sun, Y., Wu, S. and Wang, X. | A long-term global XCO2 dataset: Ensemble of satellite products | 2022 | ATMOSPHERIC RESEARCH Vol. 279 |
article | DOI |
| Abstract: Many satellites such as SCIAMACHY (scanning imaging absorption spectrometer for atmospheric cartography), GOSAT-1/2 (greenhouse gases observing satellite), OCO-2/3 (orbiting carbon observatory) and TanSat (Car-bonSat, Tan means ``carbon'' in Chinese) provide key observations of atmospheric CO2 concentration and different XCO2 retrieval algorithms have been developed for these satellite measurements. However, limited by the revisit period and scanning swath of the satellites, the effective daily observation coverage of satellites mentioned above is very small (<1%), which is a great challenge for high-resolution mapping of global XCO2. In this paper, we re-evaluated the uncertainty of each XCO2 pixel with 0.5 the global based on season, AOD (aerosol optical depth), surface albedo, uncertainty parameters of SCIAMACHY, GOSAT-1/ 2, OCO-2/3 and TanSat XCO2 products by TCCON (Total Carbon Column Observing Network) data. Then, a 30-day time window was used to smooth XCO2 datasets from satellite observations and filled in the missing values according to CarbonTracker. Finally, we ensembled global XCO2 datasets using maximum likelihood estimation (MLE) method and optimal interpolation (OI) based on the re-evaluated uncertainty. The ensemble XCO2 dataset at 0.5 degrees x 0.5 degrees spatial resolution for every three hours from January 2003 to August 2020 was generated. Compared to TCCON and WDCGG (World Data Centre for Greenhouse Gases) measurements separately on the global scale, we obtained the correlation coefficient R = 0.96, the Root Mean Square Error (RMSE) of 2.62 ppm for TCCON and R = 0.82, the RMSE of 6.75 ppm for WDCGG, respectively. The RMSE of the ensemble dataset was 6 ppm lower than that of the satellites' XCO2 used for fusion compared with WDCGG and the coverage is greatly improved at a higher spatial and temporal resolution, proving the feasibility and high precision of the method. |
|||||
BibTeX:
@article{jin22a,
author = {Jin, Chunlin and Xue, Yong and Jiang, Xingxing and Zhao, Liang and Yuan, Tao and Sun, Yuxin and Wu, Shuhui and Wang, Xiangkai},
title = {A long-term global XCO2 dataset: Ensemble of satellite products},
journal = {ATMOSPHERIC RESEARCH},
year = {2022},
volume = {279},
doi = {https://doi.org/10.1016/j.atmosres.2022.106385}
}
|
|||||
| Jing, Y., Shi, J., Wang, T. and Sussmann, R. | Mapping Global Atmospheric CO2 Concentration at High Spatiotemporal Resolution | {2014} | ATMOSPHERE Vol. {5}({4}), pp. 870-888 |
article | DOI |
| Abstract: Satellite measurements of the spatiotemporal distributions of atmospheric CO2 concentrations are a key component for better understanding global carbon cycle characteristics. Currently, several satellite instruments such as the Greenhouse gases Observing SATellite (GOSAT), SCanning Imaging Absorption Spectrometer for Atmospheric CHartographY (SCIAMACHY), and Orbiting Carbon Observatory-2 can be used to measure CO2 column-averaged dry air mole fractions. However, because of cloud effects, a single satellite can only provide limited CO2 data, resulting in significant uncertainty in the characterization of the spatiotemporal distribution of atmospheric CO2 concentrations. In this study, a new physical data fusion technique is proposed to combine the GOSAT and SCIAMACHY measurements. On the basis of the fused dataset, a gap-filling method developed by modeling the spatial correlation structures of CO2 concentrations is presented with the goal of generating global land CO2 distribution maps with high spatiotemporal resolution. The results show that, compared with the single satellite dataset (i.e., GOSAT or SCIAMACHY), the global spatial coverage of the fused dataset is significantly increased (reaching up to approximately 20%), and the temporal resolution is improved by two or three times. The spatial coverage and monthly variations of the generated global CO2 distributions are also investigated. Comparisons with ground-based Total Carbon Column Observing Network (TCCON) measurements reveal that CO2 distributions based on the gap-filling method show good agreement with TCCON records despite some biases. These results demonstrate that the fused dataset as well as the gap-filling method are rather effective to generate global CO2 distribution with high accuracies and high spatiotemporal resolution. |
|||||
BibTeX:
@article{jing14a,
author = {Jing, Yingying and Shi, Jiancheng and Wang, Tianxing and Sussmann, Ralf},
title = {Mapping Global Atmospheric CO2 Concentration at High Spatiotemporal Resolution},
journal = {ATMOSPHERE},
year = {2014},
volume = {5},
number = {4},
pages = {870--888},
doi = {https://doi.org/10.3390/atmos5040870}
}
|
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| Jing, Y., Shi, J. and Wang, T. | FUSION OF SPACE-BASED CO2 PRODUCTS AND ITS COMPARISON WITH OTHER AVAILABLE CO2 ESTIMATES | {2014} | 2014 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS), pp. 2363-2366 | inproceedings | DOI |
| Abstract: Currently, ascertaining and quantifying the global distribution of carbon dioxide from space-based measurements are greatly valuable for understanding the causes of global warming and predicting the tendency of climate change. Nevertheless, the number of valid XCO2 data points from a single space-based sensor is generally limited on the earth. Based on this problem, a fused XCO2 dataset is used to generate a continuous spatio-temporal distribution of global CO2 concentration by combining GOSAT with SCIAMACHY in this study. And this dataset is also compared with a data assimilation system Carbon Tracker as well as ground-based TCCON sites. The results reveal that the spatial coverage of the fused data is wider than individual space-based XCO2 measurements (GOSAT or SCIAMCHY) on the global scale. Meanwhile, compared to that of GOSAT or SCIAMACHY, the correlation between the fused data and Carbon Tracker is relatively better. In addition, the fused data show a good agreement with CO2 retrieval of ACOS and BESD as well as that of TCCON sites although a little biases exist. |
|||||
BibTeX:
@inproceedings{jing14b,
author = {Jing, Yingying and Shi, Jiancheng and Wang, Tianxing},
title = {FUSION OF SPACE-BASED CO2 PRODUCTS AND ITS COMPARISON WITH OTHER AVAILABLE CO2 ESTIMATES},
booktitle = {2014 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS)},
year = {2014},
pages = {2363--2366},
note = {IEEE Joint International Geoscience and Remote Sensing Symposium (IGARSS) / 35th Canadian Symposium on Remote Sensing, Quebec City, CANADA, JUL 13-18, 2014},
doi = {https://doi.org/10.1109/IGARSS.2014.6946946}
}
|
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| Jing, Y., Wang, T. and Shi, J. | TOWARD ACCURATE XCO2 LEVEL 2 MEASUREMENTS BY COMBINING DIFFERENT CO2 RETRIEVALS FROM GOSAT AND SCIAMACHY | {2014} | 2014 THIRD INTERNATIONAL WORKSHOP ON EARTH OBSERVATION AND REMOTE SENSING APPLICATIONS (EORSA 2014) | inproceedings | |
| Abstract: Carbon dioxide (CO2) is one of the most important anthropogenic greenhouse gases causing global warming. Although various space-based observations have been used to derive and identify regional and global distribution of CO2 source and sink, uncertainties and biases are still subsistent. A high spatial and temporal resolution is important to remove the CO2 uncertainties and biases. In this study, an improved ensemble median algorithm is developed by fully accounting for the variation of XCO2 on synoptic timescales. Based on this, XCO2 data sets from the improved method and EMMA are compared in terms of their spatiotemporal distributions and correlations. Meanwhile, XCO2 measurements from three TCCON sites are used to compare with these two datasets. The results reveal that although there is a good correlation between the XCO2 from improved method and that of EMMA at annual scale, large discrepancies can be still detected at most places over the world. It seems that a higher time resolution is necessary to remove the outliers. In addition, the season cycle of the two methods is generally in agreement with ground measurements. However, our improved method shows less divergence compared to that of EMMA at three ground sites. To some extent, these results proved the effectiveness of our new method and thus demonstrated the necessity for refining the Level 2 XCO2 measurements at a shorter time averaging period. |
|||||
BibTeX:
@inproceedings{jing14c,
author = {Jing, Yingying and Wang, Tianxing and Shi, Jiancheng},
title = {TOWARD ACCURATE XCO2 LEVEL 2 MEASUREMENTS BY COMBINING DIFFERENT CO2 RETRIEVALS FROM GOSAT AND SCIAMACHY},
booktitle = {2014 THIRD INTERNATIONAL WORKSHOP ON EARTH OBSERVATION AND REMOTE SENSING APPLICATIONS (EORSA 2014)},
year = {2014},
note = {3rd International Workshop on Earth Observation and Remote Sensing Applications (EORSA), Changsha, PEOPLES R CHINA, JUN 11-14, 2014}
}
|
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| Jing, Y., Shi, J. and Wang, T. | EVALUATION AND COMPARISON OF ATMOSPHERIC CO2 CONCENTRATIONS FROM MODELS AND SATELLITE RETRIEVALS | {2015} | 2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS), pp. 2202-2205 | inproceedings | |
| Abstract: In recent years, global warming caused by increased atmospheric CO2 has greatly drawn widespread attention from the public. Although satellite observations and model-simulation offer us two effective approaches to monitor and assess the global atmospheric CO2, quantification of the differences between these two different CO2 data is not fully investigated yet. In this paper, these CO2 products including satellite observations and model-simulation are inter-compared in terms of magnitude and their spatiotemporal distributions. The results reveal that these CO2 data from different data source show a good agreement all over the world, whereas many discrepancies still exist between satellite observations and model-simulation, especially in the Northern Sphere. |
|||||
BibTeX:
@inproceedings{jing15a,
author = {Jing, Yingying and Shi, Jiancheng and Wang, Tianxing},
title = {EVALUATION AND COMPARISON OF ATMOSPHERIC CO2 CONCENTRATIONS FROM MODELS AND SATELLITE RETRIEVALS},
booktitle = {2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS)},
year = {2015},
pages = {2202--2205},
note = {IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Milan, ITALY, JUL 26-31, 2015}
}
|
|||||
| Jing, Y., Wang, T., Zhang, P., Chen, L., Xu, N. and Ma, Y. | Global Atmospheric CO2 Concentrations Simulated by GEOS-Chem: Comparison with GOSAT, Carbon Tracker and Ground-Based Measurements [BibTeX] |
2018 | Atmosphere Vol. 9(5), pp. 175 |
article | URL |
BibTeX:
@article{jing18a,
author = {Jing, Yingying and Wang, Tianxing and Zhang, Peng and Chen, Lin and Xu, Na and Ma, Ya},
title = {Global Atmospheric CO2 Concentrations Simulated by GEOS-Chem: Comparison with GOSAT, Carbon Tracker and Ground-Based Measurements},
journal = {Atmosphere},
year = {2018},
volume = {9},
number = {5},
pages = {175},
url = {https://www.mdpi.com/2073-4433/9/5/175/htm}
}
|
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| Jones, L.A., Kimball, J.S., Reichle, R.H., Madani, N., Glassy, J., Ardizzone, J.V., Colliander, A., Cleverly, J., Desai, A.R., Eamus, D., Euskirchen, E.S., Hutley, L., Macfarlane, C. and Scott, R.L. | The SMAP Level 4 Carbon Product for Monitoring Ecosystem Land-Atmosphere CO2 Exchange | {2017} | IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Vol. {55}({11}), pp. 6517-6532 |
article | DOI |
| Abstract: The National Aeronautics and Space Administration's Soil Moisture Active Passive (SMAP) mission Level 4 Carbon (L4C) product provides model estimates of the Net Ecosystem CO2 exchange (NEE) incorporating SMAP soil moisture information. The L4C product includes NEE, computed as total ecosystem respiration less gross photosynthesis, at a daily time step posted to a 9-km global grid by plant functional type. Component carbon fluxes, surface soil organic carbon stocks, underlying environmental constraints, and detailed uncertainty metrics are also included. The L4C model is driven by the SMAP Level 4 Soil Moisture data assimilation product, with additional inputs from the Goddard Earth Observing System, Version 5 weather analysis, and Moderate Resolution Imaging Spectroradiometer satellite vegetation data. The L4C data record extends from March 31, 2015 to present with ongoing production and 8-12 day latency. Comparisons against concurrent global CO2 eddy flux tower measurements, satellite solar-induced canopy florescence, and other independent observation benchmarks show favorable L4C performance and accuracy, capturing the dynamic biosphere response to recent weather anomalies. Model experiments and L4C spatiotemporal variability were analyzed to understand the independent value of soil moisture and SMAP observations relative to other sources of input information. This analysis highlights the potential for microwave observations to inform models where soil moisture strongly controls land CO2 flux variability; however, skill improvement relative to flux towers is not yet discernable within the relatively short validation period. These results indicate that SMAP provides a unique and promising capability for monitoring the linked global terrestrial water and carbon cycles. |
|||||
BibTeX:
@article{jones17a,
author = {Jones, Lucas A. and Kimball, John S. and Reichle, Rolf H. and Madani, Nima and Glassy, Joe and Ardizzone, Joe V. and Colliander, Andreas and Cleverly, James and Desai, Ankur R. and Eamus, Derek and Euskirchen, Eugenie S. and Hutley, Lindsay and Macfarlane, Craig and Scott, Russell L.},
title = {The SMAP Level 4 Carbon Product for Monitoring Ecosystem Land-Atmosphere CO2 Exchange},
journal = {IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING},
year = {2017},
volume = {55},
number = {11},
pages = {6517--6532},
doi = {https://doi.org/10.1109/TGRS.2017.2729343}
}
|
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| Kanakidou, M., Dameris, M., Elbern, H., Beekmann, M., Konovalov, I.B., Nieradzik, L., Strunk, A. and Krol, M.C. | Synergistic Use of Retrieved Trace Constituent Distributions and Numerical Modelling [BibTeX] |
{2011} | REMOTE SENSING OF TROPOSPHERIC COMPOSITION FROM SPACE, pp. 451-492 | incollection | DOI |
BibTeX:
@incollection{kanakidou11a,
author = {Kanakidou, Maria and Dameris, Martin and Elbern, Hendrik and Beekmann, Matthias and Konovalov, Igor B. and Nieradzik, Lars and Strunk, Achim and Krol, Maarten C.},
title = {Synergistic Use of Retrieved Trace Constituent Distributions and Numerical Modelling},
booktitle = {REMOTE SENSING OF TROPOSPHERIC COMPOSITION FROM SPACE},
publisher = {Springer},
year = {2011},
pages = {451--492},
doi = {https://doi.org/10.1007/978-3-642-14791-3%5C_9}
}
|
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| Kang, J.-S., Kalnay, E., Liu, J., Fung, I., Miyoshi, T. and Ide, K. | ``Variable localization'' in an ensemble Kalman filter: Application to the carbon cycle data assimilation | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: In ensemble Kalman filter, space localization is used to reduce the impact of long-distance sampling errors in the ensemble estimation of the forecast error covariance. When two variables are not physically correlated, their error covariance is still estimated by the ensemble and, therefore, it is dominated by sampling errors. We introduce a ``variable localization'' method, zeroing out such covariances between unrelated variables to the problem of assimilating carbon dioxide concentrations into a dynamical model using the local ensemble transform Kalman filter (LETKF) in an observing system simulation experiments (OSSE) framework. A system where meteorological and carbon variables are simultaneously assimilated is used to estimate surface carbon fluxes that are not directly observed. A range of covariance structures are explored for the LETKF, with emphasis on configurations allowing nonzero error covariance between carbon variables and the wind field, which affects transport of atmospheric CO2, but not between CO2 and the other meteorological variables. Such variable localization scheme zeroes out the background error covariance among prognostic variables that are not physically related, thus reducing sampling errors. Results from the identical twin experiments show that the performance in the estimation of surface carbon fluxes obtained using variable localization is much better than that using a standard full covariance approach. The relative improvement increases when the surface fluxes change with time and model error becomes significant. |
|||||
BibTeX:
@article{kang11a,
author = {Kang, Ji-Sun and Kalnay, Eugenia and Liu, Junjie and Fung, Inez and Miyoshi, Takemasa and Ide, Kayo},
title = {``Variable localization'' in an ensemble Kalman filter: Application to the carbon cycle data assimilation},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2010JD014673}
}
|
|||||
| Kang, J.-S., Kalnay, E., Miyoshi, T., Liu, J. and Fung, I. | Estimation of surface carbon fluxes with an advanced data assimilation methodology | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {117} |
article | DOI |
| Abstract: We perform every 6 h a simultaneous data assimilation of surface CO2 fluxes and atmospheric CO2 concentrations along with meteorological variables using the Local Ensemble Transform Kalman Filter (LETKF) within an Observing System Simulation Experiments framework. In this paper, we focus on the impact of advanced variance inflation methods and vertical localization of column CO2 data on the analysis of CO2. With both additive inflation and adaptive multiplicative inflation, we are able to obtain encouraging multiseasonal analyses of surface CO2 fluxes in addition to atmospheric CO2 and meteorological analyses. Furthermore, we examine strategies for vertical localization in the assimilation of simulated CO2 from GOSAT that has nearly uniform sensitivity from the surface to the upper troposphere. Since atmospheric CO2 is forced by surface fluxes, its short-term variability should be largest near the surface. We take advantage of this by updating observed changes only into the lower tropospheric CO2 rather than into the full column. This results in a more accurate analysis of CO2 in terms of both RMS error and spatial patterns. Assimilating synthetic CO2 ground-based observations and CO2 retrievals from GOSAT and AIRS with the enhanced LETKF, we obtain an accurate estimation of the evolving surface fluxes even in the absence of any a priori information. We also test the system with a longer assimilation window and find that a short window with an efficient treatment for wind uncertainty is beneficial to flux inversion. Since this study assumes a perfect forecast model, future research will explore the impact of model errors. Citation: Kang, J.-S., E. Kalnay, T. Miyoshi, J. Liu, and I. Fung (2012), Estimation of surface carbon fluxes with an advanced data assimilation methodology, J. Geophys. Res., 117, D24101, doi: 10.1029/2012JD018259. |
|||||
BibTeX:
@article{kang12a,
author = {Kang, Ji-Sun and Kalnay, Eugenia and Miyoshi, Takemasa and Liu, Junjie and Fung, Inez},
title = {Estimation of surface carbon fluxes with an advanced data assimilation methodology},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2012JD018259}
}
|
|||||
| Karion, A., Sweeney, C., Tans, P. and Newberger, T. | AirCore: An Innovative Atmospheric Sampling System | {2010} | JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY Vol. {27}({11}), pp. 1839-1853 |
article | DOI |
| Abstract: This work describes the Air Core, a simple and innovative atmospheric sampling system. The AirCore used in this study is a 150-m-long stainless steel tube, open at one end and closed at the other, that relies on positive changes in ambient pressure for passive sampling of the atmosphere. The Air Core evacuates while ascending to a high altitude and collects a sample of the ambient air as it descends. It is sealed upon recovery and measured with a continuous analyzer for trace gas mole fraction. The Air Core tubing can be shaped into a variety of configurations to accommodate any sampling platform; for the testing done in this work it was shaped into a 0,75-m-diameter coil. Measurements of CO(2) and CH(4) mole fractions in laboratory tests indicate a repeatability and lack of bias to better than 0.07 ppm (one sigma) for CO, and 0.4 ppb for CH(4) under various conditions. Comparisons of AirCore data with flask data from aircraft flights indicate a standard deviation of differences of 0.3 ppm and 5 ppb for CO(2) and CH(4), respectively, with no apparent bias. Accounting for longitudinal mixing, the expected measurement resolution for CO2 is 110 m at sea level, 260 m at 8000 m. and 1500 m at 20 000 m ASL after 3 h of storage, decreasing to 170, 390, and 2300 m, after 12 h. Validation tests confirm that the AirCore is a robust sampling device for many species on a variety of platforms, including balloons, unmanned aerial vehicles (UAVs), and aircraft. |
|||||
BibTeX:
@article{karion10a,
author = {Karion, Anna and Sweeney, Colm and Tans, Pieter and Newberger, Timothy},
title = {AirCore: An Innovative Atmospheric Sampling System},
journal = {JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY},
year = {2010},
volume = {27},
number = {11},
pages = {1839--1853},
doi = {https://doi.org/10.1175/2010JTECHA1448.1}
}
|
|||||
| Karion, A., Callahan, W., Stock, M., Prinzivalli, S., Verhulst, K.R., Kim, J., Salameh, P.K., Lopez-Coto, I. and Whetstone, J. | Greenhouse gas observations from the Northeast Corridor tower network | {2020} | EARTH SYSTEM SCIENCE DATA Vol. {12}({1}), pp. {699-717} |
article | DOI URL |
| Abstract: We present the organization, structure, instrumentation, and measurements of the Northeast Corridor greenhouse gas observation network. This network of tower-based in situ carbon dioxide and methane observation stations was established in 2015 with the goal of quantifying emissions of these gases in urban areas in the northeastern United States. A specific focus of the network is the cities of Baltimore, MD, and Washington, DC, USA, with a high density of observation stations in these two urban areas. Additional observation stations are scattered throughout the northeastern US, established to complement other existing urban and regional networks and to investigate emissions throughout this complex region with a high population density and multiple metropolitan areas. Data described in this paper are archived at the National Institute of Standards and Technology and can be found at https://doi.org/10.18434/M32126 (Karion et al., 2019). | |||||
BibTeX:
@article{karion20a,
author = {Karion, Anna and Callahan, William and Stock, Michael and Prinzivalli, Steve and Verhulst, Kristal R. and Kim, Jooil and Salameh, Peter K. and Lopez-Coto, Israel and Whetstone, James},
title = {Greenhouse gas observations from the Northeast Corridor tower network},
journal = {EARTH SYSTEM SCIENCE DATA},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {12},
number = {1},
pages = {699--717},
note = {Query date: 2021-04-02 15:20:04},
url = {https://essd.copernicus.org/articles/12/699/2020/},
doi = {https://doi.org/10.5194/essd-12-699-2020}
}
|
|||||
| Karion, A., Lopez-Coto, I., Gourdji, S.M., Mueller, K., Ghosh, S., Callahan, W., Stock, M., DiGangi, E., Prinzivalli, S. and Whetstone, J. | Background conditions for an urban greenhouse gas network in the Washington, DC, and Baltimore metropolitan region | 2021 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 21(8), pp. 6257-6273 |
article | DOI |
| Abstract: As city governments take steps towards establishing emissions reduction targets, the atmospheric research community is increasingly able to assist in tracking emissions reductions. Researchers have established systems for observing atmospheric greenhouse gases in urban areas with the aim of attributing greenhouse gas concentration enhancements (and thus emissions) to the region in question. However, to attribute enhancements to a particular region, one must isolate the component of the observed concentration attributable to fluxes inside the region by removing the background, which is the component due to fluxes outside. In this study, we demonstrate methods to construct several versions of a background for our carbon dioxide and methane observing network in the Washington, DC, and Baltimore, MD, metropolitan region. Some of these versions rely on transport and flux models, while others are based on observations upwind of the domain. First, we evaluate the backgrounds in a synthetic data framework, and then we evaluate against real observations from our urban network. We find that backgrounds based on upwind observations capture the variability better than model-based backgrounds, although care must be taken to avoid bias from biospheric carbon dioxide fluxes near background stations in summer. Model-based backgrounds also perform well when upwind fluxes can be modeled accurately. Our study evaluates different background methods and provides guidance in determining background methodology that can impact the design of urban monitoring networks. |
|||||
BibTeX:
@article{karion21a,
author = {Karion, Anna and Lopez-Coto, Israel and Gourdji, Sharon M. and Mueller, Kimberly and Ghosh, Subhomoy and Callahan, William and Stock, Michael and DiGangi, Elizabeth and Prinzivalli, Steve and Whetstone, James},
title = {Background conditions for an urban greenhouse gas network in the Washington, DC, and Baltimore metropolitan region},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2021},
volume = {21},
number = {8},
pages = {6257-6273},
doi = {https://doi.org/10.5194/acp-21-6257-2021}
}
|
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| Kassem, I.I., Joshi, P., Sigler, V., Heckathorn, S. and Wang, Q. | Effect of Elevated CO2 and Drought on Soil Microbial Communities Associated with Andropogon gerardii | {2008} | JOURNAL OF INTEGRATIVE PLANT BIOLOGY Vol. {50}({11}), pp. 1406-1415 |
article | DOI |
| Abstract: Our understanding of the effects of elevated atmospheric CO2, singly and in combination with other environmental changes, on plant-soil interactions is incomplete. Elevated CO2 effects on C-4 plants, though smaller than on C-3 species, are mediated mostly via decreased stomatal conductance and thus water loss. Therefore, we characterized the interactive effect of elevated CO2 and drought on soil microbial communities associated with a dominant C-4 prairie grass, Andropogon gerardii Vitman. Elevated CO2 and drought both affected resources available to the soil microbial community. For example, elevated CO2 increased the soil C:N ratio and water content during drought, whereas drought alone decreased both. Drought significantly decreased soil microbial biomass. In contrast, elevated CO2 increased biomass while ameliorating biomass decreases that were induced under drought. Total and active direct bacterial counts and carbon substrate use (overall use and number of used sources) increased significantly under elevated CO2. Denaturing gradient gel electrophoresis analysis revealed that drought and elevated CO2, singly and combined, did not affect the soil bacteria community structure. We conclude that elevated CO2 alone increased bacterial abundance and microbial activity and carbon use, probably in response to increased root exudation. Elevated CO2 also limited drought-related impacts on microbial activity and biomass, which likely resulted from decreased plant water use under elevated CO2. These are among the first results showing that elevated CO2 and drought work in opposition to modulate plant-associated soil-bacteria responses, which should then influence soil resources and plant and ecosystem function. |
|||||
BibTeX:
@article{kassem08a,
author = {Kassem, Issmat I. and Joshi, Puneet and Sigler, Von and Heckathorn, Scott and Wang, Qi},
title = {Effect of Elevated CO2 and Drought on Soil Microbial Communities Associated with Andropogon gerardii},
journal = {JOURNAL OF INTEGRATIVE PLANT BIOLOGY},
year = {2008},
volume = {50},
number = {11},
pages = {1406--1415},
doi = {https://doi.org/10.1111/j.1744-7909.2008.00752.x}
}
|
|||||
| Kavitha, M. and Nair, P.R. | Region-dependent seasonal pattern of methane over Indian region as observed by SCIAMACHY | {2016} | ATMOSPHERIC ENVIRONMENT Vol. {131}, pp. 316-325 |
article | DOI |
| Abstract: The column averaged mixing ratio of methane (XCH4) from SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) on-board satellite ENVISAT has been used to study its regional pattern and seasonal cycle over Indian region for the period 2003-2009. XCH4 varies from 1740 to 1890 ppbv over Indian region with distinct spatial and temporal features. The peak values are observed in monsoon and post monsoon and minimum in winter months, except over southern Peninsular India which shows the distinctly different seasonal behavior with peak in October/November. The mean background level of XCH4 over Indian region is estimated as similar to 1795 ppbv. While regional patterns are strongly associated with livestock distribution, wetland emissions, including rice fields, the seasonal variations in XCH4 are predominantly associated with the rice cultivation as revealed by analysis of NDVI. (C) 2016 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{kavitha16a,
author = {Kavitha, M. and Nair, Prabha R.},
title = {Region-dependent seasonal pattern of methane over Indian region as observed by SCIAMACHY},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2016},
volume = {131},
pages = {316--325},
doi = {https://doi.org/10.1016/j.atmosenv.2016.02.008}
}
|
|||||
| Kavitha, M. and Nair, P.R. | SCIAMACHY observed changes in the column mixing ratio of methane over the Indian region and a comparison with global scenario | {2017} | ATMOSPHERIC ENVIRONMENT Vol. {166}, pp. 454-466 |
article | DOI |
| Abstract: The trends in the column averaged mixing ratio of methane (XCH4) over the Indian region during 2003 2009 periods were studied using the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) observations. Considering the sensor degradation, the trends were analyzed for 2003 to 2005 and 2006 to 2009 separately. Over India, the trend in XCH4 varied from 5.2 to 7.6 ppb per year after 2005, exhibiting a 2-4 fold increase compared to 2003-2005. While the increase over Northern parts of India is attributed to increasing CH4 emissions from rice cultivation and livestock population, those over Southern regions are due to increased oil and gas mining activities. A comparison of these trends with those over most of the hotspot regions over the globe revealed that those regions exhibited higher growth rates of XCH4 compared to Indian regions during 2006-2009. The seasonal patterns of XCH4 and near-surface CH4 at selected global network stations were also examined in detail. This analysis revealed hemispheric difference and varying seasonal patterns suggesting the inhomogeneous vertical distribution of CH4. The observed differences in the seasonal patterns of near-surface CH4 and XCH4 suggest that the surface emissions need not replicate at higher altitudes due to long-range transport, the boundary layer meteorology and lifetime of CH4 in the atmosphere. (C) 2017 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{kavitha17a,
author = {Kavitha, M. and Nair, Prabha R.},
title = {SCIAMACHY observed changes in the column mixing ratio of methane over the Indian region and a comparison with global scenario},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2017},
volume = {166},
pages = {454--466},
doi = {https://doi.org/10.1016/j.atmosenv.2017.07.044}
}
|
|||||
| Keeling, R. and Manning, A. | 5.15 - Studies of Recent Changes in Atmospheric O2\ Content | 2014 | Treatise on Geochemistry (Second Edition), pp. 385-404 | incollection | DOI URL |
| Abstract: Abstract A very close coupling exists between changes in atmospheric O2\ and CO2\ concentrations, owing to the chemistry of photosynthesis, respiration, and combustion. The coupling is not perfect, however, because CO2\ variations are partially buffered by reactions involving the inorganic carbon system in seawater, which has no effect on O2. Measurements over the past two decades document variations in O2\ on a range of space and time scales, including a long-term decrease driven mostly by fossil fuel burning and seasonal cycles driven by exchanges with the land biosphere and the oceans. In this chapter, these and other features seen in the measurements are described, also discussing variations in the tracer `atmospheric potential oxygen,' which is a linear combination of O2\ and CO2\ designed to be insensitive to exchanges from the land biosphere and thereby sensitive mostly to oceanic processes. Challenges associated with measuring variations in O2\ are addressed, and various applications of the observations are discussed, including quantifying the magnitude of the global land and ocean carbon sinks and testing ocean biogeochemical models. An updated budget for global carbon sinks based on O2\ measurements from the Scripps O2\ program is presented for the decades of the 1990s and 2000s. | |||||
BibTeX:
@incollection{keeling14a,
author = {R.F. Keeling and A.C. Manning},
title = {5.15 - Studies of Recent Changes in Atmospheric O2\ Content},
booktitle = {Treatise on Geochemistry (Second Edition)},
publisher = {Elsevier},
year = {2014},
pages = {385--404},
url = {https://www.sciencedirect.com/science/article/pii/B9780080959757004204},
doi = {https://doi.org/10.1016/B978-0-08-095975-7.00420-4}
}
|
|||||
| Kenea, S.T., Oh, Y.-S., Rhee, J.-S., Goo, T.-Y., Byun, Y.-H., Li, S., Labzovskii, L.D., Lee, H. and Banks, R.F. | Evaluation of Simulated CO2 Concentrations from the CarbonTracker-Asia Model Using In-situ Observations over East Asia for 2009-2013 | {2019} | ADVANCES IN ATMOSPHERIC SCIENCES Vol. {36}({6}), pp. {603-613} |
article | DOI URL |
| Abstract: The CarbonTracker (CT) model has been used in previous studies for understanding and predicting the sources, sinks, and dynamics that govern the distribution of atmospheric CO2 at varying ranges of spatial and temporal scales. However, there are still challenges for reproducing accurate model-simulated CO2 concentrations close to the surface, typically associated with high spatial heterogeneity and land cover. In the present study, we evaluated the performance of nested-grid CT model simulations of CO2 based on the CT2016 version through comparison with in-situ observations over East Asia covering the period 2009-13. We selected sites located in coastal, remote, inland, and mountain areas. The results are presented at diurnal and seasonal time periods. At target stations, model agreement with in-situ observations was varied in capturing the diurnal cycle. Overall, biases were less than 6.3 ppm on an all-hourly mean basis, and this was further reduced to a maximum of 4.6 ppm when considering only the daytime. For instance, at Anmyeondo, a small bias was obtained in winter, on the order of 0.2 ppm. The model revealed a diurnal amplitude of CO2 that was nearly flat in winter at Gosan and Anmyeondo stations, while slightly overestimated in the summertime. The model's performance in reproducing the diurnal cycle remains a challenge and requires improvement. The model showed better agreement with the observations in capturing the seasonal variations of CO2 during daytime at most sites, with a correlation coefficient ranging from 0.70 to 0.99. Also, model biases were within -0.3 and 1.3 ppm, except for inland stations (7.7 ppm). | |||||
BibTeX:
@article{kenea19a,
author = {Kenea, Samuel Takele and Oh, Young-Suk and Rhee, Jae-Sang and Goo, Tae-Young and Byun, Young-Hwa and Li, Shanlan and Labzovskii, Lev D. and Lee, Haeyoung and Banks, Robert F.},
title = {Evaluation of Simulated CO2 Concentrations from the CarbonTracker-Asia Model Using In-situ Observations over East Asia for 2009-2013},
journal = {ADVANCES IN ATMOSPHERIC SCIENCES},
publisher = {SCIENCE PRESS},
year = {2019},
volume = {36},
number = {6},
pages = {603--613},
note = {Query date: 2021-04-02 15:20:04},
url = {https://link.springer.com/article/10.1007/s00376-019-8150-x},
doi = {https://doi.org/10.1007/s00376-019-8150-x}
}
|
|||||
| Kenea, S.T., Labzovskii, L.D., Goo, T.-Y., Li, S., Oh, Y.-S. and Byun, Y.-H. | Comparison of Regional Simulation of Biospheric CO2 Flux from the Updated Version of CarbonTracker Asia with FLUXCOM and Other Inversions over Asia | {2020} | REMOTE SENSING Vol. {12}({1}) |
article | DOI |
| Abstract: There are still large uncertainties in the estimates of net ecosystem exchange of CO2 (NEE) with atmosphere in Asia, particularly in the boreal and eastern part of temperate Asia. To understand these uncertainties, we assessed the CarbonTracker Asia (CTA2017) estimates of the spatial and temporal distributions of NEE through a comparison with FLUXCOM and the global inversion models from the Copernicus Atmospheric Monitoring Service (CAMS), Monitoring Atmospheric Composition and Climate (MACC), and Jena CarboScope in Asia, as well as examining the impact of the nesting approach on the optimized NEE flux during the 2001-2013 period. The long-term mean carbon uptake is reduced in Asia, which is -0.32 +/- 0.22 PgC yr(-1), whereas -0.58 +/- 0.26 PgC yr(-1) is shown from CT2017 (CarbonTracker global). The domain aggregated mean carbon uptake from CTA2017 is found to be lower by 23.8%, 44.8%, and 60.5% than CAMS, MACC, and Jena CarboScope, respectively. For example, both CTA2017 and CT2017 models captured the interannual variability (IAV) of the NEE flux with a different magnitude and this leads to divergent annual aggregated results. Differences in the estimated interannual variability of NEE in response to El Nino-Southern Oscillation (ENSO) may result from differences in the transport model resolutions. These inverse models' results have a substantial difference compared to FLUXCOM, which was found to be -5.54 PgC yr(-1). On the one hand, we showed that the large NEE discrepancies between both inversion models and FLUXCOM stem mostly from the tropical forests. On the other hand, CTA2017 exhibits a slightly better correlation with FLUXCOM over grass/shrub, fields/woods/savanna, and mixed forest than CT2017. The land cover inconsistency between CTA2017 and FLUXCOM is therefore one driver of the discrepancy in the NEE estimates. The diurnal averaged NEE flux between CTA2017 and FLUXCOM exhibits better agreement during the carbon uptake period than the carbon release period. Both CTA2017 and CT2017 revealed that the overall spatial patterns of the carbon sink and source are similar, but the magnitude varied with seasons and ecosystem types, which is mainly attributed to differences in the transport model resolutions. Our findings indicate that substantial inconsistencies in the inversions and FLUXCOM mainly emerge during the carbon uptake period and over tropical forests. The main problems are underrepresentation of FLUXCOM NEE estimates by limited eddy covariance flux measurements, the role of CO2 emissions from land use change not accounted for by FLUXCOM, sparseness of surface observations of CO2 concentrations used by the assimilation systems, and land cover inconsistency. This suggested that further scrutiny on the FLUXCOM and inverse estimates is most likely required. Such efforts will reduce inconsistencies across various NEE estimates over Asia, thus mitigating ecosystem-driven errors that propagate the global carbon budget. Moreover, this work also recommends further investigation on how the changes/updates made in CarbonTracker affect the interannual variability of the aggregate and spatial pattern of NEE flux in response to the ENSO effect over the region of interest. | |||||
BibTeX:
@article{kenea20a,
author = {Kenea, Samuel Takele and Labzovskii, Lev D. and Goo, Tae-Young and Li, Shanlan and Oh, Young-Suk and Byun, Young-Hwa},
title = {Comparison of Regional Simulation of Biospheric CO2 Flux from the Updated Version of CarbonTracker Asia with FLUXCOM and Other Inversions over Asia},
journal = {REMOTE SENSING},
publisher = {MDPI},
year = {2020},
volume = {12},
number = {1},
doi = {https://doi.org/10.3390/rs12010145}
}
|
|||||
| Kenea, S.T., Lee, H., Patra, P.K., Li, S., Labzovskii, L.D. and Joo, S. | Long-term changes in CH4 emissions: Comparing Delta CH4/Delta CO2 ratios between observation and proved model in East Asia (2010-2020) | 2023 | ATMOSPHERIC ENVIRONMENT Vol. 293 |
article | DOI |
| Abstract: To understand the changes in CH4 emissions in East Asia, mainly in China, we analyzed the synoptic scale variability (SSV) of CO2 and CH4 mole fractions at Anmyeondo (AMY; 36.53 degrees N, 126.32 degrees E, 46 m above sea level) in South Korea using near-surface in-situ observations and an atmospheric chemical transport model (ACTM) to investigate the role of prescribed surface fluxes on SSV. The SSV of the tracers at AMY was mainly caused by emission variations from eastern and northeastern China during the winters in 2010-2020, as indicated by the simulated concentration footprints at AMY observed using the WRF-STILT model. The estimated SSV of Delta CH4/Delta CO2 mole fraction ratios from the observations was 4.2-6.2 ppb ppm(-1), with a mean of 5.7 +/- 0.93 ppb ppm(-1) during the winters in 2010-2020. We also calculated the CH4/CO2 emission ratio from China's total annual fossil-fuel emissions, excluding seasonal sources estimated from the Emission Database for Global Atmospheric Research. We found that the ratio was overestimated by similar to 98.1% compared to observations, which was likely driven either due to the overestimation of CH4 or underestimation of CO2. We discerned that the model-simulated SSV of the Delta CH4/Delta CO2 ratios generally reproduced the observations when the CH4 FixCoal simulation case was used. This implies that CH4 from coal was a major contributor to the observed variations in the winter period Delta CH4/Delta CO2 ratios. However, the model did not reproduce the observed ratio in 2012-this discrepancy requires further study. The trend of Delta CH4/Delta CO2 was a slight decrease over time, which was attributed to the earlier onset of CH4 emissions relative to fossil-fuel CO2, predominantly due to the reduction of CH4 emissions from coal. In 2013, a relatively low tracer ratio was noted, which was caused by the large contribution of CO2 from biomass burning. Overall, the observed AMY Delta CH4/Delta CO2 ratios provide an efficient approach for validating the existing estimates of East Asian sectoral emissions of CH4. |
|||||
BibTeX:
@article{kenea23a,
author = {Kenea, Samuel Takele and Lee, Haeyoung and Patra, Prabir K. and Li, Shanlan and Labzovskii, Lev D. and Joo, Sangwon},
title = {Long-term changes in CH4 emissions: Comparing Delta CH4/Delta CO2 ratios between observation and proved model in East Asia (2010-2020)},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2023},
volume = {293},
doi = {https://doi.org/10.1016/j.atmosenv.2022.119437}
}
|
|||||
| Keppel-Aleks, G., Wennberg, P.O. and Schneider, T. | Sources of variations in total column carbon dioxide | {2011} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {11}({8}), pp. 3581-3593 |
article | DOI |
| Abstract: Observations of gradients in the total CO(2) column, < CO(2)>, are expected to provide improved constraints on surface fluxes of CO(2). Here we use a general circulation model with a variety of prescribed carbon fluxes to investigate how variations in < CO(2)> arise. On diurnal scales, variations are small and are forced by both local fluxes and advection. On seasonal scales, gradients are set by the north-south flux distribution. On synoptic scales, variations arise due to large-scale eddy-driven disturbances of the meridional gradient. In this case, because variations in < CO(2)> are tied to synoptic activity, significant correlations exist between < CO(2)> and dynamical tracers. We illustrate how such correlations can be used to describe the north-south gradients of < CO(2)> and the underlying fluxes on continental scales. These simulations suggest a novel analysis framework for using column observations in carbon cycle science. |
|||||
BibTeX:
@article{keppel-aleks11a,
author = {Keppel-Aleks, G. and Wennberg, P. O. and Schneider, T.},
title = {Sources of variations in total column carbon dioxide},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
volume = {11},
number = {8},
pages = {3581--3593},
doi = {https://doi.org/10.5194/acp-11-3581-2011}
}
|
|||||
| Keppel-Aleks, G., Wennberg, P.O., Washenfelder, R.A., Wunch, D., Schneider, T., Toon, G.C., Andres, R.J., Blavier, J.F., Connor, B., Davis, K.J., Desai, A.R., Messerschmidt, J., Notholt, J., Roehl, C.M., Sherlock, V., Stephens, B.B., Vay, S.A. and Wofsy, S.C. | The imprint of surface fluxes and transport on variations in total column carbon dioxide | {2012} | BIOGEOSCIENCES Vol. {9}({3}), pp. 875-891 |
article | DOI |
| Abstract: New observations of the vertically integrated CO2 mixing ratio, aYCO(2)aY (c), from ground-based remote sensing show that variations in CO(2)aY (c) are primarily determined by large-scale flux patterns. They therefore provide fundamentally different information than observations made within the boundary layer, which reflect the combined influence of large-scale and local fluxes. Observations of both aYCO(2)aY (c) and CO2 concentrations in the free troposphere show that large-scale spatial gradients induce synoptic-scale temporal variations in aYCO(2)aY (c) in the Northern Hemisphere midlatitudes through horizontal advection. Rather than obscure the signature of surface fluxes on atmospheric CO2, these synoptic-scale variations provide useful information that can be used to reveal the meridional flux distribution. We estimate the meridional gradient in aYCO(2)aY (c) from covariations in aYCO(2)aY (c) and potential temperature, theta, a dynamical tracer, on synoptic timescales to evaluate surface flux estimates commonly used in carbon cycle models. We find that simulations using Carnegie Ames Stanford Approach (CASA) biospheric fluxes underestimate both the aYCO(2)aY (c) seasonal cycle amplitude throughout the Northern Hemisphere midlatitudes and the meridional gradient during the growing season. Simulations using CASA net ecosystem exchange (NEE) with increased and phase-shifted boreal fluxes better fit the observations. Our simulations suggest that climatological mean CASA fluxes underestimate boreal growing season NEE (between 45-65A degrees N) by ˜40%. We describe the implications for this large seasonal exchange on inference of the net Northern Hemisphere terrestrial carbon sink. |
|||||
BibTeX:
@article{keppel-aleks12a,
author = {Keppel-Aleks, G. and Wennberg, P. O. and Washenfelder, R. A. and Wunch, D. and Schneider, T. and Toon, G. C. and Andres, R. J. and Blavier, J. -F. and Connor, B. and Davis, K. J. and Desai, A. R. and Messerschmidt, J. and Notholt, J. and Roehl, C. M. and Sherlock, V. and Stephens, B. B. and Vay, S. A. and Wofsy, S. C.},
title = {The imprint of surface fluxes and transport on variations in total column carbon dioxide},
journal = {BIOGEOSCIENCES},
year = {2012},
volume = {9},
number = {3},
pages = {875--891},
doi = {https://doi.org/10.5194/bg-9-875-2012}
}
|
|||||
| Keppel-Aleks, G., Wennberg, P.O., O'Dell, C.W. and Wunch, D. | Towards constraints on fossil fuel emissions from total column carbon dioxide | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({8}), pp. 4349-4357 |
article | DOI |
| Abstract: We assess the large-scale, top-down constraints on regional fossil fuel emissions provided by observations of atmospheric total column CO2, X-CO2. Using an atmospheric general circulation model (GCM) with underlying fossil emissions, we determine the influence of regional fossil fuel emissions on global X-CO2 fields. We quantify the regional contrasts between source and upwind regions and probe the sensitivity of atmospheric X-CO2 to changes in fossil fuel emissions. Regional fossil fuel X-CO2 contrasts can exceed 0.7 ppm based on 2007 emission estimates, but have large seasonal variations due to biospheric fluxes. Contamination by clouds reduces the discernible fossil signatures. Nevertheless, our simulations show that atmospheric fossil X-CO2 can be tied to its source region and that changes in the regional XCO2 contrasts scale linearly with emissions. We test the GCM results against X-CO2 data from the GOSAT satellite. Regional X-CO2 contrasts in GOSAT data generally scale with the predictions from the GCM, but the comparison is limited by the moderate precision of and relatively few observations from the satellite. We discuss how this approach may be useful as a policy tool to verify national fossil emissions, as it provides an independent, observational constraint. |
|||||
BibTeX:
@article{keppel-aleks13a,
author = {Keppel-Aleks, G. and Wennberg, P. O. and O'Dell, C. W. and Wunch, D.},
title = {Towards constraints on fossil fuel emissions from total column carbon dioxide},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {8},
pages = {4349--4357},
doi = {https://doi.org/10.5194/acp-13-4349-2013}
}
|
|||||
| Kiel, M., O'Dell, C.W., Fisher, B., Eldering, A., Nassar, R., MacDonald, C.G. and Wennberg, P.O. | How bias correction goes wrong: measurement of X-CO2 affected by erroneous surface pressure estimates | {2019} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {12}({4}), pp. {2241-2259} |
article | DOI URL |
| Abstract: All measurements of X-CO2 from space have systematic errors. To reduce a large fraction of these errors, a bias correction is applied to X-CO2 retrieved from GOSAT and OCO-2 spectra using the ACOS retrieval algorithm. The bias correction uses, among other parameters, the surface pressure difference between the retrieval and the meteorological reanalysis. Relative errors in the surface pressure estimates, however, propagate nearly 1 V 1 into relative errors in biascorrected X-CO2. For OCO-2, small errors in the knowledge of the pointing of the observatory (up to similar to 130 arcsec) introduce a bias in X-CO2 in regions with rough topography. Erroneous surface pressure estimates are also caused by a coding error in ACOS version 8, sampling meteorological analyses at wrong times ( up to 3 h after the overpass time). Here, we derive new geolocations for OCO-2' s eight footprints and show how using improved knowledge of surface pressure estimates in the bias correction reduces errors in OCO-2' s v9 X-CO2 data. | |||||
BibTeX:
@article{kiel19a,
author = {Kiel, Matthaus and O'Dell, Christopher W. and Fisher, Brendan and Eldering, Annmarie and Nassar, Ray and MacDonald, Cameron G. and Wennberg, Paul O.},
title = {How bias correction goes wrong: measurement of X-CO2 affected by erroneous surface pressure estimates},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {12},
number = {4},
pages = {2241--2259},
note = {Query date: 2021-04-02 15:20:04},
url = {https://amt.copernicus.org/articles/12/2241/2019/},
doi = {https://doi.org/10.5194/amt-12-2241-2019}
}
|
|||||
| Kim, M.G. | Errors in mixed layer heights over North America: a multi-model comparison [BibTeX] |
2011 | School: University of Waterloo | mastersthesis | URL |
BibTeX:
@mastersthesis{kim11a,
author = {Kim, Myung Gwang},
title = {Errors in mixed layer heights over North America: a multi-model comparison},
school = {University of Waterloo},
year = {2011},
url = {https://uwspace.uwaterloo.ca/handle/10012/5968}
}
|
|||||
| Kim, J., Kim, H.M. and Cho, C.-H. | Application of Carbon Tracking System based on ensemble Kalman Filter on the diagnosis of Carbon Cycle in Asia [BibTeX] |
2012 | Atmosphere Vol. 22(4), pp. 415-427 |
article | URL |
BibTeX:
@article{kim12a,
author = {Kim, JinWoong and Kim, Hyun Mee and Cho, Chun-Ho},
title = {Application of Carbon Tracking System based on ensemble Kalman Filter on the diagnosis of Carbon Cycle in Asia},
journal = {Atmosphere},
year = {2012},
volume = {22},
number = {4},
pages = {415--427},
url = {http://www.koreascience.or.kr/article/ArticleFullRecord.jsp?cn=KSHHDL_2012_v22n4_415}
}
|
|||||
| Kim, J., Kim, H.M. and Cho, C.-H. | The effect of optimization and the nesting domain on carbon flux analyses in Asia using a carbon tracking system based on the ensemble Kalman filter | {2014} | ASIA-PACIFIC JOURNAL OF ATMOSPHERIC SCIENCES Vol. {50}({3}), pp. 327-344 |
article | DOI |
| Abstract: To estimate the surface carbon flux in Asia and investigate the effect of the nesting domain on carbon flux analyses in Asia, two experiments with different nesting domains were conducted using the CarbonTracker developed by the National Oceanic and Atmospheric Administration. CarbonTracker is an inverse modeling system that uses an ensemble Kalman filter (EnKF) to estimate surface carbon fluxes from surface CO2 observations. One experiment was conducted with a nesting domain centered in Asia and the other with a nesting domain centered in North America. Both experiments analyzed the surface carbon fluxes in Asia from 2001 to 2006. The results showed that prior surface carbon fluxes were underestimated in Asia compared with the optimized fluxes. The optimized biosphere fluxes of the two experiments exhibited roughly similar spatial patterns but different magnitudes. Weekly cumulative optimized fluxes showed more diverse patterns than the prior fluxes, indicating that more detailed flux analyses were conducted during the optimization. The nesting domain in Asia produced a detailed estimate of the surface carbon fluxes in Asia and exhibited better agreement with the CO2 observations. Finally, the simulated background atmospheric CO2 concentrations in the experiment with the nesting domain in Asia were more consistent with the observed CO2 concentrations than those in the experiment with the nesting domain in North America. The results of this study suggest that surface carbon fluxes in Asia can be estimated more accurately using an EnKF when the nesting domain is centered in Asian regions. |
|||||
BibTeX:
@article{kim14a,
author = {Kim, Jinwoong and Kim, Hyun Mee and Cho, Chun-Ho},
title = {The effect of optimization and the nesting domain on carbon flux analyses in Asia using a carbon tracking system based on the ensemble Kalman filter},
journal = {ASIA-PACIFIC JOURNAL OF ATMOSPHERIC SCIENCES},
year = {2014},
volume = {50},
number = {3},
pages = {327--344},
doi = {https://doi.org/10.1007/s13143-014-0020-y}
}
|
|||||
| Kim, J., Kim, H.M. and Cho, C.H. | Influence of CO2 observations on the optimized CO2 flux in an ensemble Kalman filter | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({24}), pp. 13515-13530 |
article | DOI |
| Abstract: In this study, the effect of CO2 observations on an analysis of surface CO2 flux was calculated using an influence matrix in the CarbonTracker, which is an inverse modeling system for estimating surface CO2 flux based on an ensemble Kalman filter. The influence matrix represents a sensitivity of the analysis to observations. The experimental period was from January 2000 to December 2009. The diagonal element of the influence matrix (i.e., analysis sensitivity) is globally 4.8% on average, which implies that the analysis extracts 4.8% of the information from the observations and 95.2% from the background each assimilation cycle. Because the surface CO2 flux in each week is optimized by 5 weeks of observations, the cumulative impact over 5 weeks is 19.1 %, much greater than 4.8 %. The analysis sensitivity is inversely proportional to the number of observations used in the assimilation, which is distinctly apparent in continuous observation categories with a sufficient number of observations. The time series of the globally averaged analysis sensitivities shows seasonal variations, with greater sensitivities in summer and lower sensitivities in winter, which is attributed to the surface CO2 flux uncertainty. The time-averaged analysis sensitivities in the Northern Hemisphere are greater than those in the tropics and the Southern Hemisphere. The trace of the influence matrix (i.e., information content) is a measure of the total information extracted from the observations. The information content indicates an imbalance between the observation coverage in North America and that in other regions. Approximately half of the total observational information is provided by continuous observations, mainly from North America, which indicates that continuous observations are the most informative and that comprehensive coverage of additional observations in other regions is necessary to estimate the surface CO2 flux in these areas as accurately as in North America. |
|||||
BibTeX:
@article{kim14b,
author = {Kim, J. and Kim, H. M. and Cho, C. -H.},
title = {Influence of CO2 observations on the optimized CO2 flux in an ensemble Kalman filter},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {24},
pages = {13515--13530},
doi = {https://doi.org/10.5194/acp-14-13515-2014}
}
|
|||||
| Kim, H., Kim, H.M., Kim, J. and Cho, C.-H. | A Comparison of the Atmospheric CO2 Concentrations Obtained by an Inverse Modeling System and Passenger Aircraft Based Measurement [BibTeX] |
2016 | Atmosphere Vol. 26(3), pp. 387-400 |
article | URL |
BibTeX:
@article{kim16a,
author = {Hyunjung Kim and Hyun Mee Kim and Jinwoong Kim and Chun-Ho Cho},
title = {A Comparison of the Atmospheric CO2 Concentrations Obtained by an Inverse Modeling System and Passenger Aircraft Based Measurement},
journal = {Atmosphere},
year = {2016},
volume = {26},
number = {3},
pages = {387--400},
url = {http://www.j-komes.or.kr/xml/07935/07935.pdf}
}
|
|||||
| Kim, J., Kim, H.M., Cho, C.-H., Boo, K.-O., Jacobson, A.R., Sasakawa, M., Machida, T., Arshinov, M. and Fedoseev, N. | Impact of Siberian observations on the optimization of surface CO2 flux | {2017} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {17}({4}), pp. 2881-2899 |
article | DOI |
| Abstract: To investigate the effect of additional CO2 observations in the Siberia region on the Asian and global surface CO2 flux analyses, two experiments using different observation data sets were performed for 2000-2009. One experiment was conducted using a data set that includes additional observations of Siberian tower measurements (Japan-Russia Siberian Tall Tower Inland Observation Network: JR-STATION), and the other experiment was conducted using a data set without the above additional observations. The results show that the global balance of the sources and sinks of surface CO2 fluxes was maintained for both experiments with and without the additional observations. While the magnitude of the optimized surface CO2 flux uptake and flux uncertainty in Siberia decreased from 1.17 +/- 0.93 to 0.77 +/- 0.70 PgC yr(-1), the magnitude of the optimized surface CO2 flux uptake in the other regions (e.g., Europe) of the Northern Hemisphere (NH) land increased for the experiment with the additional observations, which affect the longitudinal distribution of the total NH sinks. This change was mostly caused by changes in the magnitudes of surface CO2 flux in June and July. The observation impact measured by uncertainty reduction and self-sensitivity tests shows that additional observations provide useful information on the estimated surface CO2 flux. The average uncertainty reduction of the conifer forest of Eurasian boreal (EB) is 29.1% and the average self-sensitivities at the JR-STATION sites are approximately 60% larger than those at the towers in North America. It is expected that the Siberian observations play an important role in estimating surface CO2 flux in the NH land (e.g., Siberia and Europe) in the future. |
|||||
BibTeX:
@article{kim17a,
author = {Kim, Jinwoong and Kim, Hyun Mee and Cho, Chun-Ho and Boo, Kyung-On and Jacobson, Andrew R. and Sasakawa, Motoki and Machida, Toshinobu and Arshinov, Mikhail and Fedoseev, Nikolay},
title = {Impact of Siberian observations on the optimization of surface CO2 flux},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2017},
volume = {17},
number = {4},
pages = {2881--2899},
doi = {https://doi.org/10.5194/acp-17-2881-2017}
}
|
|||||
| Kim, H., Kim, H.M., Kim, J. and Cho, C.-H. | Effect of data assimilation parameters on the optimized surface CO2 flux in Asia | 2017 | Asia-Pacific Journal of Atmospheric Sciences, pp. 1-17 | article | DOI |
| Abstract: In this study, CarbonTracker, an inverse modeling system based on the ensemble Kalman filter, was used to evaluate the effects of data assimilation parameters (assimilation window length and ensemble size) on the estimation of surface CO2 fluxes in Asia. Several experiments with different parameters were conducted, and the results were verified using CO2 concentration observations. The assimilation window lengths tested were 3, 5, 7, and 10 weeks, and the ensemble sizes were 100, 150, and 300. Therefore, a total of 12 experiments using combinations of these parameters were conducted. The experimental period was from January 2006 to December 2009. Differences between the optimized surface CO2 fluxes of the experiments were largest in the Eurasian Boreal (EB) area, followed by Eurasian Temperate (ET) and Tropical Asia (TA), and were larger in boreal summer than in boreal winter. The effect of ensemble size on the optimized biosphere flux is larger than the effect of the assimilation window length in Asia, but the importance of them varies in specific regions in Asia. The optimized biosphere flux was more sensitive to the assimilation window length in EB, whereas it was sensitive to the ensemble size as well as the assimilation window length in ET. The larger the ensemble size and the shorter the assimilation window length, the larger the uncertainty (i.e., spread of ensemble) of optimized surface CO2 fluxes. The 10-week assimilation window and 300 ensemble size were the optimal configuration for CarbonTracker in the Asian region based on several verifications using CO2 concentration measurements. | |||||
BibTeX:
@article{kim17b,
author = {Kim, Hyunjung and Kim, Hyun Mee and Kim, Jinwoong and Cho, Chun-Ho},
title = {Effect of data assimilation parameters on the optimized surface CO2 flux in Asia},
journal = {Asia-Pacific Journal of Atmospheric Sciences},
year = {2017},
pages = {1--17},
doi = {https://doi.org/10.1007/s13143-017-0049-9}
}
|
|||||
| Kim, H., Kim, H.M., Cho, M., Park, J. and Kim, D.-H. | Development of the Aircraft CO2 Measurement Data Assimilation System to Improve the Estimation of Surface CO2 Fluxes Using an Inverse Modeling System | {2018} | ATMOSPHERE-KOREA Vol. {28}({2}), pp. {113-121} |
article | DOI |
| Abstract: In order to monitor greenhouse gases including CO2, various types of surface-, aircraft-, and satellite-based measurement projects have been conducted. These data help understand the variations of greenhouse gases and are used in atmospheric inverse modeling systems to simulate surface fluxes for greenhouse gases. CarbonTracker is a system for estimating surface CO2 flux, using an atmospheric inverse modeling method, based on only surface observation data. Because of the insufficient surface observation data available for accurate estimation of the surface CO2 flux, additional observations would be required. In this study, a system that assimilates aircraft CO2 measurement data in CarbonTracker (CT2013B) is developed, and the estimated results from this data assimilation system are evaluated. The aircraft CO2 measurement data used are obtained from the Comprehensive Observation Network for Trace gases by the Airliner (CONTRAIL) project. The developed system includes the preprocessor of the raw observation data, the observation operator, and the ensemble Kalman filter (EnKF) data assimilation process. After preprocessing the raw data, the modeled value corresponding spatially and temporally to each observation is calculated using the observation operator. These modeled values and observations are then averaged in space and time, and used in the EnKF data assimilation process. The modeled values are much closer to the observations and show smaller biases and root-mean-square errors, after the assimilation of the aircraft CO2 measurement data. This system could also be used to assimilate other aircraft CO2 measurement data in CarbonTracker. |
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BibTeX:
@article{kim18a,
author = {Kim, Hyunjung and Kim, Hyun Mee and Cho, Minkwang and Park, Jun and Kim, Dae-Hui},
title = {Development of the Aircraft CO2 Measurement Data Assimilation System to Improve the Estimation of Surface CO2 Fluxes Using an Inverse Modeling System},
journal = {ATMOSPHERE-KOREA},
year = {2018},
volume = {28},
number = {2},
pages = {113-121},
doi = {https://doi.org/10.14191/Atmos.2018.28.2.113}
}
|
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| Kim, J., Polavarapu, S.M., Chan, D. and Neish, M. | The Canadian atmospheric transport model for simulating greenhouse gas evolution on regional scales: GEM-MACH-GHG v.137-reg | {2020} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {13}({1}), pp. {269-295} |
article | DOI URL |
| Abstract: In this study, we present the development of a regional atmospheric transport model for greenhouse gas (GHG) simulation based on an operational weather forecast model and a chemical transport model at Environment and Climate Change Canada (ECCC), with the goal of improving our understanding of the high-spatiotemporal-resolution interaction between the atmosphere and surface GHG fluxes over Canada and the United States. The regional model uses 10 kmx10 km horizontal grid spacing and 80 vertical levels spanning the ground to 0.1 hPa. The lateral boundary conditions of meteorology and tracers are provided by the global transport model used for GHG simulation at ECCC. The performance of the regional model and added benefit of the regional model over our lower-resolution global models is investigated in terms of modelled CO2 concentration and meteorological forecast quality for multiple seasons in 2015. We find that our regional model has the capability to simulate the high spatial (horizontal and vertical) and temporal scales of atmospheric CO2 concentrations based on comparisons to surface and aircraft observations. In addition, the bias and standard deviation of forecast error in boreal summer are reduced by the regional model. Better representation of model topography in the regional model results in improved simulation of the CO2 diurnal cycle compared to the global model at Walnut Grove, California. The new regional model will form the basis of a flux inversion system that estimates regional-scale fluxes of GHGs over Canada. | |||||
BibTeX:
@article{kim20a,
author = {Kim, Jinwoong and Polavarapu, Saroja M. and Chan, Douglas and Neish, Michael},
title = {The Canadian atmospheric transport model for simulating greenhouse gas evolution on regional scales: GEM-MACH-GHG v.137-reg},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {13},
number = {1},
pages = {269--295},
note = {Query date: 2021-04-02 15:20:04},
url = {https://gmd.copernicus.org/articles/13/269/2020/},
doi = {https://doi.org/10.5194/gmd-13-269-2020}
}
|
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| Kim, J., Polavarapu, S.M., Jones, D.B.A., Chan, D. and Neish, M. | The Resolvable Scales of Regional-Scale CO2 Transport in the Context of Imperfect Meteorology: The Predictability of CO2 in a Limited-Area Model | 2021 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 126(20) |
article | DOI |
| Abstract: Transport model error is an important source of uncertainty when estimating surface CO2 fluxes via an atmospheric model inversion. In this study, the transport error due to uncertainty of meteorological fields is investigated with a high resolution, limited-area model. We characterize the extent to which errors in meteorological initial conditions (ICs) and lateral boundary conditions (LBCs) impact the quality of atmospheric CO2 transport across spatial scales. A series of experiments is conducted using different meteorological ICs and LBCs that possess varying levels of accuracy. We find that the transport error of CO2 is more sensitive to errors in meteorology at smaller scales O(10 km) than at larger scales O(1,000 km), and that surface CO2 fluxes can explain the predictability of CO2 at the largest scales. We also determine the spatial scales resolvable in the context of uncertain meteorology. These findings have implications for the development of regional-scale inverse modeling systems. When assimilating CO2 observations near the surface, using accurate meteorological ICs is important for resolving fine-scale spatial variability of CO2 because CO2 transport at lower levels is more sensitive to meteorological ICs and surface CO2 fluxes than to meteorological LBCs. However, when assimilating aircraft CO2 measurements or XCO2 satellite retrievals which contain information at higher altitudes, using accurate meteorological LBCs is also important. Improvement in meteorological inputs through a data assimilation system could be helpful in further resolving finer spatial scales of CO2 at regional scales. |
|||||
BibTeX:
@article{kim21a,
author = {Kim, Jinwoong and Polavarapu, Saroja M. and Jones, Dylan B. A. and Chan, Douglas and Neish, Michael},
title = {The Resolvable Scales of Regional-Scale CO2 Transport in the Context of Imperfect Meteorology: The Predictability of CO2 in a Limited-Area Model},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2021},
volume = {126},
number = {20},
doi = {https://doi.org/10.1029/2021JD034896}
}
|
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| Kimball, J.S., Jones, L.A., Glassy, J., Stavros, E.N., Madani, N., Reichle, R.H., Jackson, T. and Colliander, A. | Soil Moisture Active Passive Mission L4_C Data Product Assessment (Version 2 Validated Release) | 2016 | misc | URL | |
| Abstract: The SMAP satellite was successfully launched January 31st 2015, and began acquiring Earth observation data following in-orbit sensor calibration. Global data products derived from the SMAP L-band microwave measurements include Level 1 calibrated and geolocated … | |||||
BibTeX:
@misc{kimball16a,
author = {John S. Kimball and Lucas A. Jones and Joseph Glassy and E. Natasha Stavros and Nima Madani and Rolf H. Reichle and Thomas Jackson and Andreas Colliander},
title = {Soil Moisture Active Passive Mission L4_C Data Product Assessment (Version 2 Validated Release)},
year = {2016},
url = {https://gmao.gsfc.nasa.gov/GMAO_personnel/Reichle_Rolf/other_docs/Kimball852.pdf}
}
|
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| King, A.W., Andres, R.J., Davis, K.J., Hafer, M., Hayes, D.J., Huntzinger, D.N., de Jong, B., Kurz, W.A., McGuire, A.D., Vargas, R., Wei, Y., West, T.O. and Woodall, C.W. | North America's net terrestrial CO2 exchange with the atmosphere 1990-2009 | {2015} | BIOGEOSCIENCES Vol. {12}({2}), pp. 399-414 |
article | DOI |
| Abstract: Scientific understanding of the global carbon cycle is required for developing national and international policy to mitigate fossil fuel CO2 emissions by managing terrestrial carbon uptake. Toward that understanding and as a contribution to the REgional Carbon Cycle Assessment and Processes (RECCAP) project, this paper provides a synthesis of net land-atmosphere CO2 exchange for North America (Canada, United States, and Mexico) over the period 1990-2009. Only CO2 is considered, not methane or other greenhouse gases. This synthesis is based on results from three different methods: atmospheric inversion, inventory-based methods and terrestrial biosphere modeling. All methods indicate that the North American land surface was a sink for atmospheric CO2, with a net transfer from atmosphere to land. Estimates ranged from -890 to -280 TgC yr(-1), where the mean of atmospheric inversion estimates forms the lower bound of that range (a larger land sink) and the inventory-based estimate using the production approach the upper (a smaller land sink). This relatively large range is due in part to differences in how the approaches represent trade, fire and other disturbances and which ecosystems they include. Integrating across estimates, ``best'' estimates (i.e., measures of central tendency) are -472 +/- 281 TgC yr(-1) based on the mean and standard deviation of the distribution and -360 TgC yr(-1) (with an interquartile range of -496 to -337) based on the median. Considering both the fossil fuel emissions source and the land sink, our analysis shows that North America was, however, a net contributor to the growth of CO2 in the atmosphere in the late 20th and early 21st century. With North America's mean annual fossil fuel CO2 emissions for the period 1990-2009 equal to 1720 Tg C yr(-1) and assuming the estimate of -472 TgC yr(-1) as an approximation of the true terrestrial CO2 sink, the continent's source : sink ratio for this time period was 1720 : 472, or nearly 4 : 1. |
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BibTeX:
@article{king15a,
author = {King, A. W. and Andres, R. J. and Davis, K. J. and Hafer, M. and Hayes, D. J. and Huntzinger, D. N. and de Jong, B. and Kurz, W. A. and McGuire, A. D. and Vargas, R. and Wei, Y. and West, T. O. and Woodall, C. W.},
title = {North America's net terrestrial CO2 exchange with the atmosphere 1990-2009},
journal = {BIOGEOSCIENCES},
year = {2015},
volume = {12},
number = {2},
pages = {399--414},
doi = {https://doi.org/10.5194/bg-12-399-2015}
}
|
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| Kivi, R. and Heikkinen, P. | Fourier transform spectrometer measurements of column CO2 at Sodankyla, Finland | {2016} | GEOSCIENTIFIC INSTRUMENTATION METHODS AND DATA SYSTEMS Vol. {5}({2}), pp. 271-279 |
article | DOI |
| Abstract: Fourier transform spectrometer (FTS) observations at Sodankyla, Finland (67.4 degrees N, 26.6 degrees E) have been performed since early 2009. The FTS instrument is participating in the Total Carbon Column Observing Network (TCCON) and has been optimized to measure abundances of the key greenhouse gases in the atmosphere. Sodankyla is the only TCCON station in the Fennoscandia region. Here we report the measured CO2 time series over a 7-year period (2009-2015) and provide a description of the FTS system and data processing at Sodankyla. We find the lowest monthly column CO2 values in August and the highest monthly values during the February-May season. Inter-annual variability is the highest in the June-September period, which correlates with the growing season. During the time period of FTS measurements from 2009 to 2015, we have observed a 2.2 +/- 0.2 ppm increase per year in column CO2. The monthly mean column CO2 values have exceeded 400 ppm level for the first time in February 2014. |
|||||
BibTeX:
@article{kivi16a,
author = {Kivi, Rigel and Heikkinen, Pauli},
title = {Fourier transform spectrometer measurements of column CO2 at Sodankyla, Finland},
journal = {GEOSCIENTIFIC INSTRUMENTATION METHODS AND DATA SYSTEMS},
year = {2016},
volume = {5},
number = {2},
pages = {271--279},
doi = {https://doi.org/10.5194/gi-5-271-2016}
}
|
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| Klappenbach, F., Bertleff, M., Kostinek, J., Hase, F., Blumenstock, T., Agusti-Panareda, A., Razinger, M. and Butz, A. | Accurate mobile remote sensing of XCO2 and XCH4 latitudinal transects from aboard a research vessel | {2015} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {8}({12}), pp. 5023-5038 |
article | DOI |
| Abstract: A portable Fourier transform spectrometer (FTS), model EM27/SUN, was deployed onboard the research vessel Polarstern to measure the column-average dry air mole fractions of carbon dioxide (XCO2) and methane (XCH4) by means of direct sunlight absorption spectrometry. We report on technical developments as well as data calibration and reduction measures required to achieve the targeted accuracy of fractions of a percent in retrieved XCO2 and XCH4 while operating the instrument under field conditions onboard the moving platform during a 6-week cruise on the Atlantic from Cape Town (South Africa, 34 degrees S, 18 degrees E; 5 March 2014) to Bremerhaven (Germany, 54 degrees N, 19 degrees E; 14 April 2014). We demonstrate that our solar tracker typically achieved a tracking precision of better than 0.05 degrees toward the center of the sun throughout the ship cruise which facilitates accurate XCO2 and XCH4 retrievals even under harsh ambient wind conditions. We define several quality filters that screen spectra, e.g., when the field of view was partially obstructed by ship structures or when the lines-of-sight crossed the ship exhaust plume. The measurements in clean oceanic air, can be used to characterize a spurious air-mass dependency. After the campaign, deployment of the spectrometer alongside the TCCON (Total Carbon Column Observing Network) instrument at Karlsruhe, Germany, allowed for determining a calibration factor that makes the entire campaign record traceable to World Meteorological Organization (WMO) standards. Comparisons to observations of the GOSAT satellite and concentration fields modeled by the European Centre for Medium-Range Weather Forecasts (ECMWF) Copernicus Atmosphere Monitoring Service (CAMS) demonstrate that the observational setup is well suited to provide validation opportunities above the ocean and along interhemispheric transects. |
|||||
BibTeX:
@article{klappenbach15a,
author = {Klappenbach, F. and Bertleff, M. and Kostinek, J. and Hase, F. and Blumenstock, T. and Agusti-Panareda, A. and Razinger, M. and Butz, A.},
title = {Accurate mobile remote sensing of XCO2 and XCH4 latitudinal transects from aboard a research vessel},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2015},
volume = {8},
number = {12},
pages = {5023--5038},
doi = {https://doi.org/10.5194/amt-8-5023-2015}
}
|
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| Klappenbach, F.W. | Mobile spectroscopic measurements of atmospheric carbon dioxide and methane [BibTeX] |
2016 | School: Karlsruher Instituts für Technologie | phdthesis | URL |
BibTeX:
@phdthesis{klappenbach16a,
author = {Klappenbach, Friedrich Wilhelm},
title = {Mobile spectroscopic measurements of atmospheric carbon dioxide and methane},
school = {Karlsruher Instituts für Technologie},
year = {2016},
url = {https://d-nb.info/1114312576/34}
}
|
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| Koffi, E.N., Rayner, P.J., Scholze, M., Chevallier, F. and Kaminski, T. | Quantifying the constraint of biospheric process parameters by CO2 concentration and flux measurement networks through a carbon cycle data assimilation system | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({21}), pp. 10555-10572 |
article | DOI |
| Abstract: The sensitivity of the process parameters of the Biosphere Energy Transfer HYdrology (BETHY) model to choices of atmospheric concentration network, high frequency terrestrial fluxes, and the choice of flux measurement network is investigated by using a carbon cycle data assimilation system. We use BETHY-generated fluxes as a proxy of flux measurements. Results show that monthly mean or low-frequency observations of CO2 concentration provide strong constraints on parameters relevant for net flux (NEP) but only weak constraints for parameters controlling gross fluxes. The use of high-frequency CO2 concentration observations, which has led to great refinement of spatial scales in inversions of net flux, adds little to the observing system in the Carbon Cycle Data Assimilation System (CCDAS) case. This unexpected result is explained by the fact that the stations of the CO2 concentration network we use are not well placed to measure such high frequency signals. Indeed, CO2 concentration sensitivities relevant for such high frequency fluxes are found to be largely confined in the vicinity of the corresponding fluxes, and are therefore not well observed by background monitoring stations. In contrast, our results clearly show the potential of flux measurements to better constrain the model parameters relevant for gross primary productivity (GPP) and net primary productivity (NPP). Given uncertainties in the spatial description of ecosystem functions, we recommend a combined observing strategy. |
|||||
BibTeX:
@article{koffi13a,
author = {Koffi, E. N. and Rayner, P. J. and Scholze, M. and Chevallier, F. and Kaminski, T.},
title = {Quantifying the constraint of biospheric process parameters by CO2 concentration and flux measurement networks through a carbon cycle data assimilation system},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {21},
pages = {10555--10572},
doi = {https://doi.org/10.5194/acp-13-10555-2013}
}
|
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| Kondo, M., Ichii, K., Takagi, H. and Sasakawa, M. | Comparison of the data-driven top-down and bottom-up global terrestrial CO2 exchanges: GOSAT CO2 inversion and empirical eddy flux upscaling | {2015} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {120}({7}), pp. 1226-1245 |
article | DOI |
| Abstract: We examined the consistency between terrestrial biosphere fluxes (terrestrial CO2 exchanges) from data-driven top-down (GOSAT CO2 inversion) and bottom-up (empirical eddy flux upscaling based on a support vector regression (SVR) model) approaches over 42 global terrestrial regions from June 2009 to October 2011. Seasonal variations of the biosphere fluxes by the two approaches agreed well in boreal and temperate regions across the Northern Hemisphere. Both fluxes also exhibited strong anomalous signals in response to contrasting anomalous spring temperatures observed in North America and boreal Eurasia. This indicates that the CO2 concentration data integrated in the GOSAT inversion and the meteorological and vegetation data in the SVR models are equally effective in producing spatiotemporal variations of biosphere flux. Meanwhile, large differences in seasonality were found in subtropical and tropical South America, South Asia, and Africa. The GOSAT inversion showed seasonal variations that pivoted around CO2 neutral, while the SVR model showed seasonal variations that tended toward CO2 sink. Thus, a large difference in CO2 budget was identified between the two approaches in subtropical and tropical regions across the Southern Hemisphere. Examination of the integrated data revealed that the large tropical sink of CO2 by the SVR model was an artifact due to the underrepresented biosphere fluxes predicted by limited eddy flux data for tropical biomes. Because of the global coverage of CO2 concentration data, the GOSAT inversion provides better estimates of continental CO2 flux than the SVR model in the Southern Hemisphere. |
|||||
BibTeX:
@article{kondo15a,
author = {Kondo, Masayuki and Ichii, Kazuhito and Takagi, Hiroshi and Sasakawa, Motoki},
title = {Comparison of the data-driven top-down and bottom-up global terrestrial CO2 exchanges: GOSAT CO2 inversion and empirical eddy flux upscaling},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2015},
volume = {120},
number = {7},
pages = {1226--1245},
doi = {https://doi.org/10.1002/2014JG002866}
}
|
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| Kondo, M., Patra, P.K., Sitch, S., Friedlingstein, P., Poulter, B., Chevallier, F., Ciais, P., Canadell, J.G., Bastos, A., Lauerwald, R., Calle, L., Ichii, K., Anthoni, P., Arneth, A., Haverd, V., Jain, A.K., Kato, E., Kautz, M., Law, R.M., Lienert, S., Lombardozzi, D., Maki, T., Nakamura, T., Peylin, P., Rödenbeck, C., Zhuravlev, R., Saeki, T., Tian, H., Zhu, D. and Ziehn, T. | State of the science in reconciling top‐down and bottom‐up approaches for terrestrial CO2 budget | 2020 | GLOBAL CHANGE BIOLOGY Vol. 26(3), pp. 1068-1084 |
article | |
| Abstract: Robust estimates of CO2 budget, CO2 exchanged between the atmosphere and terrestrial biosphere, are necessary to better understand the role of the terrestrial biosphere in mitigating anthropogenic CO2 emissions. Over the past decade, this field of research has … | |||||
BibTeX:
@article{kondo20a,
author = {Masayuki Kondo and Prabir K. Patra and Stephen Sitch and Pierre Friedlingstein and Benjamin Poulter and Frederic Chevallier and Philippe Ciais and Josep G. Canadell and Ana Bastos and Ronny Lauerwald and Leonardo Calle and Kazuhito Ichii and Peter Anthoni and Almut Arneth and Vanessa Haverd and Atul K. Jain and Etsushi Kato and Markus Kautz and Rachel M. Law and Sebastian Lienert and Danica Lombardozzi and Takashi Maki and Takashi Nakamura and Philippe Peylin and Christian Rödenbeck and Ruslan Zhuravlev and Tazu Saeki and Hanqin Tian and Dan Zhu and Tilo Ziehn},
title = {State of the science in reconciling top‐down and bottom‐up approaches for terrestrial CO2 budget},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2020},
volume = {26},
number = {3},
pages = {1068-1084}
}
|
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| Kong, Y., Chen, B. and Measho, S. | Spatio-Temporal Consistency Evaluation of XCO2 Retrievals from GOSAT and OCO-2 Based on TCCON and Model Data for Joint Utilization in Carbon Cycle Research | {2019} | ATMOSPHERE Vol. {10}({7}) |
article | DOI |
| Abstract: The global carbon cycle research requires precise and sufficient observations of the column-averaged dry-air mole fraction of CO2 (XCO2) in addition to conventional surface mole fraction observations. In addition, assessing the consistency of multi-satellite data are crucial for joint utilization to better infer information about CO2 sources and sinks. In this work, we evaluate the consistency of long-term XCO2 retrievals from the Greenhouse Gases Observing Satellite (GOSAT), Orbiting Carbon Observatory 2 (OCO-2) in comparison with Total Carbon Column Observing Network (TCCON) and the 3D model of CO2 mole fractions data from CarbonTracker 2017 (CT2017). We create a consistent joint dataset and compare it with the long-term model data to assess their abilities to characterize the carbon cycle climate. The results show that, although slight increasing differences are found between the GOSAT and TCCON XCO2 in the northern temperate latitudes, the GOSAT and OCO-2 XCO2 retrievals agree well in general, with a mean bias +/- standard deviation of differences of 0.21 +/- 1.3 ppm. The differences are almost within +/- 2 ppm and are independent of time, indicating that they are well calibrated. The differences between OCO-2 and CT2017 XCO2 are much larger than those between GOSAT and CT XCO2, which can be attributed to the significantly different spatial representatives of OCO-2 and the CT-transport model 5 (TM5). The time series of the combined OCO-2/GOSAT dataset and the modeled XCO2 agree well, and both can characterize significantly increasing atmospheric CO2 under the impact of a large El Nino during 2015 and 2016. The trend calculated from the dataset using the seasonal Kendall (S-K) method indicates that atmospheric CO2 is increasing by 2-2.6 ppm per year. | |||||
BibTeX:
@article{kong19a,
author = {Kong, Yawen and Chen, Baozhang and Measho, Simon},
title = {Spatio-Temporal Consistency Evaluation of XCO2 Retrievals from GOSAT and OCO-2 Based on TCCON and Model Data for Joint Utilization in Carbon Cycle Research},
journal = {ATMOSPHERE},
publisher = {MDPI},
year = {2019},
volume = {10},
number = {7},
doi = {https://doi.org/10.3390/atmos10070354}
}
|
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| Kong, Y., Zheng, B., Zhang, Q. and He, K. | Global and regional carbon budget for 2015-2020 inferred from OCO-2 based on an ensemble Kalman filter coupled with GEOS-Chem | 2022 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 22(16), pp. 10769-10788 |
article | DOI |
| Abstract: Understanding carbon sources and sinks across the Earth's surface is fundamental in climate science and policy; thus, these topics have been extensively studied but have yet to be fully resolved and are associated with massive debate regarding the sign and magnitude of the carbon budget from global to regional scales. Developing new models and estimates based on state-of-the-art algorithms and data constraints can provide valuable knowledge and contribute to a final ensemble model in which various optimal carbon budget estimates are integrated, such as the annual global carbon budget paper. Here, we develop a new atmospheric inversion system based on the 4D local ensemble transform Kalman filter (4D-LETKF) coupled with the GEOS-Chem global transport model to infer surface-to-atmosphere net carbon fluxes from Orbiting Carbon Observatory-2 (000-2) Vl0r XCO2 retrievals. The 4D-LETKF algorithm is adapted to an OCO-2-based global carbon inversion system for the first time in this work. On average, the mean annual terrestrial and oceanic fluxes between 2015 and 2020 are estimated as - 2.02 and - 2.34 GtC yr(-1), respectively, compensating for 21 % and 24 %, respectively, of global fossil carbon dioxide (CO2) emissions (9.80 GtC yr(-1)). Our inversion results agree with the CO2 atmospheric growth rates reported by the National Oceanic and Atmospheric Administration (NOAA) and reduce the modeled CO2 concentration biases relative to the prior fluxes against surface and aircraft measurements. Our inversion-based carbon fluxes are broadly consistent with those provided by other global atmospheric inversion models, although discrepancies still occur in the land-ocean flux partitioning schemes and seasonal flux amplitudes over boreal and tropical regions, possibly due to the sparse observational constraints of the OCO-2 satellite and the divergent prior fluxes used in different inversion models. Four sensitivity experiments are performed herein to vary the prior fluxes and uncertainties in our inversion system, suggesting that regions that lack OCO-2 coverage are sensitive to the priors, especially over the tropics and high latitudes. In the further development of our inversion system, we will optimize the data-assimilation configuration to fully utilize current observations and increase the spatial and seasonal representativeness of the prior fluxes over regions that lack observations. |
|||||
BibTeX:
@article{kong22a,
author = {Kong, Yawen and Zheng, Bo and Zhang, Qiang and He, Kebin},
title = {Global and regional carbon budget for 2015-2020 inferred from OCO-2 based on an ensemble Kalman filter coupled with GEOS-Chem},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2022},
volume = {22},
number = {16},
pages = {10769-10788},
doi = {https://doi.org/10.5194/acp-22-10769-2022}
}
|
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| Konopka, P., Ploeger, F., Tao, M. and Riese, M. | Regionally Resolved Diagnostic of Transport: A Simplified Forward Model for CO2 | {2017} | JOURNAL OF THE ATMOSPHERIC SCIENCES Vol. {74}({8}), pp. 2689-2700 |
article | DOI |
| Abstract: Simply diagnostic tools are useful for understanding transport processes in complex chemistry transport models (CTMs). For this purpose, a combined use of the airmass origin fractions (AOFs) and regionally resolved mean ages (RMAs) is presented. This approach merges the concept of the origin of air with the well-known theory of the mean age of air (AoA) for different regions covering the whole Earth. The authors show how the AoA calculated relative to Earth's surface can be decomposed into regionally resolved components (i.e., into RMAs). Using both AOFs and RMAs, the authors discuss differences in the seasonality of transport from the Northern and Southern Hemispheres into the tropical tropopause layer (TTL), the asymmetries of the interhemispheric exchange, and differences in relation to the continental or oceanic origin of air. Furthermore, a simplified transport model for a chemically passive species (tracer) is formulated that has some potential to approximate the full transport within a CTM. This analytic approach uses the AOFs as well as the RMAs as parameters to propagate a tracer prescribed on Earth's surface (lower boundary condition). This method is exactly valid for sources that change linearly with time in each of the considered regions. The authors analyze how well this approach approximates the propagation of CO2 from the planetary boundary layer (PBL) into the whole atmosphere. The CO2 values in the PBL are specified by the CarbonTracker dataset. The authors discuss how this approach can be used for inverse modeling of CO2. |
|||||
BibTeX:
@article{konopka17a,
author = {Konopka, Paul and Ploeger, Felix and Tao, Mengchu and Riese, Martin},
title = {Regionally Resolved Diagnostic of Transport: A Simplified Forward Model for CO2},
journal = {JOURNAL OF THE ATMOSPHERIC SCIENCES},
year = {2017},
volume = {74},
number = {8},
pages = {2689--2700},
doi = {https://doi.org/10.1175/JAS-D-16-0367.1}
}
|
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| Konopka, P., Tao, M., Ploeger, F., Diallo, M. and Riese, M. | Tropospheric mixing and parametrization of unresolved convective updrafts as implemented in the Chemical Lagrangian Model of the Stratosphere (CLaMS v2.0) | {2019} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {12}({6}), pp. {2441-2462} |
article | DOI URL |
| Abstract: Inaccurate representation of mixing in chemistry transport models, mainly suffering from an excessive numerical diffusion, strongly influences the quantitative estimates of the stratosphere-troposphere exchange (STE). The Lagrangian view of transport offers an alternative to exploit the numerical diffusion for parametrization of the physical mixing. Here, we follow this concept and discuss how to extend the representation of tropospheric transport in the Chemical Lagrangian Model of the Stratosphere (CLaMS). Although the current transport scheme in CLaMS (v1.0) shows a good ability to represent transport of tracers in the stably stratified stratosphere (Pommrich et al., 2014, and the references therein), there are deficiencies in the representation of the effects of convective uplift and mixing due to weak vertical stability in the troposphere. We show how the CLaMS transport scheme was modified by including additional tropospheric mixing and vertical transport due to unresolved convective updrafts by parametrizing these processes in terms of the dry and moist Brunt-Vaisala frequencies. The regions with enhanced convective updrafts in the novel CLaMS simulation covering the 2005-2008 period coincide with regions of enhanced convection as diagnosed from the satellite observations of the outgoing longwave radiation (OLR). We analyze how well this approach improves the CLaMS representation of CO2 in the upper troposphere and lower stratosphere, in particular the propagation of the CO2 seasonal cycle from the planetary boundary layer (PBL) into the lower stratosphere. The CO2 values in the PBL are specified by the CarbonTracker data set (version CT2013B), and the Comprehensive Observation Network for TRace gases by AIrLiner (CONTRAIL) observations are used to validate themodel. The proposed extension of tropospheric transport increases the influence of the PBL in the middle and upper troposphere and at the same time impacts the STE. The effect on mean age away from the troposphere in the deep stratosphere is weak. | |||||
BibTeX:
@article{konopka19a,
author = {Konopka, Paul and Tao, Mengchu and Ploeger, Felix and Diallo, Mohamadou and Riese, Martin},
title = {Tropospheric mixing and parametrization of unresolved convective updrafts as implemented in the Chemical Lagrangian Model of the Stratosphere (CLaMS v2.0)},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {12},
number = {6},
pages = {2441--2462},
note = {Query date: 2021-04-02 15:20:04},
url = {https://gmd.copernicus.org/articles/12/2441/2019/},
doi = {https://doi.org/10.5194/gmd-12-2441-2019}
}
|
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| Koren, G., Schneider, L., van der Velde, I.R., van Schaik, E., Gromov, S.S., Adnew, G.A., Martino, D.J.M., Hofmann, M.E.G., Liang, M.-C., Mahata, S., Bergamaschi, P., van der Laan-Luijkx, I.T., Krol, M.C., Rockmann, T. and Peters, W. | Global 3-D Simulations of the Triple Oxygen Isotope Signature Delta O-17 in Atmospheric CO2 | {2019} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {124}({15}), pp. {8808-8836} |
article | DOI |
| Abstract: The triple oxygen isotope signature Delta O-17 in atmospheric CO2, also known as its ``O-17 excess,'' has been proposed as a tracer for gross primary production (the gross uptake of CO2 by vegetation through photosynthesis). We present the first global 3-D model simulations for Delta O-17 in atmospheric CO2 together with a detailed model description and sensitivity analyses. In our 3-D model framework we include the stratospheric source of Delta O-17 in CO2 and the surface sinks from vegetation, soils, ocean, biomass burning, and fossil fuel combustion. The effect of oxidation of atmospheric CO on Delta O-17 in CO2 is also included in our model. We estimate that the global mean Delta O-17 (defined as Delta O-17=ln(delta O-17+1)-lambda RL center dot ln(delta O-18+1) with lambda(RL) = 0.5229) of CO2 in the lowest 500m of the atmosphere is 39.6per meg, which is similar to 20per meg lower than estimates from existing box models. We compare our model results with a measured stratospheric Delta O-17 in CO2 profile from Sodankyla (Finland), which shows good agreement. In addition, we compare our model results with tropospheric measurements of Delta O-17 in CO2 from Gottingen (Germany) and Taipei (Taiwan), which shows some agreement but we also find substantial discrepancies that are subsequently discussed. Finally, we show model results for Zotino (Russia), Mauna Loa (United States), Manaus (Brazil), and South Pole, which we propose as possible locations for future measurements of Delta O-17 in tropospheric CO2 that can help to further increase our understanding of the global budget of Delta O-17 in atmospheric CO2. | |||||
BibTeX:
@article{koren19a,
author = {Koren, Gerbrand and Schneider, Linda and van der Velde, Ivar R. and van Schaik, Erik and Gromov, Sergey S. and Adnew, Getachew A. and Martino, Dorota J. Mrozek and Hofmann, Magdalena E. G. and Liang, Mao-Chang and Mahata, Sasadhar and Bergamaschi, Peter and van der Laan-Luijkx, Ingrid T. and Krol, Maarten C. and Rockmann, Thomas and Peters, Wouter},
title = {Global 3-D Simulations of the Triple Oxygen Isotope Signature Delta O-17 in Atmospheric CO2},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2019},
volume = {124},
number = {15},
pages = {8808--8836},
doi = {https://doi.org/10.1029/2019JD030387}
}
|
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| Kostinek, J., Roiger, A., Eckl, M., Fiehn, A., Luther, A., Wildmann, N., Klausner, T., Fix, A., Knote, C., Stohl, A. and Butz, A. | Estimating Upper Silesian coal mine methane emissions from airborne in situ observations and dispersion modeling | 2020 | ATMOSPHERIC CHEMISTRY AND PHYSICS | article | URL |
| Abstract: Abundant mining and industrial activities located in the Upper Silesian Coal Basin (USCB) lead to large emissions of the potent greenhouse gas (GHG) methane (CH 4). The strong localization of CH 4 emitters (mostly confined to known coal mine ventilation shafts) and the … | |||||
BibTeX:
@article{kostinek20a,
author = {Julian Kostinek and Anke Roiger and Maximilian Eckl and Alina Fiehn and Andreas Luther and Norman Wildmann and Theresa Klausner and Andreas Fix and Christoph Knote and Andreas Stohl and André́ Butz},
title = {Estimating Upper Silesian coal mine methane emissions from airborne in situ observations and dispersion modeling},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2020},
url = {https://acp.copernicus.org/preprints/acp-2020-962/}
}
|
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| Kostinek, J., Roiger, A., Eckl, M., Fiehn, A., Luther, A., Wildmann, N., Klausner, T., Fix, A., Knote, C., Stohl, A. and Butz, A. | Estimating Upper Silesian coal mine methane emissions from airborne in situ observations and dispersion modeling | 2021 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 21(11), pp. 8791-8807 |
article | DOI |
| Abstract: Abundant mining and industrial activities located in the Upper Silesian Coal Basin (USCB) lead to large emissions of the potent greenhouse gas (GHG) methane (CH4). The strong localization of CH4 emitters (mostly confined to known coal mine ventilation shafts) and the large emissions of 448 and 720 kt CH4 yr(-1) reported in the European Pollutant Release and Transfer Register (E-PRTR 2017) and the Emissions Database for Global Atmospheric Research (EDGAR v4.3.2), respectively, make the USCB a prime research target for validating and improving CH4 flux estimation techniques. High-precision observations of this GHG were made downwind of local (e.g., single facilities) to regional-scale (e.g., agglomerations) sources in the context of the CoMet 1.0 campaign in early summer 2018. A quantum cascade-interband cascade laser (QCL-ICL)-based spectrometer adapted for airborne research was deployed aboard the German Aerospace Center (DLR) Cessna 208B to sample the planetary boundary layer (PBL) in situ. Regional CH4 emission estimates for the USCB are derived using a model approach including assimilated wind soundings from three ground-based Doppler lidars. Although retrieving estimates for individual emitters is difficult using only single flights due to sparse data availability, the combination of two flights allows for exploiting different meteorological conditions (analogous to a sparse tomography algorithm) to establish confidence on facility-level estimates. Emission rates from individual sources not only are needed for unambiguous comparisons between bottom-up and top-down inventories but also become indispensable if (independently verifiable) sanctions are to be imposed on individual companies emitting GHGs. An uncertainty analysis is presented for both the regional-scale and facility-level emission estimates. We find instantaneous coal mine emission estimates of 451/423 +/- 77/79 kt CH4 yr(-1) for the morning/afternoon flight of 6 June 2018. The derived fuel-exploitation emission rates coincide (+/- 6 %) with annual-average inventorial data from E-PRTR 2017 although they are distinctly lower (-28 %/-32 %) than values reported in EDGAR v4.3.2. Discrepancies in available emission inventories could potentially be narrowed down with sufficient observations using the method described herein to bridge the gap between instantaneous emission estimates and yearly averaged inventories. |
|||||
BibTeX:
@article{kostinek21a,
author = {Kostinek, Julian and Roiger, Anke and Eckl, Maximilian and Fiehn, Alina and Luther, Andreas and Wildmann, Norman and Klausner, Theresa and Fix, Andreas and Knote, Christoph and Stohl, Andreas and Butz, Andre},
title = {Estimating Upper Silesian coal mine methane emissions from airborne in situ observations and dispersion modeling},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2021},
volume = {21},
number = {11},
pages = {8791-8807},
doi = {https://doi.org/10.5194/acp-21-8791-2021}
}
|
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| Xing-Xia, K., Zhang, M.-G. and Peng, Z. | Numerical Simulation of CO2 Concentrations in East Asia with RAMS-CMAQ [BibTeX] |
2013 | Atmospheric and Oceanic Science Letters Vol. 6(4), pp. 179-184 |
article | |
BibTeX:
@article{kou13a,
author = {Kou Xing-Xia and Zhang, Mei-Gen and Peng, Zhen},
title = {Numerical Simulation of CO2 Concentrations in East Asia with RAMS-CMAQ},
journal = {Atmospheric and Oceanic Science Letters},
year = {2013},
volume = {6},
number = {4},
pages = {179--184}
}
|
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| Kou, X., Zhang, M., Peng, Z. and Wang, Y. | Assessment of the biospheric contribution to surface atmospheric CO2 concentrations over East Asia with a regional chemical transport model | {2015} | ADVANCES IN ATMOSPHERIC SCIENCES Vol. {32}({3}), pp. 287-300 |
article | DOI |
| Abstract: A regional chemical transport model, RAMS-CMAQ, was employed to assess the impacts of biosphere-atmosphere C-2 exchange on seasonal variations in atmospheric C-2 concentrations over East Asia. Simulated C-2 concentrations were compared with observations at 12 surface stations and the comparison showed they were generally in good agreement. Both observations and simulations suggested that surface C-2 over East Asia features a summertime trough due to biospheric absorption, while in some urban areas surface C-2 has a distinct summer peak, which could be attributed to the strong impact from anthropogenic emissions. Analysis of the model results indicated that biospheric fluxes and fossil-fuel emissions are comparably important in shaping spatial distributions of C-2 near the surface over East Asia. Biospheric flux plays an important role in the prevailing spatial pattern of C-2 enhancement and reduction on the synoptic scale due to the strong seasonality of biospheric C-2 flux. The elevation of C-2 levels by the biosphere during winter was found to be larger than 5 ppm in North China and Southeast China, and during summertime a significant depletion (a (c) 3/4 7 ppm) occurred in most areas, except for the Indo-China Peninsula where positive bioflux values were found. |
|||||
BibTeX:
@article{kou15a,
author = {Kou, Xingxia and Zhang, Meigen and Peng, Zhen and Wang, Yinghong},
title = {Assessment of the biospheric contribution to surface atmospheric CO2 concentrations over East Asia with a regional chemical transport model},
journal = {ADVANCES IN ATMOSPHERIC SCIENCES},
year = {2015},
volume = {32},
number = {3},
pages = {287--300},
doi = {https://doi.org/10.1007/s00376-014-4059-6}
}
|
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| Kou, X., Tian, X., Zhang, M., Peng, Z. and Zhang, X. | Accounting for CO2 Variability over East Asia with a Regional Joint Inversion System and Its Preliminary Evaluation | {2017} | JOURNAL OF METEOROLOGICAL RESEARCH Vol. {31}({5}), pp. 834-851 |
article | DOI |
| Abstract: A regional surface carbon dioxide (CO2) flux inversion system, the Tan-Tracker-Region, was developed by incorporating an assimilation scheme into the Community Multiscale Air Quality (CMAQ) regional chemical transport model to resolve fine-scale CO2 variability over East Asia. The proper orthogonal decomposition-based ensemble four-dimensional variational data assimilation approach (POD-4DVar) is the core algorithm for the joint assimilation framework, and simultaneous assimilations of CO2 concentrations and surface CO2 fluxes are applied to help reduce the uncertainty in initial CO2 concentrations. A persistence dynamical model was developed to describe the evolution of the surface CO2 fluxes and help avoid the ``signal-to-noise'' problem; thus, CO2 fluxes could be estimated as a whole at the model grid scale, with better use of observation information. The performance of the regional inversion system was evaluated through a group of single-observation-based observing system simulation experiments (OSSEs). The results of the experiments suggest that a reliable performance of Tan-Tracker-Region is dependent on certain assimilation parameter choices, for example, an optimized window length of approximately 3 h, an ensemble size of approximately 100, and a covariance localization radius of approximately 320 km. This is probably due to the strong diurnal variation and spatial heterogeneity in the fine-scale CMAQ simulation, which could affect the performance of the regional inversion system. In addition, because all observations can be artificially obtained in OSSEs, the performance of Tan-Tracker-Region was further evaluated through different densities of the artificial observation network in different CO2 flux situations. The results indicate that more observation sites would be useful to systematically improve the estimation of CO2 concentration and flux in large areas over the model domain. The work presented here forms a foundation for future research in which a thorough estimation of CO2 flux variability over East Asia could be performed with the regional inversion system. |
|||||
BibTeX:
@article{kou17a,
author = {Kou, Xingxia and Tian, Xiangjun and Zhang, Meigen and Peng, Zhen and Zhang, Xiaoling},
title = {Accounting for CO2 Variability over East Asia with a Regional Joint Inversion System and Its Preliminary Evaluation},
journal = {JOURNAL OF METEOROLOGICAL RESEARCH},
year = {2017},
volume = {31},
number = {5},
pages = {834--851},
doi = {https://doi.org/10.1007/s13351-017-6149-8}
}
|
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| Kountouris, P., Gerbig, C., Totsche, K.U., Dolman, A.J., Meesters, A.G.C.A., Broquet, G., Maignan, F., Gioli, B., Montagnani, L. and Helfter, C. | An objective prior error quantification for regional atmospheric inverse applications | {2015} | BIOGEOSCIENCES Vol. {12}({24}), pp. 7403-7421 |
article | |
| Abstract: Assigning proper prior uncertainties for inverse modelling of CO2 is of high importance, both to regularise the otherwise ill-constrained inverse problem and to quantitatively characterise the magnitude and structure of the error between prior and `true' flux. We use surface fluxes derived from three biosphere models - VPRM, ORCHIDEE, and 5PM - and compare them against daily averaged fluxes from 53 eddy covariance sites across Europe for the year 2007 and against repeated aircraft flux measurements encompassing spatial transects. In addition we create synthetic observations using modelled fluxes instead of the observed ones to explore the potential to infer prior uncertainties from model-model residuals. To ensure the realism of the synthetic data analysis, a random measurement noise was added to the modelled tower fluxes which were used as reference. The temporal autocorrelation time for tower model-data residuals was found to be around 30 days for both VPRM and ORCHIDEE but significantly different for the 5PM model with 70 days. This difference is caused by a few sites with large biases between the data and the 5PM model. The spatial correlation of the model-data residuals for all models was found to be very short, up to few tens of kilometres but with uncertainties up to 100 % of this estimation. Propagating this error structure to annual continental scale yields an uncertainty of 0.06 Gt C and strongly underestimates uncertainties typically used from atmospheric inversion systems, revealing another potential source of errors. Long spatial e-folding correlation lengths up to several hundreds of kilometres were determined when synthetic data were used. Results from repeated aircraft transects in south-western France are consistent with those obtained from the tower sites in terms of spatial autocorrelation (35 km on average) while temporal autocorrelation is markedly lower (13 days). Our findings suggest that the different prior models have a common temporal error structure. Separating the analysis of the statistics for the model data residuals by seasons did not result in any significant differences of the spatial e-folding correlation lengths. |
|||||
BibTeX:
@article{kountouris15a,
author = {Kountouris, P. and Gerbig, C. and Totsche, K. -U. and Dolman, A. J. and Meesters, A. G. C. A. and Broquet, G. and Maignan, F. and Gioli, B. and Montagnani, L. and Helfter, C.},
title = {An objective prior error quantification for regional atmospheric inverse applications},
journal = {BIOGEOSCIENCES},
year = {2015},
volume = {12},
number = {24},
pages = {7403--7421}
}
|
|||||
| Kountouris, P., Gerbig, C., Rodenbeck, C., Karstens, U., Koch, T.F. and Heimann, M. | Technical Note: Atmospheric CO2 inversions on the mesoscale using data-driven prior uncertainties: methodology and system evaluation | {2018} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {18}({4}), pp. {3027-3045} |
article | DOI |
| Abstract: Atmospheric inversions are widely used in the optimization of surface carbon fluxes on a regional scale using information from atmospheric CO2 dry mole fractions. In many studies the prior flux uncertainty applied to the inversion schemes does not directly reflect the true flux uncertainties but is used to regularize the inverse problem. Here, we aim to implement an inversion scheme using the Jena inversion system and applying a prior flux error structure derived from a model-data residual analysis using high spatial and temporal resolution over a full year period in the European domain. We analyzed the performance of the inversion system with a synthetic experiment, in which the flux constraint is derived following the same residual analysis but applied to the model-model mismatch. The synthetic study showed a quite good agreement between posterior and ``true'' fluxes on European, country, annual and monthly scales. Posterior monthly and country-aggregated fluxes improved their correlation coefficient with the ``known truth'' by 7% compared to the prior estimates when compared to the reference, with a mean correlation of 0.92. The ratio of the SD between the posterior and reference and between the prior and reference was also reduced by 33% with a mean value of 1.15. We identified temporal and spatial scales on which the inversion system maximizes the derived information; monthly temporal scales at around 200 km spatial resolution seem to maximize the information gain. |
|||||
BibTeX:
@article{kountouris18a,
author = {Kountouris, Panagiotis and Gerbig, Christoph and Rodenbeck, Christian and Karstens, Ute and Koch, Thomas Frank and Heimann, Martin},
title = {Technical Note: Atmospheric CO2 inversions on the mesoscale using data-driven prior uncertainties: methodology and system evaluation},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2018},
volume = {18},
number = {4},
pages = {3027-3045},
doi = {https://doi.org/10.5194/acp-18-3027-2018}
}
|
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| Koven, C.D. | Role of CO2, climate and land use in regulating the seasonal amplitude increase of carbon fluxes in terrestrial ecosystems: a multimodel analysis [BibTeX] |
2016 | Biogeosciences Vol. 13(17), pp. 5121 |
article | URL |
BibTeX:
@article{koven16a,
author = {Koven, Charles D},
title = {Role of CO2, climate and land use in regulating the seasonal amplitude increase of carbon fluxes in terrestrial ecosystems: a multimodel analysis},
journal = {Biogeosciences},
year = {2016},
volume = {13},
number = {17},
pages = {5121},
url = {http://search.proquest.com/openview/6b2e171c3b3e9903f77f7fd2002927a3/1?pq-origsite=gscholar&cbl=105740}
}
|
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| Kretschmer, R., Gerbig, C., Karstens, U. and Koch, F.T. | Error characterization of CO2 vertical mixing in the atmospheric transport model WRF-VPRM | {2012} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {12}({5}), pp. 2441-2458 |
article | DOI |
| Abstract: One of the dominant uncertainties in inverse estimates of regional CO2 surface-atmosphere fluxes is related to model errors in vertical transport within the planetary boundary layer (PBL). In this study we present the results from a synthetic experiment using the atmospheric model WRF-VPRM to realistically simulate transport of CO2 for large parts of the European continent at 10 km spatial resolution. To elucidate the impact of vertical mixing error on modeled CO2 mixing ratios we simulated a month during the growing season (August 2006) with different commonly used parameterizations of the PBL (Mellor-Yamada-JanjiA double dagger (MYJ) and Yonsei-University (YSU) scheme). To isolate the effect of transport errors we prescribed the same CO2 surface fluxes for both simulations. Differences in simulated CO2 mixing ratios (model bias) were on the order of 3 ppm during daytime with larger values at night. We present a simple method to reduce this bias by 70-80% when the true height of the mixed layer is known. |
|||||
BibTeX:
@article{kretschmer12a,
author = {Kretschmer, R. and Gerbig, C. and Karstens, U. and Koch, F. -T.},
title = {Error characterization of CO2 vertical mixing in the atmospheric transport model WRF-VPRM},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2012},
volume = {12},
number = {5},
pages = {2441--2458},
doi = {https://doi.org/10.5194/acp-12-2441-2012}
}
|
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| Kubicki, J.D. and Watts, H.D. | Quantum Mechanical Modeling of the Vibrational Spectra of Minerals with a Focus on Clays | {2019} | MINERALS Vol. {9}({3}) |
article | DOI |
| Abstract: We present an overview of how to use quantum mechanical calculations to predict vibrational frequencies of molecules and materials such as clays and silicates. Other methods of estimating vibrational frequencies are mentioned, such as classical molecular dynamics simulations; references are given for additional information on these approaches. Herein, we discuss basic vibrational theory, calculating Raman and infrared intensities, steps for creating realistic models, and applications to spectroscopy, thermodynamics, and isotopic fractionation. There are a wide variety of programs and methods that can be employed to model vibrational spectra, but this work focuses on hybrid density functional theory (DFT) approaches. Many of the principles are the same when used in other programs and DFT methods, so a novice can benefit from simple examples that illustrate key points to consider when modeling vibrational spectra. Other methods and programs are listed to give the beginner a starting point for exploring and choosing which approach will be best for a given problem. The modeler should also be aware of the numerous analytical methods available for obtaining information on vibrations of atoms in molecules and materials. In addition to traditional infrared and Raman spectroscopy, sum-frequency generation (SFG) and inelastic neutron scattering (INS) are also excellent techniques for obtaining vibrational frequency information in certain circumstances. | |||||
BibTeX:
@article{kubicki19a,
author = {Kubicki, James D. and Watts, Heath D.},
title = {Quantum Mechanical Modeling of the Vibrational Spectra of Minerals with a Focus on Clays},
journal = {MINERALS},
publisher = {MDPI},
year = {2019},
volume = {9},
number = {3},
doi = {https://doi.org/10.3390/min9030141}
}
|
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| Kulawik, S.S., Jones, D.B.A., Nassar, R., Irion, F.W., Worden, J.R., Bowman, K.W., Machida, T., Matsueda, H., Sawa, Y., Biraud, S.C., Fischer, M.L. and Jacobson, A.R. | Characterization of Tropospheric Emission Spectrometer (TES) CO2 for carbon cycle science [BibTeX] |
{2010} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {10}({12}), pp. 5601-5623 |
article | DOI |
BibTeX:
@article{kulawik10a,
author = {Kulawik, S. S. and Jones, D. B. A. and Nassar, R. and Irion, F. W. and Worden, J. R. and Bowman, K. W. and Machida, T. and Matsueda, H. and Sawa, Y. and Biraud, S. C. and Fischer, M. L. and Jacobson, A. R.},
title = {Characterization of Tropospheric Emission Spectrometer (TES) CO2 for carbon cycle science},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2010},
volume = {10},
number = {12},
pages = {5601--5623},
doi = {https://doi.org/10.5194/acp-10-5601-2010}
}
|
|||||
| Kulawik, S.S., Worden, J.R., Wofsy, S.C., Biraud, S.C., Nassar, R., Jones, D.B.A., Olsen, E.T., Jimenez, R., Park, S., Santoni, G.W., Daube, B.C., Pittman, J.V., Stephens, B.B., Kort, E.A., Osterman, G.B. and Team, T. | Comparison of improved Aura Tropospheric Emission Spectrometer CO2 with HIPPO and SGP aircraft profile measurements [BibTeX] |
{2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({6}), pp. 3205-3225 |
article | DOI |
BibTeX:
@article{kulawik13a,
author = {Kulawik, S. S. and Worden, J. R. and Wofsy, S. C. and Biraud, S. C. and Nassar, R. and Jones, D. B. A. and Olsen, E. T. and Jimenez, R. and Park, S. and Santoni, G. W. and Daube, B. C. and Pittman, J. V. and Stephens, B. B. and Kort, E. A. and Osterman, G. B. and TES Team},
title = {Comparison of improved Aura Tropospheric Emission Spectrometer CO2 with HIPPO and SGP aircraft profile measurements},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {6},
pages = {3205--3225},
doi = {https://doi.org/10.5194/acp-13-3205-2013}
}
|
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| Kulawik, S., Wunch, D., O'Dell, C., Frankenberg, C., Reuter, M., Oda, T., Chevallier, F., Sherlock, V., Buchwitz, M., Osterman, G., Miller, C.E., Wennberg, P.O., Griffith, D., Morino, I., Dubey, M.K., Deutscher, N.M., Notholt, J., Hase, F., Warneke, T., Sussmann, R., Robinson, J., Strong, K., Schneider, M., De Maziere, M., Shiomi, K., Feist, D.G., Iraci, L.T. and Wolf, J. | Consistent evaluation of ACOS-GOSAT, BESD-SCIAMACHY, CarbonTracker, and MACC through comparisons to TCCON | {2016} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {9}({2}), pp. 683-709 |
article | DOI |
| Abstract: Consistent validation of satellite CO2 estimates is a prerequisite for using multiple satellite CO2 measurements for joint flux inversion, and for establishing an accurate long-term atmospheric CO2 data record. Harmonizing satellite CO2 measurements is particularly important since the differences in instruments, observing geometries, sampling strategies, etc. imbue different measurement characteristics in the various satellite CO2 data products. We focus on validating model and satellite observation attributes that impact flux estimates and CO2 assimilation, including accurate error estimates, correlated and random errors, overall biases, biases by season and latitude, the impact of coincidence criteria, validation of seasonal cycle phase and amplitude, yearly growth, and daily variability. We evaluate dry-air mole fraction (X-CO2) for Greenhouse gases Observing SATellite (GOSAT) (Atmospheric CO2 Observations from Space, ACOS b3.5) and SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) (Bremen Optimal Estimation DOAS, BESD v2.00.08) as well as the CarbonTracker (CT2013b) simulated CO2 mole fraction fields and the Monitoring Atmospheric Composition and Climate (MACC) CO2 inversion system (v13.1) and compare these to Total Carbon Column Observing Network (TCCON) observations (GGG2012/2014). We find standard deviations of 0.9, 0.9, 1.7, and 2.1 ppm vs. TCCON for CT2013b, MACC, GOSAT, and SCIAMACHY, respectively, with the single observation errors 1.9 and 0.9 times the predicted errors for GOSAT and SCIAMACHY, respectively. We quantify how satellite error drops with data averaging by interpreting according to error(2) = a(2) + b(2) / n (with n being the number of observations averaged, a the systematic (correlated) errors, and b the random (uncorrelated) errors). a and b are estimated by satellites, coincidence criteria, and hemisphere. Biases at individual stations have year-to-year variability of similar to 0.3 ppm, with biases larger than the TCCON-predicted bias uncertainty of 0.4 ppm at many stations. We find that GOSAT and CT2013b underpredict the seasonal cycle amplitude in the Northern Hemisphere (NH) between 46 and 53 degrees N, MACC overpredicts between 26 and 37 ffi N, and CT2013b underpredicts the seasonal cycle amplitude in the Southern Hemisphere (SH). The seasonal cycle phase indicates whether a data set or model lags another data set in time. We find that the GOSAT measurements improve the seasonal cycle phase substantially over the prior while SCIAMACHY measurements improve the phase significantly for just two of seven sites. The models reproduce the measured seasonal cycle phase well except for at Lauder_125HR (CT2013b) and Darwin (MACC). We compare the variability within 1 day between TCCON and models in JJA; there is correlation between 0.2 and 0.8 in the NH, with models showing 10-50% the variability of TCCON at different stations and CT2013b showing more variability than MACC. This paper highlights findings that provide inputs to estimate flux errors in model assimilations, and places where models and satellites need further investigation, e.g., the SH for models and 4567 ffi N for GOSAT and CT2013b. |
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BibTeX:
@article{kulawik16a,
author = {Kulawik, Susan and Wunch, Debra and O'Dell, Christopher and Frankenberg, Christian and Reuter, Maximilian and Oda, Tomohiro and Chevallier, Frederic and Sherlock, Vanessa and Buchwitz, Michael and Osterman, Greg and Miller, Charles E. and Wennberg, Paul O. and Griffith, David and Morino, Isamu and Dubey, Manvendra K. and Deutscher, Nicholas M. and Notholt, Justus and Hase, Frank and Warneke, Thorsten and Sussmann, Ralf and Robinson, John and Strong, Kimberly and Schneider, Matthias and De Maziere, Martine and Shiomi, Kei and Feist, Dietrich G. and Iraci, Laura T. and Wolf, Joyce},
title = {Consistent evaluation of ACOS-GOSAT, BESD-SCIAMACHY, CarbonTracker, and MACC through comparisons to TCCON},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2016},
volume = {9},
number = {2},
pages = {683--709},
doi = {https://doi.org/10.5194/amt-9-683-2016}
}
|
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| Kulawik, S.S., O'Dell, C., Payne, V.H., Kuai, L., Worden, H.M., Biraud, S.C., Sweeney, C., Stephens, B., Iraci, L.T., Yates, E.L. and Tanaka, T. | Lower-tropospheric CO2 from near-infrared ACOS-GOSAT observations | {2017} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {17}({8}), pp. 5407-5438 |
article | DOI |
| Abstract: We present two new products from near-infrared Greenhouse Gases Observing Satellite (GOSAT) observations: lowermost tropospheric (LMT, from 0 to 2.5 km) and upper tropospheric-stratospheric (U, above 2.5 km) carbon dioxide partial column mixing ratios. We compare these new products to aircraft profiles and remote surface flask measurements and find that the seasonal and year-to-year variations in the new partial column mixing ratios significantly improve upon the Atmospheric CO2 Observations from Space (ACOS) and GOSAT (ACOS-GOSAT) initial guess and/or a priori, with distinct patterns in the LMT and U seasonal cycles that match validation data. For land monthly averages, we find errors of 1.9, 0.7, and 0.8 ppm for retrieved GOSAT LMT, U, and X CO2; for ocean monthly averages, we find errors of 0.7, 0.5, and 0.5 ppm for retrieved GOSAT LMT, U, and X CO2. In the southern hemispheric biomass burning season, the new partial columns show similar patterns to MODIS fire maps and MOPITT multispectral CO for both vertical levels, despite a flat ACOS-GOSAT prior, and a CO-CO2 emission factor comparable to published values. The difference of LMT and U, useful for evaluation of model transport error, has also been validated with a monthly average error of 0.8 (1.4) ppm for ocean (land). LMT is more locally influenced than U, meaning that local fluxes can now be better separated from CO2 transported from far away. |
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BibTeX:
@article{kulawik17a,
author = {Kulawik, Susan S. and O'Dell, Chris and Payne, Vivienne H. and Kuai, Le and Worden, Helen M. and Biraud, Sebastien C. and Sweeney, Colm and Stephens, Britton and Iraci, Laura T. and Yates, Emma L. and Tanaka, Tomoaki},
title = {Lower-tropospheric CO2 from near-infrared ACOS-GOSAT observations},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2017},
volume = {17},
number = {8},
pages = {5407--5438},
doi = {https://doi.org/10.5194/acp-17-5407-2017}
}
|
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| Kumar, K.R., Tiwari, Y.K., Valsala, V. and Murtugudde, R. | On understanding the land-ocean CO2 contrast over the Bay of Bengal: A case study during 2009 summer monsoon | {2014} | ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH Vol. {21}({7}), pp. 5066-5075 |
article | DOI |
| Abstract: Ship-based observations of atmospheric carbon dioxide (CO2) concentration over the Bay of Bengal (BoB) between 17 July 2009 and 17 Aug 2009 offered an excellent opportunity to evaluate the land-ocean contrast of surface CO2 and facilitated its comparison with model simulated CO2 concentrations. Elevated values of CO2 with large variability near the coastal region and relatively low values with correspondingly lower variability over the open ocean suggest that this observed CO2 variability over the ocean essentially captures the differences in terrestrial and oceanic CO2 fluxes. Although the region under investigation is well known for its atmospheric intraseasonal oscillations of Indian summer monsoon during July and August, the limited duration of observations performed from a moving ship in a research cruise, is not able to capture any high-frequency variability of atmospheric CO2 concentrations. But band-passed sea surface temperature and wind anomalies do indicate strong intraseasonal variability over the study region during the observational period. The synoptic data, albeit quite short in duration, thus offer a clear benchmark for abrupt variability of CO2 concentration between land and ocean. |
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BibTeX:
@article{kumar14a,
author = {Kumar, K. Ravi and Tiwari, Yogesh K. and Valsala, Vinu and Murtugudde, Raghu},
title = {On understanding the land-ocean CO2 contrast over the Bay of Bengal: A case study during 2009 summer monsoon},
journal = {ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH},
year = {2014},
volume = {21},
number = {7},
pages = {5066--5075},
doi = {https://doi.org/10.1007/s11356-013-2386-2}
}
|
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| Kumar, K.R., Valsala, V., Tiwari, Y.K., Revadekar, J.V., Pillai, P., Chakraborty, S. and Murtugudde, R. | Intra-seasonal variability of atmospheric CO2 concentrations over India during summer monsoons | {2016} | ATMOSPHERIC ENVIRONMENT Vol. {142}, pp. 229-237 |
article | DOI |
| Abstract: In a study based on a data assimilation product of the terrestrial biospheric fluxes of CO2 over India, the subcontinent was hypothesized to be an anomalous source (sink) of CO2 during the active (break) spells of rain in the summer monsoon from June to September (Valsala et al., 2013). We test this hypothesis here by investigating intraseasonal variability in the atmospheric CO2 concentrations over India by utilizing a combination of ground-based and satellite observations and model outputs. The results show that the atmospheric CO2 concentration also varies in synchrony with the active and break spells of rainfall with amplitude of +/- 2 ppm which is above the instrumental uncertainty of the present day techniques of atmospheric CO2 measurements. The result is also consistent with the signs of the Net Ecosystem Exchange (NEE) flux anomalies estimated in our earlier work. The study thus offers the first observational affirmation of the above hypothesis although the data gap in the satellite measurements during monsoon season and the limited ground-based stations over India still leaves some uncertainty in the robust assertion of the hypothesis. The study highlights the need to capture these subtle variabilities and their responses to climate variability and change since it has implications for inverse estimates of terrestrial CO2 fluxes. (C) 2016 Elsevier Ltd. All rights reserved. |
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BibTeX:
@article{kumar16a,
author = {Kumar, K. Ravi and Valsala, Vinu and Tiwari, Yogesh K. and Revadekar, J. V. and Pillai, Prasanth and Chakraborty, Supriyo and Murtugudde, Raghu},
title = {Intra-seasonal variability of atmospheric CO2 concentrations over India during summer monsoons},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2016},
volume = {142},
pages = {229--237},
doi = {https://doi.org/10.1016/j.atmosenv.2016.07.023}
}
|
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| Kurz, W.A., Shaw, C.H., Boisvenue, C., Stinson, G., Metsaranta, J., Leckie, D., Dyk, A., Smyth, C. and Neilson, E.T. | Carbon in Canada's boreal forest - A synthesis | {2013} | ENVIRONMENTAL REVIEWS Vol. {21}({4}), pp. 260-292 |
article | DOI |
| Abstract: Canada's managed boreal forest, 54% of the nation's total boreal forest area, stores 28 Pg carbon (C) in biomass, dead organic matter, and soil pools. The net C balance is dominated by the difference of two large continuous fluxes: C uptake (net primary production) and release during decomposition (heterotrophic respiration). Additional releases of C can be high in years, or in areas, that experience large anthropogenic or natural disturbances. From 1990 to 2008, Canada's managed boreal forest has acted as C sink of 28 Tg C year(-1), removing CO2 from the atmosphere to replace the 17 Tg of C annually harvested and store an additional 11 Tg of C year-1 in ecosystem C pools. A large fraction (similar to 57%) of the C harvested since 1990 remains stored in wood products and solid waste disposal sites in Canada and abroad, replacing C emitted from the decay or burning of wood harvested prior to 1990 and contributing to net increases in product and landfill C pools. Wood product use has reduced emissions in other sectors by substituting for emission-intensive products (concrete, steel). The C balance of the unmanaged boreal forest is currently unknown. The future C balance of the Canadian boreal forest will affect the global atmospheric C budget and influence the mitigation efforts required to attain atmospheric CO2 stabilization targets. The single biggest threat to C stocks is human-caused climate change. Large C stocks have accumulated in the boreal because decomposition is limited by cold temperatures and often anoxic environments. Increases in temperatures and disturbance rates could result in a large net C source during the remainder of this century and beyond. Uncertainties about the impacts of global change remain high, but we emphasize the asymmetry of risk: sustained large-scale increases in productivity are unlikely to be of sufficient magnitude to offset higher emissions from increased disturbances and heterotrophic respiration. Reducing the uncertainties of the current and future C balance of Canada's 270 Mha of boreal forest requires addressing gaps in monitoring, observation, and quantification of forest C dynamics, with particular attention to 125 Mha of unmanaged boreal forest with extensive areas of deep organic soils, peatlands, and permafrost containing large quantities of C that are vulnerable to global warming. |
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BibTeX:
@article{kurz13a,
author = {Kurz, W. A. and Shaw, C. H. and Boisvenue, C. and Stinson, G. and Metsaranta, J. and Leckie, D. and Dyk, A. and Smyth, C. and Neilson, E. T.},
title = {Carbon in Canada's boreal forest - A synthesis},
journal = {ENVIRONMENTAL REVIEWS},
year = {2013},
volume = {21},
number = {4},
pages = {260--292},
doi = {https://doi.org/10.1139/er-2013-0041}
}
|
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| Kuze, A., Nakamura, Y., Oda, T., Yoshida, J., Kikuchi, N., Kataoka, F., Suto, H. and Shiomi, K. | Examining partial-column density retrieval of lower-tropospheric CO2 from GOSAT target observations over global megacities | 2022 | REMOTE SENSING OF ENVIRONMENT Vol. 273 |
article | DOI |
| Abstract: We retrieved and examined the partial-column densities of carbon dioxide (CO2) in the lower (LT, typically 0-4 km) and upper (UT, typically 4-12 km) troposphere (XCO2LT and XCO2UT) collected over six global megacities: Beijing, New Delhi, New York City, Riyadh, Shanghai, and Tokyo. The radiance spectra were collected using the Thermal And Near-infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) onboard the Greenhouse gases Observing SATellite (GOSAT). Our retrieval method uniquely utilizes reflected sunlight with two orthogonal components of polarization and thermal emissions. We defined megacity concentration enhancement due to surface CO2 emissions as XCO2LT minus XCO2UT, allowing us to overcome some of the challenges in the enhancement analysis using existing column density data. We examined the relationship between the XCO2LT enhancements from the time series of intensive target observations over megacities and the inverse of simulated wind speed, which could be potentially used to estimate surface emissions. Next, we attempted to estimate the average emission intensity for each city from the linear regression slope. We also compared our obtained emission estimates with the Open-Data Inventory for Anthropogenic CO2 (ODIAC) inventory for evaluation. Our results demonstrate the potential utility of the new partial-column density retrievals for estimating megacity CO2 emissions. More frequent and comprehensive coverage characterizing the spatial distribution of emissions is necessary to reduce random error and bias associated with the obtained estimate. |
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BibTeX:
@article{kuze22a,
author = {Kuze, A. and Nakamura, Y. and Oda, T. and Yoshida, J. and Kikuchi, N. and Kataoka, F. and Suto, H. and Shiomi, K.},
title = {Examining partial-column density retrieval of lower-tropospheric CO2 from GOSAT target observations over global megacities},
journal = {REMOTE SENSING OF ENVIRONMENT},
year = {2022},
volume = {273},
doi = {https://doi.org/10.1016/j.rse.2022.112966}
}
|
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| LaFranchi, B.W., McFarlane, K.J., Miller, J.B., Lehman, S.J., Phillips, C.L., Andrews, A.E., Tans, P.P., Chen, H., Liu, Z., Turnbull, J.C., Xu, X. and Guilderson, T.P. | Strong regional atmospheric C-14 signature of respired CO2 observed from a tall tower over the midwestern United States | {2016} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {121}({8}), pp. 2275-2295 |
article | DOI |
| Abstract: Radiocarbon in CO2 ((CO2)-C-14) measurements can aid in discriminating between fast (< 1 year) and slower (> 5-10 years) cycling of C between the atmosphere and the terrestrial biosphere due to the 14C disequilibrium between atmospheric and terrestrial C. However, (CO2)-C-14 in the atmosphere is typically much more strongly impacted by fossil fuel emissions of CO2, and, thus, observations often provide little additional constraints on respiratory flux estimates at regional scales. Here we describe a data set of (CO2)-C-14 observations from a tall tower in northern Wisconsin (USA) where fossil fuel influence is far enough removed that during the summer months, the biospheric component of the (CO2)-C-14 budget dominates. We find that the terrestrial biosphere is responsible for a significant contribution to (CO2)-C-14 that is 2-3 times higher than predicted by the Carnegie-Ames-Stanford approach terrestrial ecosystem model for observations made in 2010. This likely includes a substantial contribution from the North American boreal ecoregion, but transported biospheric emissions from outside the model domain cannot be ruled out. The (CO2)-C-14 enhancement also appears somewhat decreased in observations made over subsequent years, suggesting that 2010 may be anomalous. With these caveats acknowledged, we discuss the implications of the observation/ model comparison in terms of possible systematic biases in the model versus short-term anomalies in the observations. Going forward, this isotopic signal could be exploited as an important indicator to better constrain both the long-term carbon balance of terrestrial ecosystems and the short-term impact of disturbance-based loss of carbon to the atmosphere. |
|||||
BibTeX:
@article{lafranchi16a,
author = {LaFranchi, B. W. and McFarlane, K. J. and Miller, J. B. and Lehman, S. J. and Phillips, C. L. and Andrews, A. E. and Tans, P. P. and Chen, H. and Liu, Z. and Turnbull, J. C. and Xu, X. and Guilderson, T. P.},
title = {Strong regional atmospheric C-14 signature of respired CO2 observed from a tall tower over the midwestern United States},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2016},
volume = {121},
number = {8},
pages = {2275--2295},
doi = {https://doi.org/10.1002/2015JG003271}
}
|
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| Lan, X., Tans, P., Sweeney, C., Andrews, A., Jacobson, A., Crotwell, M., Dlugokencky, E., Kofler, J., Lang, P., Thoning, K. and Wolter, S. | Gradients of column CO2 across North America from the NOAA Global Greenhouse Gas Reference Network | {2017} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {17}({24}), pp. 15151-15165 |
article | DOI |
| Abstract: This study analyzes seasonal and spatial patterns of column carbon dioxide (CO2) over North America, calculated from aircraft and tall tower measurements from the NOAA Global Greenhouse Gas Reference Network from 2004 to 2014. Consistent with expectations, gradients between the eight regions studied are larger below 2 km than above 5 km. The 11-year mean CO2 dry mole fraction (XCO2) in the column below similar to 330 hPa (similar to 8 km above sea level) from NOAA's CO2 data assimilation model, Carbon-Tracker (CT2015), demonstrates good agreement with those calculated from calibrated measurements on aircraft and towers. Total column XCO2 was attained by combining modeled CO2 above 330 hPa from CT2015 with the measurements. We find large spatial gradients of total column XCO2 from June to August, with north and northeast regions having similar to 3 ppm stronger summer drawdown (peak-to-valley amplitude in seasonal cycle) than the south and southwest regions. The long-term averaged spatial gradients of total column XCO2 across North America show a smooth pattern that mainly reflects the large-scale circulation. We have conducted a CarbonTracker experiment to investigate the impact of Eurasian long-range transport. The result suggests that the large summertime Eurasian boreal flux contributes about half of the north-south column XCO2 gradient across North America. Our results confirm that continental-scale total column XCO2 gradients simulated by CarbonTracker are realistic and can be used to evaluate the credibility of some spatial patterns from satellite retrievals, such as the long-term average of growing-season spatial patterns from satellite retrievals reported for Europe which show a larger spatial difference (similar to 6 ppm) and scattered hot spots. |
|||||
BibTeX:
@article{lan17a,
author = {Lan, Xin and Tans, Pieter and Sweeney, Colm and Andrews, Arlyn and Jacobson, Andrew and Crotwell, Molly and Dlugokencky, Edward and Kofler, Jonathan and Lang, Patricia and Thoning, Kirk and Wolter, Sonja},
title = {Gradients of column CO2 across North America from the NOAA Global Greenhouse Gas Reference Network},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2017},
volume = {17},
number = {24},
pages = {15151--15165},
doi = {https://doi.org/10.5194/acp-17-15151-2017}
}
|
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| de lange , A. and Landgraf, J. | Methane profiles from GOSAT thermal infrared spectra | {2018} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {11}({6}), pp. {3815-3828} |
article | DOI |
| Abstract: This paper discusses the retrieval of atmospheric methane profiles from the thermal infrared band of the Japanese Greenhouse Gases Observing Satellite (GOSAT) between 1210 and 1310 cm(-1), using the RemoTeC analysis software. Approximately one degree of information on the vertical methane distribution is inferred from the measurements, with the main sensitivity at about 9 km altitude but little sensitivity to methane in the lower troposphere. For verification, we compare the GOSAT-TIR methane profile retrieval results with profiles from model fields provided by the Monitoring Atmospheric Composition and Climate (MACC) project, scaled to the total column measurements of the Total Carbon Column Observing Network (TCCON) at ground-based measurement sites. Without any radiometric corrections of GOSAT observations, differences between both data sets can be as large as 10 %. To mitigate these differences, we developed a correction scheme using a principal component analysis of spectral fit residuals and airborne observations of methane during the HIAPER pole-to-pole observations (HIPPO) campaign II and III. When the correction scheme is applied, the bias in the methane profile can be reduced to less than 2% over the whole altitude range with respect to MACC model methane fields. Furthermore, we show that, with this correction, the retrievals result in smooth methane fields over land and ocean crossings and no differences can be discerned between daytime and night-time measurements. Finally, a cloud filter is developed for the nighttime and ocean measurements. This filter is rooted in the GOSAT-TIR (thermal infrared) measurements and its performance, in terms of biases, is consistent with the cloud filter based on the GOSAT-SWIR (shortwave infrared) measurements. The TIR filter shows a higher acceptance rate of observations than the SWIR filter, at the cost of a higher uncertainty in the retrieved methane profiles. |
|||||
BibTeX:
@article{lange18a,
author = {de lange, Arno and Landgraf, Jochen},
title = {Methane profiles from GOSAT thermal infrared spectra},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2018},
volume = {11},
number = {6},
pages = {3815-3828},
doi = {https://doi.org/10.5194/amt-11-3815-2018}
}
|
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| Langley, B. | Modelling urban forest structure and services using the urban forest effects (UFORE) model [BibTeX] |
2012 | School: University of British Columbia | jurthesis | URL |
BibTeX:
@jurthesis{langley12a,
author = {Langley, Benjamin},
title = {Modelling urban forest structure and services using the urban forest effects (UFORE) model},
school = {University of British Columbia},
year = {2012},
url = {https://open.library.ubc.ca/collections/undergraduateresearch/52966/items/1.0075544}
}
|
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| Lanso, A.S., Bendtsen, J., Christensen, J.H., Sorensen, L.L., Chen, H., Meijer, H.A.J. and Geels, C. | Sensitivity of the air-sea CO2 exchange in the Baltic Sea and Danish inner waters to atmospheric short-term variability | {2015} | BIOGEOSCIENCES Vol. {12}({9}), pp. 2753-2772 |
article | DOI |
| Abstract: Minimising the uncertainties in estimates of air-sea CO2 exchange is an important step toward increasing the confidence in assessments of the CO2 cycle. Using an atmospheric transport model makes it possible to investigate the direct impact of atmospheric parameters on the air-sea CO2 flux along with its sensitivity to, for example, short-term temporal variability in wind speed, atmospheric mixing height and atmospheric CO2 concentration. With this study, the importance of high spatiotemporal resolution of atmospheric parameters for the air-sea CO2 flux is assessed for six sub-basins within the Baltic Sea and Danish inner waters. A new climatology of surface water partial pressure of CO2 (pCO(2)(w)) has been developed for this coastal area based on available data from monitoring stations and on-board pCO(2)(w) measuring systems. Parameterisations depending on wind speed were applied for the transfer velocity to calculate the air-sea CO2 flux. Two model simulations were conducted - one including short-term variability in atmospheric CO2 (VAT), and one where it was not included (CAT). A seasonal cycle in the air-sea CO2 flux was found for both simulations for all sub-basins with uptake of CO2 in summer and release of CO2 to the atmosphere in winter. During the simulated period 2005-2010, the average annual net uptake of atmospheric CO2 for the Baltic Sea, Danish straits and Kattegat was 287 and 471 Gg C yr(-1) for the VAT and CAT simulations, respectively. The obtained difference of 184 Gg C yr(-1) was found to be significant, and thus ignoring short-term variability in atmospheric CO2 does have a sizeable effect on the air-sea CO2 exchange. The combination of the atmospheric model and the new pCO(2)(w) fields has also made it possible to make an estimate of the marine part of the Danish CO2 budget for the first time. A net annual uptake of 2613 Gg C yr(-1) was found for the Danish waters. A large uncertainty is connected to the air-sea CO2 flux in particular caused by the transfer velocity parameterisation and the applied pCO(2)(w) climatology. However, as a significant difference of 184 Gg C yr(-1) is obtained between the VAT and CAT simulations, the present study underlines the importance of including short-term variability in atmospheric CO2 concentration in future model studies of the air-sea exchange in order to minimise the uncertainty. |
|||||
BibTeX:
@article{lanso15a,
author = {Lanso, A. S. and Bendtsen, J. and Christensen, J. H. and Sorensen, L. L. and Chen, H. and Meijer, H. A. J. and Geels, C.},
title = {Sensitivity of the air-sea CO2 exchange in the Baltic Sea and Danish inner waters to atmospheric short-term variability},
journal = {BIOGEOSCIENCES},
year = {2015},
volume = {12},
number = {9},
pages = {2753--2772},
doi = {https://doi.org/10.5194/bg-12-2753-2015}
}
|
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| Lanso, A.S., Sorensen, L.L., Christensen, J.H., Rutgersson, A. and Geels, C. | The influence of short-term variability in surface water pCO(2) on modelled air-sea CO2 exchange | {2017} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {69} |
article | DOI |
| Abstract: Coastal seas and estuarine systems are highly variable in both time and space and with their heterogeneity difficult to capture with measurements. Models are useful tools in obtaining a better spatiotemporal coverage or, at least, a better understanding of the impacts such heterogeneity has in driving variability in coastal oceans and estuaries. A model-based sensitivity study is constructed in this study in order to examine the effects of short-term variability in surface water pCO(2) on the annual air-sea CO2 exchange in coastal regions. An atmospheric transport model formed the basis of the modelling framework for the study of the Baltic Sea and the Danish inner waters. Several maps of surface water pCO(2) were employed in the modelling framework. While a monthly Baltic Sea climatology (BSC) had already been developed, the current study further extended this with the addition of an improved near-coastal climatology for the Danish inner waters. Furthermore, daily surface fields of pCO(2) were obtained from a mixed layer scheme constrained by surface measurements of pCO(2) (JENA). Short-term variability in surface water pCO(2) was assessed by calculating monthly mean diurnal cycles from continuous measurements of surface water pCO(2), observed at stationary sites within the Baltic Sea. No apparent diurnal cycle was evident in winter, but diurnal cycles (with amplitudes up to 27 mu atm) were found from April to October. The present study showed that the temporal resolution of surface water pCO(2) played an influential role on the annual air-sea CO2 exchange for the coastal study region. Hence, annual estimates of CO2 exchanges are sensitive to variation on much shorter time scales, and this variability should be included for any model study investigating the exchange of CO2 across the air-sea interface. Furthermore, the choice of surface pCO(2) maps also had a crucial influence on the simulated air-sea CO2 exchange. |
|||||
BibTeX:
@article{lanso17a,
author = {Lanso, Anne Sofie and Sorensen, Lise Lotte and Christensen, Jesper H. and Rutgersson, Anna and Geels, Camilla},
title = {The influence of short-term variability in surface water pCO(2) on modelled air-sea CO2 exchange},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2017},
volume = {69},
doi = {https://doi.org/10.1080/16000889.2017.1302670}
}
|
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| Lanso, A.S., Smallman, T.L., Christensen, J.H., Williams, M., Pilegaard, K., Sorensen, L.-L. and Geels, C. | Simulating the atmospheric CO2 concentration across the heterogeneous landscape of Denmark using a coupled atmosphere-biosphere mesoscale model system | {2019} | BIOGEOSCIENCES Vol. {16}({7}), pp. {1505-1524} |
article | DOI URL |
| Abstract: Although coastal regions only amount to 7% of the global oceans, their contribution to the global oceanic air-sea CO2 exchange is proportionally larger, with fluxes in some estuaries being similar in magnitude to terrestrial surface fluxes of CO2. Across a heterogeneous surface consisting of a coastal marginal sea with estuarine properties and varied land mosaics, the surface fluxes of CO2 from both marine areas and terrestrial surfaces were investigated in this study together with their impact in atmospheric CO2 concentrations by the usage of a high-resolution modelling framework. The simulated terrestrial fluxes across the study region of Denmark experienced an east-west gradient corresponding to the distribution of the land cover classification, their biological activity and the urbanised areas. Annually, the Danish terrestrial surface had an uptake of approximately -7000 GgC yr(-1). While the marine fluxes from the North Sea and the Danish inner waters were smaller annually, with about -1800 and 1300 GgC yr(-1), their sizes are comparable to annual terrestrial fluxes from individual land cover classifications in the study region and hence are not negligible. The contribution of terrestrial surfaces fluxes was easily detectable in both simulated and measured concentrations of atmospheric CO2 at the only tall tower site in the study region. Although, the tower is positioned next to Roskilde Fjord, the local marine impact was not distinguishable in the simulated concentrations. But the regional impact from the Danish inner waters and the Baltic Sea increased the atmospheric concentration by up to 0.5 ppm during the winter months. | |||||
BibTeX:
@article{lanso19a,
author = {Lanso, Anne Sofie and Smallman, Thomas Luke and Christensen, Jesper Heile and Williams, Mathew and Pilegaard, Kim and Sorensen, Lise-Lotte and Geels, Camilla},
title = {Simulating the atmospheric CO2 concentration across the heterogeneous landscape of Denmark using a coupled atmosphere-biosphere mesoscale model system},
journal = {BIOGEOSCIENCES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {16},
number = {7},
pages = {1505--1524},
note = {Query date: 2021-04-02 15:20:04},
url = {https://bg.copernicus.org/articles/16/1505/2019/},
doi = {https://doi.org/10.5194/bg-16-1505-2019}
}
|
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| Laskar, A.H., Lin, L.-C., Jiang, X. and Liang, M.-C. | Distribution of CO2 in Western Pacific, Studied Using Isotope Data Made in Taiwan, OCO‐2 Satellite Retrievals, and CarbonTracker Products [BibTeX] |
2018 | Earth and Space Science | article | URL |
BibTeX:
@article{laskar18a,
author = {Amzad H. Laskar and Li-Ching Lin and Xun Jiang and Mao-Chang Liang},
title = {Distribution of CO2 in Western Pacific, Studied Using Isotope Data Made in Taiwan, OCO‐2 Satellite Retrievals, and CarbonTracker Products},
journal = {Earth and Space Science},
year = {2018},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018EA000415}
}
|
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| Lauvaux, T., Schuh, A.E., Uliasz, M., Richardson, S., Miles, N., Andrews, A.E., Sweeney, C., Diaz, L.I., Martins, D., Shepson, P.B. and Davis, K.J. | Constraining the CO2 budget of the corn belt: exploring uncertainties from the assumptions in a mesoscale inverse system | {2012} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {12}({1}), pp. 337-354 |
article | DOI |
| Abstract: We performed an atmospheric inversion of the CO2 fluxes over Iowa and the surrounding states, from June to December 2007, at 20 km resolution and weekly timescale. Eight concentration towers were used to constrain the carbon balance in a 1000x1000 km(2) domain in this agricultural region of the US upper midwest. The CO2 concentrations of the boundaries derived from CarbonTracker were adjusted to match direct observations from aircraft profiles around the domain. The regional carbon balance ends up with a sink of 183 Tg C +/- 35 Tg C over the area for the period June-December, 2007. Potential bias from incorrect boundary conditions of about 0.55 ppm over the 7 months was corrected using mixing ratios from four different aircraft profile sites operated at a weekly time scale, acting as an additional source of uncertainty of 24 Tg C. We used two different prior flux estimates, the SiBCrop model and the inverse flux product from the CarbonTracker system. We show that inverse flux estimates using both priors converge to similar posterior estimates (20 Tg C difference), in our reference inversion, but some spatial structures from the prior fluxes remain in the posterior fluxes, revealing the importance of the prior flux resolution and distribution despite the large amount of atmospheric data available. The retrieved fluxes were compared to eddy flux towers in the corn and grassland areas, revealing an improvement in the seasonal cycles between the two compared to the prior fluxes, despite large absolute differences due to representation errors. The uncertainty of 34 Tg C (or 34 g C m(2)) was derived from the posterior uncertainty obtained with our reference inversion of about 25 to 30 Tg C and from sensitivity tests of the assumptions made in the inverse system, for a mean carbon balance over the region of -183 Tg C, slightly weaker than the reference. Because of the potential large bias (similar to 24 Tg C in this case) due to choice of background conditions, proportional to the surface but not to the regional flux, this methodology seems limited to regions with a large signal (sink or source), unless additional observations can be used to constrain the boundary inflow. |
|||||
BibTeX:
@article{lauvaux12a,
author = {Lauvaux, T. and Schuh, A. E. and Uliasz, M. and Richardson, S. and Miles, N. and Andrews, A. E. and Sweeney, C. and Diaz, L. I. and Martins, D. and Shepson, P. B. and Davis, K. J.},
title = {Constraining the CO2 budget of the corn belt: exploring uncertainties from the assumptions in a mesoscale inverse system},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2012},
volume = {12},
number = {1},
pages = {337--354},
doi = {https://doi.org/10.5194/acp-12-337-2012}
}
|
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| Lauvaux, T., Schuh, A.E., Bocquet, M., Wu, L., Richardson, S., Miles, N. and Davis, K.J. | Network design for mesoscale inversions of CO2 sources and sinks | {2012} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {64} |
article | DOI |
| Abstract: Recent instrumental deployments of regional observation networks of atmospheric CO2 mixing ratios have been used to constrain carbon sources and sinks using inversion methodologies. In this study, we performed sensitivity experiments using observation sites from the Mid Continent Intensive experiment to evaluate the required spatial density and locations of CO2 concentration towers based on flux corrections and error reduction analysis. In addition, we investigated the impact of prior flux error structures with different correlation lengths and biome information. We show here that, while the regional carbon balance converged to similar annual estimates using only two concentration towers over the region, additional sites were necessary to retrieve the spatial flux distribution of our reference case (using the entire network of eight towers). Local flux corrections required the presence of observation sites in their vicinity, suggesting that each tower was only able to retrieve major corrections within a hundred of kilometres around, despite the introduction of spatial correlation lengths (similar to 100 to 300 km) in the prior flux errors. We then quantified and evaluated the impact of the spatial correlations in the prior flux errors by estimating the improvement in the CO2 model-data mismatch of the towers not included in the inversion. The overall gain across the domain increased with the correlation length, up to 300 km, including both biome-related and non-biome-related structures. However, the spatial variability at smaller scales was not improved. We conclude that the placement of observation towers around major sources and sinks is critical for regional-scale inversions in order to obtain reliable flux distributions in space. Sparser networks seem sufficient to assess the overall regional carbon budget with the support of flux error correlations, indicating that regional signals can be recovered using hourly mixing ratios. However, the smaller spatial structures in the posterior fluxes are highly constrained by assumed prior flux error correlation lengths, with no significant improvement at only a few hundreds of kilometres away from the observation sites. |
|||||
BibTeX:
@article{lauvaux12b,
author = {Lauvaux, T. and Schuh, A. E. and Bocquet, M. and Wu, L. and Richardson, S. and Miles, N. and Davis, K. J.},
title = {Network design for mesoscale inversions of CO2 sources and sinks},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2012},
volume = {64},
doi = {https://doi.org/10.3402/tellusb.v64i0.17980}
}
|
|||||
| Lauvaux, T., Miles, N.L., Richardson, S.J., Deng, A., Stauffer, D.R., Davis, K.J., Jacobson, G., Rella, C., Calonder, G.-P. and DeCola, P.L. | Urban Emissions of CO2 from Davos, Switzerland: The First Real-Time Monitoring System Using an Atmospheric Inversion Technique | {2013} | JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY Vol. {52}({12}), pp. 2654-2668 |
article | DOI |
| Abstract: Anthropogenic emissions from urban areas represent 70% of the fossil fuel carbon emitted globally according to carbon emission inventories. The authors present here the first operational system able to monitor in near-real time daily emission estimates, using a mesoscale atmospheric inversion framework over the city of Davos, Switzerland, before, during, and after the World Economic Forum 2012 Meeting (WEF-2012). Two instruments that continuously measured atmospheric mixing ratios of greenhouse gases (GHGs) were deployed at two locations from 23 December 2011 to 3 March 2012: one site was located in the urban area and the other was out of the valley in the surrounding mountains. Carbon dioxide, methane, and carbon monoxide were measured continuously at both sites. The Weather Research and Forecasting mesoscale atmospheric model (WRF), in four-dimensional data assimilation mode, was used to simulate the transport of GHGs over the valley of Davos at 1.3-km resolution. Wintertime emissions prior to the WEF-2012 were about 40% higher than the initial annual inventory estimate, corresponding to the use of heating fuel in the winter. Daily inverse fluxes were highly correlated with the local climate, especially during the severe cold wave that affected most of Europe in early February 2012. During the WEF-2012, emissions dropped by 35% relative to the first month of the deployment, despite similar temperatures and the presence of several thousand participants at the meeting. On the basis of composite diurnal cycles of hourly CO/CO2 ratios, the absence of traffic peaks during the WEF-2012 meeting indicated that change in road emissions is potentially responsible for the observed decrease in the city emissions during the meeting. |
|||||
BibTeX:
@article{lauvaux13a,
author = {Lauvaux, Thomas and Miles, Natasha L. and Richardson, Scott J. and Deng, Aijun and Stauffer, David R. and Davis, Kenneth J. and Jacobson, Gloria and Rella, Chris and Calonder, Gian-Paul and DeCola, Philip L.},
title = {Urban Emissions of CO2 from Davos, Switzerland: The First Real-Time Monitoring System Using an Atmospheric Inversion Technique},
journal = {JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY},
year = {2013},
volume = {52},
number = {12},
pages = {2654--2668},
doi = {https://doi.org/10.1175/JAMC-D-13-038.1}
}
|
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| Lauvaux, T., Miles, N.L., Deng, A., Richardson, S.J., Cambaliza, M.O., Davis, K.J., Gaudet, B., Gurney, K.R., Huang, J., O'Keefe, D., Song, Y., Karion, A., Oda, T., Patarasuk, R., Razlivanov, I., Sarmiento, D., Shepson, P., Sweeney, C., Turnbull, J. and Wu, K. | High-resolution atmospheric inversion of urban CO2 emissions during the dormant season of the Indianapolis Flux Experiment (INFLUX) | {2016} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {121}({10}), pp. 5213-5236 |
article | DOI |
| Abstract: Based on a uniquely dense network of surface towers measuring continuously the atmospheric concentrations of greenhouse gases (GHGs), we developed the first comprehensive monitoring systems of CO2 emissions at high resolution over the city of Indianapolis. The urban inversion evaluated over the 2012-2013 dormant season showed a statistically significant increase of about 20% (from 4.5 to 5.7 MtC +/- 0.23 MtC) compared to the Hestia CO2 emission estimate, a state-of-the-art building-level emission product. Spatial structures in prior emission errors, mostly undetermined, appeared to affect the spatial pattern in the inverse solution and the total carbon budget over the entire area by up to 15%, while the inverse solution remains fairly insensitive to the CO2 boundary inflow and to the different prior emissions (i.e., ODIAC). Preceding the surface emission optimization, we improved the atmospheric simulations using a meteorological data assimilation system also informing our Bayesian inversion system through updated observations error variances. Finally, we estimated the uncertainties associated with undetermined parameters using an ensemble of inversions. The total CO2 emissions based on the ensemble mean and quartiles (5.26-5.91 MtC) were statistically different compared to the prior total emissions (4.1 to 4.5 MtC). Considering the relatively small sensitivity to the different parameters, we conclude that atmospheric inversions are potentially able to constrain the carbon budget of the city, assuming sufficient data to measure the inflow of GHG over the city, but additional information on prior emission error structures are required to determine the spatial structures of urban emissions at high resolution. |
|||||
BibTeX:
@article{lauvaux16a,
author = {Lauvaux, Thomas and Miles, Natasha L. and Deng, Aijun and Richardson, Scott J. and Cambaliza, Maria O. and Davis, Kenneth J. and Gaudet, Brian and Gurney, Kevin R. and Huang, Jianhua and O'Keefe, Darragh and Song, Yang and Karion, Anna and Oda, Tomohiro and Patarasuk, Risa and Razlivanov, Igor and Sarmiento, Daniel and Shepson, Paul and Sweeney, Colm and Turnbull, Jocelyn and Wu, Kai},
title = {High-resolution atmospheric inversion of urban CO2 emissions during the dormant season of the Indianapolis Flux Experiment (INFLUX)},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2016},
volume = {121},
number = {10},
pages = {5213--5236},
doi = {https://doi.org/10.1002/2015JD024473}
}
|
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| Lauvaux, T., Diaz-Isaac, L.I., Bocquet, M. and Bousserez, N. | Diagnosing spatial error structures in CO2 mole fractions and XCO2 column mole fractions from atmospheric transport | {2019} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {19}({18}), pp. {12007-12024} |
article | DOI URL |
| Abstract: Atmospheric inversions inform us about the magnitude and variations of greenhouse gas (GHG) sources and sinks from global to local scales. Deployment of observing systems such as spaceborne sensors and ground-based instruments distributed around the globe has started to offer an unprecedented amount of information to estimate surface exchanges of GHG at finer spatial and temporal scales. However, all inversion methods still rely on imperfect atmospheric transport models whose error structures directly affect the inverse estimates of GHG fluxes. The impact of spatial error structures on the retrieved fluxes increase concurrently with the density of the available measurements. In this study, we diagnose the spatial structures due to transport model errors affecting modeled in situ carbon dioxide (CO2) mole fractions and total-column dry air mole fractions of CO2 (XCO2). We implement a cost-effective filtering technique recently developed in the meteorological data assimilation community to describe spatial error structures using a small-size ensemble. This technique can enable ensemble-based error analysis for multiyear inversions of sources and sinks. The removal of noisy structures due to sampling errors in our small-size ensembles is evaluated by comparison with larger-size ensembles. A second filtering approach for error covariances is proposed (Wiener filter), producing similar results over the 1-month simulation period compared to a Schur filter. Based on a comparison to a reference 25-member calibrated ensemble, we demonstrate that error variances and spatial error correlation structures are recoverable from small-size ensembles of about 8 to 10 members, improving the representation of transport errors in mesoscale inversions of CO2 fluxes. Moreover, error variances of in situ near-surface and free-tropospheric CO2 mole fractions differ significantly from total-column XCO2 error variances. We conclude that error variances for remote-sensing observations need to be quantified independently of in situ CO2 mole fractions due to the complexity of spatial error structures at different altitudes. However, we show the potential use of meteorological error structures such as the mean horizontal wind speed, directly available from ensemble prediction systems, to approximate spatial error correlations of in situ CO2 mole fractions, with similarities in seasonal variations and characteristic error length scales. | |||||
BibTeX:
@article{lauvaux19a,
author = {Lauvaux, Thomas and Diaz-Isaac, Liza I. and Bocquet, Marc and Bousserez, Nicolas},
title = {Diagnosing spatial error structures in CO2 mole fractions and XCO2 column mole fractions from atmospheric transport},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {19},
number = {18},
pages = {12007--12024},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/19/12007/2019/},
doi = {https://doi.org/10.5194/acp-19-12007-2019}
}
|
|||||
| Law, R.M., Steele, L.P., Krummel, P.B. and Zahorowski, W. | Synoptic variations in atmospheric CO2 at Cape Grim: a model intercomparison | {2010} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {62}({5, SI}), pp. 810-820 |
article | DOI |
| Abstract: A `TransCom' model intercomparison is used to assess how well synoptic and diurnal variations of carbon dioxide (CO2) and 222Rn (radon) can be modelled at the coastal site, Cape Grim, Australia. Each model was run with prescribed fluxes and forced with analysed meteorology for 2000-2003. Twelve models were chosen for analysis based on each model's ability to differentiate baseline CO2 concentrations from non-baseline CO2 (influenced by regional land fluxes). Analysis focused on non-baseline events during 2002-2003. Radon was better simulated than CO2, indicating that a spatially uniform radon land flux is a reasonable assumption and that regional-scale transport was adequately captured by the models. For both radon and CO2, the ensemble model mean generally performed better than any individual model. Two case studies highlight common problems with the simulations. First, in summer and autumn the Cape Grim observations are sometimes influenced by Tasmanian rather than mainland Australian fluxes. These periods are poorly simulated. Secondly, an event with an urban plume demonstrates how the relatively low spatial resolution of the input CO2 fluxes limits the quality of the simulations. Analysis of periods with below baseline concentration indicates the possible influence of carbon uptake by winter crops in southern mainland Australia. |
|||||
BibTeX:
@article{law10a,
author = {Law, Rachel M. and Steele, L. Paul and Krummel, Paul B. and Zahorowski, Wlodek},
title = {Synoptic variations in atmospheric CO2 at Cape Grim: a model intercomparison},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2010},
volume = {62},
number = {5, SI},
pages = {810--820},
doi = {https://doi.org/10.1111/j.1600-0889.2010.00470.x}
}
|
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| Lee, T.R., De Wekker, S.F.J., Andrews, A.E., Kofler, J. and Williams, J. | Carbon dioxide variability during cold front passages and fair weather days at a forested mountaintop site | {2012} | ATMOSPHERIC ENVIRONMENT Vol. {46}, pp. 405-416 |
article | DOI |
| Abstract: This study describes temporal carbon dioxide (CO2) changes at a new meteorological site on a mountaintop in the Virginia Blue Ridge Mountains during the first year of measurements. Continental mountaintop locations are increasingly being used for CO2 monitoring, and investigations are needed to better understand measurements made at these locations. We focus on CO2 mixing ratio changes on days with cold front passages and on fair weather days. Changes in CO2 mixing ratios are largest during cold front passages outside the growing season and on clear, fair weather days in the growing season. 67% (60%) of the frontal passages during the non-growing (growing) season have larger postfrontal than prefrontal CO2 mixing ratios. The increase in CO2 mixing ratio around the frontal passage is short-lived and coincides with changes in CO and O-3. The CO2 increase can therefore be used as an additional criterion to determine the timing of frontal passages at the mountaintop station. The CO2 increase can be explained by an accumulation of trace gases along frontal boundaries. The magnitude and duration of the CO2 increase is affected by the wind speed and direction that determine the source region of the postfrontal air. Southward-moving fronts result in the largest prolonged period of elevated CO2, consistent with the postfrontal advection of air from the Northeastern United States where anthropogenic contributions are relatively large compared to other areas in the footprint of the mountaintop station. These anthropogenic contributions to the CO2 changes are confirmed through concurrent CO measurements and output from NOAA's CarbonTracker model. (C) 2011 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{lee12a,
author = {Lee, Temple R. and De Wekker, Stephan F. J. and Andrews, Arlyn E. and Kofler, Jonathan and Williams, Jonathan},
title = {Carbon dioxide variability during cold front passages and fair weather days at a forested mountaintop site},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2012},
volume = {46},
pages = {405--416},
doi = {https://doi.org/10.1016/j.atmosenv.2011.09.068}
}
|
|||||
| Lee, T.R., De Wekker, S.F.J., Pal, S., Andrews, A.E. and Kofler, J. | Meteorological controls on the diurnal variability of carbon monoxide mixing ratio at a mountaintop monitoring site in the Appalachian Mountains | {2015} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {67} |
article | DOI |
| Abstract: The variability of trace gases such as carbon monoxide (CO) at surface monitoring stations is affected by meteorological forcings that are particularly complicated over mountainous terrain. A detailed understanding of the impact of meteorological forcings on trace gas variability is challenging, but is vital to distinguish trace gas measurements affected by local pollutant sources from measurements representative of background mixing ratios. In the present study, we investigate the meteorological and CO characteristics at Pinnacles (38.61 N, 78.35 W, 1017m above mean sea level), a mountaintop monitoring site in northwestern Virginia, USA, in the Appalachian Mountains, from 2009 to 2012, and focus on understanding the dominant meteorological forcings affecting the CO variability on diurnal timescales. The annual mean diurnal CO cycle shows a minimum in the morning between 0700 and 0900 LST and a maximum in the late afternoon between 1600 and 2000 LST, with a mean (median) daily CO amplitude of 39.2 +/- 23.7 ppb (33.2 ppb). CO amplitudes show large day-to-day variability. The largest CO amplitudes, in which CO mixing ratios can change >100 ppb in >3 h, occur in the presence of synoptic disturbances. Under fair weather conditions, local-to regional-scale transport processes are found to be more important drivers of the diurnal CO variability. On fair weather days with northwesterly winds, boundary layer dilution causes a daytime CO decrease, resembling the variability observed atop tall towers in flat terrain. Fair weather days with a wind shift from the northwest to the south are characterised by an afternoon CO increase and resemble the variability observed at mountaintops influenced by the vertical transport of polluted air from adjacent valleys. |
|||||
BibTeX:
@article{lee15a,
author = {Lee, Temple R. and De Wekker, Stephan F. J. and Pal, Sandip and Andrews, Arlyn E. and Kofler, Jonathan},
title = {Meteorological controls on the diurnal variability of carbon monoxide mixing ratio at a mountaintop monitoring site in the Appalachian Mountains},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2015},
volume = {67},
doi = {https://doi.org/10.3402/tellusb.v67.25659}
}
|
|||||
| Lee, S., Kim, D., Im, J., Lee, M.-I. and Park, Y.-G. | CO2 concentration and its spatiotemporal variation in the troposphere using multi-sensor satellite data, carbon tracker, and aircraft observations | {2017} | GISCIENCE & REMOTE SENSING Vol. {54}({4}), pp. 592-613 |
article | DOI |
| Abstract: Satellite-based atmospheric CO2 observations have provided a great opportunity to improve our understanding of the global carbon cycle. However, thermal infrared (TIR)-based satellite observations, which are useful for the investigation of vertical distribution and the transport of CO2, have not yet been studied as much as the column amount products derived from shortwave infrared data. In this study, TIR-based satellite CO2 products - from Atmospheric Infrared Sounder, Tropospheric Emission Spectrometer (TES), and Thermal And Near infrared Sensor for carbon Observation - and carbon tracker mole fraction data were compared with in situ Comprehensive Observation Network for Trace gases by AIrLiner (CONTRAIL) data for different locations. The TES CO2 product showed the best agreement with CONTRAIL CO2 data resulting in R-2 similar to 0.87 and root-mean-square error similar to 0.9. The vertical distribution of CO2 derived by TES strongly depends on the geophysical characteristics of an area. Two different climate regions (i.e., southeastern Japan and southeastern Australia) were examined in terms of the vertical distribution and transport of CO2. Results show that while vertical distribution of CO2 around southeastern Japan was mainly controlled by horizontal and vertical winds, horizontal wind might be a major factor to control the CO2 transport around southeastern Australia. In addition, the vertical transport of CO2 also varies by region, which is mainly controlled by anthropogenic CO2, and horizontal and omega winds. This study improves our understanding of vertical distribution and the transport of CO2, both of which vary by region, using TIR-based satellite CO2 observations and meteorological variables. |
|||||
BibTeX:
@article{lee17a,
author = {Lee, Sanggyun and Kim, Dongmin and Im, Jungho and Lee, Myong-In and Park, Young-Gyu},
title = {CO2 concentration and its spatiotemporal variation in the troposphere using multi-sensor satellite data, carbon tracker, and aircraft observations},
journal = {GISCIENCE & REMOTE SENSING},
year = {2017},
volume = {54},
number = {4},
pages = {592--613},
doi = {https://doi.org/10.1080/15481603.2017.1317120}
}
|
|||||
| Lee, T.R., De Wekker, S.F.J. and Pal, S. | The Impact of the Afternoon Planetary Boundary-Layer Height on the Diurnal Cycle of CO and Mixing Ratios at a Low-Altitude Mountaintop | {2018} | BOUNDARY-LAYER METEOROLOGY Vol. {168}({1}), pp. {81-102} |
article | DOI |
| Abstract: Mountaintop trace-gas mixing ratios are often assumed to represent free atmospheric values, but are affected by valley planetary boundary-layer (PBL) air at certain times. We hypothesize that the afternoon valley-PBL height relative to the ridgetop is important in the diurnal cycle of mountaintop trace-gas mixing ratios. To investigate this, we use, (1) 4-years (1 January 2009-31 December 2012) of CO and mixing-ratio measurements and supporting meteorological observations from Pinnacles (, , 1017 m a.s.l.), which is a monitoring site in the Appalachian Mountains, (2) regional mixing-ratio measurements, and (3) PBL heights determined from a nearby sounding station. Results reveal that the amplitudes of the diurnal cycles of CO and mixing ratios vary as a function of the daytime maximum valley-PBL height relative to the ridgetop. The mean diurnal cycle for the subset of days when the afternoon valley-PBL height is at least 400 m below the ridgetop shows a daytime CO mixing-ratio increase, implying the transport of PBL air from the valley to the mountaintop. During the daytime, on days when the PBL heights exceed the mountaintop, PBL dilution and entrainment cause CO mixing ratios to decrease. This decrease in CO mixing ratio, especially on days when PBL heights are at least 400 m above the ridgetop, suggests that measurements from these days can be used as with afternoon measurements from flat terrain in applications requiring regionally-representative measurements. |
|||||
BibTeX:
@article{lee18a,
author = {Lee, Temple R. and De Wekker, Stephan F. J. and Pal, Sandip},
title = {The Impact of the Afternoon Planetary Boundary-Layer Height on the Diurnal Cycle of CO and Mixing Ratios at a Low-Altitude Mountaintop},
journal = {BOUNDARY-LAYER METEOROLOGY},
year = {2018},
volume = {168},
number = {1},
pages = {81-102},
doi = {https://doi.org/10.1007/s10546-018-0343-9}
}
|
|||||
| Lee, E., Zeng, F.-W., Koster, R.D., Weir, B., Ott, L.E. and Poulter, B. | The impact of spatiotemporal variability in atmospheric CO2 concentration on global terrestrial carbon fluxes | {2018} | BIOGEOSCIENCES Vol. {15}({18}), pp. {5635-5652} |
article | DOI |
| Abstract: Land carbon fluxes, e.g., gross primary production (GPP) and net biome production (NBP), are controlled in part by the responses of terrestrial ecosystems to atmospheric conditions near the Earth's surface. The Coupled Model Intercomparison Project Phase 6 (CMIP6) has recently proposed increased spatial and temporal resolutions for the surface CO2 concentrations used to calculate GPP, and yet a comprehensive evaluation of the consequences of this increased resolution for carbon cycle dynamics is missing. Here, using global offline simulations with a terrestrial biosphere model, the sensitivity of terrestrial carbon cycle fluxes to multiple facets of the spatiotemporal variability in atmospheric CO2 is quantified. Globally, the spatial variability in CO2 is found to increase the mean global GPP by a maximum of 0.05 Pg C year(-1), as more vegetated land areas benefit from higher CO2 concentrations induced by the inter-hemispheric gradient. The temporal variability in CO2, however, compensates for this increase, acting to reduce overall global GPP; in particular, consideration of the diurnal variability in atmospheric CO2 reduces multi-year mean global annual GPP by 0.5 Pg C year(-1) and net land carbon uptake by 0.1 Pg C year(-1). The relative contributions of the different facets of CO2 variability to GPP are found to vary regionally and seasonally, with the seasonal variation in atmospheric CO2, for example, having a notable impact on GPP in boreal regions during fall. Overall, in terms of estimating global GPP, the magnitudes of the sensitivities found here are minor, indicating that the common practice of applying spatially uniform and annually increasing CO2 (without higher-frequency temporal variability) in offline studies is a reasonable approach - the small errors induced by ignoring CO2 variability are undoubtedly swamped by other uncertainties in the offline calculations. Still, for certain regional-and seasonal-scale GPP estimations, the proper treatment of spatiotemporal CO2 variability appears important. | |||||
BibTeX:
@article{lee18b,
author = {Lee, Eunjee and Zeng, Fan-Wei and Koster, Randal D. and Weir, Brad and Ott, Lesley E. and Poulter, Benjamin},
title = {The impact of spatiotemporal variability in atmospheric CO2 concentration on global terrestrial carbon fluxes},
journal = {BIOGEOSCIENCES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2018},
volume = {15},
number = {18},
pages = {5635--5652},
doi = {https://doi.org/10.5194/bg-15-5635-2018}
}
|
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| Lee, E., Zeng, F.-W., Koster, R.D., Ott, L.E., Mahanama, S., Weir, B., Poulter, B. and Oda, T. | Impact of a Regional US Drought on Land and Atmospheric Carbon | {2020} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {125}({8}) |
article | DOI URL |
| Abstract: The impacts of drought on regional land and atmospheric carbon are still poorly understood. Here we quantify the impact of a regional U.S. drought on land carbon fluxes (gross primary production, or GPP, and net biosphere production) and atmospheric carbon (CO2) by imposing an idealized 3-month meteorological drought in an ensemble of coupled land-atmosphere climate simulations. The imposed drought, applied to the lower Mississippi River Valley (similar to 500,000 km(2)), leads to a 23% GPP reduction in the drought area in the month immediately following the drought's termination. The drought also caused GPP reductions in some remote areas through drought-induced impacts on remote meteorology, particularly the areas adjacent to the imposed drought. In the remote areas, the induced precipitation changes are responsible for most of the anomalous land productivity. The impact of the drought-induced meteorological anomalies on GPP is greater than that of the CO2 anomalies by at least an order of magnitude. While their impact on GPP is secondary, the drought-induced atmospheric CO2 anomalies near the land surface can be as large as 3.57 ppm. The significant CO2 anomalies cover an area up to three times of that of the imposed drought, suggesting that atmospheric transport needs to be considered in the interpretation of drought-induced CO2 anomalies in the atmosphere. The imposed drought also leads to column-averaged CO2 increases of up to 0.78 ppm, which is at the edge of the uncertainty from single soundings of current greenhouse gas observing satellites. Plain Language Summary During a regional drought, a deficiency of precipitation affects vegetation productivity, which can alter net carbon exchange between the land and the atmosphere and, in turn, the CO2 concentration in the atmosphere. Moreover, the anomalous heat and moisture fluxes at the land surface caused by the drought can generate changes in meteorology, affecting areas beyond the original drought area. Using a version of the NASA Goddard Earth Observing System Earth System Model that allows full characterization of the carbon-water-energy feedback processes, we imposed an idealized spring drought over the lower Mississippi River Valley (similar to 500,000 km(2)) and quantified the resulting changes in vegetation productivity, net carbon exchange flux, and atmospheric CO2 concentration. We found that the productivity in the drought area decreases by 23% and that the productivities in some remote areas, particularly areas adjacent to the imposed drought, are also affected through impacts on remote meteorology. The anomalous atmospheric CO2 caused by the idealized spring drought is at the edge of the measurement uncertainty of current greenhouse gas observing satellites. Due to atmospheric transport (e.g., wind), it covers an area up to three times of that of the imposed drought. | |||||
BibTeX:
@article{lee20a,
author = {Lee, Eunjee and Zeng, Fan-Wei and Koster, Randal D. and Ott, Lesley E. and Mahanama, Sarith and Weir, Brad and Poulter, Benjamin and Oda, Tomohiro},
title = {Impact of a Regional US Drought on Land and Atmospheric Carbon},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {125},
number = {8},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JG005599},
doi = {https://doi.org/10.1029/2019JG005599}
}
|
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| Lefrançois, E. | Revegetation and reclamation of oil sands process-affected material using Frankia-inoculated alders: Field and greenhouse trials [BibTeX] |
2009 | School: McGill University | mastersthesis | URL |
BibTeX:
@mastersthesis{lefrancois09a,
author = {Lefrançois, Elisabeth},
title = {Revegetation and reclamation of oil sands process-affected material using Frankia-inoculated alders: Field and greenhouse trials},
school = {McGill University},
year = {2009},
url = {http://digitool.library.mcgill.ca/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&forebear_coll=&user=GUEST&pds_handle=&pid=66758&con_lng=ENG&search_terms=&divType=&adjacency=N&rd_session=http://digitool.Library.McGill.CA:80/R/FT8AIQ9EGIVNJ1RIEL1L3JBY3VJSPXGBFKD2RGI227CGSACT1A-00024}
}
|
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| Lenton, A., Tilbrook, B., Law, R.M., Bakker, D., Doney, S.C., Gruber, N., Ishii, M., Hoppema, M., Lovenduski, N.S., Matear, R.J., McNeil, B.I., Metzl, N., Fletcher, S.E.M., Monteiro, P.M.S., Roedenbeck, C., Sweeney, C. and Takahashi, T. | Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009 | {2013} | BIOGEOSCIENCES Vol. {10}({6}), pp. 4037-4054 |
article | DOI |
| Abstract: The Southern Ocean (44-75 degrees S) plays a critical role in the global carbon cycle, yet remains one of the most poorly sampled ocean regions. Different approaches have been used to estimate sea-air CO2 fluxes in this region: synthesis of surface ocean observations, ocean biogeochemical models, and atmospheric and ocean inversions. As part of the RECCAP (REgional Carbon Cycle Assessment and Processes) project, we combine these different approaches to quantify and assess the magnitude and variability in Southern Ocean sea-air CO2 fluxes between 1990-2009. Using all models and inversions (26), the integrated median annual sea-air CO2 flux of -0.42+/-0.07 Pg C yr(-1) for the 44-75 degrees S region, is consistent with the -0.27+/-0.13 Pg C yr(-1) calculated using surface observations. The circumpolar region south of 58 degrees S has a small net annual flux (model and inversion median: -0.04+/-0.07 Pg C yr(-1) and observations: +0.04+/-0.02 Pg C yr(-1)), with most of the net annual flux located in the 44 to 58 degrees S circumpolar band (model and inversion median: -0.36+/-0.09 Pg C yr(-1) and observations: -0.35+/-0.09 Pg C yr(-1)). Seasonally, in the 44-58 degrees S region, the median of 5 ocean biogeochemical models captures the observed sea-air CO2 flux seasonal cycle, while the median of 11 atmospheric inversions shows little seasonal change in the net flux. South of 58 degrees S, neither atmospheric inversions nor ocean biogeochemical models reproduce the phase and amplitude of the observed seasonal sea-air CO2 flux, particularly in the Austral Winter. Importantly, no individual atmospheric inversion or ocean biogeochemical model is capable of reproducing both the observed annual mean uptake and the observed seasonal cycle. This raises concerns about projecting future changes in Southern Ocean CO2 fluxes. The median interannual variability from atmospheric inversions and ocean biogeochemical models is substantial in the Southern Ocean; up to 25% of the annual mean flux, with 25% of this interannual variability attributed to the region south of 58 degrees S. Resolving long-term trends is difficult due to the large interannual variability and short time frame (1990-2009) of this study; this is particularly evident from the large spread in trends from inversions and ocean biogeochemical models. Nevertheless, in the period 1990-2009 ocean biogeochemical models do show increasing oceanic uptake consistent with the expected increase of -0.05 Pg C yr(-1) decade(-1). In contrast, atmospheric inversions suggest little change in the strength of the CO2 sink broadly consistent with the results of Le Quere et al. (2007). |
|||||
BibTeX:
@article{lenton13a,
author = {Lenton, A. and Tilbrook, B. and Law, R. M. and Bakker, D. and Doney, S. C. and Gruber, N. and Ishii, M. and Hoppema, M. and Lovenduski, N. S. and Matear, R. J. and McNeil, B. I. and Metzl, N. and Fletcher, S. E. Mikaloff and Monteiro, P. M. S. and Roedenbeck, C. and Sweeney, C. and Takahashi, T.},
title = {Sea-air CO2 fluxes in the Southern Ocean for the period 1990-2009},
journal = {BIOGEOSCIENCES},
year = {2013},
volume = {10},
number = {6},
pages = {4037--4054},
doi = {https://doi.org/10.5194/bg-10-4037-2013}
}
|
|||||
| Levinson, D.H. and Lawrimore, J.H. | State of the climate in 2007 | {2008} | BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY Vol. {89}({7, S}), pp. {10+} |
article | DOI |
| Abstract: The combined land and ocean surface temperature in 2007 fell within the 10 highest on record while the average land temperature was the warmest since global records began in 1880. In the low to midtroposphere, the annual global mean temperature was among the five warmest since reliable global records began in 1958, but still cooler than the record warmest year of 1998. For the fourth consecutive year, the annual precipitation averaged over global land surfaces was above the long-term mean, although the anomaly was significantly less than in 2006 when the annual value was the eighth wettest since 1901. The globally averaged concentration of carbon dioxide (CO2) continued to increase in 2007, having risen to 382.7 ppm at the Mauna Loa Observatory in Hawaii. The average rate of rise of CO2 has been 1.6 ppm yr(-1) since 1980; however, since 2000 this has increased to 1.9 ppm yr(-1). In addition, both methane (CH4) and carbon monoxide (CO) concentrations were also higher in 2007. Over the oceans, global SST during 2007 showed significant departures from the 1971-2000 climatology. Annual average upper-ocean heat content anomalies declined between 2006 and 2007 in the eastern equatorial Pacific and increased in off-equatorial bands in that ocean basin. These changes were consistent with the transition from an El Nino in 2006 to a La Nina in 2007. The global mean see level anomaly (SLA) in 2007 was 1.1 mm higher than in 2006, which is about one standard deviation below what would be excepted from the 15-yr trend value of 3.4 mm yr(-1). In the tropics, the Atlantic hurricane season was near normal in 2007, although slightly more active than in 2006. In the north and south Indian Ocean Basins, both the seasonal totals and intensity of tropical cyclones (TC) were significantly above average, and included two Saffir-Simpson category 5 TCs in the north Indian Ocean and a world record rainfall amount of 5510 mm over a 3-8 day period on the island of Reunion in the south Indian Ocean. In the polar regions 2007 was the warmest on record for the Arctic, and continued a general, Arctic-wide warming trend that began in the mid-1960s. An unusually strong high pressure region in the Beaufort Sea during summer contributed to a record minimum Arctic sea ice cover in September. Measurements of the mass balance of glaciers and ice caps indicate that in most of the world, glaciers and ice caps indicate that in most of the world, glaciers are shrinking in mass. The Greenland ice sheet experienced records in both the duration and extent of the summer surface melt. From the continental scale as a whole the Antarctic was warmer than average in 2007, although the Antarctic Peninsula was considerably cooler than average. The size of the ozone hole was below the record levels of 2006, and near the average of the past 15 yr, due to warmer springtime temperatures in the Antarctic stratosphere. |
|||||
BibTeX:
@article{levinson08a,
author = {Levinson, D. H. and Lawrimore, J. H.},
title = {State of the climate in 2007},
journal = {BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY},
year = {2008},
volume = {89},
number = {7, S},
pages = {10+},
doi = {https://doi.org/10.1175/BAMS-89-7-StateoftheClimate}
}
|
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| Li, Z.Q., Xie, Y.S., Gu, X.F., Li, D.H., Li, K.T., Zhang, X.Y., Wu, J. and Xiong, W. | Atmospheric column CO2 measurement from a new automatic ground-based sun photometer in Beijing from 2010 to 2012 | 2012 | ATMOSPHERIC MEASUREMENT TECHNIQUES DISCUSSION | article | |
| Abstract: Carbon dioxide is generally regarded as the most important greenhouse gas affecting global warming. Many researches have been conducted to measure atmospheric CO 2 concentration, analyze CO 2 variation on both seasonal and interannual scales and predict … | |||||
BibTeX:
@article{li12a,
author = {Z. Q. Li and Y. S. Xie and X. F. Gu and D. H. Li and K. T. Li and X. Y. Zhang and J. Wu and W. Xiong},
title = {Atmospheric column CO2 measurement from a new automatic ground-based sun photometer in Beijing from 2010 to 2012},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES DISCUSSION},
year = {2012}
}
|
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| Li, C., Zhou, L., Qin, D., Liu, L., Qin, X., Wang, Z. and Ren, J. | Preliminary study of atmospheric carbon dioxide in a glacial area of the Qilian Mountains, west China | {2014} | ATMOSPHERIC ENVIRONMENT Vol. {99}, pp. 485-490 |
article | DOI |
| Abstract: Carbon dioxide represents the most important contribution to increased radiative forcing. The preliminary results of the atmospheric carbon dioxide mole fraction from the glacial region in the Qilian Mountains area, in the northeast of the Qinghai-Xizang (Tibetan) Plateau during July, 2009 to October, 2012 are presented. The annual mean CO2 mole fractions in 2010 and 2011 were 388.4 +/- 2.7 ppm and 392.7 +/- 2.6 ppm, respectively. These values were consistent with the CO2 mole fractions from the WMO/GAW stations located at high altitudes. However, both the concentration and seasonal variation were significantly lower than stations located adjacent to megacities or economic centers at low latitudes in eastern China. Shorter durations of photosynthesis of the alpine vegetation system that exceeded respiration were detected at the Qilian Mountains glacial area. The annual mean increase during the sampling period was 2.9 ppm yr(-1) and this value was higher than the global mean values. Anthropogenic activities in the cities adjacent to the Qilian Mountains may have important influences on the CO2 mole fractions, especially in summer, when north and north-north-west winds are typical. (C) 2014 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{li14a,
author = {Li, Chuanjin and Zhou, Lingxi and Qin, Dahe and Liu, Lixin and Qin, Xiang and Wang, Zebin and Ren, Jiawen},
title = {Preliminary study of atmospheric carbon dioxide in a glacial area of the Qilian Mountains, west China},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2014},
volume = {99},
pages = {485--490},
doi = {https://doi.org/10.1016/j.atmosenv.2014.10.020}
}
|
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| Li, R., Zhang, M., Chen, L., Kou, X. and Skorokhod, A. | CMAQ simulation of atmospheric CO2 concentration in East Asia: Comparison with GOSAT observations and ground measurements | {2017} | ATMOSPHERIC ENVIRONMENT Vol. {160}, pp. 176-185 |
article | DOI |
| Abstract: Satellite observations are widely used in global CO2 assimilations, but their quality for use in regional assimilation systems has not yet been thoroughly determined. Validation of satellite observations and model simulations of CO2 is crucial for carbon flux inversions. In this study, we focus on evaluating the uncertainties of model simulations and satellite observations. The atmospheric CO2 distribution in East Asia during 2012 was simulated using a regional chemical transport model (RAMS-CMAQ) and compared with both CO2 column density (XCO2) from the Gases Observing SATellite (GOSAT) and CO2 concentrations from the World Data Centre for Greenhouse Gases (WDCGG). The results indicate that simulated XCO2 is generally lower than GOSAT XCO2 by 1.19 ppm on average, and their monthly differences vary from 0.05 to 2.84 ppm, with the corresponding correlation coefficients ranging between 0.1 and 0.67. CMAQ simulations are good to capture the CO2 variation as ground-based observations, and their correlation coefficients are from 0.62 to 0.93, but the average value of CMAQ simulation is 2.4 ppm higher than ground-based observation. Thus, we inferred that the GOSAT retrievals may overestimate XCO2, which is consistent with the validation of GOSAT XCO2 using Total Carbon Column Observing Network measurements. The near-surface CO2 concentration was obviously overestimated in GOSAT XCO2. Compared with the relatively small difference between CMAQ and GOSAT XCO2, the large difference in CO2 near surface or their vertical profiles indicates more improvements are needed to reduce the uncertainties in both satellite observations and model simulations. (C) 2017 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{li17a,
author = {Li, Rong and Zhang, Meigen and Chen, Liangfu and Kou, Xingxia and Skorokhod, Andrei},
title = {CMAQ simulation of atmospheric CO2 concentration in East Asia: Comparison with GOSAT observations and ground measurements},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2017},
volume = {160},
pages = {176--185},
doi = {https://doi.org/10.1016/j.atmosenv.2017.03.056}
}
|
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| Li, X., Hu, X.-M., Ma, Y., Wang, Y., Li, L. and Zhao, Z. | Impact of planetary boundary layer structure on the formation and evolution of air-pollution episodes in Shenyang, Northeast China | {2019} | ATMOSPHERIC ENVIRONMENT Vol. {214} |
article | DOI |
| Abstract: The impact of the planetary boundary layer (PBL) structure on air pollution in Northeast China, where frequently experiences air pollution episodes in autumn and winter, is not well understood due to a lack of observations. In this study, four pollution episodes during autumn and winter of 2016 at Shenyang, a provincial capital city in Northeast China, were examined to investigate the linkage between the PBL structure and air pollution using meteorological sounding data and LiDAR-retrieved profiles of aerosol extinction coefficients. We also conducted a tracer simulation using the Weather Research and Forecasting model with Chemistry (WRF-Chem) to demonstrate the transport and vertical mixing of air pollutants in the PBL. The results indicated that a stable, moist and shallow surface layer (< 400 m) formed and remained at night due to strong surface radiative cooling after a steep decline of temperature during the first air-pollution episode (EP1, from 12:00 Local Time (LT) on November 26 to 07:00 LT on November 27). Stable stratification and stagnant winds contributed to the increase of surface pollutant concentrations in EP1. Strong surface potential temperature inversion and enhanced local emissions during evening rush hour resulted in the formation of EP2 (13:00-23:00 LT on December 2). Observations and modelling results revealed that large amount of pollutants were transported by the southerly nocturnal low-level jets from the North China Plain to Shenyang after EP2. These pollutants were trapped in the residue layer at night and then mixed to the surface after sunrise due to convective turbulence, leading to the formation of EP3 (06:00-23:00 LT on December 3). EP4 (03:00-14:00 LT on December 4) occurred in the convergence zone ahead of an approaching trough. Low wind speed (< 6 m s(-1)) and high relative humidity (> 80%) in the PBL enhanced the deterioration of air quality near the surface. | |||||
BibTeX:
@article{li19a,
author = {Li, Xiaolan and Hu, Xiao-Ming and Ma, Yanjun and Wang, Yangfeng and Li, Liguang and Zhao, Ziqi},
title = {Impact of planetary boundary layer structure on the formation and evolution of air-pollution episodes in Shenyang, Northeast China},
journal = {ATMOSPHERIC ENVIRONMENT},
publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
year = {2019},
volume = {214},
doi = {https://doi.org/10.1016/j.atmosenv.2019.116850}
}
|
|||||
| Li, X., Hu, X.-M., Cai, C., Jia, Q., Zhang, Y., Liu, J., Xue, M., Xu, J., Wen, R. and Crowell, S.M.R. | Terrestrial CO2 Fluxes, Concentrations, Sources and Budget in Northeast China: Observational and Modeling Studies | {2020} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {125}({6}) |
article | DOI URL |
| Abstract: CO2 fluxes and concentrations are not well understood in Northeast China, where dominant land surface types are mixed forest and cropland. Here, we analyzed the CO2 fluxes and concentrations using observations and the Weather Research and Forecasting model coupled with the Vegetation Photosynthesis and Respiration Model (WRF-VPRM). We also used WRF-VPRM outputs to examine CO2 transport/dispersion and budgets. Finally, we investigated the uncertainties of simulating CO2 fluxes related to four VPRM parameters (including maximum light use efficiency, photosynthetically active radiation half-saturation value, and two respiration parameters) using off-line ensemble simulations. The results indicated that mixed forests acted as a larger CO2 source and sink than rice paddies in 2016 due to a longer growth period and stronger ecosystem respiration, although measured minimum daily mean net ecosystem exchange (NEE) was smaller at rice paddy (-10 mu mol.m(-2).s(-1)) than at mixed forest (-6.5 mu mol.m(-2).s(-1)) during the growing season (May-September). The monthly fluctuation of column-averaged CO2 concentrations (XCO2) exceeded 10 ppm in Northeast China during 2016. The large summertime biogenic sinks offset about 70% of anthropogenic contribution of XCO2 in this region. WRF-VPRM modeling successfully captured seasonal and episodic variations of NEE and CO2 concentrations; however, NEE in mixed forest was overestimated during daytime, mainly due to the uncertainties of VPRM parameters, especially maximum light use efficiency. These findings suggest that the WRF-VPRM modeling framework will provide greater understanding of the natural and anthropogenic contributions to the carbon cycle in China, especially after calibration of parameters that control biogenic fluxes. | |||||
BibTeX:
@article{li20a,
author = {Li, Xiaolan and Hu, Xiao-Ming and Cai, Changjie and Jia, Qingyu and Zhang, Yao and Liu, Jingmiao and Xue, Ming and Xu, Jianming and Wen, Rihong and Crowell, Sean M. R.},
title = {Terrestrial CO2 Fluxes, Concentrations, Sources and Budget in Northeast China: Observational and Modeling Studies},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {125},
number = {6},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD031686},
doi = {https://doi.org/10.1029/2019JD031686}
}
|
|||||
| Li, J., Kug, J. and Mao, J. | The influence of atmospheric intraseasonal oscillations on terrestrial biospheric CO2 fluxes in Southeast China Forest | 2021 | CLIMATIC DYNAMICS | article | URL |
| Abstract: With its strong carbon sequestration capacity and significantly expanding trend, forest over southeast China (SEC) is an important biospheric carbon sink. As intraseasonal oscillation (ISO) is a remarkable variability of the East Asian summer monsoon---the major climate … | |||||
BibTeX:
@article{li21a,
author = {Jianying Li and Jong‐Seong Kug and Jiangyu Mao},
title = {The influence of atmospheric intraseasonal oscillations on terrestrial biospheric CO2 fluxes in Southeast China Forest},
journal = {CLIMATIC DYNAMICS},
year = {2021},
url = {https://www.researchgate.net/profile/Jianying-Li-4/publication/349664408_The_influence_of_atmospheric_intraseasonal_oscillations_on_terrestrial_biospheric_CO2_fluxes_in_Southeast_China_Forest/links/603c917092851c4ed5a4ff25/The-influence-of-atmospheric-intraseasonal-oscillations-on-terrestrial-biospheric-CO2-fluxes-in-Southeast-China-Forest.pdf}
}
|
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| Li, X., Ma, H., Ran, Y., Wang, X., Zhu, G., Liu, F., He, H., Zhang, Z. and Huang, C. | Terrestrial carbon cycle model-data fusion: Progress and challenges | 2021 | SCIENCE CHINA-EARTH SCIENCES Vol. 64(10), pp. 1645-1657 |
article | DOI |
| Abstract: The terrestrial carbon cycle is an important component of global biogeochemical cycling and is closely related to human well-being and sustainable development. However, large uncertainties exist in carbon cycle simulations and observations. Model-data fusion is a powerful technique that combines models and observational data to minimize the uncertainties in terrestrial carbon cycle estimation. In this paper, we comprehensively overview the sources and characteristics of the uncertainties in terrestrial carbon cycle models and observations. We present the mathematical principles of two model-data fusion methods, i.e., data assimilation and parameter estimation, both of which essentially achieve the optimal fusion of a model with observational data while considering the respective errors in the model and in the observations. Based upon reviewing the progress in carbon cycle models and observation techniques in recent years, we have highlighted the major challenges in terrestrial carbon cycle model-data fusion research, such as the ``equifinality'' of models, the identifiability of model parameters, the estimation of representativeness errors in surface fluxes and remote sensing observations, the potential role of the posterior probability distribution of parameters obtained from sensitivity analysis in determining the error covariance matrixes of the models, and opportunities that emerge by assimilating new remote sensing observations, such as solar-induced chlorophyll fluorescence. It is also noted that the synthesis of multisource observations into a coherent carbon data assimilation system is by no means an easy task, yet a breakthrough in this bottleneck is a prerequisite for the development of a new generation of global carbon data assimilation systems. This article also highlights the importance of carbon cycle data assimilation systems to generate reliable and physically consistent terrestrial carbon cycle reanalysis data products with high spatial resolution and long-term time series. These products are critical to the accurate estimation of carbon cycles at the global and regional scales and will help future carbon management strategies meet the goals of carbon neutrality. |
|||||
BibTeX:
@article{li21b,
author = {Li, Xin and Ma, Hanqing and Ran, Youhua and Wang, Xufeng and Zhu, Gaofeng and Liu, Feng and He, Honglin and Zhang, Zhen and Huang, Chunlin},
title = {Terrestrial carbon cycle model-data fusion: Progress and challenges},
journal = {SCIENCE CHINA-EARTH SCIENCES},
year = {2021},
volume = {64},
number = {10},
pages = {1645-1657},
doi = {https://doi.org/10.1007/s11430-020-9800-3}
}
|
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| Li, L., Lei, L., Song, H., Zeng, Z. and He, Z. | Spatiotemporal Geostatistical Analysis and Global Mapping of CH4 Columns from GOSAT Observations | 2022 | REMOTE SENSING Vol. 14(3) |
article | DOI |
| Abstract: Methane (CH4) is one of the most important greenhouse gases causing the global warming effect. The mapping data of atmospheric CH4 concentrations in space and time can help us better to understand the characteristics and driving factors of CH4 variation as to support the actions of CH4 emission reduction for preventing the continuous increase of atmospheric CH4 concentrations. In this study, we applied a spatiotemporal geostatistical analysis and prediction to develop an approach to generate the mapping CH4 dataset (Mapping-XCH4) in 1 degrees grid and three days globally using column averaged dry air mole fraction of CH4 (XCH4) data derived from observations of the Greenhouse Gases Observing Satellite (GOSAT) from April 2009 to April 2020. Cross-validation for the spatiotemporal geostatistical predictions showed better correlation coefficient of 0.97 and a mean absolute prediction error of 7.66 ppb. The standard deviation is 11.42 ppb when comparing the Mapping-XCH4 data with the ground measurements from the total carbon column observing network (TCCON). Moreover, we assessed the performance of this Mapping-XCH4 dataset by comparing with the XCH4 simulations from the CarbonTracker model and primarily investigating the variations of XCH4 from April 2009 to April 2020. The results showed that the mean annual increase in XCH4 was 7.5 ppb/yr derived from Mapping-XCH4, which was slightly greater than 7.3 ppb/yr from the ground observational network during the past 10 years from 2010. XCH4 is larger in South Asia and eastern China than in the other regions, which agrees with the XCH4 simulations. The Mapping-XCH4 shows a significant linear relationship and a correlation coefficient of determination (R-2) of 0.66, with EDGAR emission inventories over Monsoon Asia. Moreover, we found that Mapping-XCH4 could detect the reduction of XCH4 in the period of lockdown from January to April 2020 in China, likely due to the COVID-19 pandemic. In conclusion, we can apply GOSAT observations over a long period from 2009 to 2020 to generate a spatiotemporally continuous dataset globally using geostatistical analysis. This long-term Mpping-XCH4 dataset has great potential for understanding the spatiotemporal variations of CH4 concentrations induced by natural processes and anthropogenic emissions at a global and regional scale. |
|||||
BibTeX:
@article{li22a,
author = {Li, Luman and Lei, Liping and Song, Hao and Zeng, Zhaocheng and He, Zhonghua},
title = {Spatiotemporal Geostatistical Analysis and Global Mapping of CH4 Columns from GOSAT Observations},
journal = {REMOTE SENSING},
year = {2022},
volume = {14},
number = {3},
doi = {https://doi.org/10.3390/rs14030654}
}
|
|||||
| Lian, J., Breon, F.-M., Broquet, G., Lauvaux, T., Zheng, B., Ramonet, M., Xueref-Remy, I., Kotthaus, S., Haeffelin, M. and Ciais, P. | Sensitivity to the sources of uncertainties in the modeling of atmospheric CO2 concentration within and in the vicinity of Paris | 2021 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 21(13), pp. 10707-10726 |
article | DOI |
| Abstract: The top-down atmospheric inversion method that couples atmospheric CO2 observations with an atmospheric transport model has been used extensively to quantify CO2 emissions from cities. However, the potential of the method is limited by several sources of misfits between the measured and modeled CO2 that are of different origins than the targeted CO2 emissions. This study investigates the critical sources of errors that can compromise the estimates of the city-scale emissions and identifies the signal of emissions that has to be filtered when doing inversions. A set of 1-year forward simulations is carried out using the WRF-Chem model at a horizontal resolution of 1 km focusing on the Paris area with different anthropogenic emission inventories, physical parameterizations, and CO2 boundary conditions. The simulated CO2 concentrations are compared with in situ observations from six continuous monitoring stations located within Paris and its vicinity. Results highlight large nighttime model-data misfits, especially in winter within the city, which are attributed to large uncertainties in the diurnal profile of anthropogenic emissions as well as to errors in the vertical mixing near the surface in the WRF-Chem model. The nighttime biogenic respiration to the CO2 concentration is a significant source of modeling errors during the growing season outside the city. When winds are from continental Europe and the CO2 concentration of incoming air masses is influenced by remote emissions and large-scale biogenic fluxes, differences in the simulated CO2 induced by the two different boundary conditions (CAMS and CarbonTracker) can be of up to 5 ppm. Nevertheless, our results demonstrate the potential of our optimal CO2 atmospheric modeling system to be utilized in atmospheric inversions of CO2 emissions over the Paris metropolitan area. We evaluated the model performances in terms of wind, vertical mixing, and CO2 model-data mismatches, and we developed a filtering algorithm for outliers due to local contamination and unfavorable meteorological conditions. Analysis of model-data misfit indicates that future inversions at the mesoscale should only use afternoon urban CO2 measurements in winter and suburban measurements in summer. Finally, we determined that errors related to CO2 boundary conditions can be overcome by including distant background observations to constrain the boundary inflow or by assimilating CO2 gradients of upwind-downwind stations rather than by assimilating absolute CO2 concentrations. |
|||||
BibTeX:
@article{lian21a,
author = {Lian, Jinghui and Breon, Francois-Marie and Broquet, Gregoire and Lauvaux, Thomas and Zheng, Bo and Ramonet, Michel and Xueref-Remy, Irene and Kotthaus, Simone and Haeffelin, Martial and Ciais, Philippe},
title = {Sensitivity to the sources of uncertainties in the modeling of atmospheric CO2 concentration within and in the vicinity of Paris},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2021},
volume = {21},
number = {13},
pages = {10707-10726},
doi = {https://doi.org/10.5194/acp-21-10707-2021}
}
|
|||||
| Liang, M.-C., Mahata, S., Laskar, A.H. and Bhattacharya, S.K. | Spatiotemporal Variability of Oxygen Isotope Anomaly in near Surface Air CO2 over Urban, Semi-Urban and Ocean Areas in and around Taiwan | {2017} | AEROSOL AND AIR QUALITY RESEARCH Vol. {17}({3}), pp. 706-720 |
article | DOI |
| Abstract: The most commonly used tracers to probe the atmospheric and biogeochemical cycles of CO2 are (OCO)-O-16-C-12-O-16, (OCO)-O-16-C-13-O-16, and (OCO)-O-16-C-12-O-18. Considering the number and diversity of sources and sinks affecting CO2, these tracers are not always sufficient to constrain the fluxes of CO2 between the atmosphere and biosphere/hydrosphere. In this context, (OCO)-O-16-C-12-O-17 species was introduced but has rarely been used due to difficulties associated with its accurate measurement in natural samples. This tracer, expressed as an abundance anomaly in O-17, defined by Delta O-17 = ln(1 + delta O-17) - 0.516 x ln(1 + delta O-18) can independently constrain the fluxes associated with the terrestrial processes. The advantage of utilizing Delta O-17 over delta O-18 alone lies on the sensitivity of the former to the rates of biogeochemical processes involving multiple water reservoirs with spatial and temporal isotopic heterogeneities. To employ all the three oxygen isotopes for estimating fluxes of CO2, sources and processes affecting their partitioning have to be identified and quantified. Here, we measured Delta O-17 values in near surface atmospheric CO2 from Taiwan in urban and semi-urban areas and over the South China Sea. Strong spatiotemporal variation was seen, with an average Delta O-17 value of 0.332% and a mean variation of 0.043% (relative to V-SMOW; 1-sigma standard deviation for a total of 140 samples). The large variation reflects combinations of distinct air masses carrying CO2 from sources having different Delta O-17 values: negative from combustion emissions, positive from the stratosphere, and a positive water-CO2 equilibration value from isotope exchange with leaf/soil/ocean waters. We observed that the variation of the semi-urban Delta O-17 values is largely affected by local biogeochemistry and stratospheric intrusion with only minor influence from anthropogenic emissions. This is the first oxygen anomaly study for near surface CO2 covering diverse source characteristics and has enormous potential in air CO2 source identification and constraining the global carbon budget. |
|||||
BibTeX:
@article{liang17a,
author = {Liang, Mao-Chang and Mahata, Sasadhar and Laskar, Amzad H. and Bhattacharya, Sourendra K.},
title = {Spatiotemporal Variability of Oxygen Isotope Anomaly in near Surface Air CO2 over Urban, Semi-Urban and Ocean Areas in and around Taiwan},
journal = {AEROSOL AND AIR QUALITY RESEARCH},
year = {2017},
volume = {17},
number = {3},
pages = {706--720},
doi = {https://doi.org/10.4209/aaqr.2016.04.0171}
}
|
|||||
| Lin, J.C., Mallia, D.V., Wu, D. and Stephens, B.B. | How can mountaintop CO2 observations be used to constrain regional carbon fluxes? | {2017} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {17}({9}), pp. 5561-5581 |
article | DOI |
| Abstract: Despite the need for researchers to understand terrestrial biospheric carbon fluxes to account for carbon cycle feedbacks and predict future CO2 concentrations, knowledge of these fluxes at the regional scale remains poor. This is particularly true in mountainous areas, where complex meteorology and lack of observations lead to large uncertainties in carbon fluxes. Yet mountainous regions are often where significant forest cover and biomass are found - i.e., areas that have the potential to serve as carbon sinks. As CO2 observations are carried out in mountainous areas, it is imperative that they are properly interpreted to yield information about carbon fluxes. In this paper, we present CO2 observations at three sites in the mountains of the western US, along with atmospheric simulations that attempt to extract information about biospheric carbon fluxes from the CO2 observations, with emphasis on the observed and simulated diurnal cycles of CO2. We show that atmospheric models can systematically simulate the wrong diurnal cycle and significantly misinterpret the CO2 observations, due to erroneous atmospheric flows as a result of terrain that is misrepresented in the model. This problem depends on the selected vertical level in the model and is exacerbated as the spatial resolution is degraded, and our results indicate that a fine grid spacing of similar to 4 km or less may be needed to simulate a realistic diurnal cycle of CO2 for sites on top of the steep mountains examined here in the American Rockies. In the absence of higher resolution models, we recommend coarse-scale models to focus on assimilating afternoon CO2 observations on mountaintop sites over the continent to avoid misrepresentations of nocturnal transport and influence. |
|||||
BibTeX:
@article{lin17a,
author = {Lin, John C. and Mallia, Derek V. and Wu, Dien and Stephens, Britton B.},
title = {How can mountaintop CO2 observations be used to constrain regional carbon fluxes?},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2017},
volume = {17},
number = {9},
pages = {5561--5581},
doi = {https://doi.org/10.5194/acp-17-5561-2017}
}
|
|||||
| Lin, X., Rogers, B.M., Sweeney, C., Chevallier, F., Arshinov, M., Dlugokencky, E., Machida, T., Sasakawa, M., Tans, P. and Keppel-Aleks, G. | Siberian and temperate ecosystems shape Northern Hemisphere atmospheric CO2 seasonal amplification | {2020} | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Vol. {117}({35}), pp. {21079-21087} |
article | DOI URL |
| Abstract: The amplitude of the atmospheric CO2 seasonal cycle has increased by 30 to 50% in the Northern Hemisphere (NH) since the 1960s, suggesting widespread ecological changes in the northern extratropics. However, substantial uncertainty remains in the continental and regional drivers of this prominent amplitude increase. Here we present a quantitative regional attribution of CO2 seasonal amplification over the past 4 decades, using a tagged atmospheric transport model prescribed with observationally constrained fluxes. We find that seasonal flux changes in Siberian and temperate ecosystems together shape the observed amplitude increases in the NH. At the surface of northern high latitudes, enhanced seasonal carbon exchange in Siberia is the dominant contributor (followed by temperate ecosystems). Arctic-boreal North America shows much smaller changes in flux seasonality and has only localized impacts. These continental contrasts, based on an atmospheric approach, corroborate heterogeneous vegetation greening and browning trends from field and remote-sensing observations, providing independent evidence for regionally divergent ecological responses and carbon dynamics to global change drivers. Over surface midlatitudes and throughout the midtroposphere, increased seasonal carbon exchange in temperate ecosystems is the dominant contributor to CO2 amplification, albeit with considerable contributions from Siberia. Representing the mechanisms that control the high-latitude asymmetry in flux amplification found in this study should be an important goal for mechanistic land surface models moving forward. | |||||
BibTeX:
@article{lin20a,
author = {Lin, Xin and Rogers, Brendan M. and Sweeney, Colm and Chevallier, Frederic and Arshinov, Mikhail and Dlugokencky, Edward and Machida, Toshinobu and Sasakawa, Motoki and Tans, Pieter and Keppel-Aleks, Gretchen},
title = {Siberian and temperate ecosystems shape Northern Hemisphere atmospheric CO2 seasonal amplification},
journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
publisher = {NATL ACAD SCIENCES},
year = {2020},
volume = {117},
number = {35},
pages = {21079--21087},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.pnas.org/content/117/35/21079.short},
doi = {https://doi.org/10.1073/pnas.1914135117}
}
|
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| Lin, J. and Qian, T. | Earth's Climate History from 4.5 Billion Years to One Minute | 2022 | ATMOSPHERE-OCEAN Vol. 60(3-4, SI), pp. 188-232 |
article | DOI |
| Abstract: Earth's climate history is important for understanding the dynamics and feedbacks of the climate system. However, atmospheric sciences generally focus on shorter timescales, while geological sciences focus on longer timescales, but a unified picture is desired. This paper reviews the observations of Earth's climate history from 4.5 billion years to one minute with emphasis on temperature, sea level, and atmospheric carbon dioxide. Earth's climate history shows dominant climate modes such as the supercontinent cycles, interglacial cycles, millennial cycles, multi-decadal oscillation, interannual oscillation, seasonal cycle and diurnal cycle. The amplitudes of the dominant climate variability generally decrease from the billion-year timescales to interannual timescales, then significantly increase at subannual to diurnal timescales. |
|||||
BibTeX:
@article{lin22a,
author = {Lin, Jialin and Qian, Taotao},
title = {Earth's Climate History from 4.5 Billion Years to One Minute},
journal = {ATMOSPHERE-OCEAN},
year = {2022},
volume = {60},
number = {3-4, SI},
pages = {188-232},
doi = {https://doi.org/10.1080/07055900.2022.2082914}
}
|
|||||
| Lindqvist, H., O'Dell, C.W., Basu, S., Boesch, H., Chevallier, F., Deutscher, N., Feng, L., Fisher, B., Hase, F., Inoue, M., Kivi, R., Morino, I., Palmer, P.I., Parker, R., Schneider, M., Sussmann, R. and Yoshida, Y. | Does GOSAT capture the true seasonal cycle of carbon dioxide? | {2015} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {15}({22}), pp. 13023-13040 |
article | DOI |
| Abstract: The seasonal cycle accounts for a dominant mode of total column CO2 (XCO2) annual variability and is connected to CO2 uptake and release; it thus represents an important quantity to test the accuracy of the measurements from space. We quantitatively evaluate the XCO2 seasonal cycle of the Greenhouse Gases Observing Satellite (GOSAT) observations from the Atmospheric CO2 Observations from Space (ACOS) retrieval system and compare average regional seasonal cycle features to those directly measured by the Total Carbon Column Observing Network (TCCON). We analyse the mean seasonal cycle amplitude, dates of maximum and minimum XCO2, as well as the regional growth rates in XCO2 through the fitted trend over several years. We find that GOSAT/ACOS captures the seasonal cycle amplitude within 1.0 ppm accuracy compared to TCCON, except in Europe, where the difference exceeds 1.0 ppm at two sites, and the amplitude captured by GOSAT/ACOS is generally shallower compared to TCCON. This bias over Europe is not as large for the other GOSAT retrieval algorithms (NIES v02.21, RemoTeC v2.35, UoL v5.1, and NIES PPDF-S v.02.11), al-though they have significant biases at other sites. We find that the ACOS bias correction partially explains the shallow amplitude over Europe. The impact of the co-location method and aerosol changes in the ACOS algorithm were also tested and found to be few tenths of a ppm and mostly non-systematic. We find generally good agreement in the date of minimum XCO2 between ACOS and TCCON, but ACOS generally infers a date of maximum XCO2 2-3 weeks later than TCCON. We further analyse the latitudinal dependence of the seasonal cycle amplitude throughout the Northern Hemisphere and compare the dependence to that predicted by current optimized models that assimilate in situ measurements of CO2. In the zonal averages, models are consistent with the GOSAT amplitude to within 1.4 ppm, depending on the model and latitude. We also show that the seasonal cycle of XCO2 depends on longitude especially at the mid-latitudes: the amplitude of GOSAT XCO2 doubles from western USA to East Asia at 45-50 degrees N, which is only partially shown by the models. In general, we find that model-to-model differences can be larger than GOSAT-to-model differences. These results suggest that GOSAT/ACOS retrievals of the XCO2 seasonal cycle may be sufficiently accurate to evaluate land surface models in regions with significant discrepancies between the models. |
|||||
BibTeX:
@article{lindqvist15a,
author = {Lindqvist, H. and O'Dell, C. W. and Basu, S. and Boesch, H. and Chevallier, F. and Deutscher, N. and Feng, L. and Fisher, B. and Hase, F. and Inoue, M. and Kivi, R. and Morino, I. and Palmer, P. I. and Parker, R. and Schneider, M. and Sussmann, R. and Yoshida, Y.},
title = {Does GOSAT capture the true seasonal cycle of carbon dioxide?},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2015},
volume = {15},
number = {22},
pages = {13023--13040},
doi = {https://doi.org/10.5194/acp-15-13023-2015}
}
|
|||||
| Liu, J., Fung, I., Kalnay, E., Kang, J.-S., Olsen, E.T. and Chen, L. | Simultaneous assimilation of AIRS Xco(2) and meteorological observations in a carbon climate model with an ensemble Kalman filter | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {117} |
article | DOI |
| Abstract: This study is our first step toward the generation of 6 hourly 3-D CO2 fields that can be used to validate CO2 forecast models by combining CO2 observations from multiple sources using ensemble Kalman filtering. We discuss a procedure to assimilate Atmospheric Infrared Sounder (AIRS) column-averaged dry-air mole fraction of CO2 (Xco(2)) in conjunction with meteorological observations with the coupled Local Ensemble Transform Kalman Filter (LETKF)-Community Atmospheric Model version 3.5. We examine the impact of assimilating AIRS Xco(2) observations on CO2 fields by comparing the results from the AIRS-run, which assimilates both AIRS Xco(2) and meteorological observations, to those from the meteor-run, which only assimilates meteorological observations. We find that assimilating AIRS Xco(2) results in a surface CO2 seasonal cycle and the N-S surface gradient closer to the observations. When taking account of the CO2 uncertainty estimation from the LETKF, the CO2 analysis brackets the observed seasonal cycle. Verification against independent aircraft observations shows that assimilating AIRS Xco(2) improves the accuracy of the CO2 vertical profiles by about 0.5-2 ppm depending on location and altitude. The results show that the CO2 analysis ensemble spread at AIRS Xco(2) space is between 0.5 and 2 ppm, and the CO2 analysis ensemble spread around the peak level of the averaging kernels is between 1 and 2 ppm. This uncertainty estimation is consistent with the magnitude of the CO2 analysis error verified against AIRS Xco(2) observations and the independent aircraft CO2 vertical profiles. |
|||||
BibTeX:
@article{liu12a,
author = {Liu, Junjie and Fung, Inez and Kalnay, Eugenia and Kang, Ji-Sun and Olsen, Edward T. and Chen, Luke},
title = {Simultaneous assimilation of AIRS Xco(2) and meteorological observations in a carbon climate model with an ensemble Kalman filter},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2011JD016642}
}
|
|||||
| Liu, Z., Bambha, R.P., Pinto, J.P., Zeng, T., Boylan, J., Huang, M., Lei, H., Zhao, C., Liu, S., Mao, J., Schwalm, C.R., Shi, X., Wei, Y. and Michelsen, H.A. | Toward verifying fossil fuel CO2 emissions with the CMAQ model: Motivation, model description and initial simulation | {2014} | JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION Vol. {64}({4}), pp. 419-435 |
article | DOI |
| Abstract: Motivated by the question of whether and how a state-of-the-art regional chemical transport model (CTM) can facilitate characterization of CO2 spatiotemporal variability and verify CO2 fossil-fuel emissions, we for the first time applied the Community Multiscale Air Quality (CMAQ) model to simulate CO2. This paper presents methods, input data, and initial results for CO2 simulation using CMAQ over the contiguous United States in October 2007. Modeling experiments have been performed to understand the roles of fossil-fuel emissions, biosphere-atmosphere exchange, and meteorology in regulating the spatial distribution of CO2 near the surface over the contiguous United States. Three sets of net ecosystem exchange (NEE) fluxes were used as input to assess the impact of uncertainty of NEE on CO2 concentrations simulated by CMAQ. Observational data from six tall tower sites across the country were used to evaluate model performance. In particular, at the Boulder Atmospheric Observatory (BAO), a tall tower site that receives urban emissions from Denver, CO, the CMAQ model using hourly varying, high-resolution CO2 fossil-fuel emissions from the Vulcan inventory and CarbonTracker optimized NEE reproduced the observed diurnal profile of CO2 reasonably well but with a low bias in the early morning. The spatial distribution of CO2 was found to correlate with NOx, SO2, and CO, because of their similar fossil-fuel emission sources and common transport processes. These initial results from CMAQ demonstrate the potential of using a regional CTM to help interpret CO2 observations and understand CO2 variability in space and time. The ability to simulate a full suite of air pollutants in CMAQ will also facilitate investigations of their use as tracers for CO2 source attribution. This work serves as a proof of concept and the foundation for more comprehensive examinations of CO2 spatiotemporal variability and various uncertainties in the future. Implications: Atmospheric CO2 has long been modeled and studied on continental to global scales to understand the global carbon cycle. This work demonstrates the potential of modeling and studying CO2 variability at fine spatiotemporal scales with CMAQ, which has been applied extensively, to study traditionally regulated air pollutants. The abundant observational records of these air pollutants and successful experience in studying and reducing their emissions may be useful for verifying CO2 emissions. Although there remains much more to further investigate, this work opens up a discussion on whether and how to study CO2 as an air pollutant. |
|||||
BibTeX:
@article{liu14a,
author = {Liu, Zhen and Bambha, Ray P. and Pinto, Joseph P. and Zeng, Tao and Boylan, Jim and Huang, Maoyi and Lei, Huimin and Zhao, Chun and Liu, Shishi and Mao, Jiafu and Schwalm, Christopher R. and Shi, Xiaoying and Wei, Yaxing and Michelsen, Hope A.},
title = {Toward verifying fossil fuel CO2 emissions with the CMAQ model: Motivation, model description and initial simulation},
journal = {JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION},
year = {2014},
volume = {64},
number = {4},
pages = {419--435},
doi = {https://doi.org/10.1080/10962247.2013.816642}
}
|
|||||
| Liu, S., Zhuang, Q., He, Y., Noormets, A., Chen, J. and Gu, L. | Evaluating atmospheric CO2 effects on gross primary productivity and net ecosystem exchanges of terrestrial ecosystems in the conterminous United States using the AmeriFlux data and an artificial neural network approach | {2016} | AGRICULTURAL AND FOREST METEOROLOGY Vol. {220}, pp. 38-49 |
article | DOI |
| Abstract: Quantitative understanding of regional gross primary productivity (GPP) and net ecosystem exchanges (NEE) and their responses to environmental changes are critical to quantifying the feedbacks of ecosystems to the global climate system. Numerous studies have used the eddy flux data to upscale the eddy covariance derived carbon fluxes from stand scales to regional and global scales. However, few studies incorporated atmospheric carbon dioxide (CO2) concentrations into those extrapolations. Here, we consider the effect of atmospheric CO2 using an artificial neural network (ANN) approach to upscale the AmeriFlux tower of NEE and the derived GPP to the conterminous United States. Two ANN models incorporating remote sensing variables at an 8-day time step were developed. One included CO2 as an explanatory variable and the other did not. The models were first trained, validated using eddy flux data, and then extrapolated to the region at a 0.05 degrees x 0.05 degrees (latitude x longitude) resolution from 2001 to 2006. We found that both models performed well in simulating site-level carbon fluxes. The spatially averaged annual GPP with and without considering the atmospheric CO2 were 789 and 788 g Cm-2 yr(-1), respectively (for NEE, the values were 112 and 109 g Cm-2 yr(-1), respectively). Model predictions were comparable with previous published results and MODIS GPP products. However, the difference in GPP between the two models exhibited a great spatial and seasonal variability, with an annual difference of 200 g Cm-2 yr(-1). Further analysis suggested that air temperature played an important role in determining the atmospheric CO2 effects on carbon fluxes. In addition, the simulation that did not consider atmospheric CO2 failed to detect ecosystem responses to droughts in part of the US in 2006. The study suggests that the spatially and temporally varied atmospheric CO2 concentrations should be factored into carbon quantification when scaling eddy flux data to a region. (C) 2016 Elsevier B.V. All rights reserved. |
|||||
BibTeX:
@article{liu16a,
author = {Liu, Shaoqing and Zhuang, Qianlai and He, Yujie and Noormets, Asko and Chen, Jiquan and Gu, Lianhong},
title = {Evaluating atmospheric CO2 effects on gross primary productivity and net ecosystem exchanges of terrestrial ecosystems in the conterminous United States using the AmeriFlux data and an artificial neural network approach},
journal = {AGRICULTURAL AND FOREST METEOROLOGY},
year = {2016},
volume = {220},
pages = {38--49},
doi = {https://doi.org/10.1016/j.agrformet.2016.01.007}
}
|
|||||
| Liu, M., Lei, L., Liu, D. and Zeng, Z.-C. | Geostatistical Analysis of CH4 Columns over Monsoon Asia Using Five Years of GOSAT Observations | {2016} | REMOTE SENSING Vol. {8}({5}) |
article | DOI |
| Abstract: The aim of this study is to evaluate the Greenhouse gases Observation SATellite (GOSAT) column-averaged CH4 dry air mole fraction (XCH4) data by using geostatistical analysis and conducting comparisons with model simulations and surface emissions. Firstly, we propose the use of a data-driven mapping approach based on spatio-temporal geostatistics to generate a regular and gridded mapping dataset of XCH4 over Monsoon Asia using five years of XCH4 retrievals by GOSAT from June 2009 to May 2014. The prediction accuracy of the mapping approach is assessed by using cross-validation, which results in a significantly high correlation of 0.91 and a small mean absolute prediction error of 8.77 ppb between the observed dataset and the prediction dataset. Secondly, with the mapping data, we investigate the spatial and temporal variations of XCH4 over Monsoon Asia and compare the results with previous studies on ground and other satellite observations. Thirdly, we compare the mapping XCH4 with model simulations from CarbonTracker-CH4 and find their spatial patterns very consistent, but GOSAT observations are more able to capture the local variability of XCH4. Finally, by correlating the mapping data with surface emission inventory, we find the geographical distribution of high CH4 values correspond well with strong emissions as indicated in the inventory map. Over the five-year period, the two datasets show a significant high correlation coefficient (0.80), indicating the dominant role of surface emissions in determining the distribution of XCH4 concentration in this region and suggesting a promising statistical way of constraining surface CH4 sources and sinks, which is simple and easy to implement using satellite observations over a long term period. |
|||||
BibTeX:
@article{liu16b,
author = {Liu, Min and Lei, Liping and Liu, Da and Zeng, Zhao-Cheng},
title = {Geostatistical Analysis of CH4 Columns over Monsoon Asia Using Five Years of GOSAT Observations},
journal = {REMOTE SENSING},
year = {2016},
volume = {8},
number = {5},
doi = {https://doi.org/10.3390/rs8050361}
}
|
|||||
| Liu, J., Bowman, K.W. and Lee, M. | Comparison between the Local Ensemble Transform Kalman Filter (LETKF) and 4D-Var in atmospheric CO2 flux inversion with the Goddard Earth Observing System-Chem model and the observation impact diagnostics from the LETKF [BibTeX] |
{2016} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {121}({21}), pp. 13066-13087 |
article | DOI |
BibTeX:
@article{liu16c,
author = {Liu, Junjie and Bowman, Kevin W. and Lee, Meemong},
title = {Comparison between the Local Ensemble Transform Kalman Filter (LETKF) and 4D-Var in atmospheric CO2 flux inversion with the Goddard Earth Observing System-Chem model and the observation impact diagnostics from the LETKF},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2016},
volume = {121},
number = {21},
pages = {13066--13087},
doi = {https://doi.org/10.1002/2016JD025100}
}
|
|||||
| Liu, S. | Quantifying terrestrial ecosystem carbon dynamics with mechanistically-based biogeochemistry models and in situ and remotely sensed data [BibTeX] |
2016 | School: Purdue University | phdthesis | URL |
BibTeX:
@phdthesis{liu16d,
author = {Liu, Shaoqing},
title = {Quantifying terrestrial ecosystem carbon dynamics with mechanistically-based biogeochemistry models and in situ and remotely sensed data},
school = {Purdue University},
year = {2016},
url = {http://search.proquest.com/openview/6c838317951d8ea5b5e0409c75ea25e9/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
|||||
| Liu, S., Zhuang, Q., Chen, M. and Gu, L. | Quantifying spatially and temporally explicit CO2 fertilization effects on global terrestrial ecosystem carbon dynamics [BibTeX] |
2016 | Ecosphere Vol. 7(7) |
article | DOI |
BibTeX:
@article{liu16e,
author = {Liu, Shaoqing and Zhuang, Qianlai and Chen, Min and Gu, Lianhong},
title = {Quantifying spatially and temporally explicit CO2 fertilization effects on global terrestrial ecosystem carbon dynamics},
journal = {Ecosphere},
year = {2016},
volume = {7},
number = {7},
doi = {https://doi.org/10.1002/ecs2.1391/full}
}
|
|||||
| Liu, Z., Ballantyne, A.P., Poulter, B., Anderegg, W.R.L., Li, W., Bastos, A. and Ciais, P. | Precipitation thresholds regulate net carbon exchange at the continental scale | {2018} | NATURE COMMUNICATIONS Vol. {9} |
article | DOI |
| Abstract: Understanding the sensitivity of ecosystem production and respiration to climate change is critical for predicting terrestrial carbon dynamics. Here we show that the primary control on the inter-annual variability of net ecosystem carbon exchange switches from production to respiration at a precipitation threshold between 750 and 950 mm yr(-1) in the contiguous United States. This precipitation threshold is evident across multiple datasets and scales of observation indicating that it is a robust result and provides a new scaling relationship between climate and carbon dynamics. However, this empirical precipitation threshold is not captured by dynamic global vegetation models, which tend to overestimate the sensitivity of production and underestimate the sensitivity of respiration to water availability in more mesic regions. Our results suggest that the short-term carbon balance of ecosystems may be more sensitive to respiration losses than previously thought and that model simulations may underestimate the positive carbon-climate feedbacks associated with respiration. |
|||||
BibTeX:
@article{liu18a,
author = {Liu, Zhihua and Ballantyne, Ashley P. and Poulter, Benjamin and Anderegg, William R. L. and Li, Wei and Bastos, Ana and Ciais, Philippe},
title = {Precipitation thresholds regulate net carbon exchange at the continental scale},
journal = {NATURE COMMUNICATIONS},
year = {2018},
volume = {9},
doi = {https://doi.org/10.1038/s41467-018-05948-1}
}
|
|||||
| Liu, J., Bowman, K., Parazoo, N.C., Bloom, A.A., Wunch, D., Jiang, Z., Gurney, K.R. and Schimel, D. | Detecting drought impact on terrestrial biosphere carbon fluxes over contiguous US with satellite observations | {2018} | ENVIRONMENTAL RESEARCH LETTERS Vol. {13}({9}) |
article | DOI |
| Abstract: With projections of increasing drought in the future, understanding how the natural carbon cycle responds to drought events is needed to predict the fate of the land carbon sink and future atmospheric CO2 concentrations and climate. We quantified the impacts of the 2011 and 2012 droughts on terrestrial ecosystem carbon uptake anomalies over the contiguous US (CONUS) relative to non-drought years during 2010-2015 using satellite observations and the carbon monitoring system-flux inversion modeling framework. Soilmoisture and temperature anomalies are good predictors of gross primary production anomalies (R-2 > 0.6) in summer but less so for net biosphere production (NBP) anomalies, reflecting different respiration responses. We showed that regional responses combine in complicated ways to produce the observed CONUS responses. Because of the compensating effect of the carbonflux anomalies between northern and southern CONUS in 2011 and between spring and summer in 2012, the annual NBP decreased by 0.10 +/- 0.16 GtC in 2011, and increased by 0.10 +/- 0.16 GtC in 2012 over CONUS, consistent with previous reported results. Over the 2011 and 2012 drought-impacted regions, the reductions in NBP were similar to 40% of the regional annual fossil fuel emissions, underscoring the importance of quantifying natural carbon flux variability as part of an overall observing strategy. The NBP reductions over the 2011 and 2012 CONUS drought-impacted region were opposite to the global atmospheric CO2 growth rate anomaly, implying that global atmospheric CO2 growth rate is an offsetting effect between enhanced uptake and emission, and enhancing the understanding of regional carbon-cycle climate relationship is necessary to improve the projections of future climate. |
|||||
BibTeX:
@article{liu18b,
author = {Liu, Junjie and Bowman, Kevin and Parazoo, Nicholas C. and Bloom, A. Anthony and Wunch, Debra and Jiang, Zhe and Gurney, Kevin R. and Schimel, Dave},
title = {Detecting drought impact on terrestrial biosphere carbon fluxes over contiguous US with satellite observations},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
year = {2018},
volume = {13},
number = {9},
doi = {https://doi.org/10.1088/1748-9326/aad5ef}
}
|
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| Liu, Y., Yue, T., Zhang, L., Zhao, N., Zhao, M. and Liu, Y. | Simulation and analysis of XCO2 in North China based on high accuracy surface modeling | {2018} | ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH Vol. {25}({27, SI}), pp. {27378-27392} |
article | DOI |
| Abstract: As an important cause of global warming, CO2 concentrations and their changes have aroused worldwide concern. Establishing explicit understanding of the spatial and temporal distributions of CO2 concentrations at regional scale is a crucial technical problem for climate change research. High accuracy surface modeling (HASM) is employed in this paper using the output of the CO2 concentrations from weather research and forecasting-chemistry (WRF-CHEM) as the driving fields, and the greenhouse gases observing satellite (GOSAT) retrieval XCO2 data as the accuracy control conditions to obtain high accuracy XCO2 fields. WRF-CHEM is an atmospheric chemical transport model designed for regional studies of CO2 concentrations. Verified by ground- and space-based observations, WRF-CHEM has a limited ability to simulate the conditions of CO2 concentrations. After conducting HASM, we obtain a higher accuracy distribution of the CO2 in North China than those calculated using the classical Kriging and inverse distance weighted (IDW) interpolation methods, which were often used in past studies. The cross-validation also shows that the averaging mean absolute error (MAE) of the results from HASM is 1.12 ppmv, and the averaging root mean square error (RMSE) is 1.41 ppmv, both of which are lower than those of the Kriging and IDW methods. This study also analyses the space-time distributions and variations of the XCO2 from the HASM results. This analysis shows that in February and March, there was the high value zone in the southern region of study area relating to heating in the winter and the dense population. The XCO2 concentration decreased by the end of the heating period and during the growing period of April and May, and only some relatively high value zones continued to exist. |
|||||
BibTeX:
@article{liu18c,
author = {Liu, Yu and Yue, Tianxiang and Zhang, Lili and Zhao, Na and Zhao, Miaomiao and Liu, Yi},
title = {Simulation and analysis of XCO2 in North China based on high accuracy surface modeling},
journal = {ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH},
year = {2018},
volume = {25},
number = {27, SI},
pages = {27378-27392},
doi = {https://doi.org/10.1007/s11356-018-2683-x}
}
|
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| Liu, L., Zhao, W., Wu, J., Liu, S., Teng, Y., Yang, J. and Han, X. | The Impacts of Growth and Environmental Parameters on Solar-Induced Chlorophyll Fluorescence at Seasonal and Diurnal Scales | {2019} | REMOTE SENSING Vol. {11}({17}) |
article | DOI |
| Abstract: Solar-induced chlorophyll fluorescence (SIF) is considered to be a potential indicator of photosynthesis. However, the impact of growth and environmental parameters on SIF at different time-scales remains unclear, which has greatly restricted the application of SIF in detecting photosynthesis variations. Thus, in this study, the impact of growth and environmental parameters on SIF was thoroughly clarified. Here, continuous time series of canopy SIF (760 nm, F760) over wheat and maize was measured based on an automated spectroscopy system. Meanwhile, field measurements of growth and environmental parameters were also collected using commercial-grade devices. Relationships of these parameters with F760, apparent SIF (F760/solar radiance, AF760), and SIF yield (F760/canopy radiance of 685 nm, Fy760) were analyzed using principal component analysis (PCA) and Pearson correlation to reveal their impacts on SIF. Results showed that F760 at seasonal and diurnal scales were mainly driven by solar radiation (SWR), leaf area index (LAI), chlorophyll content (Chl), mean leaf inclination angle (MTA), and relative water content (RWC). Other environmental parameters, including air temperature (Ta), relative humidity (Rh), vapor pressure deficit (VPD), and soil moisture (SM), contribute less to the variation of seasonal or diurnal F760. AF760 and Fy760 are likely to be less dependent on Ta, Rh, and VPD due to the removal of the impact from SWR, but an enhanced relationship of AF760 (and Fy760) with SM was observed, particularly under water stress. Compared with F760, wheat AF760 was better correlated to LAI and RWC as expected, while maize AF760 did not show an enhanced relationship with all growth parameters, probably due to its complicated canopy structure. The relationship of wheat Fy760 with canopy structure parameters was further reduced, except for maize measurements. Furthermore, SM-induced water stress and phenological stages should be taken into consideration when we interpret the seasonal and diurnal patterns of SIF since they were closely related to photosynthesis and plant growth (e.g., LAI in our study). To our knowledge, this is the first exploration of the impacts of growth and environmental parameters on SIF based on continuous ground measurements, not only at a seasonal scale but also at a diurnal scale. Our results could provide deep insight into the variation of SIF signals and also promote the further application of SIF in the health assessments of terrestrial ecosystems. | |||||
BibTeX:
@article{liu19a,
author = {Liu, Leizhen and Zhao, Wenhui and Wu, Jianjun and Liu, Shasha and Teng, Yanguo and Yang, Jianhua and Han, Xinyi},
title = {The Impacts of Growth and Environmental Parameters on Solar-Induced Chlorophyll Fluorescence at Seasonal and Diurnal Scales},
journal = {REMOTE SENSING},
publisher = {MDPI},
year = {2019},
volume = {11},
number = {17},
doi = {https://doi.org/10.3390/rs11172002}
}
|
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| Liu, Y., Kalnay, E., Zeng, N., Asrar, G., Chen, Z. and Jia, B. | Estimating surface carbon fluxes based on a local ensemble transform Kalman filter with a short assimilation window and a long observation window: an observing system simulation experiment test in GEOS-Chem 10.1 | {2019} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {12}({7}), pp. {2899-2914} |
article | DOI URL |
| Abstract: We developed a carbon data assimilation system to estimate surface carbon fluxes using the local ensemble transform Kalman filter (LETKF) and atmospheric transport model GEOS-Chem driven by the MERRA-1 reanalysis of the meteorological field based on the Goddard Earth Observing System model, version 5 (GEOS-5). This assimilation system is inspired by the method of Kang et al. (2011, 2012), who estimated the surface carbon fluxes in an observing system simulation experiment (OSSE) as evolving parameters in the assimilation of the atmospheric CO2, using a short assimilation window of 6 h. They included the assimilation of the standard meteorological variables, so that the ensemble provided a measure of the uncertainty in the CO2 transport. After introducing new techniques such as ``variable localization'', and increased observation weights near the surface, they obtained accurate surface carbon fluxes at grid-point resolution. We developed a new version of the local ensemble transform Kalman filter related to the ``runningin- place'' (RIP) method used to accelerate the spin-up of ensemble Kalman filter (EnKF) data assimilation (Kalnay and Yang, 2010; Wang et al., 2013; Yang et al., 2012). Like RIP, the new assimilation system uses the ``no cost smoothing'' algorithm for the LETKF (Kalnay et al., 2007b), which allows shifting the Kalman filter solution forward or backward within an assimilation window at no cost. In the new scheme a long ``observation window'' (e.g., 7 d or longer) is used to create a LETKF ensemble at 7 d. Then, the RIP smoother is used to obtain an accurate final analysis at 1 d. This new approach has the advantage of being based on a short assimilation window, which makes it more accurate, and of having been exposed to the future 7 d observations, which improves the analysis and accelerates the spin-up. The assimilation and observation windows are then shifted forward by 1 d, and the process is repeated. This reduces significantly the analysis error, suggesting that the newly developed assimilation method can be used with other Earth system models, especially in order to make greater use of observations in conjunction with models. | |||||
BibTeX:
@article{liu19b,
author = {Liu, Yun and Kalnay, Eugenia and Zeng, Ning and Asrar, Ghassem and Chen, Zhaohui and Jia, Binghao},
title = {Estimating surface carbon fluxes based on a local ensemble transform Kalman filter with a short assimilation window and a long observation window: an observing system simulation experiment test in GEOS-Chem 10.1},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {12},
number = {7},
pages = {2899--2914},
note = {Query date: 2021-04-02 15:20:04},
url = {https://gmd.copernicus.org/articles/12/2899/2019/},
doi = {https://doi.org/10.5194/gmd-12-2899-2019}
}
|
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| Liu, X., Weinbren, A.L., Chang, H., Jovan Tadic, ́, Mountain, M.E., Trudeau, M.E., Andrews, A.E., Chen, Z. and Miller, S.M. | Data reduction for inverse modeling: an adaptive approach v1. 0 | 2020 | GEOSCIENTIFIC MODEL DEVELOPMENT | article | |
| Abstract: The number of greenhouse gas (GHG) observing satellites has greatly expanded in recent years, and these new datasets provide an unprecedented constraint on global GHG sources and sinks. However, a continuing challenge for inverse models that are used to estimate … | |||||
BibTeX:
@article{liu20a,
author = {Xiaoling Liu and August L. Weinbren and He Chang and Jovan Tadic ́ and Marikate E. Mountain and Michael E. Trudeau and Arlyn E. Andrews and Zichong Chen and and Scot M. Miller},
title = {Data reduction for inverse modeling: an adaptive approach v1. 0},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2020}
}
|
|||||
| Liu, Z., Kimball, J.S., Parazoo, N.C., Ballantyne, A.P., Wang, W.J., Madani, N., Pan, C.G., Watts, J.D., Reichle, R.H., Sonnentag, O., Marsh, P., Hurkuck, M., Helbig, M., Quinton, W.L., Euskirchen, E.S., Zona, D., Ueyama, M. and Kobayashi, H. | Increased high‐latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition | 2020 | GLOBAL CHANGE BIOLOGY | article | |
| Abstract: Arctic and boreal ecosystems play an important role in the global carbon (C) budget, and whether they act as a future net C sink or source depends on climate and environmental change. Here, we used complementary in situ measurements, model simulations, and … | |||||
BibTeX:
@article{liu20b,
author = {Zhihua Liu and John S. Kimball and Nicholas C. Parazoo and Ashley P. Ballantyne and Wen J. Wang and Nima Madani and Caleb G. Pan and Jennifer D. Watts and Rolf H. Reichle and Oliver Sonnentag and Philip Marsh and Miriam Hurkuck and Manuel Helbig and William L. Quinton and Eugé́nie S. Euskirchen and Donatella Zona and Masahito Ueyama and Hideki Kobayashi},
title = {Increased high‐latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2020}
}
|
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| Liu, X., Huang, J., Huang, J., Li, C., Ding, L. and Meng, W. | Estimation of Gridded Atmospheric Oxygen Consumption from 1975 to 2018 | {2020} | JOURNAL OF METEOROLOGICAL RESEARCH Vol. {34}({3}), pp. {646-658} |
article | DOI URL |
| Abstract: Atmospheric Oxygen (O-2) is one of the dominating features that allow the earth to be a habitable planet with advanced civilization and diverse biology. However, since the late 1980s, observational data have indicated a steady decline in O(2)content on the scale of parts-per-million level. The current scientific consensus is that the decline is caused by the fossil-fuel combustion; however, few works have been done to quantitatively evaluate the response of O(2)cycle under the anthropogenic impact, at both the global and regional scales. This paper manages to quantify the land O(2)flux and makes the initial step to quantificationally describe the anthropogenic impacts on the global O(2)budget. Our estimation reveals that the global O(2)consumption has experienced an increase from 33.69 +/- 1.11 to 47.63 +/- 0.80 Gt (gigaton, 10(9)t) O(2)yr(-1)between 2000 and 2018, while the land production of O-2(totaling 11.34 +/- 13.48 Gt O(2)yr(-1)averaged over the same period) increased only slightly. In 2018, the combustion of fossil-fuel and industrial activities (38.45 +/- 0.61 Gt O(2)yr(-1)) contributed the most to consumption, followed by wildfires (4.97 +/- 0.48 Gt O(2)yr(-1)) as well as livestock and human respiration processes (2.48 +/- 0.16 and 1.73 +/- 0.13 Gt O(2)yr(-1), respectively). Burning of fossil-fuel that causes large O(2)fluxes occurs in East Asia, India, North America, and Europe, while wildfires that cause large fluxes in comparable magnitude are mainly distributed in central Africa. | |||||
BibTeX:
@article{liu20c,
author = {Liu, Xiaoyue and Huang, Jianping and Huang, Jiping and Li, Changyu and Ding, Lei and Meng, Wenjun},
title = {Estimation of Gridded Atmospheric Oxygen Consumption from 1975 to 2018},
journal = {JOURNAL OF METEOROLOGICAL RESEARCH},
publisher = {SPRINGER HEIDELBERG},
year = {2020},
volume = {34},
number = {3},
pages = {646--658},
note = {Query date: 2021-04-02 15:20:04},
url = {https://link.springer.com/article/10.1007/s13351-020-9133-7},
doi = {https://doi.org/10.1007/s13351-020-9133-7}
}
|
|||||
| Liu, J., Baskaran, L., Bowman, K., Schimel, D., Bloom, A.A., Parazoo, N.C., Oda, T., Carroll, D., Menemenlis, D., Joiner, J., Commane, R., Daube, B., Gatti V, L., McKain, K., Miller, J., Stephens, B.B., Sweeney, C. and Wofsy, S. | Carbon Monitoring System Flux Net Biosphere Exchange 2020 (CMS-Flux NBE 2020) | {2021} | EARTH SYSTEM SCIENCE DATA Vol. {13}({2}), pp. {299-330} |
article | DOI URL |
| Abstract: Here we present a global and regionally resolved terrestrial net biosphere exchange (NBE) dataset with corresponding uncertainties between 2010-2018: Carbon Monitoring System Flux Net Biosphere Exchange 2020 (CMS-Flux NBE 2020). It is estimated using the NASA Carbon Monitoring System Flux (CMS-Flux) top-down flux inversion system that assimilates column CO2 observations from the Greenhouse Gases Observing Satellite (GOSAT) and NASA's Observing Carbon Observatory 2 (OCO-2). The regional monthly fluxes are readily accessible as tabular files, and the gridded fluxes are available in NetCDF format. The fluxes and their uncertainties are evaluated by extensively comparing the posterior CO2 mole fractions with CO2 observations from aircraft and the NOAA marine boundary layer reference sites. We describe the characteristics of the dataset as the global total, regional climatological mean, and regional annual fluxes and seasonal cycles. We find that the global total fluxes of the dataset agree with atmospheric CO2 growth observed by the surface-observation network within uncertainty. Averaged between 2010 and 2018, the tropical regions range from close to neutral in tropical South America to a net source in Africa; these contrast with the extra-tropics, which are a net sink of 2.5 +/- 0.3 Gt C/year. The regional satellite-constrained NBE estimates provide a unique perspective for understanding the terrestrial biosphere carbon dynamics and monitoring changes in regional contributions to the changes of atmospheric CO2 growth rate. The gridded and regional aggregated dataset can be accessed at https://doi.org/10.25966/4v02-c391 (Liu et al., 2020). | |||||
BibTeX:
@article{liu21a,
author = {Liu, Junjie and Baskaran, Latha and Bowman, Kevin and Schimel, David and Bloom, A. Anthony and Parazoo, Nicholas C. and Oda, Tomohiro and Carroll, Dustin and Menemenlis, Dimitris and Joiner, Joanna and Commane, Roisin and Daube, Bruce and Gatti, V, Lucianna and McKain, Kathryn and Miller, John and Stephens, Britton B. and Sweeney, Colm and Wofsy, Steven},
title = {Carbon Monitoring System Flux Net Biosphere Exchange 2020 (CMS-Flux NBE 2020)},
journal = {EARTH SYSTEM SCIENCE DATA},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2021},
volume = {13},
number = {2},
pages = {299--330},
note = {Query date: 2021-04-02 15:20:04},
url = {https://essd.copernicus.org/articles/13/299/2021/},
doi = {https://doi.org/10.5194/essd-13-299-2021}
}
|
|||||
| Liu, X., Weinbren, A.L., Chang, H., Tadic, J.M., Mountain, M.E., Trudeau, M.E., Andrews, A.E., Chen, Z. and Miller, S.M. | Data reduction for inverse modeling: an adaptive approach v1.0 | 2021 | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. 14(7), pp. 4683-4696 |
article | DOI |
| Abstract: The number of greenhouse gas (GHG) observing satellites has greatly expanded in recent years, and these new datasets provide an unprecedented constraint on global GHG sources and sinks. However, a continuing challenge for inverse models that are used to estimate these sources and sinks is the sheer number of satellite observations, sometimes in the millions per day. These massive datasets often make it prohibitive to implement inverse modeling calculations and/or assimilate the observations using many types of atmospheric models. Although these satellite datasets are very large, the information content of any single observation is often modest and non-exclusive due to redundancy with neighboring observations and due to measurement noise. In this study, we develop an adaptive approach to reduce the size of satellite datasets using geostatistics. A guiding principle is to reduce the data more in regions with little variability in the observations and less in regions with high variability. We subsequently tune and evaluate the approach using synthetic and real data case studies for North America from NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite. The proposed approach to data reduction yields more accurate CO2 flux estimates than the commonly used method of binning and averaging the satellite data. We further develop a metric for choosing a level of data reduction; we can reduce the satellite dataset to an average of one observation per similar to 80-140 km for the specific case studies here without substantially compromising the flux estimate, but we find that reducing the data further quickly degrades the accuracy of the estimated fluxes. Overall, the approach developed here could be applied to a range of inverse problems that use very large trace gas datasets. |
|||||
BibTeX:
@article{liu21b,
author = {Liu, Xiaoling and Weinbren, August L. and Chang, He and Tadic, Jovan M. and Mountain, Marikate E. and Trudeau, Michael E. and Andrews, Arlyn E. and Chen, Zichong and Miller, Scot M.},
title = {Data reduction for inverse modeling: an adaptive approach v1.0},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2021},
volume = {14},
number = {7},
pages = {4683-4696},
doi = {https://doi.org/10.5194/gmd-14-4683-2021}
}
|
|||||
| Liu, L., Huang, Y., Gyakum, J.R., Turner, D.D. and Gero, P.J. | Trends in Downwelling Longwave Radiance Over the Southern Great plains | 2022 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 127(6) |
article | DOI |
| Abstract: Downwelling longwave radiation is an important part of the surface energy budget. Spectral trends in the downwelling longwave radiance (DLR) provide insight into the radiative drivers of climate change. In this research, we process and analyze a 23-year DLR record measured by the Atmospheric Emitted Radiance Interferometer (AERI) at the U.S. Department of Energy Atmospheric Radiation Program Southern Great Plains (SGP) site. Two AERIs were deployed at SGP with an overlapping observation period of about 10 years, which allows us to examine the consistency and accuracy of the measurements and to account for discrepancies between them due to errors associated with the instruments themselves. We then analyzed the all-sky radiance trends in DLR, which are associated with the surface warming trend at SGP during this same period and also the complex changes in meteorological conditions. For instance, the observed radiance in the CO2 absorption band follows closely the near-surface air temperature variations. The significant positive radiance trends in weak absorption channels, such as in the wings of the CO2 band and in the weak absorption channels in the H2O vibration-rotational band, show earlier detectability of climate change. The magnitude of the radiance trend uncertainty in the DLR record mainly results from internal climate variability rather than from measurement error, which highlights the importance of continuing the DLR spectral measurements to unambiguously detect and attribute climate change. |
|||||
BibTeX:
@article{liu22a,
author = {Liu, Lei and Huang, Yi and Gyakum, John R. and Turner, David D. and Gero, P. Jonathan},
title = {Trends in Downwelling Longwave Radiance Over the Southern Great plains},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2022},
volume = {127},
number = {6},
doi = {https://doi.org/10.1029/2021JD035949}
}
|
|||||
| Liu, Z., Zeng, N., Liu, Y., Kalnay, E., Asrar, G., Wu, B., Cai, Q., Liu, D. and Han, P. | Improving the joint estimation of CO2 and surface carbon fluxes using a constrained ensemble Kalman filter in COLA (v1.0) | 2022 | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. 15(14), pp. 5511-5528 |
article | DOI |
| Abstract: Atmospheric inversion of carbon dioxide (CO2) measurements to better understand carbon sources and sinks has made great progress over the last 2 decades. However, most of the studies, including a four-dimensional variational ensemble Kalman filter and Bayesian synthesis approaches, directly obtain only fluxes, while CO2 concentration is derived with the forward model as part of a post-analysis. Kang et al. (2012) used the local ensemble transform Kalman filter (LETKF), which updates the CO2, surface carbon flux (SCF), and meteorology fields simultaneously. Following this track, a system with a short assimilation window and a long observation window was developed (Liu et al., 2019). However, this data assimilation system faces the challenge of maintaining carbon mass conservation. To overcome this shortcoming, here we apply a constrained ensemble Kalman filter (CEnKF) approach to ensure the conservation of global CO2 mass. After a standard LETKF procedure, an additional assimilation is used to adjust CO2 at each model grid point and to ensure the consistency between the analysis and the first guess of the global CO2 mass. Compared to an observing system simulation experiment without mass conservation, the CEnKF significantly reduces the annual global SCF bias from similar to 0.2 to less than 0.06 Gt and slightly improves the seasonal and annual performance over tropical and southern extratropical regions. We show that this system can accurately track the spatial distribution of annual mean SCF. And the system reduces the seasonal flux root mean square error from a priori to analysis by 48 %-90 %, depending on the continental region. Moreover, the 2015-2016 El Nino impact is well captured with anomalies mainly in the tropics. |
|||||
BibTeX:
@article{liu22b,
author = {Liu, Zhiqiang and Zeng, Ning and Liu, Yun and Kalnay, Eugenia and Asrar, Ghassem and Wu, Bo and Cai, Qixiang and Liu, Di and Han, Pengfei},
title = {Improving the joint estimation of CO2 and surface carbon fluxes using a constrained ensemble Kalman filter in COLA (v1.0)},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2022},
volume = {15},
number = {14},
pages = {5511-5528},
doi = {https://doi.org/10.5194/gmd-15-5511-2022}
}
|
|||||
| Liu, Z., Kimball, J.S., Ballantyne, A.P., Parazoo, N.C., Wang, W.J., Bastos, A., Madani, N., Natali, S.M., Watts, J.D., Rogers, B.M., Ciais, P., Yu, K., Virkkala, A.-M., Chevallier, F., Peters, W., Patra, P.K. and Chandra, N. | Respiratory loss during late-growing season determines the net carbon dioxide sink in northern permafrost regions | 2022 | NATURE COMMUNICATIONS Vol. 13(1) |
article | DOI |
| Abstract: Warming of northern high latitude regions (NHL, > 50 degrees N) has increased both photosynthesis and respiration which results in considerable uncertainty regarding the net carbon dioxide (CO2) balance of NHL ecosystems. Using estimates constrained from atmospheric observations from 1980 to 2017, we find that the increasing trends of net CO2 uptake in the early-growing season are of similar magnitude across the tree cover gradient in the NHL. However, the trend of respiratory CO2 loss during late-growing season increases significantly with increasing tree cover, offsetting a larger fraction of photosynthetic CO2 uptake, and thus resulting in a slower rate of increasing annual net CO2 uptake in areas with higher tree cover, especially in central and southern boreal forest regions. The magnitude of this seasonal compensation effect explains the difference in net CO2 uptake trends along the NHL vegetation- permafrost gradient. Such seasonal compensation dynamics are not captured by dynamic global vegetation models, which simulate weaker respiration control on carbon exchange during the late-growing season, and thus calls into question projections of increasing net CO2 uptake as high latitude ecosystems respond to warming climate conditions. |
|||||
BibTeX:
@article{liu22c,
author = {Liu, Zhihua and Kimball, John S. and Ballantyne, Ashley P. and Parazoo, Nicholas C. and Wang, Wen J. and Bastos, Ana and Madani, Nima and Natali, Susan M. and Watts, Jennifer D. and Rogers, Brendan M. and Ciais, Philippe and Yu, Kailiang and Virkkala, Anna-Maria and Chevallier, Frederic and Peters, Wouter and Patra, Prabir K. and Chandra, Naveen},
title = {Respiratory loss during late-growing season determines the net carbon dioxide sink in northern permafrost regions},
journal = {NATURE COMMUNICATIONS},
year = {2022},
volume = {13},
number = {1},
doi = {https://doi.org/10.1038/s41467-022-33293-x}
}
|
|||||
| Lokupitiya, R.S., Zupanski, D., Denning, A.S., Kawa, S.R., Gurney, K.R. and Zupanski, M. | Estimation of global CO2 fluxes at regional scale using the maximum likelihood ensemble filter | {2008} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {113}({D20}) |
article | DOI |
| Abstract: We use an ensemble-based data assimilation method, known as the maximum likelihood ensemble filter (MLEF), which has been coupled with a global atmospheric transport model to estimate slowly varying biases of carbon surface fluxes. Carbon fluxes for this test consist of hourly gross primary production and ecosystem, respiration over land, and air-sea gas exchange. Persistent multiplicative biases intended to represent incorrectly simulated biogeochemical or land-management processes such as stand age, soil fertility, or coarse woody debris were estimated for 1 year at 10 degrees longitude by 6 degrees latitude spatial resolution and with an 8-week time window. We tested the model using a pseudodata experiment with an existing observation network that includes flasks, aircraft profiles, and continuous measurements. Because of the underconstrained nature of the problem, strong covariance smoothing was applied in the first data assimilation cycle, and localization schemes have been introduced. Error covariance was propagated in subsequent cycles. The coupled model satisfactorily recovered the land biases in densely observed areas. Ocean biases, however, were poorly constrained by the atmospheric observations. Unlike in batch mode inversions, the MLEF has a capability of assimilating large observation vectors and hence is suitable for assimilating hourly continuous observations and satellite observations in the future. Uncertainty was reduced further in our pseudodata experiment than by previous batch methods because of the ability to assimilate a large observation vector. Propagation of spatial covariance and dynamic localization avoid the need for prescribed spatial patterns of error covariance centered at observation sites as in previous grid-scale methods. |
|||||
BibTeX:
@article{lokupitiya08a,
author = {Lokupitiya, R. S. and Zupanski, D. and Denning, A. S. and Kawa, S. R. and Gurney, K. R. and Zupanski, M.},
title = {Estimation of global CO2 fluxes at regional scale using the maximum likelihood ensemble filter},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2008},
volume = {113},
number = {D20},
doi = {https://doi.org/10.1029/2007JD009679}
}
|
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| Long, W. and Ernstberger, J. | Modeling atmospheric carbon dioxide over the United States | 2013 | SIAM Undergraduate ResearchLaGrange College | misc | URL |
| Abstract: In this undergraduate research project, we implement a published, component-based model of the total carbon dioxide concentration in the atmosphere above the United States. To do so we use a simple ordinary differential equation to quantify the behavior of the carbon cycle … | |||||
BibTeX:
@misc{long13a,
author = {WE Long and J Ernstberger},
title = {Modeling atmospheric carbon dioxide over the United States},
journal = {SIAM Undergraduate Research},
year = {2013},
url = {https://pdfs.semanticscholar.org/eef1/7dd1a059d3d5657bd815681205ed6868afbf.pdf}
}
|
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| Long, M.C., Stephens, B.B., McKain, K., Sweeney, C., Keeling, R.F., Kort, E.A., Morgan, E.J., Bent, J.D., Chandra, N., Chevallier, F., Commane, R., Daube, B.C., Krummel, P.B., Loh, Z., Luijkx, I.T., Munro, D., Patra, P., Peters, W., Ramonet, M., Rodenbeck, C., Stavert, A., Tans, P. and Wofsy, S.C. | Strong Southern Ocean carbon uptake evident in airborne observations | 2021 | SCIENCE Vol. 374(6572), pp. 1275+ |
article | DOI |
| Abstract: The Southern Ocean plays an important role in determining atmospheric carbon dioxide (CO2), yet estimates of air-sea CO2 flux for the region diverge widely. In this study, we constrained Southern Ocean air-sea CO2 exchange by relating fluxes to horizontal and vertical CO2 gradients in atmospheric transport models and applying atmospheric observations of these gradients to estimate fluxes. Aircraft-based measurements of the vertical atmospheric CO2 gradient provide robust flux constraints. We found an annual mean flux of -0.53 +/- 0.23 petagrams of carbon per year (net uptake) south of 45 degrees S during the period 2009-2018. This is consistent with the mean of atmospheric inversion estimates and surface-ocean partial pressure of CO2 (P-CO2)-based products, but our data indicate stronger annual mean uptake than suggested by recent interpretations of profiling float observations. |
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BibTeX:
@article{long21a,
author = {Long, Matthew C. and Stephens, Britton B. and McKain, Kathryn and Sweeney, Colm and Keeling, Ralph F. and Kort, Eric A. and Morgan, Eric J. and Bent, Jonathan D. and Chandra, Naveen and Chevallier, Frederic and Commane, Roisin and Daube, Bruce C. and Krummel, Paul B. and Loh, Zoe and Luijkx, Ingrid T. and Munro, David and Patra, Prabir and Peters, Wouter and Ramonet, Michel and Rodenbeck, Christian and Stavert, Ann and Tans, Pieter and Wofsy, Steven C.},
title = {Strong Southern Ocean carbon uptake evident in airborne observations},
journal = {SCIENCE},
year = {2021},
volume = {374},
number = {6572},
pages = {1275+},
doi = {https://doi.org/10.1126/science.abi4355}
}
|
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| Luan, T., LingXi, Z., ShuangXi, F., Yao, B., Wang, H. and Liu, Z. | Atmospheric CO2 Data Filtering Method and Characteristics of the Molar Fractions at the Longfengshan WMO/GAW Regional Station in China [BibTeX] |
2014 | Environmental Science Vol. 35(8) |
article | URL |
BibTeX:
@article{luan14a,
author = {Luan, Tian and Zhou LingXi and Fang ShuangXi and Yao, Bo and Wang, Hongyang and Liu, Zhao},
title = {Atmospheric CO2 Data Filtering Method and Characteristics of the Molar Fractions at the Longfengshan WMO/GAW Regional Station in China},
journal = {Environmental Science},
year = {2014},
volume = {35},
number = {8},
url = {http://www.hjkx.ac.cn/hjkx/ch/html/20140804.htm}
}
|
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| Lubin, D., Zhang, D., Silber, I., Scott, R.C., Kalogeras, P., Battaglia, A., Bromwich, D.H., Cadeddu, M., Eloranta, E., Fridlind, A., Frossard, A., Hines, K.M., Kneifel, S., Leaitch, W.R., Lin, W., Nicolas, J., Powers, H., Quinn, P.K., Rowe, P., Russell, L.M., Sharma, S., Verlinde, J. and Vogelmann, A.M. | The Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment | {2020} | BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY Vol. {101}({7}), pp. {E1069-E1091} |
article | DOI URL |
| Abstract: The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment (AWARE) performed comprehensive meteorological and aerosol measurements and ground-based atmospheric remote sensing at two Antarctic stations using the most advanced instrumentation available. A suite of cloud research radars, lidars, spectral and broadband radiometers, aerosol chemical and microphysical sampling equipment, and meteorological instrumentation was deployed at McMurdo Station on Ross Island from December 2015 through December 2016. A smaller suite of radiometers and meteorological equipment, including radiosondes optimized for surface energy budget measurement, was deployed on the West Antarctic Ice Sheet between 4 December 2015 and 17 January 2016. AWARE provided Antarctic atmospheric data comparable to several well-instrumented high Arctic sites that have operated for many years and that reveal numerous contrasts with the Arctic in aerosol and cloud microphysical properties. These include persistent differences in liquid cloud occurrence, cloud height, and cloud thickness. Antarctic aerosol properties are also quite different from the Arctic in both seasonal cycle and composition, due to the continent's isolation from lower latitudes by Southern Ocean storm tracks. Antarctic aerosol number and mass concentrations are not only non-negligible but perhaps play a more important role than previously recognized because of the higher sensitivities of clouds at the very low concentrations caused by the large-scale dynamical isolation. Antarctic aerosol chemical composition, particularly organic components, has implications for local cloud microphysics. The AWARE dataset, fully available online in the ARM Program data archive, offers numerous case studies for unique and rigorous evaluation of mixed-phase cloud parameterization in climate models. | |||||
BibTeX:
@article{lubin20a,
author = {Lubin, Dan and Zhang, Damao and Silber, Israel and Scott, Ryan C. and Kalogeras, Petros and Battaglia, Alessandro and Bromwich, David H. and Cadeddu, Maria and Eloranta, Edwin and Fridlind, Ann and Frossard, Amanda and Hines, Keith M. and Kneifel, Stefan and Leaitch, W. Richard and Lin, Wuyin and Nicolas, Julien and Powers, Heath and Quinn, Patricia K. and Rowe, Penny and Russell, Lynn M. and Sharma, Sangeeta and Verlinde, Johannes and Vogelmann, Andrew M.},
title = {The Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment},
journal = {BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY},
publisher = {AMER METEOROLOGICAL SOC},
year = {2020},
volume = {101},
number = {7},
pages = {E1069-E1091},
note = {Query date: 2021-04-02 15:20:04},
url = {https://journals.ametsoc.org/view/journals/bams/101/7/bamsD180278.xml},
doi = {https://doi.org/10.1175/BAMS-D-18-0278.1}
}
|
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| Lukyanov, A.N., Gan'shin, A.V., Zhuravlev, R.V., Maksyutov, S.S. and Varlagin, A.V. | Global Lagrangian Atmospheric Dispersion Model | {2015} | IZVESTIYA ATMOSPHERIC AND OCEANIC PHYSICS Vol. {51}({5}), pp. 505-511 |
article | DOI |
| Abstract: The Global Lagrangian Atmospheric Dispersion Model (GLADIM) is described. GLADIM is based on the global trajectory model, which had been developed earlier and uses fields of weather parameters from different atmospheric reanalysis centers for calculations of trajectories of air mass that include trace gases. GLADIM includes the parameterization of turbulent diffusion and allows the forward calculation of concentrations of atmospheric tracers at nodes of a global regular grid when a source is specified. Thus, GLADIM can be used for the forward simulation of pollutant propagation (volcanic ash, radionuclides, and so on). Working in the reverse direction, GLADIM allows the detection of remote sources that mainly contribute to the tracer concentration at an observation point. This property of Lagrangian models is widely used for data analysis and the reverse modeling of emission sources of a pollutant specified. In this work we describe the model and some results of its validation through a comparison with results of a similar model and observation data. |
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BibTeX:
@article{lukyanov15a,
author = {Lukyanov, A. N. and Gan'shin, A. V. and Zhuravlev, R. V. and Maksyutov, Sh. Sh. and Varlagin, A. V.},
title = {Global Lagrangian Atmospheric Dispersion Model},
journal = {IZVESTIYA ATMOSPHERIC AND OCEANIC PHYSICS},
year = {2015},
volume = {51},
number = {5},
pages = {505--511},
doi = {https://doi.org/10.1134/S0001433815040076}
}
|
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| Luus, K.A. and Lin, J.C. | The Polar Vegetation Photosynthesis and Respiration Model: a parsimonious, satellite-data-driven model of high-latitude CO2 exchange | {2015} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {8}({8}), pp. 2655-2674 |
article | DOI |
| Abstract: We introduce the Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM), a remote-sensing-based approach for generating accurate, high-resolution (>= 1 km(2), 3 hourly) estimates of net ecosystem CO2 exchange (NEE). PolarVPRM simulates NEE using polar-specific vegetation classes, and by representing high-latitude influences on NEE, such as the influence of soil temperature on subnivean respiration. We present a description, validation and error analysis (first-order Taylor expansion) of PolarVPRM, followed by an examination of per-pixel trends (2001-2012) in model output for the North American terrestrial region north of 55 degrees N. PolarVPRM was validated against eddy covariance (EC) observations from nine North American sites, of which three were used in model calibration. Comparisons of EC NEE to NEE from three models indicated that PolarVPRM displayed similar or better statistical agreement with eddy covariance observations than existing models showed. Trend analysis (2001-2012) indicated that warming air temperatures and drought stress in forests increased growing season rates of respiration, and decreased rates of net carbon uptake by vegetation when air temperatures exceeded optimal temperatures for photosynthesis. Concurrent increases in growing season length at Arctic tundra sites allowed for increases in photosynthetic uptake over time by tundra vegetation. PolarVPRM estimated that the North American high-latitude region changed from a carbon source (2001-2004) to a carbon sink (2005-2010) to again a source (2011-2012) in response to changing environmental conditions. |
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BibTeX:
@article{luus15a,
author = {Luus, K. A. and Lin, J. C.},
title = {The Polar Vegetation Photosynthesis and Respiration Model: a parsimonious, satellite-data-driven model of high-latitude CO2 exchange},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2015},
volume = {8},
number = {8},
pages = {2655--2674},
doi = {https://doi.org/10.5194/gmd-8-2655-2015}
}
|
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| Ma, C., Wang, T., Mizzi, A.P., Anderson, J.L., Zhuang, B., Xie, M. and Wu, R. | Multiconstituent Data Assimilation With WRF-Chem/DART: Potential for Adjusting Anthropogenic Emissions and Improving Air Quality Forecasts Over Eastern China | {2019} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {124}({13}), pp. {7393-7412} |
article | DOI |
| Abstract: We use the Weather Research and Forecasting Model with the chemistry/Data Assimilation Research Testbed (WRF-Chem/DART) chemical weather forecasting/data assimilation system with multiconstituent data assimilation to investigate the improvement of air quality forecasts over eastern China. We assimilate surface in situ observations of sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O-3), carbon monoxide (CO), particulate matter with diameters less than 2.5 mu m (PM2.5) and 10 mu m (PM10), and satellite aerosol optical depth to adjust the related anthropogenic emissions as well as the chemical initial conditions. We validate our forecast results out to 72 hr by comparison with the in situ observations. Results show that updated emissions improve the model performance between 10% and 65% root mean square error reduction for the assimilated species except particulate matter with a diameter between 2.5 and 10 mu m (PM2.5-10), which is slightly improved due to the limited anthropogenic contribution to it. In a sensitivity experiment with a different update interval, the CO improvement is found to be sensitive to the cycling time used to update the CO emissions. In another sensitivity experiment when NO2 observations are not assimilated and nitrogen oxides (NOx) emission are adjusted by only O-3, NO2 forecasts show similar root mean square error improvement but have lower spatial correlation, indicating the value and limitation of the O-3-NOx cross-variable relationship. | |||||
BibTeX:
@article{ma19a,
author = {Ma, Chaoqun and Wang, Tijian and Mizzi, Arthur P. and Anderson, Jeffrey L. and Zhuang, Bingliang and Xie, Min and Wu, Rongsheng},
title = {Multiconstituent Data Assimilation With WRF-Chem/DART: Potential for Adjusting Anthropogenic Emissions and Improving Air Quality Forecasts Over Eastern China},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2019},
volume = {124},
number = {13},
pages = {7393--7412},
doi = {https://doi.org/10.1029/2019JD030421}
}
|
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| Ma, L., Hurtt, G., Ott, L., Sahajpal, R., Fisk, J., Lamb, R., Tang, H., Flanagan, S., Chini, L., Chatterjee, A. and Sullivan, J. | Global evaluation of the Ecosystem Demography model (ED v3.0) | 2022 | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. 15(5), pp. 1971-1994 |
article | DOI |
| Abstract: Terrestrial ecosystems play a critical role in the global carbon cycle but have highly uncertain future dynamics. Ecosystem modeling that includes the scaling up of underlying mechanistic ecological processes has the potential to improve the accuracy of future projections while retaining key process-level detail. Over the past two decades, multiple modeling advances have been made to meet this challenge, such as the Ecosystem Demography (ED) model and its derivatives, including ED2 and FATES. Here, we present the global evaluation of the Ecosystem Demography model (ED v3.0), which, like its predecessors, features the formal scaling of physiological processes for individual-based vegetation dynamics to ecosystem scales, together with integrated submodules of soil biogeochemistry and soil hydrology, while retaining explicit tracking of vegetation 3-D structure. This new model version builds on previous versions and provides the first global calibration and evaluation, global tracking of the effects of climate and land-use change on vegetation 3-D structure, spin-up process and input datasets, as well as numerous other advances. Model evaluation was performed with respect to a set of important benchmarking datasets, and model estimates were within observational constraints for multiple key variables, including (i) global patterns of dominant plant functional types (broadleaf vs. evergreen), (ii) the spatial distribution, seasonal cycle, and interannual trends for global gross primary production (GPP), (iii) the global interannual variability of net biome production (NBP) and (iv) global patterns of vertical structure, including leaf area and canopy height. With this global model version, it is now possible to simulate vegetation dynamics from local to global scales and from seconds to centuries with a consistent mechanistic modeling framework amendable to data from multiple traditional and new remote sensing sources, including lidar. |
|||||
BibTeX:
@article{ma22a,
author = {Ma, Lei and Hurtt, George and Ott, Lesley and Sahajpal, Ritvik and Fisk, Justin and Lamb, Rachel and Tang, Hao and Flanagan, Steve and Chini, Louise and Chatterjee, Abhishek and Sullivan, Joseph},
title = {Global evaluation of the Ecosystem Demography model (ED v3.0)},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2022},
volume = {15},
number = {5},
pages = {1971-1994},
doi = {https://doi.org/10.5194/gmd-15-1971-2022}
}
|
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| Mabuchi, K., Takagi, H. and Maksyutov, S. | Relationships between CO2 Flux Estimated by Inverse Analysis and Land Surface Elements in South America and Africa | {2016} | JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN Vol. {94}({5}), pp. 415-430 |
article | DOI |
| Abstract: Inverse analysis estimates the regional flux of greenhouse gases between the earth's surface and atmosphere using observed atmospheric concentration data that include satellite data. In particular, this method is effective in estimating the flux in regions where observational flux data are limited. However, inverse analysis is basically a mathematical optimization method. Therefore, confirmation of the causal validity of the spatial and temporal changes in the estimated flux is necessary. One confirmation method is validation of the relationship with physical and biological observation data (analysis data) of confirmed accuracy. In this study, the features and validity of changes in the carbon dioxide (CO2) flux estimated by inverse analysis were verified via interrelation analysis, with changes in precipitation, short-wave radiation, surface temperature, and Normalized Difference Vegetation Index (NDVI) in regions of South America and Africa where CO2 flux observation data are limited. Sufficient accuracy of the land surface elements is required for the analysis results to confirm the CO2 flux estimated by inverse analysis. An examination of the correlation of anomalies showed consistent relationships among the precipitation, short-wave radiation, surface temperature, and NDVI data used in this study, which were independently created. The relationships between change in the estimated CO2 flux and characteristic changes in the land surface elements in South America and Africa were consistent for each region. This study confirmed the physical and biological validity of the changes in the CO2 flux estimated by inverse analysis. During the period of this study, the NDVI anomaly was influential in South America and the precipitation (soil wetness) anomaly was an essential factor in Africa for the CO2 flux anomaly. The short-wave radiation anomaly was also influential in both South America and Africa. The distinctive relationships are more clearly detected in the results of inverse analysis using both ground-based CO2 concentration data and the Greenhouse gases Observing SATellite (GOSAT) data than in the results using only ground-based CO2 concentration data. This demonstrates the usefulness of GOSAT data in regions with limited atmospheric CO2 concentration data. |
|||||
BibTeX:
@article{mabuchi16a,
author = {Mabuchi, Kazuo and Takagi, Hiroshi and Maksyutov, Shamil},
title = {Relationships between CO2 Flux Estimated by Inverse Analysis and Land Surface Elements in South America and Africa},
journal = {JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN},
year = {2016},
volume = {94},
number = {5},
pages = {415--430},
doi = {https://doi.org/10.2151/jmsj.2016-021}
}
|
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| Macatangay, R., Warneke, T., Gerbig, C., Koerner, S., Ahmadov, R., Heimann, M. and Notholt, J. | A framework for comparing remotely sensed and in-situ CO2 concentrations | {2008} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {8}({9}), pp. 2555-2568 |
article | DOI |
| Abstract: A framework has been developed that allows validating CO2 column averaged volume mixing ratios (VMRs) retrieved from ground-based solar absorption measurements using Fourier transform infrared spectrometry (FTS) against measurements made in-situ (such as from aircrafts and tall towers). Since in-situ measurements are done frequently and at high accuracy on the global calibration scale, linking this scale with FTS total column retrievals ultimately provides a calibration scale for remote sensing. FTS, tower and aircraft data were analyzed from measurements during the CarboEurope Regional Experiment Strategy (CERES) from May to June 2005 in Biscarrosse, France. Carbon dioxide VMRs from the MetAir Dimona aircraft, the TM3 global transport model and Observations of the Middle Stratosphere (OMS) balloon based experiments were combined and integrated to compare with the FTS measurements. The comparison allows for calibrating the retrieved carbon dioxide VMRs from the FTS. The Stochastic Time Inverted Lagrangian Transport (STILT) model was then utilized to identify differences in surface influence regions or footprints between the FTS and the aircraft CO2 concentrations. Additionally, the STILT model was used to compare carbon dioxide concentrations from a tall tower situated in close proximity to the FTS station. The STILT model was then modified to produce column concentrations of CO2 to facilitate comparison with the FTS data. These comparisons were additionally verified by using the Weather Research and Forecasting -; Vegetation Photosynthesis and Respiration Model (WRF-VPRM). The differences between the model-tower and the model-FTS were then used to calculate an effective bias of approximately -2.5 ppm between the FTS and the tower. This bias is attributed to the scaling factor used in the FTS CO2 data, which was to a large extent derived from the aircraft measurements made within a 50 km distance from the FTS station: spatial heterogeneity of carbon dioxide in the coastal area caused a low bias in the FTS calibration. Using STILT for comparing remotely sensed CO2 data with tower measurements of carbon dioxide and quantifying this comparison by means of an effective bias, provided a framework or a `transfer standard' that allowed validating the FTS retrievals versus measurements made in-situ. |
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BibTeX:
@article{macatangay08a,
author = {Macatangay, R. and Warneke, T. and Gerbig, C. and Koerner, S. and Ahmadov, R. and Heimann, M. and Notholt, J.},
title = {A framework for comparing remotely sensed and in-situ CO2 concentrations},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2008},
volume = {8},
number = {9},
pages = {2555--2568},
doi = {https://doi.org/10.5194/acp-8-2555-2008}
}
|
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| Macatangay, R.C. | Project MANTRA: Multi-platform ANalysis of TRace Gases and Aerosols with Measurements a Focus on for Atmospheric Southeast Asia CO2 | 2018 | book | URL | |
| Abstract: This chapter gives an overview of Project MANTRA (Multi-platform Analysis of Trace gases and Aerosols) focusing on atmospheric carbon dioxide. Specifically, this chapter addresses how surface CO2 data can be measured in a costeffective manner. Applications are shown … | |||||
BibTeX:
@book{macatangay18a,
author = {Ronald C. Macatangay},
title = {Project MANTRA: Multi-platform ANalysis of TRace Gases and Aerosols with Measurements a Focus on for Atmospheric Southeast Asia CO2},
publisher = {SPRINGER},
year = {2018},
url = {https://books.google.com/books?hl=en&lr=&id=d1FTDwAAQBAJ&oi=fnd&pg=PA303&ots=t9ZPnMOTRr&sig=ypOCJ9GbtsfU4aG-rYt14XCojn4}
}
|
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| Maddy, E., Barnet, C., Goldberg, M., Sweeney, C. and Liu, X. | CO2 retrievals from the Atmospheric Infrared Sounder: Methodology and validation [BibTeX] |
2008 | Journal of Geophysical Research: Atmospheres Vol. 113(D11) |
article | DOI |
BibTeX:
@article{maddy08a,
author = {Maddy, ES and Barnet, CD and Goldberg, M and Sweeney, C and Liu, X},
title = {CO2 retrievals from the Atmospheric Infrared Sounder: Methodology and validation},
journal = {Journal of Geophysical Research: Atmospheres},
year = {2008},
volume = {113},
number = {D11},
doi = {https://doi.org/10.1029/2007JD009402/full}
}
|
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| Mahata, S., Wang, C.-H., Bhattacharya, S.K. and Liang, M.-C. | Near Surface CO2 Triple Oxygen Isotope Composition | {2016} | TERRESTRIAL ATMOSPHERIC AND OCEANIC SCIENCES Vol. {27}({1}), pp. 99-106 |
article | DOI |
| Abstract: The isotopic composition of carbon dioxide in the atmosphere is a powerful tool for constraining its sources and sinks. In particular, the O-17 oxygen anomaly [Delta O-17 = 1000 x ln(1 + delta O-17/1000) - 0.516 x 1000 x ln(1 + delta O-18/1000)], with a value > 0.5 parts per thousand produced in the middle atmosphere, provides an ideal tool for probing the exchange of carbon dioxide between the biosphere/hydrosphere and atmosphere. The biosphere/hydrosphere and anthropogenic emissions give values <= 0.3 parts per thousand. Therefore, any anomaly in near surface CO2 would reflect the balance between stratospheric input and exchange with the aforementioned surface sources. We have analyzed Delta O-17 values of CO2 separated from air samples collected in Taipei, Taiwan, located in the western Pacific region. The obtained mean anomaly is 0.42 +/- 0.14 parts per thousand (1-sigma standard deviation), in good agreement with model prediction and a published decadal record. Apart from typically used delta C-13 and delta O-18 values, the Delta O-17 value could provide an additional tracer for constraining the carbon cycle. |
|||||
BibTeX:
@article{mahata16a,
author = {Mahata, Sasadhar and Wang, Chung-Ho and Bhattacharya, Sourendra Kumar and Liang, Mao-Chang},
title = {Near Surface CO2 Triple Oxygen Isotope Composition},
journal = {TERRESTRIAL ATMOSPHERIC AND OCEANIC SCIENCES},
year = {2016},
volume = {27},
number = {1},
pages = {99--106},
doi = {https://doi.org/10.3319/TAO.2015.09.16.01(A)}
}
|
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| Mai, B., An, X., Deng, X., Zhou, L., Wang, C., Huang, J., Chen, L. and Yin, S. | Simulation analysis and verification of surface CO2 flux over Pearl River Delta, China [BibTeX] |
2014 | China Environmental Science Vol. 34(8), pp. 1960-1971 |
article | URL |
BibTeX:
@article{mai14a,
author = {Mai, Boru and An, Xingqin and Deng, Xuejiao and Zhou, Lingxi and Wang, Chunlin and Huang, Jianping and Chen, Ling and Yin, Shuxian},
title = {Simulation analysis and verification of surface CO2 flux over Pearl River Delta, China},
journal = {China Environmental Science},
year = {2014},
volume = {34},
number = {8},
pages = {1960--1971},
url = {http://manu36.magtech.com.cn/Jweb_zghjkx/CN/article/downloadArticleFile.do?attachType=PDF&id=13755}
}
|
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| Mai, B., Deng, X., Zhang, F., He, H., Luan, T., Li, F. and Liu, X. | Background Characteristics of Atmospheric CO2 and the Potential Source Regions in the Pearl River Delta Region of China | {2020} | ADVANCES IN ATMOSPHERIC SCIENCES Vol. {37}({6, SI}), pp. {557-568} |
article | DOI URL |
| Abstract: Mole fractions of atmospheric CO2 (XCO2) have been continuously measured from October 2014 to March 2016 at the Guangzhou Panyu Atmospheric Composition Site (23.00 degrees N, 113.21 degrees E; 140 m MSL) in the Pearl River Delta (PRD) region using a cavity ring-down spectrometer. Approximately 66.63%, 19.28%, and 14.09% of the observed values were filtered as background, pollutant source, and sink due to biospheric uptake, respectively, by applying a robust local regression procedure. Their corresponding mean values were 424.12 +/- 10.12 ppm (x10(-6) mol mol(-1)), 447.83 +/- 13.63 ppm, and 408.83 +/- 7.75 ppm. The background XCO2 levels were highest in spring and winter, moderate in autumn, and lowest in summer. The diurnal XCO2 was at a minimum from 1400-1600 LST (Local Standard Time) and a maximum at 0500 LST the next day. The increase of XCO2 in spring and summer was mainly associated with polluted air masses from south coastal Vietnam, the South China Sea, and the southeast Pearl River Estuary. With the exception of summer, airflow primarily from marine regions southeast of Taiwan that passed over the Pearl River Estuary had a greater impact on XCO2, suggesting an important potential source region. | |||||
BibTeX:
@article{mai20a,
author = {Mai, Boru and Deng, Xuejiao and Zhang, Fang and He, Hao and Luan, Tian and Li, Fei and Liu, Xia},
title = {Background Characteristics of Atmospheric CO2 and the Potential Source Regions in the Pearl River Delta Region of China},
journal = {ADVANCES IN ATMOSPHERIC SCIENCES},
publisher = {SCIENCE PRESS},
year = {2020},
volume = {37},
number = {6, SI},
pages = {557--568},
note = {1st China Greenhouse Gas Monitoring Conference, Beijing, PEOPLES R CHINA, MAY 30-31, 2019},
url = {https://link.springer.com/content/pdf/10.1007/s00376-020-9238-z.pdf},
doi = {https://doi.org/10.1007/s00376-020-9238-z}
}
|
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| Majkut, J.D. | Variability and Trends in the Carbon Cycle [BibTeX] |
2014 | School: Princeton University | phdthesis | URL |
BibTeX:
@phdthesis{majkut14a,
author = {Majkut, Joseph Daniel},
title = {Variability and Trends in the Carbon Cycle},
school = {Princeton University},
year = {2014},
url = {http://search.proquest.com/openview/e90b562d689cf3a0ab70ffe5a30cd505/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Maki, T., Ikegami, M., Fujita, T., Hirahara, T., Yamada, K., Mori, K., Takeuchi, A., Tsutsumi, Y., Suda, K. and Conway, T.J. | New technique to analyse global distributions of CO2 concentrations and fluxes from non-processed observational data | {2010} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {62}({5, SI}), pp. 797-809 |
article | DOI |
| Abstract: We have developed a new observational screening technique for inverse model. This technique was applied to our transport models with re-analysed meteorological data and the inverse model to estimate the global distribution of CO2 concentrations and fluxes. During the 1990s, we estimated a total CO2 uptake by the biosphere of 1.4-1.5 PgC yr-1 and a total CO2 uptake by the oceans of 1.7-1.8 PgC yr-1. The uncertainty of global CO2 flux estimation is about 0.3 PgC yr-1. We also obtained monthly surface CO2 concentrations in the marine boundary layer to precisions of 0.5-1.0 ppm. To utilize non-processed (statistical monthly mean) observational data in our analysis, we developed a quality control procedure for such observational data including a repetition of inversion. This technique is suitable for other inversion setups. Observational data by ships were placed into grids and used in our analysis to add to the available data from fixed stations. The estimated global distributions are updated and extended every year. |
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BibTeX:
@article{maki10a,
author = {Maki, T. and Ikegami, M. and Fujita, T. and Hirahara, T. and Yamada, K. and Mori, K. and Takeuchi, A. and Tsutsumi, Y. and Suda, K. and Conway, T. J.},
title = {New technique to analyse global distributions of CO2 concentrations and fluxes from non-processed observational data},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2010},
volume = {62},
number = {5, SI},
pages = {797--809},
doi = {https://doi.org/10.1111/j.1600-0889.2010.00488.x}
}
|
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| Maksyutov, S., Takagi, H., Belikov, D.A., Saeki, T., Zhuravlev, R., Ganshin, A., Lukyanov, A., Yoshida, Y., Oshchepkov, S., Bril, A., Saito, M., Oda, T., Valsala, V.K., Saito, R., Andres, R.J., Conway, T., Tans, P. and Yokota, T. | Estimation of regional surface CO2 fluxes with GOSAT observations using two inverse modeling approaches | {2012} | Vol. {8529}REMOTE SENSING AND MODELING OF THE ATMOSPHERE, OCEANS, AND INTERACTIONS IV |
inproceedings | DOI |
| Abstract: Inverse estimation of surface CO2 fluxes is performed with atmospheric transport model using ground-based and GOSAT observations. The NIES-retrieved CO2 column mixing (X-CO2) and column averaging kernel are provided by GOSAT Level 2 product v. 2.0 and PPDF-DOAS method. Monthly mean CO2 fluxes for 64 regions are estimated together with a global mean offset between GOSAT data and ground-based data. We used the fixed-lag Kalman filter to infer monthly fluxes for 42 sub-continental terrestrial regions and 22 oceanic basins. We estimate fluxes and compare results obtained by two inverse modeling approaches. In basic approach adopted in GOSAT Level 4 product v. 2.01, we use aggregation of the GOSAT observations into monthly mean over 5x5 degree grids, fluxes are estimated independently for each region, and NIES atmospheric transport model is used for forward simulation. In the alternative method, the model-observation misfit is estimated for each observation separately and fluxes are spatially correlated using EOF analysis of the simulated flux variability similar to geostatistical approach, while transport simulation is enhanced by coupling with a Lagrangian transport model Flexpart. Both methods use using the same set of prior fluxes and region maps. Daily net ecosystem exchange (NEE) is predicted by the Vegetation Integrative SImulator for Trace gases (VISIT) optimized to match seasonal cycle of the atmospheric CO2. Monthly ocean-atmosphere CO2 fluxes are produced with an ocean pCO(2) data assimilation system. Biomass burning fluxes were provided by the Global Fire Emissions Database (GFED); and monthly fossil fuel CO2 emissions are estimated with ODIAC inventory. The results of analyzing one year of the GOSAT data suggest that when both GOSAT and ground-based data are used together, fluxes in tropical and other remote regions with lower associated uncertainties are obtained than in the analysis using only ground-based data. With version 2.0 of L2 X-CO2 the fluxes appear reasonable for many regions and seasons, however there is a need for improving the L2 bias correction, data filtering and the inverse modeling method to reduce estimated flux anomalies visible in some areas. We also observe that application of spatial flux correlations with EOF-based approach reduces flux anomalies. |
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BibTeX:
@inproceedings{maksyutov12a,
author = {Maksyutov, Shamil and Takagi, Hiroshi and Belikov, Dmitry A. and Saeki, Tazu and Zhuravlev, Ruslan and Ganshin, Alexander and Lukyanov, Alexander and Yoshida, Yukio and Oshchepkov, Sergey and Bril, Andrey and Saito, Makoto and Oda, Tomohiro and Valsala, Vinu K. and Saito, Ryu and Andres, Robert J. and Conway, Thomas and Tans, Pieter and Yokota, Tatsuya},
title = {Estimation of regional surface CO2 fluxes with GOSAT observations using two inverse modeling approaches},
booktitle = {REMOTE SENSING AND MODELING OF THE ATMOSPHERE, OCEANS, AND INTERACTIONS IV},
year = {2012},
volume = {8529},
note = {Conference on Remote Sensing and Modeling of the Atmosphere, Oceans, and Interactions IV, Kyoto, JAPAN, OCT 31-NOV 01, 2012},
doi = {https://doi.org/10.1117/12.979664}
}
|
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| Maksyutov, S., Takagi, H., Valsala, V.K., Saito, M., Oda, T., Saeki, T., Belikov, D.A., Saito, R., Ito, A., Yoshida, Y., Morino, I., Uchino, O., Andres, R.J. and Yokota, T. | Regional CO2 flux estimates for 2009-2010 based on GOSAT and ground-based CO2 observations | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({18}), pp. 9351-9373 |
article | DOI |
| Abstract: We present the application of a global carbon cycle modeling system to the estimation of monthly regional CO2 fluxes from the column-averaged mole fractions of CO2 (X-CO2) retrieved from spectral observations made by the Greenhouse gases Observing SATellite (GOSAT). The regional flux estimates are to be publicly disseminated as the GOSAT Level 4 data product. The forward modeling components of the system include an atmospheric tracer transport model, an anthropogenic emissions inventory, a terrestrial biosphere exchange model, and an oceanic flux model. The atmospheric tracer transport was simulated using isentropic coordinates in the stratosphere and was tuned to reproduce the age of air. We used a fossil fuel emission inventory based on large point source data and observations of night-time lights. The terrestrial biospheric model was optimized by fitting model parameters to observed atmospheric CO2 seasonal cycle, net primary production data, and a biomass distribution map. The oceanic surface pCO(2) distribution was estimated with a 4-D variational data assimilation system based on reanalyzed ocean currents. Monthly CO2 fluxes of 64 sub-continental regions, between June 2009 and May 2010, were estimated from GOSAT FTS SWIR Level 2 X-CO2 retrievals (ver. 02.00) gridded to 5 degrees x 5 degrees cells and averaged on a monthly basis and monthly-mean GLOBALVIEW-CO2 data. Our result indicated that adding the GOSAT X-CO2 retrievals to the GLOBALVIEW data in the flux estimation brings changes to fluxes of tropics and other remote regions where the surface-based data are sparse. The uncertainties of these remote fluxes were reduced by as much as 60% through such addition. Optimized fluxes estimated for many of these regions, were brought closer to the prior fluxes by the addition of the GOSAT retrievals. In most of the regions and seasons considered here, the estimated fluxes fell within the range of natural flux variabilities estimated with the component models. |
|||||
BibTeX:
@article{maksyutov13a,
author = {Maksyutov, S. and Takagi, H. and Valsala, V. K. and Saito, M. and Oda, T. and Saeki, T. and Belikov, D. A. and Saito, R. and Ito, A. and Yoshida, Y. and Morino, I. and Uchino, O. and Andres, R. J. and Yokota, T.},
title = {Regional CO2 flux estimates for 2009-2010 based on GOSAT and ground-based CO2 observations},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {18},
pages = {9351--9373},
doi = {https://doi.org/10.5194/acp-13-9351-2013}
}
|
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| Maksyutov, S., Oda, T., Saito, M., Janardanan, R., Belikov, D., Kaiser, J.W., Zhuravlev, R., Ganshin, A., Valsala, V.K., Andrews, A., Chmura, L., Dlugokencky, E., Haszpra, L., Langenfelds, R.L., Machida, T., Nakazawa, T., Ramonet, M., Sweeney, C. and Worthy, D. | Technical note: A high-resolution inverse modelling technique for estimating surface CO2 fluxes based on the NIES-TM-FLEXPART coupled transport model and its adjoint | {2021} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {21}({2}), pp. {1245-1266} |
article | DOI URL |
| Abstract: We developed a high-resolution surface flux inversion system based on the global Eulerian-Lagrangian coupled tracer transport model composed of the National Institute for Environmental Studies (NIES) transport model (TM; collectively NIES-TM) and the FLEXible PARTicle dispersion model (FLEXPART). The inversion system is named NTFVAR (NIES-TM-FLEXPART-variational) as it applies a variational optimization to estimate surface fluxes. We tested the system by estimating optimized corrections to natural surface CO2 fluxes to achieve the best fit to atmospheric CO2 data collected by the global in situ network as a necessary step towards the capability of estimating anthropogenic CO2 emissions. We employed the Lagrangian particle dispersion model (LPDM) FLEXPART to calculate surface flux footprints of CO2 observations at a spatial resolution of 0.1 degrees x0.1 degrees. The LPDM is coupled with a global atmospheric tracer transport model (NIES-TM). Our inversion technique uses an adjoint of the coupled transport model in an iterative optimization procedure. The flux error covariance operator was implemented via implicit diffusion. Biweekly flux corrections to prior flux fields were estimated for the years 2010-2012 from in situ CO2 data included in the Observation Package (ObsPack) data set. High-resolution prior flux fields were prepared using the Open-Data Inventory for Anthropogenic Carbon dioxide (ODIAC) for fossil fuel combustion, the Global Fire Assimilation System (GFAS) for biomass burning, the Vegetation Integrative SImulator for Trace gases (VISIT) model for terrestrial biosphere exchange, and the Ocean Tracer Transport Model (OTTM) for oceanic exchange. The terrestrial biospheric flux field was constructed using a vegetation mosaic map and a separate simulation of CO2 fluxes at a daily time step by the VISIT model for each vegetation type. The prior flux uncertainty for the terrestrial biosphere was scaled proportionally to the monthly mean gross primary production (GPP) by the Moderate Resolution Imaging Spectroradiometer (MODIS) MOD17 product. The inverse system calculates flux corrections to the prior fluxes in the form of a relatively smooth field multiplied by high-resolution patterns of the prior flux uncertainties for land and ocean, following the coastlines and fine-scale vegetation productivity gradients. The resulting flux estimates improved the fit to the observations taken at continuous observation sites, reproducing both the seasonal and short-term concentration variabilities including high CO2 concentration events associated with anthropogenic emissions. The use of a high-resolution atmospheric transport in global CO2 flux inversions has the advantage of better resolving the transported mixed signals from the anthropogenic and biospheric sources in densely populated continental regions. Thus, it has the potential to achieve better separation between fluxes from terrestrial ecosystems and strong localized sources, such as anthropogenic emissions and forest fires. Further improvements in the modelling system are needed as our posterior fit was better than that of the National Oceanic and Atmospheric Administration (NOAA)'s CarbonTracker for only a fraction of the monitoring sites, i.e. mostly at coastal and island locations where background and local flux signals are mixed. | |||||
BibTeX:
@article{maksyutov21a,
author = {Maksyutov, Shamil and Oda, Tomohiro and Saito, Makoto and Janardanan, Rajesh and Belikov, Dmitry and Kaiser, Johannes W. and Zhuravlev, Ruslan and Ganshin, Alexander and Valsala, Vinu K. and Andrews, Arlyn and Chmura, Lukasz and Dlugokencky, Edward and Haszpra, Laszlo and Langenfelds, Ray L. and Machida, Toshinobu and Nakazawa, Takakiyo and Ramonet, Michel and Sweeney, Colm and Worthy, Douglas},
title = {Technical note: A high-resolution inverse modelling technique for estimating surface CO2 fluxes based on the NIES-TM-FLEXPART coupled transport model and its adjoint},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2021},
volume = {21},
number = {2},
pages = {1245--1266},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/21/1245/2021/},
doi = {https://doi.org/10.5194/acp-21-1245-2021}
}
|
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| Mallia, D.V., Lin, J.C., Urbanski, S., Ehleringer, J. and Nehrkorn, T. | Impacts of upwind wildfire emissions on CO, CO2, and PM2.5 concentrations in Salt Lake City, Utah | {2015} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {120}({1}), pp. 147-166 |
article | DOI |
| Abstract: Biomass burning is known to contribute large quantities of CO2, CO, and PM2.5 to the atmosphere. Biomass burning not only affects the area in the vicinity of fire but may also impact the air quality far downwind from the fire. The 2007 and 2012 western U.S. wildfire seasons were characterized by significant wildfire activity across much of the Intermountain West and California. In this study, we determined the locations of wildfire-derived emissions and their aggregate impacts on Salt Lake City, a major urban center downwind of the fires. To determine the influences of biomass burning emissions, we initiated an ensemble of stochastic back trajectories at the Salt Lake City receptor within the Stochastic Time-Inverted Lagrangian Transport (STILT) model, driven by wind fields from the Weather Research and Forecasting (WRF) model. The trajectories were combined with a new, high-resolution biomass burning emissions inventorythe Wildfire Emissions Inventory. Initial results showed that the WRF-STILT model was able to replicate many periods of enhanced wildfire activity observed in the measurements. Most of the contributions for the 2007 and 2012 wildfire seasons originated from fires located in Utah and central Idaho. The model results suggested that during intense episodes of upwind wildfires in 2007 and 2012, fires contributed as much as 250ppb of CO during a 3 h period and 15 mu g/m(3) of PM2.5 averaged over 24 h at Salt Lake City. Wildfires had a much smaller impact on CO2 concentrations in Salt Lake City, with contributions rarely exceeding 2ppm enhancements. Key Points |
|||||
BibTeX:
@article{mallia15a,
author = {Mallia, D. V. and Lin, J. C. and Urbanski, S. and Ehleringer, J. and Nehrkorn, T.},
title = {Impacts of upwind wildfire emissions on CO, CO2, and PM2.5 concentrations in Salt Lake City, Utah},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2015},
volume = {120},
number = {1},
pages = {147--166},
doi = {https://doi.org/10.1002/2014JD022472}
}
|
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| Manning, A.C., Nisbet, E.G., Keeling, R.F. and Liss, P.S. | Greenhouse gases in the Earth system: setting the agenda to 2030 | {2011} | PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES Vol. {369}({1943}), pp. 1885-1890 |
article | DOI |
| Abstract: What do we need to know about greenhouse gases? Over the next 20 years, how should scientists study the role of greenhouse gases in the Earth system and the changes that are taking place? These questions were addressed at a Royal Society scientific Discussion Meeting in London on 22-23 February 2010, with over 300 participants. |
|||||
BibTeX:
@article{manning11a,
author = {Manning, Andrew C. and Nisbet, Euan G. and Keeling, Ralph F. and Liss, Peter S.},
title = {Greenhouse gases in the Earth system: setting the agenda to 2030},
journal = {PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES},
year = {2011},
volume = {369},
number = {1943},
pages = {1885--1890},
doi = {https://doi.org/10.1098/rsta.2011.0076}
}
|
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| Marino, B.D. | System of systems for monitoring greenhouse gas fluxes [BibTeX] |
2010 | misc | URL | |
BibTeX:
@misc{marino10a,
author = {Marino, Bruno DV},
title = {System of systems for monitoring greenhouse gas fluxes},
publisher = {Google Patents},
year = {2010},
url = {https://patents.google.com/patent/US20100198736A1/en}
}
|
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| Marquis, M. and Tans, P. | Climate change - Carbon crucible [BibTeX] |
{2008} | SCIENCE Vol. {320}({5875}), pp. 460-461 |
article | DOI |
BibTeX:
@article{marquis08a,
author = {Marquis, Melinda and Tans, Pieter},
title = {Climate change - Carbon crucible},
journal = {SCIENCE},
year = {2008},
volume = {320},
number = {5875},
pages = {460--461},
doi = {https://doi.org/10.1126/science.1156451}
}
|
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| Martin, C.R. | Estimates of Regional Carbon Dioxide Fluxes Using a Dense Network of Low-Cost In Situ Observations | 2018 | School: University of Maryland | phdthesis | URL |
| Abstract: Current inverse modeling-based estimates of carbon dioxide (CO2) fluxes in urban areas typically use a network of 10-20 observation sites featuring high-accuracy gas analyzers that can cost over $100,000 each. Recently, commercially available, low-cost sensors to … | |||||
BibTeX:
@phdthesis{martin18a,
author = {Cory Ray Martin},
title = {Estimates of Regional Carbon Dioxide Fluxes Using a Dense Network of Low-Cost In Situ Observations},
school = {University of Maryland},
year = {2018},
url = {https://drum.lib.umd.edu/handle/1903/22156}
}
|
|||||
| Martin, C.R., Zeng, N., Karion, A., Mueller, K., Ghosh, S., Lopez-Coto, I., Gurney, K.R., Oda, T., Prasad, K., Liu, J., Dickerson, R. and Whetstone, J. | Investigating sources of variability and error in simulations of carbon dioxide in an urban region [BibTeX] |
2019 | ATMOSPHERIC ENVIRONMENT Vol. 199, pp. 55-69 |
article | URL |
BibTeX:
@article{martin19a,
author = {Martin, Cory R. and Zeng, N. and Karion, A. and Mueller, K. and Ghosh, S. and Lopez-Coto, I. and Gurney, K. R. and Oda, T. and Prasad, K. and Liu, J. and Dickerson, R.R. and Whetstone, J.},
title = {Investigating sources of variability and error in simulations of carbon dioxide in an urban region},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2019},
volume = {199},
pages = {55-69},
url = {https://www.sciencedirect.com/science/article/pii/S1352231018307799}
}
|
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| Martins, D.K., Sweeney, C., Stirm, B.H. and Shepson, P.B. | Regional surface flux of CO2 inferred from changes in the advected CO2 column density | {2009} | AGRICULTURAL AND FOREST METEOROLOGY Vol. {149}({10}), pp. 1674-1685 |
article | DOI |
| Abstract: A Lagrangian experiment was conducted over Iowa during the daytime (9:00-17:30 LT) on June 19,2007 as part of the North American Carbon Program's Mid-Continent Intensive using a light-weight and operationally flexible aircraft to measure a net drawdown of CO2 concentration within the boundary layer. The drawdown can be related to net ecosystem exchange when anthropogenic emissions are estimated using a combination of the Vulcan fossil fuel emissions inventory coupled with a source contribution analysis using HYSPLIT. Results show a temporally and spatially averaged net CO2 flux Of -9.0 +/- 2.4 mu mol m(-2) s(-1) measured from the aircraft data. The average flux from anthropogenic emissions over the measurement area was 0.3 +/- 0.1 mu mol CO2 m(-2) s(-1). Large-scale subsidence occurred during the experiment, entraining 1.0 +/- 0.2 mu mol CO2 m(-2) s(-1) into the boundary layer. Thus, the CO2 flux attributable to the vegetation and soils is -10.3 +/- 2.4 mu mol m(-2) s(-1). The magnitude of the calculated daytime biospheric flux is consistent with tower-based eddy covariance fluxes over corn and soybeans given existing land-use estimates for this agricultural region. Flux values are relatively insensitive to the choice of integration height above the boundary layer and emission footprint area. Flux uncertainties are relatively small compared to the biospheric fluxes, though the measurements were conducted at the height of the growing season. (C) 2009 Elsevier B.V. All rights reserved. |
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BibTeX:
@article{martins09a,
author = {Martins, Douglas K. and Sweeney, Colm and Stirm, Brian H. and Shepson, Paul B.},
title = {Regional surface flux of CO2 inferred from changes in the advected CO2 column density},
journal = {AGRICULTURAL AND FOREST METEOROLOGY},
year = {2009},
volume = {149},
number = {10},
pages = {1674--1685},
doi = {https://doi.org/10.1016/j.agrformet.2009.05.005}
}
|
|||||
| Martins, D.K. | Development of methods for measurement of biosphere-atmosphere exchange of carbon and nitrogen [BibTeX] |
2009 | School: Purdue University | phdthesis | URL |
BibTeX:
@phdthesis{martins09b,
author = {Martins, Douglas K},
title = {Development of methods for measurement of biosphere-atmosphere exchange of carbon and nitrogen},
school = {Purdue University},
year = {2009},
url = {http://search.proquest.com/openview/fbdc1f23ed5696bf082a793577dd4459/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Masarie, K.A., Petron, G., Andrews, A., Bruhwiler, L., Conway, T.J., Jacobson, A.R., Miller, J.B., Tans, P.P., Worthy, D.E. and Peters, W. | Impact of CO2 measurement bias on CarbonTracker surface flux estimates | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: For over 20 years, atmospheric measurements of CO2 dry air mole fractions have been used to derive estimates of CO2 surface fluxes. Historically, only a few research laboratories made these measurements. Today, many laboratories are making CO2 observations using a variety of analysis techniques and, in some instances, using different calibration scales. As a result, the risk of biases in individual CO2 mole fraction records, or even in complete monitoring networks, has increased over the last decades. Ongoing experiments comparing independent, well-calibrated measurements of atmospheric CO2 show that biases can and do exist between measurement records. Biases in measurements create artificial spatial and temporal CO2 gradients, which are then interpreted by an inversion system, leading to erroneous flux estimates. Here we evaluate the impact of a constant bias introduced into the National Oceanic and Atmospheric Administration (NOAA) quasi-continuous measurement record at the Park Falls, Wisconsin (LEF), tall tower site on CarbonTracker flux estimates. We derive a linear relationship between the magnitude of the introduced bias at LEF and the CarbonTracker surface flux responses. Temperate North American net flux estimates are most sensitive to a bias at LEF in our CarbonTracker inversion, and its linear response rate is 68 Tg C yr(-1) (similar to 10% of the estimated North American annual terrestrial uptake) for every 1 ppm of bias in the LEF record. This sensitivity increases when (1) measurement biases approached assumed model errors and (2) fewer other measurement records are available to anchor the flux estimates despite the presence of bias in one record. Flux estimate errors are also calculated beyond North America. For example, biospheric uptake in Europe and boreal Eurasia combined increases by 25 Tg C yr(-1) per ppm CO2 to partially compensate for changes in the North American flux totals. These results illustrate the importance of well-calibrated, high-precision CO2 dry air mole fraction measurements, as well as the value of an effective strategy for detecting bias in measurements. This study stresses the need for a monitoring network with the necessary density to anchor regional, continental, and hemispheric fluxes more tightly and to lessen the impact of potentially undetected biases in observational networks operated by different national and international research programs. |
|||||
BibTeX:
@article{masarie11a,
author = {Masarie, K. A. and Petron, G. and Andrews, A. and Bruhwiler, L. and Conway, T. J. and Jacobson, A. R. and Miller, J. B. and Tans, P. P. and Worthy, D. E. and Peters, W.},
title = {Impact of CO2 measurement bias on CarbonTracker surface flux estimates},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2011JD016270}
}
|
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| Masarie, K.A., Peters, W., Jacobson, A.R. and Tans, P.P. | ObsPack: a framework for the preparation, delivery, and attribution of atmospheric greenhouse gas measurements | {2014} | EARTH SYSTEM SCIENCE DATA Vol. {6}({2}), pp. 375-384 |
article | DOI |
| Abstract: Observation Package (ObsPack) is a framework designed to bring together atmospheric greenhouse gas observations from a variety of sampling platforms, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. Data products created using the ObsPack framework (called ``ObsPack products'') are intended to support carbon cycle modeling studies and represent a next generation of value-added greenhouse gas observation products modeled after the cooperative GLOBALVIEW products introduced in 1996. Depending on intended use, ObsPack products may include data in their original form reformatted using the ObsPack framework or may contain derived data consisting of averages, subsets, or smoothed representations of original data. All products include extensive ancillary information (metadata) intended to help ensure the data are used appropriately, their calibration and quality assurance history are clearly described, and that individuals responsible for the measurements (data providers or principal investigators (PIs)) are properly acknowledged for their work. ObsPack products are made freely available using a distribution strategy designed to improve communication between data providers and product users. The strategy includes a data usage policy that requires users to directly communicate with data providers and an automated e-mail notification system triggered when a product is accessed. ObsPack products will be assigned a unique digital object identifier (DOI) to ensure each product can be unambiguously identified in scientific literature. Here we describe the ObsPack framework and its potential role in supporting the evolving needs of both data providers and product users. |
|||||
BibTeX:
@article{masarie14a,
author = {Masarie, K. A. and Peters, W. and Jacobson, A. R. and Tans, P. P.},
title = {ObsPack: a framework for the preparation, delivery, and attribution of atmospheric greenhouse gas measurements},
journal = {EARTH SYSTEM SCIENCE DATA},
year = {2014},
volume = {6},
number = {2},
pages = {375--384},
doi = {https://doi.org/10.5194/essd-6-375-2014}
}
|
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| Medvigy, D. and Moorcroft, P.R. | Predicting ecosystem dynamics at regional scales: an evaluation of a terrestrial biosphere model for the forests of northeastern North America | {2012} | PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES Vol. {367}({1586}), pp. 222-235 |
article | DOI |
| Abstract: Terrestrial biosphere models are important tools for diagnosing both the current state of the terrestrial carbon cycle and forecasting terrestrial ecosystem responses to global change. While there are a number of ongoing assessments of the short-term predictive capabilities of terrestrial biosphere models using flux-tower measurements, to date there have been relatively few assessments of their ability to predict longer term, decadal-scale biomass dynamics. Here, we present the results of a regional-scale evaluation of the Ecosystem Demography version 2 (ED2)-structured terrestrial biosphere model, evaluating the model's predictions against forest inventory measurements for the northeast USA and Quebec from 1985 to 1995. Simulations were conducted using a default parametrization, which used parameter values from the literature, and a constrained model parametrization, which had been developed by constraining the model's predictions against 2 years of measurements from a single site, Harvard Forest (42.5 degrees N, 72.1 degrees W). The analysis shows that the constrained model parametrization offered marked improvements over the default model formulation, capturing large-scale variation in patterns of biomass dynamics despite marked differences in climate forcing, land-use history and species-composition across the region. These results imply that data-constrained parametrizations of structured biosphere models such as ED2 can be successfully used for regional-scale ecosystem prediction and forecasting. We also assess the model's ability to capture sub-grid scale heterogeneity in the dynamics of biomass growth and mortality of different sizes and types of trees, and then discuss the implications of these analyses for further reducing the remaining biases in the model's predictions. |
|||||
BibTeX:
@article{medvigy12a,
author = {Medvigy, David and Moorcroft, Paul R.},
title = {Predicting ecosystem dynamics at regional scales: an evaluation of a terrestrial biosphere model for the forests of northeastern North America},
journal = {PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES},
year = {2012},
volume = {367},
number = {1586},
pages = {222--235},
doi = {https://doi.org/10.1098/rstb.2011.0253}
}
|
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| Meirink, J.F., Bergamaschi, P., Frankenberg, C., d'Amelio , M.T.S., Dlugokencky, E.J., Gatti, L.V., Houweling, S., Miller, J.B., Roeckmann, T., Villani, M.G. and Krol, M.C. | Four-dimensional variational data assimilation for inverse modeling of atmospheric methane emissions: Analysis of SCIAMACHY observations | {2008} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {113}({D17}) |
article | DOI |
| Abstract: Recent observations from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instrument aboard ENVISAT have brought new insights in the global distribution of atmospheric methane. In particular, the observations showed higher methane concentrations in the tropics than previously assumed. Here, we analyze the SCIAMACHY observations and their implications for emission estimates in detail using a four-dimensional variational (4D-Var) data assimilation system. We focus on the period September to November 2003 and on the South American continent, for which the satellite observations showed the largest deviations from model simulations. In this set-up the advantages of the 4D-Var approach and the zooming capability of the underlying TM5 atmospheric transport model are fully exploited. After application of a latitude-dependent bias correction to the SCIAMACHY observations, the assimilation system is able to accurately fit those observations, while retaining consistency with a network of surface methane measurements. The main emission increments resulting from the inversion are an increase in the tropics, a decrease in South Asia, and a decrease at northern hemispheric high latitudes. The SCIAMACHY observations yield considerable additional emission uncertainty reduction, particularly in the (sub-)tropical regions, which are poorly constrained by the surface network. For tropical South America, the inversion suggests more than a doubling of emissions compared to the a priori during the 3 months considered. Extensive sensitivity experiments, in which key assumptions of the inversion set-up are varied, show that this finding is robust. Independent airborne observations in the Amazon basin support the presence of considerable local methane sources. However, these observations also indicate that emissions from eastern South America may be smaller than estimated from SCIAMACHY observations. In this respect it must be realized that the bias correction applied to the satellite observations does not take into account potential regional systematic errors, which - if identified in the future - will lead to shifts in the overall distribution of emission estimates. |
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BibTeX:
@article{meirink08a,
author = {Meirink, Jan Fokke and Bergamaschi, Peter and Frankenberg, Christian and d'Amelio, Monica T. S. and Dlugokencky, Edward J. and Gatti, Luciana V. and Houweling, Sander and Miller, John B. and Roeckmann, Thomas and Villani, M. Gabriella and Krol, Maarten C.},
title = {Four-dimensional variational data assimilation for inverse modeling of atmospheric methane emissions: Analysis of SCIAMACHY observations},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2008},
volume = {113},
number = {D17},
doi = {https://doi.org/10.1029/2007JD009740}
}
|
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| Mekonnen, Z.A. | Modeling the impacts of recent climate change on ecosystem productivity across North America [BibTeX] |
2015 | School: University of Alberta | phdthesis | URL |
BibTeX:
@phdthesis{mekonnen15a,
author = {Mekonnen, Zelalem A},
title = {Modeling the impacts of recent climate change on ecosystem productivity across North America},
school = {University of Alberta},
year = {2015},
url = {https://era.library.ualberta.ca/files/3r074x723}
}
|
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| Mekonnen, Z.A., Grant, R.F. and Schwalm, C. | Carbon sources and sinks of North America as affected by major drought events during the past 30 years | {2017} | AGRICULTURAL AND FOREST METEOROLOGY Vol. {244}, pp. 42-56 |
article | DOI |
| Abstract: The North American (NA) terrestrial biosphere has been a long-term carbon sink but impacts of climate extremes such as drought on ecosystem carbon exchange remain largely uncertain. Here, changes in biospheric carbon fluxes with recent climate change and impacts of the major droughts of the past 30 years on continental carbon cycle across NA were studied using a comprehensive mathematical process model, ecosys. In test of these model responses at continental scale, the spatial anomalies in modeled leaf area indices, fully prognostic in the model, from long-term (1980-2010) means during major drought events in 1988 and 2002 agreed well with those in AVHRR NDVI (R-2 = 0.84 in 1988, 0.71 in 2002). Net ecosystem productivity (NEP) modeled across NA declined by 92% (0.50 Pg C yr(-1)) and 90% (0.49 Pg C yr(-1)) from the long-term mean (+0.54 Pg C yr(-1)), in 1988 and 2002 respectively. These significant drops in NEP offset 28% of the carbon gains modeled over the last three decades. Although the long-term average modeled terrestrial carbon sink was estimated to offset similar to 30% of the fossil fuel emissions of NA, only 0.03% and 3.2% were offset in 1988 and 2002 leaving almost all fossil fuel emissions to the atmosphere. These major drought events controlled much of the continental-scale interannual variability and mainly occurred in parts of the Great Plains, southwest US and northern Mexico. Although warming in northern ecosystems caused increasing carbon sinks to be modeled as a result of greater gross primary productivity with longer growing seasons, elsewhere in the continent frequent drought events of the past 30 years reduced carbon uptake and hence net carbon sinks of the NA. |
|||||
BibTeX:
@article{mekonnen17a,
author = {Mekonnen, Zelalem A. and Grant, Robert F. and Schwalm, Christopher},
title = {Carbon sources and sinks of North America as affected by major drought events during the past 30 years},
journal = {AGRICULTURAL AND FOREST METEOROLOGY},
year = {2017},
volume = {244},
pages = {42--56},
doi = {https://doi.org/10.1016/j.agrformet.2017.05.006}
}
|
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| de Mendoza, I.H., Boucher, E., Gennaretti, F., Lavergne, A., Field, R. and Andreu-Hayles, L. | A new snow module improves predictions of the isotope-enabled MAIDENiso forest growth model | 2022 | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. 15(5), pp. 1931-1952 |
article | DOI |
| Abstract: The representation of snow processes in forest growth models is necessary to accurately predict the hydrological cycle in boreal ecosystems and the isotopic signature of soil water extracted by trees, photosynthates and tree-ring cellulose. Yet, most process-based models do not include a snow module; consequently, their simulations may be biased in cold environments. Here, we modified the MAIDENiso model to incorporate a new snow module that simulates snow accumulation, melting and sublimation, as well as thermal exchanges driving freezing and thawing of the snow and the soil. We tested these implementations in two sites in eastern and western Canada for black spruce (Picea mariana (Mill.) B.S.P.) and white spruce (Picea glauca (Moench) Voss) forests, respectively. The new snow module improves the skills of the model to predict components of the hydrological cycle. The MAIDENiso model is now able to reproduce the spring discharge peak and to simulate stable oxygen isotopes in tree-ring cellulose more realistically than in the original snow-free version of the model. The new implementation also results in simulations with a higher contribution from the source water on the oxygen isotopic composition of the simulated cellulose, leading to more accurate estimates of cellulose isotopic composition. Future work may include the development of inverse modelling with this new version of MAIDENiso to produce robust reconstructions of the hydrological cycle and isotope processes in cold environments. |
|||||
BibTeX:
@article{mendoza22a,
author = {de Mendoza, Ignacio Hermoso and Boucher, Etienne and Gennaretti, Fabio and Lavergne, Alienor and Field, Robert and Andreu-Hayles, Laia},
title = {A new snow module improves predictions of the isotope-enabled MAIDENiso forest growth model},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2022},
volume = {15},
number = {5},
pages = {1931-1952},
doi = {https://doi.org/10.5194/gmd-15-1931-2022}
}
|
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| Mengistu, A.G. and Tsidu, G.M. | On the performance of satellite-based observations of X CO2 in capturing the NOAA Carbon Tracker model and ground-based flask observations over Africa's land mass | {2020} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {13}({7}), pp. {4009-4033} |
article | DOI URL |
| Abstract: Africa is one of the most data-scarce regions as satellite observation at the Equator is limited by cloud cover and there is a very limited number of ground-based measurements. As a result, the use of simulations from models is mandatory to fill this data gap. A comparison of satellite observation with model and available in situ observations will be useful to estimate the performance of satellites in the region. In this study, GOSAT column-averaged carbon dioxide dry-air mole fraction (XCO2) is compared with the NOAA CT2016 and six flask observations over Africa using 5 years of data covering the period from May 2009 to April 2014. Ditto for OCO-2 XCO2 against NOAA CT16NRT17 and eight flask observations over Africa using 2 years of data covering the period from January 2015 to December 2016. The analysis shows that the XCO2 from GOSAT is higher than XCO2 simulated by CT2016 by 0.28 +/- 1.05 ppm, whereas OCO-2 X CO2 is lower than CT16NRT17 by 0.34 +/- 0.9 ppm on the African land mass on average. The mean correlations of 0.83 +/- 1.12 and 0.60 +/- 1.41 and average root mean square deviation (RMSD) of 2.30 +/- 1.45 and 2.57 +/- 0.89 ppm are found between the model and the respective datasets from GOSAT and OCO-2, implying the existence of a reasonably good agreement between CT and the two satellites over Africa's land region. However, significant variations were observed in some regions. For example, OCO-2 XCO2 are lower than that of CT16NRT17 by up to 3 ppm over some regions in North Africa (e.g. Egypt, Libya, and Mali), whereas it exceeds CT16NRT17 XCO2 by 2 ppm over Equatorial Africa (10 degrees S-10 degrees N). This regional difference is also noted in the comparison of model simulations and satellite observations with flask observations over the continent. For ex-ample, CT shows a better sensitivity in capturing flask observations over sites located in North Africa. In contrast, satellite observations have better sensitivity in capturing flask observations in lower-altitude island sites. CT2016 shows a high spatial mean of seasonal mean RMSD of 1.91 ppm during DJF with respect to GOSAT, while CT16NRT17 shows 1.75 ppm during MAM with respect to OCO-2. On the other hand, low RMSDs of 1.00 and 1.07 ppm during SON in the model X CO2 with respect to GOSAT and OCO-2 are respectively determined, indicating better agreement during autumn. The model simulation and satellite observations exhibit similar seasonal cycles of XCO2 with a small discrepancy over Southern Africa (35-10 degrees S) and during wet seasons over all regions. | |||||
BibTeX:
@article{mengistu20a,
author = {Mengistu, Anteneh Getachew and Tsidu, Gizaw Mengistu},
title = {On the performance of satellite-based observations of X CO2 in capturing the NOAA Carbon Tracker model and ground-based flask observations over Africa's land mass},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {13},
number = {7},
pages = {4009--4033},
note = {Query date: 2021-04-02 15:20:04},
url = {https://amt.copernicus.org/articles/13/4009/2020/},
doi = {https://doi.org/10.5194/amt-13-4009-2020}
}
|
|||||
| Mengistu, A.G. and Mengistu Tsidu, G. | Comparison of CO2 from NOAA Carbon Tracker reanalysis model and satellites over Africa [BibTeX] |
2018 | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. 2018, pp. 1-31 |
article | URL |
BibTeX:
@article{mengistua18a,
author = {Mengistu, A. G. and Mengistu Tsidu, G.},
title = {Comparison of CO2 from NOAA Carbon Tracker reanalysis model and satellites over Africa},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2018},
volume = {2018},
pages = {1-31},
url = {https://www.atmos-meas-tech-discuss.net/amt-2018-84/amt-2018-84.pdf}
}
|
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| Messerschmidt, J., Parazoo, N., Wunch, D., Deutscher, N.M., Roehl, C., Warneke, T. and Wennberg, P.O. | Evaluation of seasonal atmosphere-biosphere exchange estimations with TCCON measurements | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({10}), pp. 5103-5115 |
article | DOI |
| Abstract: We evaluate three estimates of the atmosphere-biosphere exchange against total column CO2 observations from the Total Carbon Column Observing Network (TCCON). Using the GEOS-Chem transport model, we produce forward simulations of atmospheric CO2 concentrations for the 2006-2010 time period using the Carnegie-Ames-Stanford Approach (CASA), the Simple Biosphere (SiB) and the GBiome-BGC models. Large differences in the CO2 simulations result from the choice of the atmosphere-biosphere model. We evaluate the seasonal cycle phase, amplitude and shape of the simulations. The version of CASA currently used as the a priori model by the GEOS-Chem carbon cycle community poorly represents the season cycle in total column CO2. Consistent with earlier studies, enhancing the CO2 uptake in the boreal forest and shifting the onset of the growing season earlier significantly improve the simulated seasonal CO2 cycle using CASA estimates. The SiB model gives a better representation of the seasonal cycle dynamics. The difference in the seasonality of net ecosystem exchange (NEE) between these models is not the absolute gross primary productivity (GPP), but rather the differential phasing of ecosystem respiration (RE) with respect to GPP between these models. |
|||||
BibTeX:
@article{messerschmidt13a,
author = {Messerschmidt, J. and Parazoo, N. and Wunch, D. and Deutscher, N. M. and Roehl, C. and Warneke, T. and Wennberg, P. O.},
title = {Evaluation of seasonal atmosphere-biosphere exchange estimations with TCCON measurements},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {10},
pages = {5103--5115},
doi = {https://doi.org/10.5194/acp-13-5103-2013}
}
|
|||||
| Miles, N.L., Richardson, S.J., Davis, K.J., Lauvaux, T., Andrews, A.E., West, T.O., Bandaru, V. and Crosson, E.R. | Large amplitude spatial and temporal gradients in atmospheric boundary layer CO2 mole fractions detected with a tower-based network in the U.S. upper Midwest | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {117} |
article | DOI |
| Abstract: This study presents observations of atmospheric boundary layer CO2 mole fraction from a nine-tower regional network deployed during the North American Carbon Program's Mid-Continent Intensive (MCI) during 2007-2009. The MCI region is largely agricultural, with well-documented carbon exchange available via agricultural inventories. By combining vegetation maps and tower footprints, we show the fractional influence of corn, soy, grass, and forest biomes varies widely across the MCI. Differences in the magnitude of CO2 flux from each of these biomes lead to large spatial gradients in the monthly averaged CO2 mole fraction observed in the MCI. In other words, the monthly averaged gradients are tied to regional patterns in net ecosystem exchange (NEE). The daily scale gradients are more weakly connected to regional NEE, instead being governed by local weather and large-scale weather patterns. With this network of tower-based mole fraction measurements, we detect climate-driven interannual changes in crop growth that are confirmed by satellite and inventory methods. These observations show that regional-scale CO2 mole fraction networks yield large, coherent signals governed largely by regional sources and sinks of CO2. |
|||||
BibTeX:
@article{miles12a,
author = {Miles, Natasha L. and Richardson, Scott J. and Davis, Kenneth J. and Lauvaux, Thomas and Andrews, Arlyn E. and West, Tristram O. and Bandaru, Varaprasad and Crosson, Eric R.},
title = {Large amplitude spatial and temporal gradients in atmospheric boundary layer CO2 mole fractions detected with a tower-based network in the U.S. upper Midwest},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2011JG001781}
}
|
|||||
| Miles, N.L., Davis, K.J., Richardson, S.J., Lauvaux, T., Martins, D.K., Deng, A.J., Balashov, N., Gurney, K.R., Liang, J., Roest, G., Wang, J.A. and Turnbull, J.C. | The influence of near-field fluxes on seasonal carbon dioxide enhancements: results from the Indianapolis Flux Experiment (INFLUX) | 2021 | CARBON BALANCE AND MANAGEMENT Vol. 16(1) |
article | DOI |
| Abstract: Background: Networks of tower-based CO2 mole fraction sensors have been deployed by various groups in and around cities across the world to quantify anthropogenic CO2 emissions from metropolitan areas. A critical aspect in these approaches is the separation of atmospheric signatures from distant sources and sinks (i.e., the background) from local emissions and biogenic fluxes. We examined CO2 enhancements compared to forested and agricultural background towers in Indianapolis, Indiana, USA, as a function of season and compared them to modeled results, as a part of the Indianapolis Flux (INFLUX) project. Results: At the INFLUX urban tower sites, daytime growing season enhancement on a monthly timescale was up to 4.3-6.5 ppm, 2.6 times as large as those in the dormant season, on average. The enhancement differed significantly depending on choice of background and time of year, being 2.8 ppm higher in June and 1.8 ppm lower in August using a forested background tower compared to an agricultural background tower. A prediction based on land cover and observed CO2 fluxes showed that differences in phenology and drawdown intensities drove measured differences in enhancements. Forward modelled CO2 enhancements using fossil fuel and biogenic fluxes indicated growing season model-data mismatch of 1.1 +/- 1.7 ppm for the agricultural background and 2.1 +/- 0.5 ppm for the forested background, corresponding to 25-29% of the modelled CO2 enhancements. The model-data total CO2 mismatch during the dormant season was low, - 0.1 +/- 0.5 ppm. Conclusions: Because growing season biogenic fluxes at the background towers are large, the urban enhancements must be disentangled from the biogenic signal, and growing season increases in CO2 enhancement could be misinterpreted as increased anthropogenic fluxes if the background ecosystem CO2 drawdown is not considered. The magnitude and timing of enhancements depend on the land cover type and net fluxes surrounding each background tower, so a simple box model is not appropriate for interpretation of these data. Quantification of the seasonality and magnitude of the biological fluxes in the study region using high-resolution and detailed biogenic models is necessary for the interpretation of tower-based urban CO2 networks for cities with significant vegetation. |
|||||
BibTeX:
@article{miles21a,
author = {Miles, Natasha L. and Davis, Kenneth J. and Richardson, Scott J. and Lauvaux, Thomas and Martins, Douglas K. and Deng, A. J. and Balashov, Nikolay and Gurney, Kevin R. and Liang, Jianming and Roest, Geoff and Wang, Jonathan A. and Turnbull, Jocelyn C.},
title = {The influence of near-field fluxes on seasonal carbon dioxide enhancements: results from the Indianapolis Flux Experiment (INFLUX)},
journal = {CARBON BALANCE AND MANAGEMENT},
year = {2021},
volume = {16},
number = {1},
doi = {https://doi.org/10.1186/s13021-020-00166-z}
}
|
|||||
| Miller, S.M., Matross, D.M., Andrews, A.E., Millet, D.B., Longo, M., Gottlieb, E.W., Hirsch, A.I., Gerbig, C., Lin, J.C., Daube, B.C., Hudman, R.C., Dias, P.L.S., Chow, V.Y. and Wofsy, S.C. | Sources of carbon monoxide and formaldehyde in North America determined from high-resolution atmospheric data | {2008} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {8}({24}), pp. 7673-7696 |
article | DOI |
| Abstract: We analyze the North American budget for carbon monoxide using data for CO and formaldehyde concentrations from tall towers and aircraft in a model-data assimilation framework. The Stochastic Time-Inverted Lagrangian Transport model for CO (STILT-CO) determines local to regional-scale CO contributions associated with production from fossil fuel combustion, biomass burning, and oxidation of volatile organic compounds (VOCs) using an ensemble of Lagrangian particles driven by high resolution assimilated meteorology. In many cases, the model demonstrates high fidelity simulations of hourly surface data from tall towers and point measurements from aircraft, with somewhat less satisfactory performance in coastal regions and when CO from large biomass fires in Alaska and the Yukon Territory influence the continental US. Inversions of STILT-CO simulations for CO and formaldehyde show that current inventories of CO emissions from fossil fuel combustion are significantly too high, by almost a factor of three in summer and a factor two in early spring, consistent with recent analyses of data from the INTEXA aircraft program. Formaldehyde data help to show that sources of CO from oxidation of CH4 and other VOCs represent the dominant sources of CO over North America in summer. |
|||||
BibTeX:
@article{miller08a,
author = {Miller, S. M. and Matross, D. M. and Andrews, A. E. and Millet, D. B. and Longo, M. and Gottlieb, E. W. and Hirsch, A. I. and Gerbig, C. and Lin, J. C. and Daube, B. C. and Hudman, R. C. and Dias, P. L. S. and Chow, V. Y. and Wofsy, S. C.},
title = {Sources of carbon monoxide and formaldehyde in North America determined from high-resolution atmospheric data},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2008},
volume = {8},
number = {24},
pages = {7673--7696},
doi = {https://doi.org/10.5194/acp-8-7673-2008}
}
|
|||||
| Miller, J.B., Lehman, S.J., Montzka, S.A., Sweeney, C., Miller, B.R., Karion, A., Wolak, C., Dlugokencky, E.J., Southon, J., Turnbull, J.C. and Tans, P.P. | Linking emissions of fossil fuel CO2 and other anthropogenic trace gases using atmospheric (CO2)-C-14 | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {117} |
article | DOI |
| Abstract: Atmospheric CO2 gradients are usually dominated by the signal from net terrestrial biological fluxes, despite the fact that fossil fuel combustion fluxes are larger in the annual mean. Here, we use a six year long series of (CO2)-C-14 and CO2 measurements obtained from vertical profiles at two northeast U.S. aircraft sampling sites to partition lower troposphere CO2 enhancements (and depletions) into terrestrial biological and fossil fuel components (C-bio and C-ff). Mean C-ff is 1.5 ppm, and 2.4 ppm when we consider only planetary boundary layer samples. However, we find that the contribution of C-bio to CO2 enhancements is large throughout the year, and averages 60% in winter. Paired observations of C-ff and the lower troposphere enhancements (Delta(gas)) of 22 other anthropogenic gases (CH4, CO, halo- and hydrocarbons and others) measured in the same samples are used to determine apparent emission ratios for each gas. We then scale these ratios by the well known U.S. fossil fuel CO2 emissions to provide observationally based estimates of national emissions for each gas and compare these to ``bottom up'' estimates from inventories. Correlations of Delta(gas) with C-ff for almost all gases are statistically significant with median r(2) for winter, summer and the entire year of 0.59, 0.45, and 0.42, respectively. Many gases exhibit statistically significant winter: summer differences in ratios that indicate seasonality of emissions or chemical destruction. The variability of ratios in a given season is not readily attributable to meteorological or geographic variables and instead most likely reflects real, short-term spatiotemporal variability of emissions. |
|||||
BibTeX:
@article{miller12a,
author = {Miller, John B. and Lehman, Scott J. and Montzka, Stephen A. and Sweeney, Colm and Miller, Benjamin R. and Karion, Anna and Wolak, Chad and Dlugokencky, Ed J. and Southon, John and Turnbull, Jocelyn C. and Tans, Pieter P.},
title = {Linking emissions of fossil fuel CO2 and other anthropogenic trace gases using atmospheric (CO2)-C-14},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2011JD017048}
}
|
|||||
| Miller, S.M., Michalak, A.M. and Levi, P.J. | Atmospheric inverse modeling with known physical bounds: an example from trace gas emissions | {2014} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {7}({1}), pp. 303-315 |
article | DOI |
| Abstract: Many inverse problems in the atmospheric sciences involve parameters with known physical constraints. Examples include nonnegativity (e. g., emissions of some urban air pollutants) or upward limits implied by reaction or solubility constants. However, probabilistic inverse modeling approaches based on Gaussian assumptions cannot incorporate such bounds and thus often produce unrealistic results. The atmospheric literature lacks consensus on the best means to overcome this problem, and existing atmospheric studies rely on a limited number of the possible methods with little examination of the relative merits of each. This paper investigates the applicability of several approaches to bounded inverse problems. A common method of data transformations is found to unrealistically skew estimates for the examined example application. The method of Lagrange multipliers and two Markov chain Monte Carlo (MCMC) methods yield more realistic and accurate results. In general, the examined MCMC approaches produce the most realistic result but can require substantial computational time. Lagrange multipliers offer an appealing option for large, computationally intensive problems when exact uncertainty bounds are less central to the analysis. A synthetic data inversion of US anthropogenic methane emissions illustrates the strengths and weaknesses of each approach. |
|||||
BibTeX:
@article{miller14a,
author = {Miller, S. M. and Michalak, A. M. and Levi, P. J.},
title = {Atmospheric inverse modeling with known physical bounds: an example from trace gas emissions},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2014},
volume = {7},
number = {1},
pages = {303--315},
doi = {https://doi.org/10.5194/gmd-7-303-2014}
}
|
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| Miller, S.M., Hayek, M.N., Andrews, A.E., Fung, I. and Liu, J. | Biases in atmospheric CO2 estimates from correlated meteorology modeling errors | {2015} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {15}({5}), pp. 2903-2914 |
article | DOI |
| Abstract: Estimates of CO2 fluxes that are based on atmospheric measurements rely upon a meteorology model to simulate atmospheric transport. These models provide a quantitative link between the surface fluxes and CO2 measurements taken downwind. Errors in the meteorology can therefore cause errors in the estimated CO2 fluxes. Meteorology errors that correlate or covary across time and/or space are particularly worrisome; they can cause biases in modeled atmospheric CO2 that are easily confused with the CO2 signal from surface fluxes, and they are difficult to characterize. In this paper, we leverage an ensemble of global meteorology model outputs combined with a data assimilation system to estimate these biases in modeled atmospheric CO2. In one case study, we estimate the magnitude of month-long CO2 biases relative to CO2 boundary layer enhancements and quantify how that answer changes if we either include or remove error correlations or covariances. In a second case study, we investigate which meteorological conditions are associated with these CO2 biases. In the first case study, we estimate uncertainties of 0.57 ppm in monthly-averaged CO2 concentrations, depending upon location (95% confidence interval). These uncertainties correspond to 13-150% of the mean afternoon CO2 boundary layer enhancement at individual observation sites. When we remove error covariances, however, this range drops to 222 %. Top-down studies that ignore these covariances could therefore underestimate the uncertainties and/or propagate transport errors into the flux estimate. In the second case study, we find that these month-long errors in atmospheric transport are anti-correlated with temperature and planetary boundary layer (PBL) height over terrestrial regions. In marine environments, by contrast, these errors are more strongly associated with weak zonal winds. Many errors, however, are not correlated with a single meteorological parameter, suggesting that a single meteorological proxy is not sufficient to characterize uncertainties in atmospheric CO2. Together, these two case studies provide information to improve the setup of future top-down inverse modeling studies, preventing unforeseen biases in estimated CO2 fluxes. |
|||||
BibTeX:
@article{miller15a,
author = {Miller, S. M. and Hayek, M. N. and Andrews, A. E. and Fung, I. and Liu, J.},
title = {Biases in atmospheric CO2 estimates from correlated meteorology modeling errors},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2015},
volume = {15},
number = {5},
pages = {2903--2914},
doi = {https://doi.org/10.5194/acp-15-2903-2015}
}
|
|||||
| Miller, S.M., Saibaba, A.K., Trudeau, M.E., Mountain, M.E. and Andrews, A.E. | Geostatistical inverse modeling with very large datasets: an example from the Orbiting Carbon Observatory 2 (OCO-2) satellite | {2020} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {13}({3}), pp. {1771-1785} |
article | DOI URL |
| Abstract: Geostatistical inverse modeling (GIM) has become a common approach to estimating greenhouse gas fluxes at the Earth's surface using atmospheric observations. GIMs are unique relative to other commonly used approaches because they do not require a single emissions inventory or a bottom-up model to serve as an initial guess of the fluxes. Instead, a modeler can incorporate a wide range of environmental, economic, and/or land use data to estimate the fluxes. Traditionally, GIMs have been paired with in situ observations that number in the thousands or tens of thousands. However, the number of available atmospheric greenhouse gas observations has been increasing enormously as the number of satellites, airborne measurement campaigns, and in situ monitoring stations continues to increase. This era of prolific greenhouse gas observations presents computational and statistical challenges for inverse modeling frameworks that have traditionally been paired with a limited number of in situ monitoring sites. In this article, we discuss the challenges of estimating greenhouse gas fluxes using large atmospheric datasets with a particular focus on GIMs. We subsequently discuss several strategies for estimating the fluxes and quantifying uncertainties, strategies that are adapted from hydrology, applied math, or other academic fields and are compatible with a wide variety of atmospheric models. We further evaluate the accuracy and computational burden of each strategy using a synthetic CO2 case study based upon NASA's Orbiting Carbon Observatory 2 (OCO-2) satellite. Specifically, we simultaneously estimate a full year of 3-hourly CO2 fluxes across North America in one case study - a total of 9.4 x 10(6) unknown fluxes using 9.9 x 10(4) synthetic observations. The strategies discussed here provide accurate estimates of CO2 fluxes that are comparable to fluxes calculated directly or analytically. We are also able to approximate posterior uncertainties in the fluxes, but these approximations are, typically, an over- or underestimate depending upon the strategy employed and the degree of approximation required to make the calculations manageable. | |||||
BibTeX:
@article{miller20a,
author = {Miller, Scot M. and Saibaba, Arvind K. and Trudeau, Michael E. and Mountain, Marikate E. and Andrews, Arlyn E.},
title = {Geostatistical inverse modeling with very large datasets: an example from the Orbiting Carbon Observatory 2 (OCO-2) satellite},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {13},
number = {3},
pages = {1771--1785},
note = {Query date: 2021-04-02 15:20:04},
url = {https://gmd.copernicus.org/articles/13/1771/2020/},
doi = {https://doi.org/10.5194/gmd-13-1771-2020}
}
|
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| Mingwei, Z., Tianxiang, Y., Xingying, Z., Jinglu, S., Ling, J. and Chun, W. | Fusion of multi-source near-surface CO2 concentration data based on high accuracy surface modeling | {2017} | ATMOSPHERIC POLLUTION RESEARCH Vol. {8}({6}), pp. 1170-1178 |
article | DOI |
| Abstract: Under the background of growing greenhouse gas emissions and the resulting global warming, researches about the spatial-temporal variation analysis of the concentration of carbon dioxide in the regional and global scale has become one of the most important topics in the scientific community. Simulating and analyzing the spatial-temporal variation of the carbon dioxide concentration on a global scale under limited observation data has become one of the key problems to be solved in the research field of spatial analysis technology. A new research approach based on high accuracy surface modeling data fusion (HASM-DF) method was proposed in this paper, in which the output of the CO2 concentration of the GEOS-Chem model were taken as driving field, and the observation values of CO2 concentration at ground observation station were taken as accuracy control conditions. The new approach's objective is to fulfill the fusion of the two kinds of CO2 data, and obtain the distribution of CO2 on a global scale with a higher accuracy than the results of GEOS-Chem. Root mean square error (RMSE) was chosen as the basic accuracy index, and the experimental analysis shows that the RMSE of the result of the proposed approach is 1.886 ppm, which is significantly lower than that of the GEOS-Chem's 2.239 ppm. Furthermore, compared with the results created by the interpolation methods used the observation values at stations; the fusion results keep a good spatial heterogeneity similar to the results of GEOS-Chem. This research analyzed the spatial distribution and time series variation of the near-surface CO2 based on the fusion result on a global scale. And it can found that areas such as East Asia, Western North American, Central South America and Central Africa and other region show a relatively high value of the near-surface CO2 concentration. And we also found that the near-surface CO2 concentration changes with season, especially in North America and Eurasia, the near-surface CO2 in summer was significantly lower than winter in these areas. (C) 2017 Turkish National Committee for Air Pollution Research and Control. Production and hosting by Elsevier B.V. All rights reserved. |
|||||
BibTeX:
@article{mingwei17a,
author = {Zhao Mingwei and Yue Tianxiang and Zhang Xingying and Sun Jinglu and Jiang Ling and Wang Chun},
title = {Fusion of multi-source near-surface CO2 concentration data based on high accuracy surface modeling},
journal = {ATMOSPHERIC POLLUTION RESEARCH},
year = {2017},
volume = {8},
number = {6},
pages = {1170--1178},
doi = {https://doi.org/10.1016/j.apr.2017.05.003}
}
|
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| Mitchell, L.E., Lin, J.C., Bowling, D.R., Pataki, D.E., Strong, C., Schauer, A.J., Bares, R., Bush, S.E., Stephens, B.B., Mendoza, D., Mallia, D., Holland, L., Gurney, K.R. and Ehleringer, J.R. | Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth | {2018} | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Vol. {115}({12}), pp. {2912-2917} |
article | DOI |
| Abstract: Cities are concentrated areas of CO2 emissions and have become the foci of policies for mitigation actions. However, atmospheric measurement networks suitable for evaluating urban emissions over time are scarce. Here we present a unique long-term (decadal) record of CO2 mole fractions from five sites across Utah's metropolitan Salt Lake Valley. We examine ``excess'' CO2 above background conditions resulting from local emissions and meteorological conditions. We ascribe CO2 trends to changes in emissions, since we did not find long-term trends in atmospheric mixing proxies. Three contrasting CO2 trends emerged across urban types: negative trends at a residential-industrial site, positive trends at a site surrounded by rapid suburban growth, and relatively constant CO2 over time at multiple sites in the established, residential, and commercial urban core. Analysis of population within the atmospheric footprints of the different sites reveals approximately equal increases in population influencing the observed CO2, implying a nonlinear relationship with CO2 emissions: Population growth in rural areas that experienced suburban development was associated with increasing emissions while population growth in the developed urban core was associated with stable emissions. Four state-of-the-art global-scale emission inventories also have a nonlinear relationship with population density across the city; however, in contrast to our observations, they all have nearly constant emissions over time. Our results indicate that decadal scale changes in urban CO2 emissions are detectable through monitoring networks and constitute a valuable approach to evaluate emission inventories and studies of urban carbon cycles. |
|||||
BibTeX:
@article{mitchell18a,
author = {Mitchell, Logan E. and Lin, John C. and Bowling, David R. and Pataki, Diane E. and Strong, Courtenay and Schauer, Andrew J. and Bares, Ryan and Bush, Susan E. and Stephens, Britton B. and Mendoza, Daniel and Mallia, Derek and Holland, Lacey and Gurney, Kevin R. and Ehleringer, James R.},
title = {Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth},
journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
year = {2018},
volume = {115},
number = {12},
pages = {2912-2917},
doi = {https://doi.org/10.1073/pnas.1702393115}
}
|
|||||
| Mitchell, L.E., Lin, J.C., Hutyra, L.R., Bowling, D.R., Cohen, R.C., Davis, K.J., DiGangi, E., Duren, R.M., Ehleringer, J.R., Fain, C., Falk, M., Guha, A., Karion, A., Keeling, R.F., Kim, J., Miles, N.L., Miller, C.E., Newman, S., Pataki, D.E., Prinzivalli, S., Ren, X., Rice, A., Richardson, S.J., Sargent, M., Stephens, B.B., Turnbull, J.C., Verhulst, K.R., Vogel, F., Weiss, R.F., Whetstone, J. and Wofsy, S.C. | A multi-city urban atmospheric greenhouse gas measurement data synthesis | 2022 | SCIENTIFIC DATA Vol. 9(1) |
article | DOI |
| Abstract: Urban regions emit a large fraction of anthropogenic emissions of greenhouse gases (GHG) such as carbon dioxide (CO2) and methane (CH4) that contribute to modern-day climate change. As such, a growing number of urban policymakers and stakeholders are adopting emission reduction targets and implementing policies to reach those targets. Over the past two decades research teams have established urban GHG monitoring networks to determine how much, where, and why a particular city emits GHGs, and to track changes in emissions over time. Coordination among these efforts has been limited, restricting the scope of analyses and insights. Here we present a harmonized data set synthesizing urban GHG observations from cities with monitoring networks across North America that will facilitate cross-city analyses and address scientific questions that are difficult to address in isolation. |
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BibTeX:
@article{mitchell22a,
author = {Mitchell, Logan E. and Lin, John C. and Hutyra, Lucy R. and Bowling, David R. and Cohen, Ronald C. and Davis, Kenneth J. and DiGangi, Elizabeth and Duren, Riley M. and Ehleringer, James R. and Fain, Clayton and Falk, Matthias and Guha, Abhinav and Karion, Anna and Keeling, Ralph F. and Kim, Jooil and Miles, Natasha L. and Miller, Charles E. and Newman, Sally and Pataki, Diane E. and Prinzivalli, Steve and Ren, Xinrong and Rice, Andrew and Richardson, Scott J. and Sargent, Maryann and Stephens, Britton B. and Turnbull, Jocelyn C. and Verhulst, Kristal R. and Vogel, Felix and Weiss, Ray F. and Whetstone, James and Wofsy, Steven C.},
title = {A multi-city urban atmospheric greenhouse gas measurement data synthesis},
journal = {SCIENTIFIC DATA},
year = {2022},
volume = {9},
number = {1},
doi = {https://doi.org/10.1038/s41597-022-01467-3}
}
|
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| Mogollon, R. and Calil, P.H.R. | Counterintuitive effects of global warming-induced wind patterns on primary production in the Northern Humboldt Current System | {2018} | GLOBAL CHANGE BIOLOGY Vol. {24}({7}), pp. {3187-3198} |
article | DOI |
| Abstract: It has been hypothesized that global warming will strengthen upwelling-favorable winds in the Northern Humboldt Current System (NHCS) as a consequence of the increase of the land-sea thermal gradient along the Peruvian coast. The effect of strengthened winds in this region is assessed with the use of a coupled physical-biogeochemical model forced with projected and climatological winds. Strengthened winds induce an increase in primary production of 2% per latitudinal degree from 9.5 degrees S to 5 degrees S. In some important coastal upwelling sites primary production is reduced. This is due to a complex balance between nutrient availability, nutrient use efficiency, as well as eddy- and wind-driven factors. Mesoscale activity induces a net offshore transport of inorganic nutrients, thus reducing primary production in the coastal upwelling region. Wind mixing, in general disadvantageous for primary producers, leads to shorter residence times in the southern and central coastal zones. Overall, instead of a proportional enhancement in primary production due to increased winds, the NHCS becomes only 5% more productive (+5molCm(-2) year(-1)), 10% less limited by nutrients and 15% less efficient due to eddy-driven effects. It is found that regions with a initial strong nutrient limitation are more efficient in terms of nutrient assimilation which makes them more resilient in face of the acceleration of the upwelling circulation. |
|||||
BibTeX:
@article{mogollon18a,
author = {Mogollon, Rodrigo and Calil, Paulo H. R.},
title = {Counterintuitive effects of global warming-induced wind patterns on primary production in the Northern Humboldt Current System},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2018},
volume = {24},
number = {7},
pages = {3187-3198},
doi = {https://doi.org/10.1111/gcb.14171}
}
|
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| Mohanty, P.C., Shetty, S., Mahendra, R.S., Nayak, R.K., Sharma, L.K. and Rao, E.P.R. | Spatio-temporal changes of mangrove cover and its impact on bio-carbon flux along the West Bengal coast, Northeast coast of India | 2021 | EUROPEAN JOURNAL OF REMOTE SENSING Vol. 54(1), pp. 524-536 |
article | DOI |
| Abstract: The present study assesses patio-temporal variability of the greenness index of Indian mangroves of the Sundarban forest with bio-carbon flux during 1990-2020. The analysis of NDVI derived using Landsat data reveals the mangrove stress level was very high during the years 1990, 2006, 2007, 2009 and 2011, with 2011 km(2) mangroves were severely affected out of a total 2215 km(2). The improved and healthy condition prevailed during 1999, 2000, 2001, 2015, 2016 and 2019 and normal condition during 2002, 2005, 2008 and 2010. The net change in mangrove cover during 1990-2020 shows distinct loss and gain regions across the study region. The shoreline change analysis shows that nearly 90 km(2) of mangroves were lost on the seaward side due to coastal erosion. Whereas, 50 km(2 )of newly developed mangroveswere observed in western parts of Southern Parganas due to accretion and no loss/gain was recorded in the rest of the areas. A significant positive correlation (coefficients 0.76 at p=0.01) was recorded between the increase in the extent of the mangrove region and bio-carbon fluxes for the years of normal and high-stress level condition as the dominant classes. Conversely, correlation is insignificant for the years dominated by healthy conditions. |
|||||
BibTeX:
@article{mohanty21a,
author = {Mohanty, P. C. and Shetty, S. and Mahendra, R. S. and Nayak, R. K. and Sharma, L. K. and Rao, E. Pattbhi Rama},
title = {Spatio-temporal changes of mangrove cover and its impact on bio-carbon flux along the West Bengal coast, Northeast coast of India},
journal = {EUROPEAN JOURNAL OF REMOTE SENSING},
year = {2021},
volume = {54},
number = {1},
pages = {524-536},
doi = {https://doi.org/10.1080/22797254.2021.1977183}
}
|
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| van der Molen, M.K., de Jeu, R.A.M., Wagner, W., van der Velde, I.R., Kolari, P., Kurbatova, J., Varlagin, A., Maximov, T.C., Kononov, A.V., Ohta, T., Kotani, A., Krol, M.C. and Peters, W. | The effect of assimilating satellite-derived soil moisture data in SiBCASA on simulated carbon fluxes in Boreal Eurasia | {2016} | HYDROLOGY AND EARTH SYSTEM SCIENCES Vol. {20}({2}), pp. 605-624 |
article | DOI |
| Abstract: Boreal Eurasia is a region where the interaction between droughts and the carbon cycle may have significant impacts on the global carbon cycle. Yet the region is extremely data sparse with respect to meteorology, soil moisture, and carbon fluxes as compared to e.g. Europe. To better constrain our vegetation model SiBCASA, we increase data usage by assimilating two streams of satellite-derived soil moisture. We study whether the assimilation improved SiBCASA's soil moisture and its effect on the simulated carbon fluxes. By comparing to unique in situ soil moisture observations, we show that the passive microwave soil moisture product did not improve the soil moisture simulated by SiBCASA, but the active data seem promising in some aspects. The match between SiBCASA and ASCAT soil moisture is best in the summer months over low vegetation. Nevertheless, ASCAT failed to detect the major droughts occurring between 2007 and 2013. The performance of ASCAT soil moisture seems to be particularly sensitive to ponding, rather than to biomass. The effect on the simulated carbon fluxes is large, 5-10% on annual GPP and TER, tens of percent on local NEE, and 2% on area-integrated NEE, which is the same order of magnitude as the inter-annual variations. Consequently, this study shows that assimilation of satellite-derived soil moisture has potentially large impacts, while at the same time further research is needed to understand under which conditions the satellite-derived soil moisture improves the simulated soil moisture. |
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BibTeX:
@article{molen16a,
author = {van der Molen, M. K. and de Jeu, R. A. M. and Wagner, W. and van der Velde, I. R. and Kolari, P. and Kurbatova, J. and Varlagin, A. and Maximov, T. C. and Kononov, A. V. and Ohta, T. and Kotani, A. and Krol, M. C. and Peters, W.},
title = {The effect of assimilating satellite-derived soil moisture data in SiBCASA on simulated carbon fluxes in Boreal Eurasia},
journal = {HYDROLOGY AND EARTH SYSTEM SCIENCES},
year = {2016},
volume = {20},
number = {2},
pages = {605--624},
doi = {https://doi.org/10.5194/hess-20-605-2016}
}
|
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| Monteil, G., Houweling, S., Butz, A., Guerlet, S., Schepers, D., Hasekamp, O., Frankenberg, C., Scheepmaker, R., Aben, I. and Rockmann, T. | Comparison of CH4 inversions based on 15 months of GOSAT and SCIAMACHY observations | {2013} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {118}({20}), pp. 11807-11823 |
article | DOI |
| Abstract: [1] Over the past decade the development of Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) retrievals has increased the interest in the use of satellite measurements for studying the global sources and sinks of methane. Meanwhile, measurements are becoming available from the more advanced Greenhouse Gases Observing Satellite (GOSAT). The aim of this study is to investigate the application of GOSAT retrievals to inverse modeling, for which we make use of the TM5-4DVAR inverse modeling framework. Inverse modeling calculations are performed using data from two different retrieval approaches: a full physics and a lightpath proxy ratio method. The performance of these inversions is analyzed in comparison with inversions using SCIAMACHY retrievals and measurements from the National Oceanic and Atmospheric Administration-Earth System Research Laboratory flask-sampling network. In addition, we compare the inversion results against independent surface, aircraft, and total-column measurements. Inversions with GOSAT data show good agreement with surface measurements, whereas for SCIAMACHY a similar performance can only be achieved after significant bias corrections. Some inconsistencies between surface and total-column methane remain in the Southern Hemisphere. However, comparisons with measurements from the Total Column Carbon Observing Network in situ Fourier transform spectrometer network indicate that those may be caused by systematic model errors rather than by shortcomings in the GOSAT retrievals. The global patterns of methane emissions derived from SCIAMACHY (with bias correction) and GOSAT retrievals are in remarkable agreement and allow an increased resolution of tropical emissions. The satellite inversions increase tropical methane emission by 30 to 60 Tg CH4/yr compared to initial a priori estimates, partly counterbalanced by reductions in emissions at midlatitudes to high latitudes. |
|||||
BibTeX:
@article{monteil13a,
author = {Monteil, Guillaume and Houweling, Sander and Butz, Andre and Guerlet, Sandrine and Schepers, Dinand and Hasekamp, Otto and Frankenberg, Christian and Scheepmaker, Remco and Aben, Ilse and Rockmann, Thomas},
title = {Comparison of CH4 inversions based on 15 months of GOSAT and SCIAMACHY observations},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2013},
volume = {118},
number = {20},
pages = {11807--11823},
doi = {https://doi.org/10.1002/2013JD019760}
}
|
|||||
| Monteil, G., Broquet, G., Scholze, M., Lang, M., Karstens, U., Gerbig, C., Koch, F.-T., Smith, N.E., Thompson, R.L., Luijkx, I.T., White, E., Meesters, A., Ciais, P., Ganesan, A.L., Manning, A., Mischurow, M., Peters, W., Peylin, P., Tarniewicz, J., Rigby, M., Rodenbeck, C., Vermeulen, A. and Walton, E.M. | The regional European atmospheric transport inversion comparison, EUROCOM: first results on European-wide terrestrial carbon fluxes for the period 2006-2015 | {2020} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {20}({20}), pp. {12063-12091} |
article | DOI URL |
| Abstract: Atmospheric inversions have been used for the past two decades to derive large-scale constraints on the sources and sinks of CO2 into the atmosphere. The development of dense in situ surface observation networks, such as ICOS in Europe, enables in theory inversions at a resolution close to the country scale in Europe. This has led to the development of many regional inversion systems capable of assimilating these high-resolution data, in Europe and elsewhere. The EUROCOM (European atmospheric transport inversion comparison) project is a collaboration between seven European research institutes, which aims at producing a collective assessment of the net carbon flux between the terrestrial ecosystems and the atmosphere in Europe for the period 2006-2015. It aims in particular at investigating the capacity of the inversions to deliver consistent flux estimates from the country scale up to the continental scale. The project participants were provided with a common database of in situ-observed CO2 concentrations (including the observation sites that are now part of the ICOS network) and were tasked with providing their best estimate of the net terrestrial carbon flux for that period, and for a large domain covering the entire European Union. The inversion systems differ by the transport model, the inversion approach, and the choice of observation and prior constraints, enabling us to widely explore the space of uncertainties. This paper describes the intercomparison protocol and the participating systems, and it presents the first results from a reference set of inversions, at the continental scale and in four large regions. At the continental scale, the regional inversions support the assumption that European ecosystems are a relatively small sink (-0.21 +/- 0.2 Pg C yr(-1)). We find that the convergence of the regional inversions at this scale is not better than that obtained in state-of-the-art global inversions. However, more robust results are obtained for subregions within Europe, and in these areas with dense observational coverage, the objective of delivering robust country-scale flux estimates appears achievable in the near future. | |||||
BibTeX:
@article{monteil20a,
author = {Monteil, Guillaume and Broquet, Gregoire and Scholze, Marko and Lang, Matthew and Karstens, Ute and Gerbig, Christoph and Koch, Frank-Thomas and Smith, Naomi E. and Thompson, Rona L. and Luijkx, Ingrid T. and White, Emily and Meesters, Antoon and Ciais, Philippe and Ganesan, Anita L. and Manning, Alistair and Mischurow, Michael and Peters, Wouter and Peylin, Philippe and Tarniewicz, Jerome and Rigby, Matt and Rodenbeck, Christian and Vermeulen, Alex and Walton, Evie M.},
title = {The regional European atmospheric transport inversion comparison, EUROCOM: first results on European-wide terrestrial carbon fluxes for the period 2006-2015},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {20},
number = {20},
pages = {12063--12091},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/20/12063/2020/},
doi = {https://doi.org/10.5194/acp-20-12063-2020}
}
|
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| Monteil, G. and Scholze, M. | Regional CO2 inversions with LUMIA, the Lund University Modular Inversion Algorithm, v1.0 | 2021 | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. 14(6), pp. 3383-3406 |
article | DOI |
| Abstract: Atmospheric inversions are used to derive constraints on the net sources and sinks of CO2 and other stable atmospheric tracers from their observed concentrations. The resolution and accuracy that the fluxes can be estimated with depends, among other factors, on the quality and density of the observational coverage, on the precision and accuracy of the transport model used by the inversion to relate fluxes to observations, and on the adaptation of the statistical approach to the problem studied. In recent years, there has been an increasing demand from stakeholders for inversions at higher spatial resolution (country scale), in particular in the framework of the Paris agreement. This step up in resolution is in theory enabled by the growing availability of observations from surface in situ networks (such as ICOS in Europe) and from remote sensing products (OCO-2, GOSAT-2). The increase in the resolution of inversions is also a necessary step to provide efficient feedback to the bottom-up modeling community (vegetation models, fossil fuel emission inventories, etc.). However, it calls for new developments in the inverse models: diversification of the inversion approaches, shift from global to regional inversions, and improvement in the computational efficiency. In this context, we developed LUMIA, the Lund University Modular Inversion Algorithm. LUMIA is a Python library for inverse modeling built around the central idea of modularity: it aims to be a platform that enables users to construct and experiment with new inverse modeling setups while remaining easy to use and maintain. It is in particular designed to be transport-model-agnostic, which should facilitate isolating the transport model errors from those introduced by the inversion setup itself. We have constructed a first regional inversion setup using the LUMIA framework to conduct regional CO2 inversions in Europe using in situ data from surface and tall-tower observation sites. The inversions rely on a new offline coupling between the regional high-resolution FLEXPART Lagrangian particle dispersion model and the global coarseresolution TM5 transport model. This test setup is intended both as a demonstration and as a reference for comparison with future LUMIA developments. The aims of this paper are to present the LUMIA framework (motivations for building it, development principles and future prospects) and to describe and test this first implementation of regional CO2 inversions in LUMIA. |
|||||
BibTeX:
@article{monteil21a,
author = {Monteil, Guillaume and Scholze, Marko},
title = {Regional CO2 inversions with LUMIA, the Lund University Modular Inversion Algorithm, v1.0},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2021},
volume = {14},
number = {6},
pages = {3383-3406},
doi = {https://doi.org/10.5194/gmd-14-3383-2021}
}
|
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| Montzka, S.A., Dlugokencky, E.J. and Butler, J.H. | Non-CO2 greenhouse gases and climate change | {2011} | NATURE Vol. {476}({7358}), pp. 43-50 |
article | DOI |
| Abstract: Earth's climate is warming as a result of anthropogenic emissions of greenhouse gases, particularly carbon dioxide (CO2) from fossil fuel combustion. Anthropogenic emissions of non-CO2 greenhouse gases, such as methane, nitrous oxide and ozone-depleting substances (largely from sources other than fossil fuels), also contribute significantly to warming. Some non-CO2 greenhouse gases have much shorter lifetimes than CO2, so reducing their emissions offers an additional opportunity to lessen future climate change. Although it is clear that sustainably reducing the warming influence of greenhouse gases will be possible only with substantial cuts in emissions of CO2, reducing non-CO2 greenhouse gas emissions would be a relatively quick way of contributing to this goal. |
|||||
BibTeX:
@article{montzka11a,
author = {Montzka, S. A. and Dlugokencky, E. J. and Butler, J. H.},
title = {Non-CO2 greenhouse gases and climate change},
journal = {NATURE},
year = {2011},
volume = {476},
number = {7358},
pages = {43--50},
doi = {https://doi.org/10.1038/nature10322}
}
|
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| Montzka, S., Reimann, S., O'Doherty, S., Engel, A., Krüger, K. and Sturges, W. | Ozone-depleting substances (ODSs) and related chemicals [BibTeX] |
2011 | book | URL | |
BibTeX:
@book{montzka11b,
author = {Montzka, S and Reimann, SCLA and O'Doherty, S and Engel, A and Krüger, Kirstin and Sturges, WT},
title = {Ozone-depleting substances (ODSs) and related chemicals},
publisher = {World Meteorological Organization},
year = {2011},
url = {http://oceanrep.geomar.de/10405/2/03-Chapter_1.pdf}
}
|
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| Moore III, B., Crowell, S.M.R., Rayner, P.J., Kumer, J., O'Dell, C.W., O'Brien, D., Utembe, S., Polonsky, I., Schimel, D. and Lemen, J. | The Potential of the Geostationary Carbon Cycle Observatory (GeoCarb) to Provide Multi-scale Constraints on the Carbon Cycle in the Americas | {2018} | FRONTIERS IN ENVIRONMENTAL SCIENCE Vol. {6} |
article | DOI |
| Abstract: The second NASA Earth Venture Mission, Geostationary Carbon Cycle Observatory (GeoCarb), will provide measurements of atmospheric carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and solar-induced fluorescence (SIF) from Geostationary Orbit (GEO). The GeoCarb mission will deliver daily maps of column concentrations of CO2, CH4, and CO over the observed landmasses in the Americas at a spatial resolution of roughly 10 x 10 km. Persistent measurements of CO2, CH4, CO, and SIF will contribute significantly to resolving carbon emissions and illuminating biotic processes at urban to continental scales, which will allow the improvement of modeled biogeochemical processes in Earth System Models as well as monitor the response of the biosphere to disturbance. This is essential to improve understanding of the Carbon-Climate connection. In this paper, we introduce the instrument and the GeoCarb Mission, and we demonstrate the potential scientific contribution of the mission through a series of CO2 and CH4 simulation experiments. We find that GeoCarb will be able to constrain emissions at urban to continental spatial scales on weekly to annual time scales. The GeoCarb mission particularly builds upon the Orbiting Carbon Obserevatory-2 (OCO-2), which is flying in Low Earth Orbit. |
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BibTeX:
@article{moore18a,
author = {Moore, III, Berrien and Crowell, Sean M. R. and Rayner, Peter J. and Kumer, Jack and O'Dell, Christopher W. and O'Brien, Denis and Utembe, Steven and Polonsky, Igor and Schimel, David and Lemen, James},
title = {The Potential of the Geostationary Carbon Cycle Observatory (GeoCarb) to Provide Multi-scale Constraints on the Carbon Cycle in the Americas},
journal = {FRONTIERS IN ENVIRONMENTAL SCIENCE},
year = {2018},
volume = {6},
doi = {https://doi.org/10.3389/fenvs.2018.00109}
}
|
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| Moreira, D.S., Freitas, S.R., Bonatti, J.P., Mercado, L.M., Rosario, N.M.E., Longo, K.M., Miller, J.B., Gloor, M. and Gatti, L.V. | Coupling between the JULES land-surface scheme and the CCATT-BRAMS atmospheric chemistry model (JULES-CCATT-BRAMS1.0): applications to numerical weather forecasting and the CO2 budget in South America | {2013} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {6}({4}), pp. 1243-1259 |
article | DOI |
| Abstract: This article presents the coupling of the JULES surface model to the CCATT-BRAMS atmospheric chemistry model. This new numerical system is denominated JULES-CCATT-BRAMS. We demonstrate the performance of this new model system in relation to several meteorological variables and the CO2 mixing ratio over a large part of South America, focusing on the Amazon basin. The evaluation was conducted for two time periods, the wet (March) and dry (September) seasons of 2010. The model errors were calculated in relation to meteorological observations at conventional stations in airports and automatic stations. In addition, CO2 mixing ratios in the first model level were compared with meteorological tower measurements and vertical CO2 profiles were compared with observations obtained with airborne instruments. The results of this study show that the JULES-CCATT-BRAMS modeling system provided a significant gain in performance for the considered atmospheric fields relative to those simulated by the LEAF (version 3) surface model originally employed by CCATT-BRAMS. In addition, the new system significantly increases the ability to simulate processes involving air-surface interactions, due to the ability of JULES to simulate photosynthesis, respiration and dynamic vegetation, among other processes. We also discuss a wide range of numerical studies involving coupled atmospheric, land surface and chemistry processes that could be done with the system introduced here. Thus, this work presents to the scientific community a free modeling tool, with good performance in comparison with observational data and reanalysis model data, at least for the region and time period discussed here. Therefore, in principle, this model is able to produce atmospheric hindcast/forecast simulations at different spatial resolutions for any time period and any region of the globe. |
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BibTeX:
@article{moreira13a,
author = {Moreira, D. S. and Freitas, S. R. and Bonatti, J. P. and Mercado, L. M. and Rosario, N. M. E. and Longo, K. M. and Miller, J. B. and Gloor, M. and Gatti, L. V.},
title = {Coupling between the JULES land-surface scheme and the CCATT-BRAMS atmospheric chemistry model (JULES-CCATT-BRAMS1.0): applications to numerical weather forecasting and the CO2 budget in South America},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2013},
volume = {6},
number = {4},
pages = {1243--1259},
doi = {https://doi.org/10.5194/gmd-6-1243-2013}
}
|
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| Moreira, D.S., Longo, K.M., Freitas, S.R., Yamasoe, M.A., Mercado, L.M., Rosario, N.E., Gloor, E., Viana, R.S.M., Miller, J.B., Gatti, L.V., Wiedemann, K.T., Domingues, L.K.G. and Correia, C.C.S. | Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region | {2017} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {17}({23}), pp. 14785-14810 |
article | DOI |
| Abstract: Every year, a dense smoke haze covers a large portion of South America originating from fires in the Amazon Basin and central parts of Brazil during the dry biomass burning season between August and October. Over a large portion of South America, the average aerosol optical depth at 550 nm exceeds 1.0 during the fire season, while the background value during the rainy season is below 0.2. Biomass burning aerosol particles increase scattering and absorption of the incident solar radiation. The regional-scale aerosol layer reduces the amount of solar energy reaching the surface, cools the near-surface air, and increases the diffuse radiation fraction over a large disturbed area of the Amazon rainforest. These factors affect the energy and CO2 fluxes at the surface. In this work, we applied a fully integrated at-mospheric model to assess the impact of biomass burning aerosols in CO2 fluxes in the Amazon region during 2010. We address the effects of the attenuation of global solar radiation and the enhancement of the diffuse solar radiation flux inside the vegetation canopy. Our results indicate that biomass burning aerosols led to increases of about 27% in the gross primary productivity of Amazonia and 10% in plant respiration as well as a decline in soil respiration of 3%. Consequently, in our model Amazonia became a net carbon sink; net ecosystem exchange during September 2010 dropped from +101 to -104 TgC when the aerosol effects are considered, mainly due to the aerosol diffuse radiation effect. For the forest biome, our results point to a dominance of the diffuse radiation effect on CO2 fluxes, reaching a balance of 50-50% between the diffuse and direct aerosol effects for high aerosol loads. For C3 grasses and savanna (cerrado), as expected, the contribution of the diffuse radiation effect is much lower, tending to zero with the increase in aerosol load. Taking all biomes together, our model shows the Amazon during the dry season, in the presence of high biomass burning aerosol loads, changing from being a source to being a sink of CO2 to the atmosphere. |
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BibTeX:
@article{moreira17a,
author = {Moreira, Demerval S. and Longo, Karla M. and Freitas, Saulo R. and Yamasoe, Marcia A. and Mercado, Lina M. and Rosario, Nilton E. and Gloor, Emauel and Viana, Rosane S. M. and Miller, John B. and Gatti, Luciana V. and Wiedemann, Kenia T. and Domingues, Lucas K. G. and Correia, Caio C. S.},
title = {Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2017},
volume = {17},
number = {23},
pages = {14785--14810},
doi = {https://doi.org/10.5194/acp-17-14785-2017}
}
|
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| Moro, S., Danicic, A., Alic, N., Usechak, N.G. and Radic, S. | Widely-tunable parametric short-wave infrared transmitter for CO2 trace detection | {2011} | OPTICS EXPRESS Vol. {19}({9}), pp. 8173-8178 |
article | DOI |
| Abstract: An all-fiber, tunable, short-wave infrared transmitter is demonstrated using efficient four-wave mixing in conventional L and O bands. To realize this source a highly-nonlinear fiber, exhibiting low bend loss over the short-wave infrared spectral band, is employed because of its advantageous properties as a nonlinear mixing medium. The transmitter was subsequently exploited to probe and detect trace levels of carbon dioxide in the 2051-nm spectral region where its beam properties, tunability, narrow linewidth, and stability all coalesce to permit this application. This work indicates this transmitter can serve as a robust source for sensing carbon dioxide and other trace gasses in the short-wave infrared spectral region and should therefore play an important role in future applications. (C) 2011 Optical Society of America |
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BibTeX:
@article{moro11a,
author = {Moro, Slaven and Danicic, Aleksandar and Alic, Nikola and Usechak, Nicholas G. and Radic, Stojan},
title = {Widely-tunable parametric short-wave infrared transmitter for CO2 trace detection},
journal = {OPTICS EXPRESS},
year = {2011},
volume = {19},
number = {9},
pages = {8173--8178},
doi = {https://doi.org/10.1364/OE.19.008173}
}
|
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| Moro, S. | Parametrically-aided sensing in the short-wave infrared frequency band and beyond [BibTeX] |
2011 | School: University of California San Diego | phdthesis | URL |
BibTeX:
@phdthesis{moro11b,
author = {Slaven Moro},
title = {Parametrically-aided sensing in the short-wave infrared frequency band and beyond},
school = {University of California San Diego},
year = {2011},
url = {http://search.proquest.com/openview/09a727bd0d87d88df6a4f2d824b3521b/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Mu, M., Randerson, J.T., van der Werf, G.R., Giglio, L., Kasibhatla, P., Morton, D., Collatz, G.J., DeFries, R.S., Hyer, E.J., Prins, E.M., Griffith, D.W.T., Wunch, D., Toon, G.C., Sherlock, V. and Wennberg, P.O. | Daily and 3-hourly variability in global fire emissions and consequences for atmospheric model predictions of carbon monoxide | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: Attribution of the causes of atmospheric trace gas and aerosol variability often requires the use of high resolution time series of anthropogenic and natural emissions inventories. Here we developed an approach for representing synoptic-and diurnal-scale temporal variability in fire emissions for the Global Fire Emissions Database version 3 (GFED3). We disaggregated monthly GFED3 emissions during 2003-2009 to a daily time step using Moderate Resolution Imaging Spectroradiometer (MODIS)-derived measurements of active fires from Terra and Aqua satellites. In parallel, mean diurnal cycles were constructed from Geostationary Operational Environmental Satellite (GOES) Wildfire Automated Biomass Burning Algorithm (WF_ABBA) active fire observations. Daily variability in fires varied considerably across different biomes, with short but intense periods of daily emissions in boreal ecosystems and lower intensity (but more continuous) periods of burning in savannas. These patterns were consistent with earlier field and modeling work characterizing fire behavior dynamics in different ecosystems. On diurnal timescales, our analysis of the GOES WF_ABBA active fires indicated that fires in savannas, grasslands, and croplands occurred earlier in the day as compared to fires in nearby forests. Comparison with Total Carbon Column Observing Network (TCCON) and Measurements of Pollution in the Troposphere (MOPITT) column CO observations provided evidence that including daily variability in emissions moderately improved atmospheric model simulations, particularly during the fire season and near regions with high levels of biomass burning. The high temporal resolution estimates of fire emissions developed here may ultimately reduce uncertainties related to fire contributions to atmospheric trace gases and aerosols. Important future directions include reconciling top-down and bottom up estimates of fire radiative power and integrating burned area and active fire time series from multiple satellite sensors to improve daily emissions estimates. |
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BibTeX:
@article{mu11a,
author = {Mu, M. and Randerson, J. T. and van der Werf, G. R. and Giglio, L. and Kasibhatla, P. and Morton, D. and Collatz, G. J. and DeFries, R. S. and Hyer, E. J. and Prins, E. M. and Griffith, D. W. T. and Wunch, D. and Toon, G. C. and Sherlock, V. and Wennberg, P. O.},
title = {Daily and 3-hourly variability in global fire emissions and consequences for atmospheric model predictions of carbon monoxide},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2011JD016245}
}
|
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| Muelleman, A., Schell, J., Glazer, S. and Glaser, R. | Thermochemistry of a Biomimetic and Rubisco-Inspired CO2 Capture System from Air [BibTeX] |
2016 | C Vol. 2(3) |
article | URL |
BibTeX:
@article{muelleman16a,
author = {Muelleman, Andrew and Schell, Joseph and Glazer, Spencer and Glaser, Rainer},
title = {Thermochemistry of a Biomimetic and Rubisco-Inspired CO2 Capture System from Air},
journal = {C},
year = {2016},
volume = {2},
number = {3},
url = {http://www.mdpi.com/2311-5629/2/3/18/htm}
}
|
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| Mueller, K.L., Gourdji, S.M. and Michalak, A.M. | Global monthly averaged CO2 fluxes recovered using a geostatistical inverse modeling approach: 1. Results using atmospheric measurements | {2008} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {113}({D21}) |
article | DOI |
| Abstract: This study presents monthly CO2 fluxes from 1997 to 2001 at a 3.75 degrees latitude x 5 degrees longitude resolution, inferred using a geostatistical inverse modeling approach. The approach focuses on quantifying the information content of measurements from the NOAA-ESRL cooperative air sampling network with regard to the global CO2 budget at different spatial and temporal scales. The geostatistical approach avoids the use of explicit prior flux estimates that have formed the basis of previous synthesis Bayesian inversions and does not prescribe spatial patterns of flux for large, aggregated regions. Instead, the method relies strongly on the atmospheric measurements and the inferred spatial autocorrelation of the fluxes to estimate sources and sinks and their associated uncertainties at the resolution of the atmospheric transport model. Results show that grid-scale estimates exhibit high uncertainty and relatively little small-scale variability, but generally reflect reasonable fluxes in areas that are relatively well constrained by measurements. The aggregated continental-scale fluxes are better constrained, and estimates are consistent with results from previous synthesis Bayesian inversion studies for many regions. Observed differences at the continental scale are primarily attributable to the choice of a priori assumptions in the current work relative to those in other synthesis Bayesian studies. Overall, the results indicate that the geostatistical inverse modeling approach is able to estimate global fluxes using the limited atmospheric measurement network without relying on assumptions about a priori estimates of the flux distribution. As such, the method provides a means of isolating the information content of the atmospheric measurements, and thus serves as a valuable tool for reconciling top-down and bottom-up estimates of CO2 flux variability. |
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BibTeX:
@article{mueller08a,
author = {Mueller, Kim L. and Gourdji, Sharon M. and Michalak, Anna M.},
title = {Global monthly averaged CO2 fluxes recovered using a geostatistical inverse modeling approach: 1. Results using atmospheric measurements},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2008},
volume = {113},
number = {D21},
doi = {https://doi.org/10.1029/2007JD009734}
}
|
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| Mueller, K.L. | A data-driven multi-scale statistical investigation of regional sources and sinks to improve knowledge of terrestrial carbon cycling [BibTeX] |
2011 | School: University of Michigan | phdthesis | URL |
BibTeX:
@phdthesis{mueller11a,
author = {Mueller, Kimberly L},
title = {A data-driven multi-scale statistical investigation of regional sources and sinks to improve knowledge of terrestrial carbon cycling},
school = {University of Michigan},
year = {2011},
url = {http://search.proquest.com/openview/df727968d2cc116d449bf05fe1596bb9/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Mueller, K., Yadav, V., Lopez-Coto, I., Karion, A., Gourdji, S., Martin, C. and Whetstone, J. | Siting Background Towers to Characterize Incoming Air for Urban Greenhouse Gas Estimation: A Case Study in the Washington, DC/Baltimore Area | {2018} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {123}({5}), pp. {2910-2926} |
article | DOI |
| Abstract: There is increased interest in understanding urban greenhouse gas (GHG) emissions. To accurately estimate city emissions, the influence of extraurban fluxes must first be removed from urban greenhouse gas (GHG) observations. This is especially true for regions, such as the U.S. Northeastern Corridor-Baltimore/Washington, DC (NEC-B/W), downwind of large fluxes. To help site background towers for the NEC-B/W, we use a coupled Bayesian Information Criteria and geostatistical regression approach to help site four background locations that best explain CO2 variability due to extraurban fluxes modeled at 12 urban towers. The synthetic experiment uses an atmospheric transport and dispersion model coupled with two different flux inventories to create modeled observations and evaluate 15 candidate towers located along the urban domain for February and July 2013. The analysis shows that the average ratios of extraurban inflow to total modeled enhancements at urban towers are 21% to 36% in February and 31% to 43% in July. In July, the incoming air dominates the total variability of synthetic enhancements at the urban towers (R-2=0.58). Modeled observations from the selected background towers generally capture the variability in the synthetic CO2 enhancements at urban towers (R-2=0.75, root-mean-square error (RMSE)=3.64ppm; R-2=0.43, RMSE=4.96ppm for February and July). However, errors associated with representing background air can be up to 10ppm for any given observation even with an optimal background tower configuration. More sophisticated methods may be necessary to represent background air to accurately estimate urban GHG emissions. |
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BibTeX:
@article{mueller18a,
author = {Mueller, K. and Yadav, V. and Lopez-Coto, I. and Karion, A. and Gourdji, S. and Martin, C. and Whetstone, J.},
title = {Siting Background Towers to Characterize Incoming Air for Urban Greenhouse Gas Estimation: A Case Study in the Washington, DC/Baltimore Area},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2018},
volume = {123},
number = {5},
pages = {2910-2926},
doi = {https://doi.org/10.1002/2017JD027364}
}
|
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| Mueller, K.L., Lauvaux, T., Gurney, K.R., Roest, G., Ghosh, S., Gourdji, S.M., Karion, A., DeCola, P. and Whetstone, J. | An emerging GHG estimation approach can help cities achieve their climate and sustainability goals | 2021 | ENVIRONMENTAL RESEARCH LETTERS Vol. 16(8) |
article | DOI |
| Abstract: A credible assessment of a city's greenhouse gas (GHG) mitigation policies requires a valid account of a city's emissions. However, questions persist as to whether cities' `self-reported inventories' (SRIs) are accurate, precise, and consistent enough to track progress toward city mitigation goals. Although useful for broad policy initiatives, city SRIs provide annual snapshots that may have limited use to city managers looking to develop targeted mitigation policies that overlap with other issues like equity, air quality, and human health. An emerging approach from the research community that integrates `bottom-up' hourly, street-level emission data products with `top-down' GHG atmospheric observations have begun to yield production-based (scope 1) GHG estimates that can track changes in emissions at annual and sub-annual timeframes. The use of this integrated approach offers a much-needed assessment of SRIs: the atmospheric observations are tied to international standards and the bottom-up information incorporates multiple overlapping socio-economic data. The emissions are mapped at fine scales which helps link them to attribute information (e.g. fuel types) that can further facilitate mitigation actions. Here, we describe this approach and compare results to the SRI from the City of Indianapolis which shows a yearly difference of 35% in scope 1 emissions. In the City of Baltimore, we show that granular emission information can help address multiple issues, e.g. GHG emissions, air pollution, and inequity, at the sub-zip code scale where many roots and causes for each issue exist. Finally, we show that the incorporation of atmospheric concentrations within an integrated system provides rapid, near-real-time feedback on CO2 emissions anomalies that can uncover important behavioral and economic relationships. An integrated approach to GHG monitoring, reporting and verification can ensure uniformity, and provide accuracy to city-scale GHG emissions, scalable to states and the nation-ultimately helping cities meet stated ambitions. |
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BibTeX:
@article{mueller21a,
author = {Mueller, K. L. and Lauvaux, T. and Gurney, K. R. and Roest, G. and Ghosh, S. and Gourdji, S. M. and Karion, A. and DeCola, P. and Whetstone, J.},
title = {An emerging GHG estimation approach can help cities achieve their climate and sustainability goals},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
year = {2021},
volume = {16},
number = {8},
doi = {https://doi.org/10.1088/1748-9326/ac0f25}
}
|
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| Mukherjee, R., Rollend, D., Christie, G., Hadzic, A., Matson, S., Saksena, A. and Hughes, M. | Towards Indirect Top-Down Road Transport Emissions Estimation | 2021 | School: Johns Hopkins University Applied Physics Laboratory | techreport | URL |
| Abstract: Road transportation is one of the largest sectors of greenhouse gas (GHG) emissions affecting climate change. Tackling climate change as a global community will require new capabilities to measure and inventory road transport emissions. However, the large scale … | |||||
BibTeX:
@techreport{mukherjee21a,
author = {Ryan Mukherjee, Derek Rollend, Gordon Christie, Armin Hadzic, Sally Matson, Anshu Saksena, Marisa Hughes},
title = {Towards Indirect Top-Down Road Transport Emissions Estimation},
school = {Johns Hopkins University Applied Physics Laboratory},
year = {2021},
url = {https://arxiv.org/abs/2103.08829}
}
|
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| Murray-Tortarolo, G., Poulter, B., Vargas, R., Hayes, D., Michalak, A.M., Williams, C., Windham-Myers, L., Wang, J.A., Wickland, K.P., Butman, D., Tian, H., Sitch, S., Friedlingstein, P., O'Sullivan, M., Briggs, P., Arora, V., Lombardozzi, D., Jain, A.K., Yuan, W., Seferian, R., Nabel, J., Wiltshire, A., Arneth, A., Lienert, S., Zaehle, S., Bastrikov, V., Goll, D., Vuichard, N., Walker, A., Kato, E., Yue, X., Zhang, Z., Chaterjee, A. and Kurz, W. | A Process-Model Perspective on Recent Changes in the Carbon Cycle of North America | 2022 | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. 127(9) |
article | DOI |
| Abstract: Continental North America has been found to be a carbon (C) sink over recent decades by multiple studies employing a variety of estimation approaches. However, several key questions and uncertainties remain with these assessments. Here we used results from an ensemble of 19 state-of-the-art dynamic global vegetation models from the TRENDYv9 project to improve these estimates and study the drivers of its interannual variability. Our results show that North America has been a C sink with a magnitude of 0.37 +/- 0.38 (mean and one standard deviation) PgC year(-1) for the period 2000-2019 (0.31 and 0.44 PgC year(-1) in each decade); split into 0.18 +/- 0.12 PgC year(-1) in Canada (0.15 and 0.20), 0.16 +/- 0.17 in the United States (0.14 and 0.17), 0.02 +/- 0.05 PgC year(-1) in Mexico (0.02 and 0.02) and 0.01 +/- 0.02 in Central America and the Caribbean (0.01 and 0.01). About 57% of the new C assimilated by terrestrial ecosystems is allocated into vegetation, 30% into soils, and 13% into litter. Losses of C due to fire account for 41% of the interannual variability of the mean net biome productivity for all North America in the model ensemble. Finally, we show that drought years (e.g., 2002) have the potential to shift the region to a small net C source in the simulations (-0.02 +/- 0.46 PgC year(-1)). Our results highlight the importance of identifying the major drivers of the interannual variability of the continental-scale land C cycle along with the spatial distribution of local sink-source dynamics. |
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BibTeX:
@article{murray-tortarolo22a,
author = {Murray-Tortarolo, Guillermo and Poulter, Benjamin and Vargas, Rodrigo and Hayes, Daniel and Michalak, Anna M. and Williams, Christopher and Windham-Myers, Lisamarie and Wang, Jonathan A. and Wickland, Kimberly P. and Butman, David and Tian, Hanqin and Sitch, Stephen and Friedlingstein, Pierre and O'Sullivan, Mike and Briggs, Peter and Arora, Vivek and Lombardozzi, Danica and Jain, Atul K. and Yuan, Wenping and Seferian, Roland and Nabel, Julia and Wiltshire, Andy and Arneth, Almut and Lienert, Sebastian and Zaehle, Sonke and Bastrikov, Vladislav and Goll, Daniel and Vuichard, Nicolas and Walker, Anthony and Kato, Etsushi and Yue, Xu and Zhang, Zhen and Chaterjee, Abhishek and Kurz, Werner},
title = {A Process-Model Perspective on Recent Changes in the Carbon Cycle of North America},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2022},
volume = {127},
number = {9},
doi = {https://doi.org/10.1029/2022JG006904}
}
|
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| Mustafa, F., Bu, L., Wang, Q., Ali, M.A., Bilal, M., Shahzaman, M. and Qiu, Z. | Multi-Year Comparison of CO(2)Concentration from NOAA Carbon Tracker Reanalysis Model with Data from GOSAT and OCO-2 over Asia | {2020} | REMOTE SENSING Vol. {12}({15}) |
article | DOI URL |
| Abstract: Accurate knowledge of the carbon budget on global and regional scales is critically important to design mitigation strategies aimed at stabilizing the atmospheric carbon dioxide (CO2) emissions. For a better understanding of CO(2)variation trends over Asia, in this study, the column-averaged CO(2)dry air mole fraction (XCO2) derived from the National Oceanic and Atmospheric Administration (NOAA) CarbonTracker (CT) was compared with that of Greenhouse Gases Observing Satellite (GOSAT) from September 2009 to August 2019 and with Orbiting Carbon Observatory 2 (OCO-2) from September 2014 until August 2019. Moreover, monthly averaged time-series and seasonal climatology comparisons were also performed separately over the five regions of Asia; i.e., Central Asia, East Asia, South Asia, Southeast Asia, and Western Asia. The results show that XCO(2)from GOSAT is higher than the XCO(2)simulated by CT by an amount of 0.61 ppm, whereas, OCO-2 XCO(2)is lower than CT by 0.31 ppm on average, over Asia. The mean spatial correlations of 0.93 and 0.89 and average Root Mean Square Deviations (RMSDs) of 2.61 and 2.16 ppm were found between the CT and GOSAT, and CT and OCO-2, respectively, implying the existence of a good agreement between the CT and the other two satellites datasets. The spatial distribution of the datasets shows that the larger uncertainties exist over the southwest part of China. Over Asia, NOAA CT shows a good agreement with GOSAT and OCO-2 in terms of spatial distribution, monthly averaged time series, and seasonal climatology with small biases. These results suggest that CO(2)can be used from either of the datasets to understand its role in the carbon budget, climate change, and air quality at regional to global scales. | |||||
BibTeX:
@article{mustafa20a,
author = {Mustafa, Farhan and Bu, Lingbing and Wang, Qin and Ali, Md Arfan and Bilal, Muhammad and Shahzaman, Muhammad and Qiu, Zhongfeng},
title = {Multi-Year Comparison of CO(2)Concentration from NOAA Carbon Tracker Reanalysis Model with Data from GOSAT and OCO-2 over Asia},
journal = {REMOTE SENSING},
publisher = {MDPI},
year = {2020},
volume = {12},
number = {15},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.mdpi.com/2072-4292/12/15/2498},
doi = {https://doi.org/10.3390/rs12152498}
}
|
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| Nalini, K., Uma, K., Sijikumar, S., Tiwari, Y.K. and Ramachandran, R. | Satellite- and ground-based measurements of CO2 over the Indian region: its seasonal dependencies, spatial variability, and model estimates [BibTeX] |
2018 | INTERNATIONAL JOURNAL OF REMOTE SENSING Vol. 39(22), pp. 7881-7900 |
article | URL |
BibTeX:
@article{nalini18a,
author = {Nalini, K. and Uma, K.N. and Sijikumar, S. and Tiwari, Yogesh K. and Ramachandran, Radhika},
title = {Satellite- and ground-based measurements of CO2 over the Indian region: its seasonal dependencies, spatial variability, and model estimates},
journal = {INTERNATIONAL JOURNAL OF REMOTE SENSING},
year = {2018},
volume = {39},
number = {22},
pages = {7881-7900},
url = {https://www.tandfonline.com/doi/abs/10.1080/01431161.2018.1479787}
}
|
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| Nassar, R., Jones, D.B.A., Kulawik, S.S., Worden, J.R., Bowman, K.W., Andres, R.J., Suntharalingam, P., Chen, J.M., Brenninkmeijer, C.A.M., Schuck, T.J., Conway, T.J. and Worthy, D.E. | Inverse modeling of CO2 sources and sinks using satellite observations of CO2 from TES and surface flask measurements | {2011} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {11}({12}), pp. 6029-6047 |
article | DOI |
| Abstract: We infer CO2 surface fluxes using satellite observations of mid-tropospheric CO2 from the Tropospheric Emission Spectrometer (TES) and measurements of CO2 from surface flasks in a time-independent inversion analysis based on the GEOS-Chem model. Using TES CO2 observations over oceans, spanning 40 degrees S-40 degrees N, we find that the horizontal and vertical coverage of the TES and flask data are complementary. This complementarity is demonstrated by combining the datasets in a joint inversion, which provides better constraints than from either dataset alone, when a posteriori CO2 distributions are evaluated against independent ship and aircraft CO2 data. In particular, the joint inversion offers improved constraints in the tropics where surface measurements are sparse, such as the tropical forests of South America. Aggregating the annual surface-to-atmosphere fluxes from the joint inversion for the year 2006 yields -1.13 +/- 0.21 PgC for the global ocean, -2.77 +/- 0.20 PgC for the global land biosphere and -3.90 +/- 0.29 PgC for the total global natural flux (defined as the sum of all biospheric, oceanic, and biomass burning contributions but excluding CO2 emissions from fossil fuel combustion). These global ocean and global land fluxes are shown to be near the median of the broad range of values from other inversion results for 2006. To achieve these results, a bias in TES CO2 in the Southern Hemisphere was assessed and corrected using aircraft flask data, and we demonstrate that our results have low sensitivity to variations in the bias correction approach. Overall, this analysis suggests that future carbon data assimilation systems can benefit by integrating in situ and satellite observations of CO2 and that the vertical information provided by satellite observations of mid-tropospheric CO2 combined with measurements of surface CO2, provides an important additional constraint for flux inversions. |
|||||
BibTeX:
@article{nassar11a,
author = {Nassar, R. and Jones, D. B. A. and Kulawik, S. S. and Worden, J. R. and Bowman, K. W. and Andres, R. J. and Suntharalingam, P. and Chen, J. M. and Brenninkmeijer, C. A. M. and Schuck, T. J. and Conway, T. J. and Worthy, D. E.},
title = {Inverse modeling of CO2 sources and sinks using satellite observations of CO2 from TES and surface flask measurements},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
volume = {11},
number = {12},
pages = {6029--6047},
doi = {https://doi.org/10.5194/acp-11-6029-2011}
}
|
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| Nassar, R., Napier-Linton, L., Gurney, K.R., Andres, R.J., Oda, T., Vogel, F.R. and Deng, F. | Improving the temporal and spatial distribution of CO2 emissions from global fossil fuel emission data sets | {2013} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {118}({2}), pp. 917-933 |
article | DOI |
| Abstract: Through an analysis of multiple global fossil fuel CO2 emission data sets, Vulcan emission data for the United States, Canada's National Inventory Report, and NO2 variability based on satellite observations, we derive scale factors that can be applied to global emission data sets to represent weekly and diurnal CO2 emission variability. This is important for inverse modeling and data assimilation of CO2, which use in situ or satellite measurements subject to variability on these time scales. Model simulations applying the weekly and diurnal scaling show that, although the impacts are minor far away from sources, surface atmospheric CO2 is perturbed by up to 1.5-8 ppm and column-averaged CO2 is perturbed by 0.1-0.5 ppm over some major cities, suggesting the magnitude of model biases for urban areas when these modes of temporal variability are not represented. In addition, we also derive scale factors to account for the large per capita differences in CO2 emissions between Canadian provinces that arise from differences in per capita energy use and the proportion of energy generated by methods that do not emit CO2, which are not accounted for in population-based global emission data sets. The resulting products of these analyses are global 0.25 degrees x 0.25 degrees gridded scale factor maps that can be applied to global fossil fuel CO2 emission data sets to represent weekly and diurnal variability and 1 degrees x 1 degrees scale factor maps to redistribute spatially emissions from two common global data sets to account for differences in per capita emissions within Canada. |
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BibTeX:
@article{nassar13a,
author = {Nassar, Ray and Napier-Linton, Louis and Gurney, Kevin R. and Andres, Robert J. and Oda, Tomohiro and Vogel, Felix R. and Deng, Feng},
title = {Improving the temporal and spatial distribution of CO2 emissions from global fossil fuel emission data sets},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2013},
volume = {118},
number = {2},
pages = {917--933},
doi = {https://doi.org/10.1029/2012JD018196}
}
|
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| Nassar, R., Sioris, C.E., Jones, D.B.A. and McConnell, J.C. | Satellite observations of CO2 from a highly elliptical orbit for studies of the Arctic and boreal carbon cycle | {2014} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {119}({5}), pp. 2654-2673 |
article | DOI |
| Abstract: Here we report on an observing system simulation experiment (OSSE) to compare the efficacy of near-infrared satellite observations of CO2 from a highly elliptical orbit (HEO) and a low Earth orbit (LEO), for constraining Arctic and boreal CO2 sources and sinks. The carbon cycle at these latitudes (similar to 50-90 degrees N) is primarily driven by the boreal forests, but increasing anthropogenic activity and the effects of climate change such as thawing of permafrost throughout this region could also have an important role in the coming years. A HEO enables quasi-geostationary observations of Earth's northern high latitudes, which are not observed from a geostationary orbit. The orbit and observing characteristics for the HEO mission are based on the Weather, Climate and Air quality (WCA) concept proposed for the Polar Communications and Weather (PCW) mission, while those for the LEO mission are based on the Greenhouse gases Observing Satellite (GOSAT). Two WCA instrument configurations were investigated. Adopting the Optimal configuration yielded an observation data set that gave annual Arctic and boreal regional terrestrial biospheric CO2 flux uncertainties an average of 30% lower than those from GOSAT, while a smaller instrument configuration resulted in uncertainties averaging 20% lower than those from GOSAT. For either WCA instrument configuration, much greater reductions in uncertainty occur for spring, summer, and autumn than for winter, with Optimal flux uncertainties for June-August nearly 50% lower than from GOSAT. These findings demonstrate that CO2 observations from HEO offer significant advantages over LEO for constraining CO2 fluxes from the Arctic and boreal regions. Key Points satellites can improve high-latitude coverage CO2 from GOSAT and a HEO mission constraining Arctic and boreal CO2 fluxes |
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BibTeX:
@article{nassar14a,
author = {Nassar, Ray and Sioris, Chris E. and Jones, Dylan B. A. and McConnell, John C.},
title = {Satellite observations of CO2 from a highly elliptical orbit for studies of the Arctic and boreal carbon cycle},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2014},
volume = {119},
number = {5},
pages = {2654--2673},
doi = {https://doi.org/10.1002/2013JD020337}
}
|
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| Negra, C., Sweedo, C.C., Cavender-Bares, K. and O'Malley, R. | Indicators of carbon storage in US ecosystems: Baseline for terrestrial carbon | {2008} | JOURNAL OF ENVIRONMENTAL QUALITY Vol. {37}({4}), pp. 1376-1382 |
article | DOI |
| Abstract: Policymakers, program managers, and landowners need information about net terrestrial carbon sequestration in forests, croplands, grasslands, and shrublands to understand the cumulative effects of carbon trading programs, expanding biofuels production, and changing environmental conditions in addition to agricultural and forestry uses. Objective information systems that establish credible baselines and track changes in carbon storage can provide the accountability needed for carbon trading programs to achieve durable carbon sequestration and for biofuels initiatives to reduce net greenhouse gas emissions. A multi-sector stakeholder design process was used to produce a new indicator for the 2008 State of the Nation's Ecosystems report that presents metrics of carbon storage for major ecosystem types, specifically change in the amount of carbon gained or lost over time and the amount of carbon stored per unit area (carbon density). These metrics have been developed for national scale use, but are suitable for adaptation to multiple scales such as individual farm and forest parcels, carbon offset markets and integrated national and international assessments. To acquire the data necessary for a complete understanding of how much, and where, carbon is gained or lost by U.S. ecosystems, expansion and integration of monitoring programs will be required. |
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BibTeX:
@article{negra08a,
author = {Negra, Christine and Sweedo, Caroline Cremer and Cavender-Bares, Kent and O'Malley, Robin},
title = {Indicators of carbon storage in US ecosystems: Baseline for terrestrial carbon},
journal = {JOURNAL OF ENVIRONMENTAL QUALITY},
year = {2008},
volume = {37},
number = {4},
pages = {1376--1382},
note = {4th USDA Greenhouse Gas Symposium on Positioning Agriculture and Forestry to Meet the Challenges of Climate Change, Baltimore, MD, FEB 06-08, 2007},
doi = {https://doi.org/10.2134/jeq2007.0290}
}
|
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| Nelson, R.R., O'Dell, C.W., Taylor, T.E., Mandrake, L. and Smyth, M. | The potential of clear-sky carbon dioxide satellite retrievals | {2016} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {9}({4}), pp. 1671-1684 |
article | DOI |
| Abstract: Since the launch of the Greenhouse Gases Observing Satellite (GOSAT) in 2009, retrieval algorithms designed to infer the column-averaged dry-air mole fraction of carbon dioxide (X-CO2) from hyperspectral near-infrared observations of reflected sunlight have been greatly improved. They now generally include the scattering effects of clouds and aerosols, as early work found that absorption-only retrievals, which neglected these effects, often incurred unacceptably large errors, even for scenes with optically thin cloud or aerosol layers. However, these ``full-physics'' retrievals tend to be computationally expensive and may incur biases from trying to deduce the properties of clouds and aerosols when there are none present. Additionally, algorithms are now available that can quickly and effectively identify and remove most scenes in which cloud or aerosol scattering plays a significant role. In this work, we test the hypothesis that non-scattering, or ``clear-sky'', retrievals may perform as well as full-physics retrievals for sufficiently clear scenes. Clear-sky retrievals could potentially avoid errors and biases brought about by trying to infer properties of clouds and aerosols when none are present. Clear-sky retrievals are also desirable because they are orders of magnitude faster than full-physics retrievals. Here we use a simplified version of the Atmospheric Carbon Observations from Space (ACOS) X-CO2 retrieval algorithm that does not include the scattering and absorption effects of clouds or aerosols. It was found that for simulated Orbiting Carbon Observatory-2 (OCO-2) measurements, the clear-sky retrieval had errors comparable to those of the full-physics retrieval. For real GOSAT data, the clear-sky retrieval had errors 0-20% larger than the full-physics retrieval over land and errors roughly 20-35% larger over ocean, depending on filtration level. In general, the clear-sky retrieval had X-CO2 root-mean-square errors (RMSEs) of less than 2.0 ppm, relative to Total Carbon Column Observing Network (TCCON) measurements and a suite of CO2 models, when adequately filtered through the use of a custom genetic algorithm filtering system. These results imply that non-scattering X-CO2 retrievals are potentially more useful than previous literature suggests, as the filtering methods we employ are able to remove measurements in which scattering can cause significant errors. Additionally, the computational benefits of non-scattering retrievals means they may be useful for certain applications that require large amounts of data but have less stringent error requirements. |
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BibTeX:
@article{nelson16a,
author = {Nelson, Robert R. and O'Dell, Christopher W. and Taylor, Thomas E. and Mandrake, Lukas and Smyth, Mike},
title = {The potential of clear-sky carbon dioxide satellite retrievals},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2016},
volume = {9},
number = {4},
pages = {1671--1684},
doi = {https://doi.org/10.5194/amt-9-1671-2016}
}
|
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| Nelson, K.S. | Biofilm response to ocean acidification and the effects on serpulid polychaete settlement [BibTeX] |
2016 | School: University of Otago | mastersthesis | URL |
BibTeX:
@mastersthesis{nelson16b,
author = {Nelson, Kathryn Sarah},
title = {Biofilm response to ocean acidification and the effects on serpulid polychaete settlement},
school = {University of Otago},
year = {2016},
url = {https://otago.ourarchive.ac.nz/handle/10523/6783}
}
|
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| Nelson, R.R. and O'Dell, C.W. | The impact of improved aerosol priors on near-infrared measurements of carbon dioxide | {2019} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {12}({3}), pp. {1495-1512} |
article | DOI |
| Abstract: The Orbiting Carbon Observatory-2 (OCO-2) was launched in 2014 with the goal of measuring the column-averaged dry-air mole fraction of carbon dioxide (X-CO2) with sufficient precision and accuracy to infer regional carbon sources and sinks. One of the primary sources of error in near-infrared measurements of X-CO2 is the scattering effects of cloud and aerosol layers. In this work, we study the impact of ingesting better informed aerosol priors from the Goddard Earth Observing System Model, Version 5 (GEOS-5) into the OCO-2 ACOS V8 retrieval algorithm with the objective of reducing the error in X-CO2 from real measurements. Multiple levels of both aerosol setup complexity and uncertainty on the aerosol priors were tested, ranging from a mostly unconstrained aerosol optical depth (AOD) setup to ingesting full aerosol profiles with high confidence. We find that using co-located GEOS-5 aerosol types and AODs with low uncertainty results in a small improvement in the retrieved X-CO2 against the Total Carbon Column Observing Network relative to V8. In contrast, attempting to use modeled vertical information in the aerosol prior to improve the X-CO2 retrieval generally gives poor results, as aerosol models struggle with the vertical placement of aerosol layers. To assess regional differences in X-CO2, we compare our results to a global CO2 model validation suite. We find that the GEOS-5 setup performs better than V8 over northern Africa and central Asia, with the standard deviation of the X-CO2 error reduced from 2.12 to 1.83 ppm, due to a combination of smaller prior AODs and lower prior uncertainty. In general, the use of better informed aerosol priors shows promise but may be restricted by the current accuracy of aerosol models. | |||||
BibTeX:
@article{nelson19a,
author = {Nelson, Robert R. and O'Dell, Christopher W.},
title = {The impact of improved aerosol priors on near-infrared measurements of carbon dioxide},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {12},
number = {3},
pages = {1495--1512},
doi = {https://doi.org/10.5194/amt-12-1495-2019}
}
|
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| Nevison, C., Andrews, A., Thoning, K., Dlugokencky, E., Sweeney, C., Miller, S., Saikawa, E., Benmergui, J., Fischer, M., Mountain, M. and Nehrkorn, T. | Nitrous Oxide Emissions Estimated With the CarbonTracker-Lagrange North American Regional Inversion Framework | {2018} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {32}({3}), pp. {463-485} |
article | DOI |
| Abstract: North American nitrous oxide (N2O) emissions of 1.60.3TgN/yr over 2008-2014 are estimated using the CarbonTracker-Lagrange regional inversion framework. The estimated N2O emissions are largely consistent with the EDGAR (Emission Database for Global Atmospheric Research) global inventory and with the results of global atmospheric inversions but offer more spatial and temporal detail over North America. Emissions are strongest from the Midwestern Corn/Soybean Belt, which accounts for nearly one third of the total North American N2O source. The emissions are maximum in spring/early summer, consistent with a nitrogen fertilizer-driven source, and also show a late winter spike suggestive of freeze-thaw effects. Interannual variability in emissions across the primary months of fertilizer application is positively correlated to mean precipitation. The estimated N2O flux from the Midwestern Corn/Soybean Belt and the more northerly United States/Canadian wheat belt corresponds to 4.2-4.6% and 2.2-3.0%, respectively, of total synthetic+organic N fertilizer applied to those regions. Consideration of nonagricultural sources and additional N inputs from soybean N-2 fixation could reduce the N2O yield from the Midwestern Corn/Soybean Belt to similar to 2.2-2.4% of total N inputs. Plain Language Summary Emissions of nitrous oxide (N2O) emissions over North America were estimated based on an inverse model, in which atmospheric concentrations of N2O measured at 40 different National Oceanographic Atmospheric Administration (NOAA) sites were inverted to estimate surface sources. The estimated N2O emissions showed a clear hot spot in the Midwestern corn/soybean belt, which accounted for nearly one third (0.48 0.02 x 10(12)gN/yr) of the total North American N2O source (1.6 0.3x10(12)gN/yr). The emissions were maximum in spring and early summer, consistent with the timing of nitrogen fertilizer application to the corn/soybean belt. Interannual variability across 2007-2015 in the inferred emissions suggested that climate may interact with fertilizer to influence N2O source strength, with the warm drought year 2012 showing substantially lower emissions than other years. |
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BibTeX:
@article{nevison18a,
author = {Nevison, Cynthia and Andrews, Arlyn and Thoning, Kirk and Dlugokencky, Ed and Sweeney, Colm and Miller, Scot and Saikawa, Eri and Benmergui, Joshua and Fischer, Marc and Mountain, Marikate and Nehrkorn, Thomas},
title = {Nitrous Oxide Emissions Estimated With the CarbonTracker-Lagrange North American Regional Inversion Framework},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2018},
volume = {32},
number = {3},
pages = {463-485},
doi = {https://doi.org/10.1002/2017GB005759}
}
|
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| Nguyen, H., Osterman, G., Wunch, D., O'Dell, C., Mandrake, L., Wennberg, P., Fisher, B. and Castano, R. | A method for colocating satellite X-CO2 data to ground-based data and its application to ACOS-GOSAT and TCCON | {2014} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {7}({8}), pp. 2631-2644 |
article | DOI |
| Abstract: Satellite measurements are often compared with higher-precision ground-based measurements as part of validation efforts. The satellite soundings are rarely perfectly coincident in space and time with the ground-based measurements, so a colocation methodology is needed to aggregate ``nearby'' soundings into what the instrument would have seen at the location and time of interest. We are particularly interested in validation efforts for satellite-retrieved total column carbon dioxide (X-CO2), where X-CO2 data from Greenhouse Gas Observing Satellite (GOSAT) retrievals (ACOS, NIES, RemoteC, PPDF, etc.) or SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIA-MACHY) are often colocated and compared to ground-based column X-CO2 measurement from Total Carbon Column Observing Network (TCCON). Current colocation methodologies for comparing satellite measurements of total column dry-air mole fractions of CO2 (X-CO2) with ground-based measurements typically involve locating and averaging the satellite measurements within a latitudinal, longitudinal, and temporal window. We examine a geostatistical colocation methodology that takes a weighted average of satellite observations depending on the ``distance'' of each observation from a ground-based location of interest. The ``distance'' function that we use is a modified Euclidian distance with respect to latitude, longitude, time, and midtropospheric temperature at 700 hPa. We apply this methodology to X-CO2 retrieved from GOSAT spectra by the ACOS team, cross-validate the results to TCCON X-CO2 ground-based data, and present some comparisons between our methodology and standard existing colocation methods showing that, in general, geostatistical colocation produces smaller mean-squared error. |
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BibTeX:
@article{nguyen14a,
author = {Nguyen, H. and Osterman, G. and Wunch, D. and O'Dell, C. and Mandrake, L. and Wennberg, P. and Fisher, B. and Castano, R.},
title = {A method for colocating satellite X-CO2 data to ground-based data and its application to ACOS-GOSAT and TCCON},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2014},
volume = {7},
number = {8},
pages = {2631--2644},
doi = {https://doi.org/10.5194/amt-7-2631-2014}
}
|
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| Nisbet, E. and Manning, M. | 2009 | webpage | URL | ||
| Abstract: Depuis 50 ans, époque où Dave Keeling a commencé à surveiller le dioxyde de carbone à Mauna Loa, Hawa\i, et au pôle Sud, les scientifiques ont suivi l'évolution des gaz à effet de serre et d'autres gaz à l'état de traces dans l'atmosphère du globe. Les résultats ainsi … | |||||
BibTeX:
@webpage{nisbet09a,
author = {E Nisbet and M Manning},
year = {2009},
url = {https://public.wmo.int/fr/bulletin/l%E2%80%99atmosph%C3%A8re-de-la-plan%C3%A8te-les-gaz-%C3%A0-effet-de-serre-et-la-pollution-urbaine}
}
|
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| Niu, S., Luo, Y., Fei, S., Montagnani, L., Bohrer, G., Janssens, I.A., Gielen, B., Rambal, S., Moors, E. and Matteucci, G. | Seasonal hysteresis of net ecosystem exchange in response to temperature change: patterns and causes | {2011} | GLOBAL CHANGE BIOLOGY Vol. {17}({10}), pp. 3102-3114 |
article | DOI |
| Abstract: Understanding how net ecosystem exchange (NEE) changes with temperature is central to the debate on climate change-carbon cycle feedbacks, but still remains unclear. Here, we used eddy covariance measurements of NEE from 20 FLUXNET sites (203 site-years of data) in mid-and high-latitude forests to investigate the temperature response of NEE. Years were divided into two half thermal years (increasing temperature in spring and decreasing temperature in autumn) using the maximum daily mean temperature. We observed a parabolic-like pattern of NEE in response to temperature change in both the spring and autumn half thermal years. However, at similar temperatures, NEE was considerably depressed during the decreasing temperature season as compared with the increasing temperature season, inducing a counter-clockwise hysteresis pattern in the NEE-temperature relation at most sites. The magnitude of this hysteresis was attributable mostly (68%) to gross primary production (GPP) differences but little (8%) to ecosystem respiration (ER) differences between the two half thermal years. The main environmental factors contributing to the hysteresis responses of NEE and GPP were daily accumulated radiation. Soil water content (SWC) also contributed to the hysteresis response of GPP but only at some sites. Shorter day length, lower light intensity, lower SWC and reduced photosynthetic capacity may all have contributed to the depressed GPP and net carbon uptake during the decreasing temperature seasons. The resultant hysteresis loop is an important indicator of the existence of limiting factors. As such, the role of radiation, LAI and SWC should be considered when modeling the dynamics of carbon cycling in response to temperature change. |
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BibTeX:
@article{niu11a,
author = {Niu, Shuli and Luo, Yiqi and Fei, Shenfeng and Montagnani, Leonardo and Bohrer, Gil and Janssens, Ivan A. and Gielen, Bert and Rambal, Serge and Moors, Eddy and Matteucci, Giorgio},
title = {Seasonal hysteresis of net ecosystem exchange in response to temperature change: patterns and causes},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2011},
volume = {17},
number = {10},
pages = {3102--3114},
doi = {https://doi.org/10.1111/j.1365-2486.2011.02459.x}
}
|
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| Niwa, Y., Machida, T., Sawa, Y., Matsueda, H., Schuck, T.J., Brenninkmeijer, C.A.M., Imasu, R. and Satoh, M. | Imposing strong constraints on tropical terrestrial CO2 fluxes using passenger aircraft based measurements | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {117} |
article | DOI |
| Abstract: Because very few measurements of atmospheric carbon dioxide (CO2) are available in the tropics, estimates of surface CO2 fluxes in tropical regions are beset with considerable uncertainties. To improve estimates of tropical terrestrial fluxes, atmospheric CO2 inversion was performed using passenger aircraft based measurements of the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project in addition to the surface measurement data set of GLOBALVIEW-CO2. Regional monthly fluxes at the earth's surface were estimated using the Bayesian synthesis approach focusing on the period 2006-2008 using the Nonhydrostatic Icosahedral Atmospheric Model-based Transport Model (NICAM-TM). By adding the aircraft to the surface data, the posterior flux errors were greatly reduced; specifically, error reductions of up to 64% were found for tropical Asia regions. This strong impact is closely related to efficient vertical transport in the tropics. The optimized surface fluxes using the CONTRAIL data were evaluated by comparing the simulated atmospheric CO2 distributions with independent aircraft measurements of the Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container (CARIBIC) project. The inversion with the CONTRAIL data yields the global carbon sequestration rates of 2.22 +/- 0.28 Pg C yr(-1) for the terrestrial biosphere and 2.24 +/- 0.27 Pg C yr(-1) for the oceans (the both are adjusted by riverine input of CO2). For the first time the CONTRAIL CO2 measurements were used in an inversion system to identify the areas of greatest impact in terms of reducing flux uncertainties. |
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BibTeX:
@article{niwa12a,
author = {Niwa, Yosuke and Machida, Toshinobu and Sawa, Yousuke and Matsueda, Hidekazu and Schuck, Tanja J. and Brenninkmeijer, Carl A. M. and Imasu, Ryoichi and Satoh, Masaki},
title = {Imposing strong constraints on tropical terrestrial CO2 fluxes using passenger aircraft based measurements},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2012JD017474}
}
|
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| Niwa, Y., Ishijima, K., Ito, A. and Iida, Y. | Toward a long-term atmospheric CO2 inversion for elucidating natural carbon fluxes: technical notes of NISMON-CO2 v2021.1 | 2022 | PROGRESS IN EARTH AND PLANETARY SCIENCE Vol. 9(1) |
article | DOI |
| Abstract: Accurate estimates of the carbon dioxide (CO2) fluxes at the earth's surface are imperative for comprehending the carbon cycle mechanisms and providing reliable global warming predictions. Furthermore, they can also provide valuable science-based information that will be helpful in reducing human-induced CO2 emissions. Inverse analysis is a prominent method of quantitatively estimating spatiotemporal variations in CO2 fluxes; however, it involves a certain level of uncertainty and requires technical refinement, specifically to improve the horizontal resolution so that local fluxes can be compared with other estimates made at the regional or national level. In this study, a novel set of inversion schemes was incorporated into a state-of-the-art inverse analysis system named NISMON-CO2. The introduced schemes include a grid conversion, observational weighting, and anisotropic prior error covariance, the details of which are described. Moreover, pseudo-observation experiments were performed to examine the effect of the new schemes and to assess the reliability of NISMON-CO2 for long-term analysis with practical inhomogeneous observations. The experiment results evidently demonstrate the advantages of the grid conversion scheme for high-resolution flux estimates (1 degrees x 1 degrees), with notable improvements being achieved through the observational weighting and anisotropic prior error covariance. Furthermore, the estimated seasonal and interannual variations in regional CO2 fluxes were confirmed to be reliable, although some potential bias in terms of global land-ocean partitioning was observed. Thus, these results are useful for interpreting the flux variations that result from real-observation inverse analysis by NISMON-CO2 ver. 2021.1. |
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BibTeX:
@article{niwa22a,
author = {Niwa, Yosuke and Ishijima, Kentaro and Ito, Akihiko and Iida, Yosuke},
title = {Toward a long-term atmospheric CO2 inversion for elucidating natural carbon fluxes: technical notes of NISMON-CO2 v2021.1},
journal = {PROGRESS IN EARTH AND PLANETARY SCIENCE},
year = {2022},
volume = {9},
number = {1},
doi = {https://doi.org/10.1186/s40645-022-00502-6}
}
|
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| Noel, S., Bramstedt, K., Hilker, M., Liebing, P., Plieninger, J., Reuter, M., Rozanov, A., Sioris, C.E., Bovensmann, H. and Burrows, J.P. | Stratospheric CH4 and CO2 profiles derived from SCIAMACHY solar occultation measurements | {2016} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {9}({4}), pp. 1485-1503 |
article | DOI |
| Abstract: Stratospheric profiles of methane (CH4) and carbon dioxide (CO2) have been derived from solar occultation measurements of the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). The retrieval is performed using a method called onion peeling DOAS (ONPD), which combines an onion peeling approach with a weighting function DOAS (differential optical absorption spectroscopy) fit in the spectral region between 1559 and 1671 nm. By use of updated pointing information and optimisation of the data selection as well as of the retrieval approach, the altitude range for reasonable CH4 could be broadened from 20 to 40 km to about 17 to 45 km. Furthermore, the quality of the derived CO2 has been assessed such that now the first stratospheric profiles (17-45 km) of CO2 from SCIAMACHY are available. Comparisons with independent data sets yield an estimated accuracy of the new SCIAMACHY stratospheric profiles of about 5-10% for CH4 and 2-3% for CO2. The accuracy of the products is currently mainly restricted by the appearance of unexpected vertical oscillations in the derived profiles which need further investigation. Using the improved ONPD retrieval, CH4 and CO2 stratospheric data sets covering the whole SCIAMACHY time series (August 2002-April 2012) and the latitudinal range between about 50 and 70 degrees N have been derived. Based on these time series, CH4 and CO2 trends have been estimated. CH4 trends above about 20 km are not significantly different from zero and the trend at 17 km is about 3 ppbv year(-1). The derived CO2 trends show a general decrease with altitude with values of about 1.9 ppmv year(-1) at 21 km and about 1.3 ppmv year(-1) at 39 km. These results are in reasonable agreement with total column trends for these gases. This shows that the new SCIAMACHY data sets can provide valuable information about the stratosphere. |
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BibTeX:
@article{noel16a,
author = {Noel, Stefan and Bramstedt, Klaus and Hilker, Michael and Liebing, Patricia and Plieninger, Johannes and Reuter, Max and Rozanov, Alexei and Sioris, Christopher E. and Bovensmann, Heinrich and Burrows, John P.},
title = {Stratospheric CH4 and CO2 profiles derived from SCIAMACHY solar occultation measurements},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2016},
volume = {9},
number = {4},
pages = {1485--1503},
doi = {https://doi.org/10.5194/amt-9-1485-2016}
}
|
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| Normile, C.P. | Assessment of Uncertainties in Atmospheric Transport and Surface Flux of Carbon from the North American Terrestrial Biosphere | 2017 | School: The Pennsylvania State University | phdthesis | |
| Abstract: The North American terrestrial biosphere acts as a strong sink of atmospheric CO2 and therefore plays a key role in the global carbon cycle. The atmospheric inversion approach is used to quantify the magnitude and distribution land-atmosphere carbon exchange, and … | |||||
BibTeX:
@phdthesis{normile17a,
author = {Caroline Palmer Normile},
title = {Assessment of Uncertainties in Atmospheric Transport and Surface Flux of Carbon from the North American Terrestrial Biosphere},
school = {The Pennsylvania State University},
year = {2017}
}
|
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| Northcott, D., Sevadjian, J., Sancho-Gallegos, D.A., Wahl, C., Friederich, J. and Chavez, F.P. | Impacts of urban carbon dioxide emissions on sea-air flux and ocean acidification in nearshore waters | {2019} | PLOS ONE Vol. {14}({3}) |
article | DOI URL |
| Abstract: Greatly enhanced atmospheric carbon dioxide (CO2) levels relative to well-mixed marine air are observed during periods of offshore winds at coastal sensor platforms in Monterey Bay, California, USA. The highest concentrations originate from urban and agricultural areas, are driven by diurnal winds, and peak in the early morning. These enhanced atmospheric levels can be detected across a similar to 100km wide nearshore area and represent a significant addition to total oceanic CO2 uptake. A global estimate puts the added sea-air flux of CO2 from these greatly enhanced atmospheric CO2 levels at 25 million tonnes, roughly 1% of the ocean's annual CO2 uptake. The increased uptake over the 100 km coastal swath is of order 20%, indicating a potentially large impact on ocean acidification in productive coastal waters. | |||||
BibTeX:
@article{northcott19a,
author = {Northcott, Devon and Sevadjian, Jeff and Sancho-Gallegos, Diego A. and Wahl, Chris and Friederich, Jules and Chavez, Francisco P.},
title = {Impacts of urban carbon dioxide emissions on sea-air flux and ocean acidification in nearshore waters},
journal = {PLOS ONE},
publisher = {PUBLIC LIBRARY SCIENCE},
year = {2019},
volume = {14},
number = {3},
note = {Query date: 2021-04-02 15:20:04},
url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0214403},
doi = {https://doi.org/10.1371/journal.pone.0214403}
}
|
|||||
| Novick, K.A., Ficklin, D.L., Stoy, P.C., Williams, C.A., Bohrer, G., Oishi, A.C., Papuga, S.A., Blanken, P.D., Noormets, A., Sulman, B.N., Scott, R.L., Wang, L. and Phillips, R.P. | The increasing importance of atmospheric demand for ecosystem water and carbon fluxes | {2016} | NATURE CLIMATE CHANGE Vol. {6}({11}), pp. 1023-1027 |
article | DOI |
| Abstract: Soil moisture supply and atmospheric demand for water independently limit-and profoundly affect-vegetation productivity and water use during periods of hydrologic stress(1-4). Disentangling the impact of these two drivers on ecosystem carbon and water cycling is difficult because they are often correlated, and experimental tools for manipulating atmospheric demand in the field are lacking. Consequently, the role of atmospheric demand is often not adequately factored into experiments or represented in models(5-7). Here we show that atmospheric demand limits surface conductance and evapotranspiration to a greater extent than soil moisture in many biomes, including mesic forests that are of particular importance to the terrestrial carbon sink(8,9). Further, using projections from ten general circulation models, we show that climate change will increase the importance of atmospheric constraints to carbon and water fluxes in all ecosystems. Consequently, atmospheric demand will become increasingly important for vegetation function, accounting for >70% of growing season limitation to surface conductance in mesic temperate forests. Our results suggest that failure to consider the limiting role of atmospheric demand in experimental designs, simulation models and land management strategies will lead to incorrect projections of ecosystem responses to future climate conditions. |
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BibTeX:
@article{novick16a,
author = {Novick, Kimberly A. and Ficklin, Darren L. and Stoy, Paul C. and Williams, Christopher A. and Bohrer, Gil and Oishi, A. Christopher and Papuga, Shirley A. and Blanken, Peter D. and Noormets, Asko and Sulman, Benjamin N. and Scott, Russell L. and Wang, Lixin and Phillips, Richard P.},
title = {The increasing importance of atmospheric demand for ecosystem water and carbon fluxes},
journal = {NATURE CLIMATE CHANGE},
year = {2016},
volume = {6},
number = {11},
pages = {1023--1027},
doi = {https://doi.org/10.1038/NCLIMATE3114}
}
|
|||||
| Novick, K.A., Metzger, S., Anderegg, W.R.L., Barnes, M., Cala, D.S., Guan, K., Hemes, K.S., Hollinger, D.Y., Kumar, J., Litvak, M., Lombardozzi, D., Normile, C.P., Oikawa, P., Runkle, B.R.K., Torn, M. and Wiesner, S. | Informing Nature-based Climate Solutions for the United States with the best-available science | 2022 | GLOBAL CHANGE BIOLOGY Vol. 28(12), pp. 3778-3794 |
article | DOI |
| Abstract: Nature-based Climate Solutions (NbCS) are managed alterations to ecosystems designed to increase carbon sequestration or reduce greenhouse gas emissions. While they have growing public and private support, the realizable benefits and unintended consequences of NbCS are not well understood. At regional scales where policy decisions are often made, NbCS benefits are estimated from soil and tree survey data that can miss important carbon sources and sinks within an ecosystem, and do not reveal the biophysical impacts of NbCS for local water and energy cycles. The only direct observations of ecosystem-scale carbon fluxes, for example, by eddy covariance flux towers, have not yet been systematically assessed for what they can tell us about NbCS potentials, and state-of-the-art remote sensing products and land-surface models are not yet being widely used to inform NbCS policymaking or implementation. As a result, there is a critical mismatch between the point- and tree-scale data most often used to assess NbCS benefits and impacts, the ecosystem and landscape scales where NbCS projects are implemented, and the regional to continental scales most relevant to policymaking. Here, we propose a research agenda to confront these gaps using data and tools that have long been used to understand the mechanisms driving ecosystem carbon and energy cycling, but have not yet been widely applied to NbCS. We outline steps for creating robust NbCS assessments at both local to regional scales that are informed by ecosystem-scale observations, and which consider concurrent biophysical impacts, future climate feedbacks, and the need for equitable and inclusive NbCS implementation strategies. We contend that these research goals can largely be accomplished by shifting the scales at which pre-existing tools are applied and blended together, although we also highlight some opportunities for more radical shifts in approach. |
|||||
BibTeX:
@article{novick22a,
author = {Novick, Kimberly A. and Metzger, Stefan and Anderegg, William R. L. and Barnes, Mallory and Cala, Daniela S. and Guan, Kaiyu and Hemes, Kyle S. and Hollinger, David Y. and Kumar, Jitendra and Litvak, Marcy and Lombardozzi, Danica and Normile, Caroline P. and Oikawa, Patty and Runkle, Benjamin R. K. and Torn, Margaret and Wiesner, Susanne},
title = {Informing Nature-based Climate Solutions for the United States with the best-available science},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2022},
volume = {28},
number = {12},
pages = {3778-3794},
doi = {https://doi.org/10.1111/gcb.16156}
}
|
|||||
| Oda, T., Maksyutov, S. and Andres, R. | The Open-source Data Inventory for Anthropogenic CO2, version 2016 (ODIAC2016): a global monthly fossil fuel CO2 gridded emissions data product for tracer transport simulations and surface flux inversions | 2018 | Earth System Science Data Vol. {10}({1}), pp. {87-107} |
article | DOI |
| Abstract: The Open-source Data Inventory for Anthropogenic CO2 (ODIAC) is a global high-spatial-resolution gridded emissions data product that distributes carbon dioxide (CO2) emissions from fossil fuel combustion. The emissions spatial distributions are estimated at a 1 x 1 km spatial resolution over land using power plant profiles (emissions intensity and geographical location) and satellite-observed nighttime lights. This paper describes the year 2016 version of the ODIAC emissions data product (ODIAC2016) and presents analyses that help guide data users, especially for atmospheric CO2 tracer transport simulations and flux inversion analysis. Since the original publication in 2011, we have made modifications to our emissions modeling framework in order to deliver a comprehensive global gridded emissions data product. Major changes from the 2011 publication are (1) the use of emissions estimates made by the Carbon Dioxide Information Analysis Center (CDIAC) at the Oak Ridge National Laboratory (ORNL) by fuel type (solid, liquid, gas, cement manufacturing, gas flaring, and international aviation and marine bunkers); (2) the use of multiple spatial emissions proxies by fuel type such as (a) nighttime light data specific to gas flaring and (b) ship/aircraft fleet tracks; and (3) the inclusion of emissions temporal variations. Using global fuel consumption data, we extrapolated the CDIAC emissions estimates for the recent years and produced the ODIAC2016 emissions data product that covers 2000-2015. Our emissions data can be viewed as an extended version of CDIAC gridded emissions data product, which should allow data users to impose global fossil fuel emissions in a more comprehensive manner than the original CDIAC product. Our new emissions modeling framework allows us to produce future versions of the ODIAC emissions data product with a timely update. Such capability has become more significant given the CDIAC/ORNL's shutdown. The ODIAC data product could play an important role in supporting carbon cycle science, especially modeling studies with space-based CO2 data collected in near real time by ongoing carbon observing missions such as the Japanese Greenhouse gases Observing SATellite (GOSAT), NASA's Orbiting Carbon Observatory-2 (OCO-2), and upcoming future missions. The ODIAC emissions data product including the latest version of the ODIAC emissions data (ODIAC2017, 2000-2016) is distributed from http://db.cger.nies.go. jp/dataset/ODIAC/ with a DOI (https://doi.org/10.17595/20170411.001). |
|||||
BibTeX:
@article{oda18a,
author = {T Oda and S Maksyutov and RJ Andres},
title = {The Open-source Data Inventory for Anthropogenic CO2, version 2016 (ODIAC2016): a global monthly fossil fuel CO2 gridded emissions data product for tracer transport simulations and surface flux inversions},
journal = {Earth System Science Data},
year = {2018},
volume = {10},
number = {1},
pages = {87-107},
doi = {https://doi.org/10.5194/essd-10-87-2018}
}
|
|||||
| Oda, T., Bun, R., Kinakh, V., Topylko, P., Halushchak, M., Marland, G., Lauvaux, T., Jonas, M., Maksyutov, S., Nahorski, Z., Lesiv, M., Danylo, O. and Horabik-Pyzel, J. | Errors and uncertainties in a gridded carbon dioxide emissions inventory | {2019} | MITIGATION AND ADAPTATION STRATEGIES FOR GLOBAL CHANGE Vol. {24}({6, SI}), pp. {1007-1050} |
article | DOI URL |
| Abstract: Emission inventories (EIs) are the fundamental tool to monitor compliance with greenhouse gas (GHG) emissions and emission reduction commitments. Inventory accounting guidelines provide the best practices to help EI compilers across different countries and regions make comparable, national emission estimates regardless of differences in data availability. However, there are a variety of sources of error and uncertainty that originate beyond what the inventory guidelines can define. Spatially explicit EIs, which are a key product for atmospheric modeling applications, are often developed for research purposes and there are no specific guidelines to achieve spatial emission estimates. The errors and uncertainties associated with the spatial estimates are unique to the approaches employed and are often difficult to assess. This study compares the global, high-resolution (1 km), fossil fuel, carbon dioxide (CO2), gridded EI Open-source Data Inventory for Anthropogenic CO2 (ODIAC) with the multi-resolution, spatially explicit bottom-up EI geoinformation technologies, spatio-temporal approaches, and full carbon account for improving the accuracy of GHG inventories (GESAPU) over the domain of Poland. By taking full advantage of the data granularity that bottom-up EI offers, this study characterized the potential biases in spatial disaggregation by emission sector (point and non-point emissions) across different scales (national, subnational/regional, and urban policy-relevant scales) and identified the root causes. While two EIs are in agreement in total and sectoral emissions (2.2% for the total emissions), the emission spatial patterns showed large differences (10100% relative differences at 1 km) especially at the urban-rural transitioning areas (90-100%). We however found that the agreement of emissions over urban areas is surprisingly good compared with the estimates previously reported for US cities. This paper also discusses the use of spatially explicit EIs for climate mitigation applications beyond the common use in atmospheric modeling. We conclude with a discussion of current and future challenges of EIs in support of successful implementation of GHG emission monitoring and mitigation activity under the Paris Climate Agreement from the United Nations Framework Convention on Climate Change (UNFCCC) 21st Conference of the Parties (COP21). We highlight the importance of capacity building for EI development and coordinated research efforts of EI, atmospheric observations, and modeling to overcome the challenges. | |||||
BibTeX:
@article{oda19a,
author = {Oda, Tomohiro and Bun, Rostyslav and Kinakh, Vitaliy and Topylko, Petro and Halushchak, Mariia and Marland, Gregg and Lauvaux, Thomas and Jonas, Matthias and Maksyutov, Shamil and Nahorski, Zbigniew and Lesiv, Myroslava and Danylo, Olha and Horabik-Pyzel, Joanna},
title = {Errors and uncertainties in a gridded carbon dioxide emissions inventory},
journal = {MITIGATION AND ADAPTATION STRATEGIES FOR GLOBAL CHANGE},
publisher = {SPRINGER},
year = {2019},
volume = {24},
number = {6, SI},
pages = {1007--1050},
note = {Query date: 2021-04-02 15:20:04},
url = {https://link.springer.com/article/10.1007/s11027-019-09877-2},
doi = {https://doi.org/10.1007/s11027-019-09877-2}
}
|
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| O'Dell, C.W., Eldering, A., Wennberg, P.O., Crisp, D., Gunson, M.R., Fisher, B., Frankenberg, C., Kiel, M., Lindqvist, H., Mandrake, L., Merrelli, A., Natraj, V., Nelson, R.R., Osterman, G.B., Payne, V.H., Taylor, T.E., Wunch, D., Drouin, B.J., Oyafuso, F., Chang, A., McDuffie, J., Smyth, M., Baker, D.F., Basu, S., Chevallier, F., Crowell, S.M.R., Feng, L., Palmer, P.I., Dubey, M., Garcia, O.E., Griffith, D.W.T., Hase, F., Iraci, L.T., Kivi, R., Morino, I., Notholt, J., Ohyama, H., Petri, C., Roehl, C.M., Sha, M.K., Strong, K., Sussmann, R., Te, Y., Uchino, O. and Velazco, V.A. | Improved retrievals of carbon dioxide from Orbiting Carbon Observatory-2 with the version 8 ACOS algorithm | {2018} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {11}({12}), pp. {6539-6576} |
article | DOI |
| Abstract: Since September 2014, NASA's Orbiting Carbon Observatory-2 (OCO-2) satellite has been taking measurements of reflected solar spectra and using them to infer atmospheric carbon dioxide levels. This work provides details of the OCO-2 retrieval algorithm, versions 7 and 8, used to derive the column-averaged dry air mole fraction of atmospheric CO2 (X-CO2) for the roughly 100 000 cloud-free measurements recorded by OCO-2 each day. The algorithm is based on the Atmospheric Carbon Observations from Space (ACOS) algorithm which has been applied to observations from the Greenhouse Gases Observing SATellite (GOSAT) since 2009, with modifications necessary for OCO-2. Because high accuracy, better than 0.25 %, is required in order to accurately infer carbon sources and sinks from X-CO2, significant errors and regional-scale biases in the measurements must be minimized. We discuss efforts to filter out poor-quality measurements, and correct the remaining good-quality measurements to minimize regional-scale biases. Updates to the radiance calibration and retrieval forward model in version 8 have improved many aspects of the retrieved data products. The version 8 data appear to have reduced regional-scale biases overall, and demonstrate a clear improvement over the version 7 data. In particular, error variance with respect to TCCON was reduced by 20% over land and 40% over ocean between versions 7 and 8, and nadir and glint observations over land are now more consistent. While this paper documents the significant improvements in the ACOS algorithm, it will continue to evolve and improve as the CO2 data record continues to expand. |
|||||
BibTeX:
@article{odell18a,
author = {O'Dell, Christopher W. and Eldering, Annmarie and Wennberg, Paul O. and Crisp, David and Gunson, Michael R. and Fisher, Brendan and Frankenberg, Christian and Kiel, Matthaus and Lindqvist, Hannakaisa and Mandrake, Lukas and Merrelli, Aronne and Natraj, Vijay and Nelson, Robert R. and Osterman, Gregory B. and Payne, Vivienne H. and Taylor, Thomas E. and Wunch, Debra and Drouin, Brian J. and Oyafuso, Fabiano and Chang, Albert and McDuffie, James and Smyth, Michael and Baker, David F. and Basu, Sourish and Chevallier, Frederic and Crowell, Sean M. R. and Feng, Liang and Palmer, Paul I. and Dubey, Mavendra and Garcia, Omaira E. and Griffith, David W. T. and Hase, Frank and Iraci, Laura T. and Kivi, Rigel and Morino, Isamu and Notholt, Justus and Ohyama, Hirofumi and Petri, Christof and Roehl, Coleen M. and Sha, Mahesh K. and Strong, Kimberly and Sussmann, Ralf and Te, Yao and Uchino, Osamu and Velazco, Voltaire A.},
title = {Improved retrievals of carbon dioxide from Orbiting Carbon Observatory-2 with the version 8 ACOS algorithm},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2018},
volume = {11},
number = {12},
pages = {6539-6576},
doi = {https://doi.org/10.5194/amt-11-6539-2018}
}
|
|||||
| Ogle, S.M., Davis, K., Lauvaux, T., Schuh, A., Cooley, D., West, T.O., Heath, L.S., Miles, N.L., Richardson, S., Breidt, F.J., Smith, J.E., McCarty, J.L., Gurney, K.R., Tans, P. and Denning, A.S. | An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO2 concentration data | {2015} | ENVIRONMENTAL RESEARCH LETTERS Vol. {10}({3}) |
article | DOI |
| Abstract: Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country's contribution to GHG concentrations in the atmosphere. Furthermore, verifying biogenic fluxes provides a check on estimated emissions associated with managing lands for carbon sequestration and other activities, which often have large uncertainties. We report here on the challenges and results associated with a case study using atmospheric measurements of CO2 concentrations and inverse modeling to verify nationally-reported biogenic CO2 emissions. The biogenic CO2 emissions inventory was compiled for the Mid-Continent region of United States based on methods and data used by the US government for reporting to the UNFCCC, along with additional sources and sinks to produce a full carbon balance. The biogenic emissions inventory produced an estimated flux of -408 +/- 136 TgCO(2) for the entire study region, which was not statistically different from the biogenic flux of -478 +/- 146 TgCO(2) that was estimated using the atmospheric CO2 concentration data. At sub-regional scales, the spatial density of atmospheric observations did not appear sufficient to verify emissions in general. However, a difference between the inventory and inversion results was found in one isolated area of West-central Wisconsin. This part of the region is dominated by forestlands, suggesting that further investigation may be warranted into the forest Cstock or harvested wood product data from this portion of the study area. The results suggest that observations of atmospheric CO2 concentration data and inverse modeling could be used to verify biogenic emissions, and provide more confidence in biogenic GHG emissions reporting to the UNFCCC. |
|||||
BibTeX:
@article{ogle15a,
author = {Ogle, Stephen M. and Davis, Kenneth and Lauvaux, Thomas and Schuh, Andrew and Cooley, Dan and West, Tristram O. and Heath, Linda S. and Miles, Natasha L. and Richardson, Scott and Breidt, F. Jay and Smith, James E. and McCarty, Jessica L. and Gurney, Kevin R. and Tans, Pieter and Denning, A. Scott},
title = {An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO2 concentration data},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
year = {2015},
volume = {10},
number = {3},
doi = {https://doi.org/10.1088/1748-9326/10/3/034012}
}
|
|||||
| Oney, B.J. | Toward using atmospheric carbon dioxide observations to estimate the biospheric carbon flux of the Swiss Plateau | 2016 | School: ETH ZURICH | phdthesis | URL |
| Abstract: The lack of knowledge of the terrestrial carbon cycle translates into uncertain climate change projections due to the strong, yet uncertain relationship between terrestrial carbon fluxes and climate. Atmospheric carbon observations (defined here as the sum of CO2, CH4, and … | |||||
BibTeX:
@phdthesis{oney16a,
author = {Brian Johannes Oney},
title = {Toward using atmospheric carbon dioxide observations to estimate the biospheric carbon flux of the Swiss Plateau},
school = {ETH ZURICH},
year = {2016},
url = {https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/155750/eth-49352-02.pdf}
}
|
|||||
| Orphal, J. and Höpfner, P. | Mobile spectroscopic measurements of atmospheric carbon dioxide and methane | 2016 | School: Karlsruher Instituts fü̈r Technologie | phdthesis | URL |
| Abstract: Carbon dioxide and methane are the most important anthropogenic greenhouse gases. The sources and sinks of these gases can be inferred with the ``top-down'' approach from accurate and representative measurements. Ground based remote sensing uses rotational … | |||||
BibTeX:
@phdthesis{orphal16a,
author = {J Orphal and PDDM Höpfner},
title = {Mobile spectroscopic measurements of atmospheric carbon dioxide and methane},
school = {Karlsruher Instituts fü̈r Technologie},
year = {2016},
url = {https://core.ac.uk/download/pdf/197523072.pdf}
}
|
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| Palko, H.C. | EXPLORING POTENTIAL SITES FOR SALINITY GRADIENT RENEWABLE ENERGY ON THE NORTH CAROLINA COAST AND EVALUATING THE POTENTIAL EFFECTS OF LOCAL SALINITY REGIME VARIATION ON SAV COMMUNITIES DUE TO REVERSE ELECTRODIALYSIS EFFLUENT | 2017 | School: University of North Carolina at Chapel Hill | phdthesis | URL |
| Abstract: North Carolina has many rivers, tributaries, and back barrier sounds that form complex estuarine systems, the largest of which is the Albemarle Pamlico Estuarine System. The extensive nature of North Carolina estuaries' vertical and horizontal salinity gradients makes … | |||||
BibTeX:
@phdthesis{palko17a,
author = {Hannah Catherine Palko},
title = {EXPLORING POTENTIAL SITES FOR SALINITY GRADIENT RENEWABLE ENERGY ON THE NORTH CAROLINA COAST AND EVALUATING THE POTENTIAL EFFECTS OF LOCAL SALINITY REGIME VARIATION ON SAV COMMUNITIES DUE TO REVERSE ELECTRODIALYSIS EFFLUENT},
school = {University of North Carolina at Chapel Hill},
year = {2017},
url = {https://cdr.lib.unc.edu/concern/dissertations/1v53jx67d}
}
|
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| Pan, Y., Chen, J.M., Birdsey, R., McCullough, K., He, L. and Deng, F. | Age structure and disturbance legacy of North American forests | {2011} | BIOGEOSCIENCES Vol. {8}({3}), pp. 715-732 |
article | DOI |
| Abstract: Most forests of the world are recovering from a past disturbance. It is well known that forest disturbances profoundly affect carbon stocks and fluxes in forest ecosystems, yet it has been a great challenge to assess disturbance impacts in estimates of forest carbon budgets. Net sequestration or loss of CO(2) by forests after disturbance follows a predictable pattern with forest recovery. Forest age, which is related to time since disturbance, is a useful surrogate variable for analyses of the impact of disturbance on forest carbon. In this study, we compiled the first continental forest age map of North America by combining forest inventory data, historical fire data, optical satellite data and the dataset from NASA's Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) project. A companion map of the standard deviations for age estimates was developed for quantifying uncertainty. We discuss the significance of the disturbance legacy from the past, as represented by current forest age structure in different regions of the US and Canada, by analyzing the causes of disturbances from land management and nature over centuries and at various scales. We also show how such information can be used with inventory data for analyzing carbon management opportunities. By combining geographic information about forest age with estimated C dynamics by forest type, it is possible to conduct a simple but powerful analysis of the net CO2 uptake by forests, and the potential for increasing (or decreasing) this rate as a result of direct human intervention in the disturbance/age status. Finally, we describe how the forest age data can be used in large-scale carbon modeling, both for land-based biogeochemistry models and atmosphere-based inversion models, in order to improve the spatial accuracy of carbon cycle simulations. |
|||||
BibTeX:
@article{pan11a,
author = {Pan, Y. and Chen, J. M. and Birdsey, R. and McCullough, K. and He, L. and Deng, F.},
title = {Age structure and disturbance legacy of North American forests},
journal = {BIOGEOSCIENCES},
year = {2011},
volume = {8},
number = {3},
pages = {715--732},
doi = {https://doi.org/10.5194/bg-8-715-2011}
}
|
|||||
| Pan, G., Xu, Y. and Ma, J. | The potential of CO2 satellite monitoring for climate governance: A review | {2021} | JOURNAL OF ENVIRONMENTAL MANAGEMENT Vol. {277} |
article | DOI |
| Abstract: Good-quality CO2 emission data are fundamental for effective climate policy and governance. Data manipulation should be deterred, while developing countries are generally weaker than developed countries in compiling bottom-up CO2 emission inventories due to less adequate data collection capacity. This paper assesses the capabilities of CO2 satellites as objective, independent, potentially low-cost and external data sources for monitoring energy-related anthropogenic CO2 emissions at regional/national, megacity and point-source geographical scales. After overviewing all major CO2 satellites, SCIAMACHY, GOSAT and OCO-2 are focused on due to their wider research applications and higher CO2 sensitivity in total column measurements that include near surface emissions. Nighttime light satellite data for proxy CO2 monitoring are also brought into comparison to distinguish the importance of direct CO2 satellite monitoring. Studies are reviewed from the perspectives of spatial and temporal capability and accuracy to comprehend the current statuses of applications, assess the strengths and weaknesses of research methods, investigate major challenges and propose suggestions for future progress. We conclude that CO2 satellite monitoring can strengthen the data foundation for implementing international climate treaties and domestic climate policies. | |||||
BibTeX:
@article{pan21a,
author = {Pan, Guanna and Xu, Yuan and Ma, Jieqi},
title = {The potential of CO2 satellite monitoring for climate governance: A review},
journal = {JOURNAL OF ENVIRONMENTAL MANAGEMENT},
publisher = {ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD},
year = {2021},
volume = {277},
doi = {https://doi.org/10.1016/j.jenvman.2020.111423}
}
|
|||||
| Pandey, R., Paul, V., Sehgal, V.K., Singh, M.P. and Bandyopadhyay, K. | Monitoring of CO2 exchange and carbon pools in vegetation and soil [BibTeX] |
2013 | Indian Journal of Plant Physiology Vol. 18(2), pp. 98-117 |
article | DOI |
BibTeX:
@article{pandey13a,
author = {Pandey, Rakesh and Paul, Vijay and Sehgal, Vinay Kumar and Singh, Madan Pal and Bandyopadhyay, Kalikinkar},
title = {Monitoring of CO2 exchange and carbon pools in vegetation and soil},
journal = {Indian Journal of Plant Physiology},
year = {2013},
volume = {18},
number = {2},
pages = {98--117},
doi = {https://doi.org/10.1007/s40502-013-0016-0}
}
|
|||||
| Pandey, S., Houweling, S., Krol, M., Aben, I. and Rockmann, T. | On the use of satellite-derived CH4 : CO2 columns in a joint inversion of CH4 and CO2 fluxes | {2015} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {15}({15}), pp. 8615-8629 |
article | DOI |
| Abstract: We present a method for assimilating total column CH4 : CO2 ratio measurements from satellites for inverse modeling of CH4 and CO2 fluxes using the variational approach. Unlike conventional approaches, in which retrieved CH4 : CO2 are multiplied by model-derived total column CO2 and only the resulting CH4 is assimilated, our method assimilates the ratio of CH4 and CO2 directly and is therefore called the ratio method. It is a dual tracer inversion, in which surface fluxes of CH4 and CO2 are optimized simultaneously. The optimization of CO2 fluxes turns the hard constraint of prescribing model-derived CO2 fields into a weak constraint on CO2, which allows us to account for uncertainties in CO2. The method has been successfully tested in a synthetic inversion setup. We show that the ratio method is able to reproduce assumed true CH4 and CO2 fluxes starting from a prior, which is derived by perturbing the true fluxes randomly. We compare the performance of the ratio method with that of the traditional proxy approach and the use of only surface measurements for estimating CH4 fluxes. Our results confirm that the optimized CH4 fluxes are sensitive to the treatment of CO2, and that hard constraints on CO2 may significantly compromise results that are obtained for CH4. We find that the relative performance of ratio and proxy methods have a regional dependence. The ratio method performs better than the proxy method in regions where the CO2 fluxes are most uncertain. However, both ratio and proxy methods perform better than the surface-measurement-only inversion, confirming the potential of spaceborne measurements for accurately determining fluxes of CH4 and other greenhouse gases (GHGs). |
|||||
BibTeX:
@article{pandey15a,
author = {Pandey, S. and Houweling, S. and Krol, M. and Aben, I. and Rockmann, T.},
title = {On the use of satellite-derived CH4 : CO2 columns in a joint inversion of CH4 and CO2 fluxes},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2015},
volume = {15},
number = {15},
pages = {8615--8629},
doi = {https://doi.org/10.5194/acp-15-8615-2015}
}
|
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| Pandey, S., Houweling, S., Krol, M., Aben, I., Chevallier, F., Dlugokencky, E.J., Gatti, L.V., Gloor, E., Miller, J.B., Detmers, R., Machida, T. and Rockmann, T. | Inverse modeling of GOSAT-retrieved ratios of total column CH4 and CO2 for 2009 and 2010 | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({8}), pp. 5043-5062 |
article | DOI |
| Abstract: This study investigates the constraint provided by greenhouse gas measurements from space on surface fluxes. Imperfect knowledge of the light path through the atmosphere, arising from scattering by clouds and aerosols, can create biases in column measurements retrieved from space. To minimize the impact of such biases, ratios of total column retrieved CH4 and CO2 (X-ratio) have been used. We apply the ratio inversion method described in Pandey et al. (2015) to retrievals from the Greenhouse Gases Observing SATellite (GOSAT). The ratio inversion method uses the measured X-ratio as a weak constraint on CO2 fluxes. In contrast, the more common approach of inverting proxy CH4 retrievals (Frankenberg et al., 2005) prescribes atmospheric CO2 fields and optimizes only CH4 fluxes. The TM5-4DVAR (Tracer Transport Model version 5-variational data assimilation system) inverse modeling system is used to simultaneously optimize the fluxes of CH4 and CO2 for 2009 and 2010. The results are compared to proxy inversions using model-derived CO2 mixing ratios (XCO2model) from CarbonTracker and the Monitoring Atmospheric Composition and Climate (MACC) Reanalysis CO2 product. The performance of the inverse models is evaluated using measurements from three aircraft measurement projects. X-ratio and XCO2model are compared with TCCON retrievals to quantify the relative importance of errors in these components of the proxy XCH4 retrieval (XCH4proxy). We find that the retrieval errors in X-ratio (meanaEuro- = aEuro-0.61aEuro-%) are generally larger than the errors in XCO2model (meanaEuro- = aEuro-0.24 and 0.01aEuro-% for CarbonTracker and MACC, respectively). On the annual timescale, the CH4 fluxes from the different satellite inversions are generally in agreement with each other, suggesting that errors in XCO2model do not limit the overall accuracy of the CH4 flux estimates. On the seasonal timescale, however, larger differences are found due to uncertainties in XCO2model, particularly over Australia and in the tropics. The ratio method stays closer to the a priori CH4 flux in these regions, because it is capable of simultaneously adjusting the CO2 fluxes. Over tropical South America, comparison to independent measurements shows that CO2 fields derived from the ratio method are less realistic than those used in the proxy method. However, the CH4 fluxes are more realistic, because the impact of unaccounted systematic uncertainties is more evenly distributed between CO2 and CH4. The ratio inversion estimates an enhanced CO2 release from tropical South America during the dry season of 2010, which is in accordance with the findings of Gatti et al. (2014) and Van der Laan et al. (2015). The performance of the ratio method is encouraging, because despite the added nonlinearity due to the assimilation of X-ratio and the significant increase in the degree of freedom by optimizing CO2 fluxes, still consistent results are obtained with respect to other CH4 inversions.. |
|||||
BibTeX:
@article{pandey16a,
author = {Pandey, Sudhanshu and Houweling, Sander and Krol, Maarten and Aben, Ilse and Chevallier, Frederic and Dlugokencky, Edward J. and Gatti, Luciana V. and Gloor, Emanuel and Miller, John B. and Detmers, Rob and Machida, Toshinobu and Rockmann, Thomas},
title = {Inverse modeling of GOSAT-retrieved ratios of total column CH4 and CO2 for 2009 and 2010},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {8},
pages = {5043--5062},
doi = {https://doi.org/10.5194/acp-16-5043-2016}
}
|
|||||
| Pandey, S. | Advancing the use of satellites to constrain atmospheric methane fluxes [BibTeX] |
2017 | School: Utrecht University | phdthesis | URL |
BibTeX:
@phdthesis{pandey17a,
author = {Pandey, Sudhanshu},
title = {Advancing the use of satellites to constrain atmospheric methane fluxes},
school = {Utrecht University},
year = {2017},
url = {https://dspace.library.uu.nl/handle/1874/345119}
}
|
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| Pandeyl, R., Paull, V., Sehgals, V., al Singh, M.P. and Bandyopadhyay, K. | CAPACITIES AND UNCERTAINTIES IN MONITORING THE CARBON DIOXIDE FLUXES AND CARBON POOLS AT DIFFERENT SCALES IN TERRESTRIAL … [BibTeX] |
2013 | Physiology of Nutrition and Environmental Stresses on Crop Productivity | article | |
BibTeX:
@article{pandeyl13a,
author = {Pandeyl, Rakesh and Paull, Vijay and Sehgals, Vinay and al Singh, Madan P and Bandyopadhyay, Kalikinkar},
title = {CAPACITIES AND UNCERTAINTIES IN MONITORING THE CARBON DIOXIDE FLUXES AND CARBON POOLS AT DIFFERENT SCALES IN TERRESTRIAL …},
journal = {Physiology of Nutrition and Environmental Stresses on Crop Productivity},
year = {2013}
}
|
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| Pappas, C., Maillet, J., Rakowski, S., Baltzer, J.L., Barr, A.G., Black, T.A., Fatichi, S., Laroque, C.P., Matheny, A.M., Roy, A., Sonnentag, O. and Zha, T. | Aboveground tree growth is a minor and decoupled fraction of boreal forest carbon input | {2020} | AGRICULTURAL AND FOREST METEOROLOGY Vol. {290} |
article | DOI URL |
| Abstract: The boreal biome accounts for approximately one third of the terrestrial carbon (C) sink. However, estimates of its individual C pools remain uncertain. Here, focusing on the southern boreal forest, we quantified the magnitude and temporal dynamics of C allocation to aboveground tree growth at a mature black spruce (Picea mariana)-dominated forest stand in Saskatchewan, Canada. We reconstructed aboveground tree biomass increments (AGBi) using a biometric approach, i.e., species-specific allometry combined with forest stand characteristics and tree ring widths collected with a C-oriented sampling design. We explored the links between boreal tree growth and ecosystem C input by comparing AGBi with eddy-covariance-derived ecosystem C fluxes from 1999 to 2015 and we synthesized our findings with a refined meta-analysis of published values of boreal forest C use efficiency (CUE). Mean AGBi at the study site was decoupled from ecosystem C input and equal to 71 +/- 7 g C m(-2) (1999-2015), which is only a minor fraction of gross ecosystem production (GEP; i.e., AGBi / GEP approximate to 9 %). Moreover, C allocation to AGBi remained stable over time (AGBi / GEP; -0.0001 yr(-1) ; p-value = 0.775), contrary to significant trends in GEP ( + 5.72 g C m(-2) yr(-2) ; p-value = 0.02) and CUE (-0.0041 yr(-1), p-value =0.007). CUE was estimated as 0.50 +/- 0.03 at the study area and 0.41 +/- 0.12 across the reviewed boreal forests. These findings highlight the importance of belowground tree C investments, together with the substantial contribution of understory, ground cover and soil to the boreal forest C balance. Our quantitative insights into the dynamics of aboveground boreal tree C allocation offer additional observational constraints for terrestrial ecosystem models that are often biased in converting C input to biomass, and can guide forest-management strategies for mitigating carbon dioxide emissions. | |||||
BibTeX:
@article{pappas20a,
author = {Pappas, Christoforos and Maillet, Jason and Rakowski, Sharon and Baltzer, Jennifer L. and Barr, Alan G. and Black, T. Andrew and Fatichi, Simone and Laroque, Colin P. and Matheny, Ashley M. and Roy, Alexandre and Sonnentag, Oliver and Zha, Tianshan},
title = {Aboveground tree growth is a minor and decoupled fraction of boreal forest carbon input},
journal = {AGRICULTURAL AND FOREST METEOROLOGY},
publisher = {ELSEVIER},
year = {2020},
volume = {290},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S0168192320301325},
doi = {https://doi.org/10.1016/j.agrformet.2020.108030}
}
|
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| Parazoo, N.C. | Moist synoptic transport of CO₂ along midlatitude storm tracks, transport uncertainty, and implications for flux estimation [BibTeX] |
2011 | School: Colorado State University | phdthesis | URL |
BibTeX:
@phdthesis{parazoo11a,
author = {Parazoo, Nicholas C},
title = {Moist synoptic transport of CO₂ along midlatitude storm tracks, transport uncertainty, and implications for flux estimation},
school = {Colorado State University},
year = {2011},
url = {https://dspace.library.colostate.edu/handle/10217/48164}
}
|
|||||
| Parazoo, N.C., Arneth, A., Pugh, T.A.M., Smith, B., Steiner, N., Luus, K., Commane, R., Benmergui, J., Stofferahn, E., Liu, J., Roedenbeck, C., Kawa, R., Euskirchen, E., Zona, D., Arndt, K., Oechel, W. and Miller, C. | Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing | {2018} | GLOBAL CHANGE BIOLOGY Vol. {24}({8}), pp. {3416-3435} |
article | DOI |
| Abstract: The springtime transition to regional-scale onset of photosynthesis and net ecosystem carbon uptake in boreal and tundra ecosystems are linked to the soil freeze-thaw state. We present evidence from diagnostic and inversion models constrained by satellite fluorescence and airborne CO2 from 2012 to 2014 indicating the timing and magnitude of spring carbon uptake in Alaska correlates with landscape thaw and ecoregion. Landscape thaw in boreal forests typically occurs in late April (DOY 111 +/- 7) with a 29 +/- 6 day lag until photosynthetic onset. North Slope tundra thaws 3weeks later (DOY 133 +/- 5) but experiences only a 20 +/- 5 day lag until photosynthetic onset. These time lag differences reflect efficient cold season adaptation in tundra shrub and the longer dehardening period for boreal evergreens. Despite the short transition from thaw to photosynthetic onset in tundra, synchrony of tundra respiration with snow melt and landscape thaw delays the transition from net carbon loss (at photosynthetic onset) to net uptake by 13 +/- 7 days, thus reducing the tundra net carbon uptake period. Two global CO2 inversions using a CASA-GFED model prior estimate earlier northern high latitude net carbon uptake compared to our regional inversion, which we attribute to (i) early photosynthetic-onset model prior bias, (ii) inverse method (scaling factor+optimization window), and (iii) sparsity of available Alaskan CO2 observations. Another global inversion with zero prior estimates the same timing for net carbon uptake as the regional model but smaller seasonal amplitude. The analysis of Alaskan eddy covariance observations confirms regional scale findings for tundra, but indicates that photosynthesis and net carbon uptake occur up to 1 month earlier in evergreens than captured by models or CO2 inversions, with better correlation to above-freezing air temperature than date of primary thaw. Further collection and analysis of boreal evergreen species over multiple years and at additional subarctic flux towers are critically needed. |
|||||
BibTeX:
@article{parazoo18a,
author = {Parazoo, Nicholas C. and Arneth, Almut and Pugh, Thomas A. M. and Smith, Ben and Steiner, Nicholas and Luus, Kristina and Commane, Roisin and Benmergui, Josh and Stofferahn, Eric and Liu, Junjie and Roedenbeck, Christian and Kawa, Randy and Euskirchen, Eugenie and Zona, Donatella and Arndt, Kyle and Oechel, Walt and Miller, Charles},
title = {Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2018},
volume = {24},
number = {8},
pages = {3416-3435},
doi = {https://doi.org/10.1111/gcb.14283}
}
|
|||||
| Parazoo, N.C., Bowman, K.W., Baier, B.C., Liu, J., Lee, M., Kuai, L., Shiga, Y., Baker, I., Whelan, M.E., Feng, S., Krol, M., Sweeney, C., Runkle, B.R., Tajfar, E. and Davis, K.J. | Covariation of Airborne Biogenic Tracers (CO2, COS, and CO) Supports Stronger Than Expected Growing Season Photosynthetic Uptake in the Southeastern US | 2021 | GLOBAL BIOGEOCHEMICAL CYCLES Vol. 35(10) |
article | DOI |
| Abstract: The Atmospheric Carbon Transport (ACT)-America Earth Venture mission conducted five airborne campaigns across four seasons from 2016 to 2019, to study the transport and fluxes of Greenhouse gases across the eastern United States. Unprecedented spatial sampling of atmospheric tracers (CO2, carbon monoxide [CO], carbonyl sulfide [COS]) related to biospheric processes offers opportunities to improve our qualitative and quantitative understanding of seasonal and spatial patterns of biospheric carbon uptake. Here, we examine co-variation of boundary layer enhancements of CO2, CO, and COS across three diverse regions: the crop-dominated Midwest, evergreen-dominated South, and deciduous broadleaf-dominated Northeast. To understand the biogeochemical processes controlling these tracers, we compare the observed co-variation to simulated co-variation resulting from model- and satellite- constrained surface carbon fluxes. We found indication of a common terrestrial biogenic sink of CO2 and COS and secondary production of CO from biogenic sources in summer throughout the eastern US, driven by stomatal conductance. Upper Midwest crops drive Delta CO2 and Delta COS depletion from early to late summer. Northeastern temperate forests drive Delta CO2 and Delta COS depletion in late summer. The unprecedented ACT-America flask samples uncovered evidence that southern humid temperate forests photosynthesize and absorb CO2 and COS, and emit CO precursors, deep into the growing season. Satellite- constrained carbon fluxes capture much of the observed seasonal and spatial variability, but underestimate the magnitude of net CO2 and COS depletion in the South, indicating a stronger than expected net sink of CO2 in late summer. Additional sampling of the South will more accurately constrain underlying biological processes and climate sensitivities governing southern carbon dynamics. |
|||||
BibTeX:
@article{parazoo21a,
author = {Parazoo, Nicholas C. and Bowman, Kevin W. and Baier, Bianca C. and Liu, Junjie and Lee, Meemong and Kuai, Le and Shiga, Yoichi and Baker, Ian and Whelan, Mary E. and Feng, Sha and Krol, Maarten and Sweeney, Colm and Runkle, Benjamin R. and Tajfar, Elahe and Davis, Kenneth J.},
title = {Covariation of Airborne Biogenic Tracers (CO2, COS, and CO) Supports Stronger Than Expected Growing Season Photosynthetic Uptake in the Southeastern US},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2021},
volume = {35},
number = {10},
doi = {https://doi.org/10.1029/2021GB006956}
}
|
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| Park, J. | EVIDENCE FOR OCEANIC CONTROL OF INTERANNUAL CARBON CYCLE FEEDBACKS | {2011} | AMERICAN JOURNAL OF SCIENCE Vol. {311}({6}), pp. 485-516 |
article | DOI |
| Abstract: Large-scale carbon-cycle feedbacks within Earth's climate system can be inferred from the statistical correlation of atmospheric CO2 and other climate observations. These statistical relationships can serve as validation targets for global carbon-cycle models. Fourier-transform coherence between atmospheric CO2 measured at Mauna Loa, Hawaii, and Hadley Centre global-average temperatures changed in the late 20th century at interannual frequencies, from a 6-month time lag to a 90 phase lag that scaled CO2 fluctuations to a time-integral of the global-average temperature anomaly. Wavelet coherence estimates argue that this change occurred with a recognized ocean-circulation climate transition during the late 1970s. General features of these CO2-temperature correlations are confirmed using global-average temperature from other sources and atmospheric CO2 measured at other locations, though only the Mauna Loa CO2 record is long enough to resolve well the coherence properties before the 1970s transition. The CO2-coherence phase for the global-average surface-air temperature time series from NASA-GISS and the lower-troposphere temperature series from the MSU satellite is more complex than for the Hadley-Centre dataset, the only estimate that incorporates sea-surface temperature (SST) observations. Near f = 0.25 cyc/year, 4-year oscillation period, the CO2-coherence is particularly strong for the Hadley-Centre gridpoint temperature-anomaly time series from low-latitude oceans. This suggests that sea-surface temperature is a primary driver of the correlation, at least for the 0.2 < f < 0.5 cyc/yr bandpass where the El-Nino/Southern-Oscillation (ENSO) climate process dominates. Outside, the ENSO bandpass coherence is significant between 14 long-running GLOBALVIEW CO2-observing sites and the sea-level-pressure-based Southern Oscillation Index (SOI) and North Atlantic Oscillation (NAO) time series, consistent with wind stress and mixed-layer-thickness influences on ocean-atmosphere CO2 flux, independent of temperature fluctuations. Evidence for terrestrial biosphere influence is strongest in the leading principal component of GLOBALVIEW CO2-variability at f = 0.25 cpy, where a larger amplitude and a 4-month phase shift distinguish the mid- and high-latitude Northern Hemisphere CO2 fluctuations from those of the tropics and the Southern Hemisphere. The terrestrial signal we infer, however, coheres more strongly with oceanic-gridpoint temperatures than to continental-gridpoint temperatures. |
|||||
BibTeX:
@article{park11a,
author = {Park, Jeffrey},
title = {EVIDENCE FOR OCEANIC CONTROL OF INTERANNUAL CARBON CYCLE FEEDBACKS},
journal = {AMERICAN JOURNAL OF SCIENCE},
year = {2011},
volume = {311},
number = {6},
pages = {485--516},
doi = {https://doi.org/10.2475/06.2011.01}
}
|
|||||
| Changhyoun Park, H.W.L. | Simulation of Atmospheric CO2 Over Coastal Basin Urban Areas Using Meteorology-Vegetation Model | 2017 | Journal of Environmental Science International | article | URL |
| Abstract: Abstract The Weather Research and Forecasting (WRF) model and Vegetation Photosynthesis and Respiration Model (VPRM) were coupled to simulate atmospheric CO_2 concentrations. The performance of the WRF-VPRM to simulate regional scale … | |||||
BibTeX:
@article{park17a,
author = {Changhyoun Park, Hwa Woon Lee},
title = {Simulation of Atmospheric CO2 Over Coastal Basin Urban Areas Using Meteorology-Vegetation Model},
journal = {Journal of Environmental Science International},
year = {2017},
url = {https://www.koreascience.or.kr/article/JAKO201719950757913.page}
}
|
|||||
| Park, C., Lee, K. and Jung, W.-S. | Comparisons of Aircraft Observations and Simulation Results of Atmospheric CO2 over Coastal Basin Areas | 2017 | Journal of Environmental Science International | article | URL |
| Abstract: A model coupling a meteorological predictive model and a vegetation photosynthesis and respiration model was used to simulate CO_2 concentrations over coastal basin areas, and modeling results were estimated with aircraft observations during a massive sampling … | |||||
BibTeX:
@article{park17b,
author = {Changhyoun Park and KwiOk Lee and Woo-Sik Jung},
title = {Comparisons of Aircraft Observations and Simulation Results of Atmospheric CO2 over Coastal Basin Areas},
journal = {Journal of Environmental Science International},
year = {2017},
url = {https://www.koreascience.or.kr/article/JAKO201719950757916.page}
}
|
|||||
| Park, C., Gerbig, C., Newman, S., Ahmadov, R., Feng, S., Gurney, K.R., Carmichael, G.R., Park, S.-Y., Lee, H.-W., Goulden, M., Stutz, J., Peischl, J. and Ryerson, T. | CO2 Transport, Variability, and Budget over the Southern California Air Basin Using the High-Resolution WRF-VPRM Model during the CalNex 2010 Campaign | {2018} | JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY Vol. {57}({6}), pp. {1337-1352} |
article | DOI |
| Abstract: To study regional-scale carbon dioxide (CO2) transport, temporal variability, and budget over the Southern California Air Basin (SoCAB) during the California Research at the Nexus of Air Quality and Climate Change (CalNex) 2010 campaign period, a model that couples the Weather Research and Forecasting (WRF) Model with the Vegetation Photosynthesis and Respiration Model (VPRM) has been used. Our numerical simulations use anthropogenic CO2 emissions of the Hestia Project 2010 fossil-fuel CO2 emissions data products along with optimized VPRM parameters at ``FLUXNET'' sites, for biospheric CO2 fluxes over SoCAB. The simulated meteorological conditions have been validated with ground and aircraft observations, as well as with background CO2 concentrations from the coastal Palos Verdes site. The model captures the temporal pattern of CO2 concentrations at the ground site at the California Institute of Technology in Pasadena, but it overestimates the magnitude in early daytime. Analysis of CO2 by wind directions reveals the overestimate is due to advection from the south and southwest, where downtown Los Angeles is located. The model also captures the vertical profile of CO2 concentrations along with the flight tracks. The optimized VPRM parameters have significantly improved simulated net ecosystem exchange at each vegetation-class site and thus the regional CO2 budget. The total biospheric contribution ranges approximately from -24% to -20% (daytime) of the total anthropogenic CO2 emissions during the study period. |
|||||
BibTeX:
@article{park18a,
author = {Park, Changhyoun and Gerbig, Christoph and Newman, Sally and Ahmadov, Ravan and Feng, Sha and Gurney, Kevin R. and Carmichael, Gregory R. and Park, Soon-Young and Lee, Hwa-Woon and Goulden, Mike and Stutz, Jochen and Peischl, Jeff and Ryerson, Tom},
title = {CO2 Transport, Variability, and Budget over the Southern California Air Basin Using the High-Resolution WRF-VPRM Model during the CalNex 2010 Campaign},
journal = {JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY},
year = {2018},
volume = {57},
number = {6},
pages = {1337-1352},
doi = {https://doi.org/10.1175/JAMC-D-17-0358.1}
}
|
|||||
| Park, C., Park, S.-Y., Gurney, K.R., Gerbig, C., DiGangi, J.P., Choi, Y. and Lee, H.W. | Numerical simulation of atmospheric CO2 concentration and flux over the Korean Peninsula using WRF-VPRM model during Korus-AQ 2016 campaign | {2020} | PLOS ONE Vol. {15}({1}) |
article | DOI |
| Abstract: We conducted regional scale CO2 simulations using the Weather Research and Forecasting model (WRF) coupled with the Vegetation Photosynthesis and Respiration Model (VPRM). We contrasted simulated concentrations with column, ground and aircraft observations during the Korea-United States Air Quality (KORUS-AQ) 2016 field campaign. Overall, WRF-VPRM slightly underestimates CO2 concentrations at ground and column monitoring sites, but it significantly underestimates at an inland tower measurement site, especially within the stable (nocturnal) boundary layer in nighttime. The model successfully captures the airborne vertical profiles but showed a large offset within the planetary boundary layer (PBL) in the areas surrounding Seoul and around the Taeahn point source emissions in the west coastal area of the Korean Peninsula. A case study flight intended to capture Chinese influence observed no clear signals of long-range transport of CO2, due mainly to the much larger magnitude of background CO2 concentrations. The calculated Net Ecosystem Exchange (NEE) with flux measurements at a tower site in the South Korean Peninsula has also been evaluated comparing with CO2 flux measurements at a flux tower site, resulting in the under-estimation by less than a factor of 1. | |||||
BibTeX:
@article{park20a,
author = {Park, Changhyoun and Park, Soon-Young and Gurney, Kevin R. and Gerbig, Christoph and DiGangi, Joshua P. and Choi, Yonghoon and Lee, Hwa Woon},
title = {Numerical simulation of atmospheric CO2 concentration and flux over the Korean Peninsula using WRF-VPRM model during Korus-AQ 2016 campaign},
journal = {PLOS ONE},
publisher = {PUBLIC LIBRARY SCIENCE},
year = {2020},
volume = {15},
number = {1},
doi = {https://doi.org/10.1371/journal.pone.0228106}
}
|
|||||
| Park, C., Jeong, S., Park, H., Yun, J. and Liu, J. | Evaluation of the potential use of satellite-derived XCO 2 in detecting CO 2 enhancement in megacities with limited ground observations: a case study in Seoul using … | 2020 | Asia-Pacific journal of atmospheric … | article | URL |
| Abstract: Exact assessment of urban atmospheric CO 2 enhancement, which is higher than background CO 2 concentrations, is critical to mitigate carbon emissions in the city. However, ground-based atmospheric CO 2 measurements covering the diverse landscape … | |||||
BibTeX:
@article{park20b,
author = {C Park and S Jeong and H Park and J Yun and J Liu},
title = {Evaluation of the potential use of satellite-derived XCO 2 in detecting CO 2 enhancement in megacities with limited ground observations: a case study in Seoul using …},
journal = {Asia-Pacific journal of atmospheric …},
publisher = {Springer},
year = {2020},
note = {Query date: 2021-04-02 15:20:04},
url = {https://link.springer.com/article/10.1007/s13143-020-00202-5}
}
|
|||||
| Park, J. and Kim, H.M. | Design and evaluation of CO2 observation network to optimize surface CO2 fluxes in Asia using observation system simulation experiments | {2020} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {20}({8}), pp. {5175-5195} |
article | DOI |
| Abstract: Continuous efforts have been made to monitor atmospheric CO2 mole fractions as it is one of the most influential greenhouse gases in Earth's atmosphere. The atmospheric CO2 mole fractions are mostly determined by CO2 exchanges at the Earth's surface (i.e., surface CO2 flux). Inverse modeling, which is a method to estimate the CO2 exchanges at the Earth's surface, derives surface CO2 fluxes using modeled and observed atmospheric CO2 mole fraction data. Although observation data are crucial for successful modeling, comparatively fewer in situ observation sites are located in Asia compared to Europe or North America. Based on the importance of the terrestrial ecosystem of Asia for global carbon exchanges, more observation stations and an effective observation network design are required. In this paper, several observation network experiments were conducted to optimize the surface CO2 flux of Asia using CarbonTracker and observation system simulation experiments (OSSEs). The impacts of the redistribution of and additions to the existing observation network of Asia were evaluated using hypothetical in situ observation sites. In the case of the addition experiments, 10 observation stations, which is a practical number for real implementation, were added through three strategies: random addition, the influence matrix (i.e., self-sensitivity), and ecoregion information within the model. The simulated surface CO2 flux in Asia in summer can be improved by redistributing the existing observation network. The addition experiments revealed that considering both the distribution of normalized self-sensitivity and ecoregion information can yield better simulated surface CO2 fluxes compared to random addition, regardless of the season. This study provides a diagnosis of the existing ob- servation network and useful information for future observation network design in Asia to estimate the surface CO2 flux and also suggests the use of an influence matrix for designing CO2 observation networks. Unlike other previous observation network studies with many numerical experiments for optimization, comparatively fewer experiments were required in this study. Thus, the methodology used in this study may be used for designing observation networks for monitoring greenhouse gases at both continental and global scales. | |||||
BibTeX:
@article{park20c,
author = {Park, Jun and Kim, Hyun Mee},
title = {Design and evaluation of CO2 observation network to optimize surface CO2 fluxes in Asia using observation system simulation experiments},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {20},
number = {8},
pages = {5175--5195},
doi = {https://doi.org/10.5194/acp-20-5175-2020}
}
|
|||||
| Park, C., Jeong, S., Park, H., Yun, J. and Liu, J. | Evaluation of the Potential Use of Satellite-Derived XCO2 in Detecting CO2 Enhancement in Megacities with Limited Ground Observations: A Case Study in Seoul Using Orbiting Carbon Observatory-2 | 2021 | ASIA-PACIFIC JOURNAL OF ATMOSPHERIC SCIENCES Vol. 57(2), pp. 289-299 |
article | DOI |
| Abstract: Exact assessment of urban atmospheric CO2 enhancement, which is higher than background CO2 concentrations, is critical to mitigate carbon emissions in the city. However, ground-based atmospheric CO2 measurements covering the diverse landscape across the city are still limited. This study utilizes the column integrated CO2 concentration (XCO2) data obtained from the NASA Orbiting Carbon Observatory-2 (OCO-2) to evaluate urban CO2 enhancements over Seoul Capital Area (SCA) of South Korea for the period 2014-2018. In this study, Jirisan National Park (JNP), which is the cleanest area on the same orbit track with SCA, is defined as the background area considering its strong vegetation activity and low anthropogenic carbon emissions. By comparing XCO2 between SCA and JNP based on wind speed, we find an apparent increase in XCO2 by 1.71 to 2.21 ppm over SCA only on the days with wind speed less than 4 m s(-1). Strong wind speed (e.g., over 4 m s(-1)) disrupts the identification of XCO2 enhancements over SCA due to atmospheric mixing between SCA and JNP. In addition, we compare estimated XCO2 differences between SCA and JNP from OCO-2 with other low-resolution data. This increase in XCO2 over SCA is only observed in OCO-2. Overall, our results suggest that high-resolution satellite remote sensing of XCO2 constrained by wind speed has strong potential to open up the possibility of identifying atmospheric CO2 enhancements in the city where ground-based observations are limited. |
|||||
BibTeX:
@article{park21a,
author = {Park, Chaerin and Jeong, Sujong and Park, Hoonyoung and Yun, Jeongmin and Liu, Junjie},
title = {Evaluation of the Potential Use of Satellite-Derived XCO2 in Detecting CO2 Enhancement in Megacities with Limited Ground Observations: A Case Study in Seoul Using Orbiting Carbon Observatory-2},
journal = {ASIA-PACIFIC JOURNAL OF ATMOSPHERIC SCIENCES},
year = {2021},
volume = {57},
number = {2},
pages = {289-299},
doi = {https://doi.org/10.1007/s13143-020-00202-5}
}
|
|||||
| Parker, R., Boesch, H., Cogan, A., Fraser, A., Feng, L., Palmer, P.I., Messerschmidt, J., Deutscher, N., Griffith, D.W.T., Notholt, J., Wennberg, P.O. and Wunch, D. | Methane observations from the Greenhouse Gases Observing SATellite: Comparison to ground-based TCCON data and model calculations | {2011} | GEOPHYSICAL RESEARCH LETTERS Vol. {38} |
article | DOI |
| Abstract: We report new short-wave infrared (SWIR) column retrievals of atmospheric methane (X(CH4)) from the Japanese Greenhouse Gases Observing SATellite (GOSAT) and compare observed spatial and temporal variations with correlative ground-based measurements from the Total Carbon Column Observing Network (TCCON) and with the global 3-D GEOS-Chem chemistry transport model. GOSAT X(CH4) retrievals are compared with daily TCCON observations at six sites between April 2009 and July 2010 (Bialystok, Park Falls, Lamont, Orleans, Darwin and Wollongong). GOSAT reproduces the site-dependent seasonal cycles as observed by TCCON with correlations typically between 0.5 and 0.7 with an estimated single-sounding precision between 0.4-0.8%. We find a latitudinal-dependent difference between the X(CH4) retrievals from GOSAT and TCCON which ranges from 17.9 ppb at the most northerly site (Bialystok) to -14.6 ppb at the site with the lowest latitude (Darwin). We estimate that the mean smoothing error difference included in the GOSAT to TCCON comparisons can account for 15.7 to 17.4 ppb for the northerly sites and for 1.1 ppb at the lowest latitude site. The GOSAT X(CH4) retrievals agree well with the GEOS-Chem model on annual (August 2009 - July 2010) and monthly timescales, capturing over 80% of the zonal variability. Differences between model and observed X(CH4) are found over key source regions such as Southeast Asia and central Africa which will be further investigated using a formal inverse model analysis. Citation: Parker, R., et al. (2011), Methane observations from the Greenhouse Gases Observing SATellite: Comparison to ground-based TCCON data and model calculations, Geophys. Res. Lett., 38, L15807, doi:10.1029/2011GL047871. |
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BibTeX:
@article{parker11a,
author = {Parker, Robert and Boesch, Hartmut and Cogan, Austin and Fraser, Annemarie and Feng, Liang and Palmer, Paul I. and Messerschmidt, Janina and Deutscher, Nicholas and Griffith, David W. T. and Notholt, Justus and Wennberg, Paul O. and Wunch, Debra},
title = {Methane observations from the Greenhouse Gases Observing SATellite: Comparison to ground-based TCCON data and model calculations},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2011},
volume = {38},
doi = {https://doi.org/10.1029/2011GL047871}
}
|
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| Parker, R.J., Boesch, H., Byckling, K., Webb, A.J., Palmer, P.I., Feng, L., Bergamaschi, P., Chevallier, F., Notholt, J., Deutscher, N., Warneke, T., Hase, F., Sussmann, R., Kawakami, S., Kivi, R., Griffith, D.W.T. and Velazco, V. | Assessing 5 years of GOSAT Proxy XCH4 data and associated uncertainties | {2015} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {8}({11}), pp. 4785-4801 |
article | DOI |
| Abstract: We present 5 years of GOSAT XCH4 retrieved using the ``proxy'' approach. The Proxy XCH4 data are validated against ground-based TCCON observations and are found to be of high quality with a small bias of 4.8 ppb (similar to 0.27 %) and a single-sounding precision of 13.4 ppb (similar to 0.74 %). The station-to-station bias (a measure of the relative accuracy) is found to be 4.2 ppb. For the first time the XCH4 = XCO2 ratio component of the Proxy retrieval is validated (bias of 0.014 ppbppm 1 (similar to 0.30 %), single-sounding precision of 0.033 ppbppm 1 (similar to 0.72 %)). The uncertainty relating to the model XCO2 component of the Proxy XCH4 is assessed through the use of an ensemble of XCO2 models. While each individual XCO2 model is found to agree well with the TCCON validation data (r = 0.94-0.97), it is not possible to select one model as the best from our comparisons. The median XCO2 value of the ensemble has a smaller scatter against TCCON (a standard deviation of 0.92 ppm) than any of the individual models whilst maintaining a small bias (0.15 ppm). This model median XCO2 is used to calculate the Proxy XCH4 with the maximum deviation of the ensemble from the median used as an estimate of the uncertainty. We compare this uncertainty to the a posteriori retrieval error (which is assumed to reduce with sqrt(N)) and find typically that the model XCO2 uncertainty becomes significant during summer months when the a posteriori error is at its lowest due to the increase in signal related to increased summertime reflected sunlight. We assess the significance of these model and retrieval uncertainties on flux inversion by comparing the GOSAT XCH4 against modelled XCH4 from TM5-4DVAR constrained by NOAA surface observations (MACC reanalysis scenario S1-NOAA). We find that for the majority of regions the differences are much larger than the estimated uncertainties. Our findings show that useful information will be provided to the inversions for the majority of regions in addition to that already provided by the assimilated surface measurements. |
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BibTeX:
@article{parker15a,
author = {Parker, R. J. and Boesch, H. and Byckling, K. and Webb, A. J. and Palmer, P. I. and Feng, L. and Bergamaschi, P. and Chevallier, F. and Notholt, J. and Deutscher, N. and Warneke, T. and Hase, F. and Sussmann, R. and Kawakami, S. and Kivi, R. and Griffith, D. W. T. and Velazco, V.},
title = {Assessing 5 years of GOSAT Proxy XCH4 data and associated uncertainties},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2015},
volume = {8},
number = {11},
pages = {4785--4801},
doi = {https://doi.org/10.5194/amt-8-4785-2015}
}
|
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| Parker, R.J., Webb, A., Boesch, H., Somkuti, P., Guillo, R.B., Di Noia, A., Kalaitzi, N., Anand, J.S., Bergamaschi, P., Chevallier, F., Palmer I, P., Feng, L., Deutscher, N.M., Feist, D.G., Griffith, D.W.T., Hase, F., Kivi, R., Morino, I., Notholt, J., Oh, Y.-S., Ohyama, H., Petri, C., Pollard, D.F., Roehl, C., Sha, M.K., Shiomi, K., Strong, K., Sussmann, R., Te, Y., Velazco, V.A., Warneke, T., Wennberg, P.O. and Wunch, D. | A decade of GOSAT Proxy satellite CH4 observations | {2020} | EARTH SYSTEM SCIENCE DATA Vol. {12}({4}), pp. {3383-3412} |
article | DOI URL |
| Abstract: This work presents the latest release (v9.0) of the University of Leicester GOSAT Proxy XCH4 dataset. Since the launch of the GOSAT satellite in 2009, these data have been produced by the UK National Centre for Earth Observation (NCEO) as part of the ESA Greenhouse Gas Climate Change Initiative (GHG-CCI) and Copernicus Climate Change Services (C3S) projects. With now over a decade of observations, we outline the many scientific studies achieved using past versions of these data in order to highlight how this latest version may be used in the future. We describe in detail how the data are generated, providing information and statistics for the entire processing chain from the L1B spectral data through to the final quality-filtered column-averaged dry-air mole fraction (XCH4) data. We show that out of the 19.5 million observations made between April 2009 and December 2019, we determine that 7.3 million of these are sufficiently cloud-free (37.6 %) to process further and ultimately obtain 4.6 million (23.5 %) high-quality XCH4 observations. We separate these totals by observation mode (land and ocean sun glint) and by month, to provide data users with the expected data coverage, including highlighting periods with reduced observations due to instrumental issues. We perform extensive validation of the data against the Total Carbon Column Observing Network (TCCON), comparing to ground-based observations at 22 locations worldwide. We find excellent agreement with TCCON, with an overall correlation coefficient of 0.92 for the 88 345 co-located measurements. The single-measurement precision is found to be 13.72 ppb, and an overall global bias of 9.06 ppb is determined and removed from the Proxy XCH4 data. Additionally, we validate the separate components of the Proxy (namely the modelled XCO2 and the XCH4/XCO2 ratio) and find these to be in excellent agreement with TCCON. In order to show the utility of the data for future studies, we compare against simulated XCH4 from the TM5 model. We find a high degree of consistency between the model and observations throughout both space and time. When focusing on specific regions, we find average differences ranging from just 3.9 to 15.4 ppb. We find the phase and magnitude of the seasonal cycle to be in excellent agreement, with an average correlation coefficient of 0.93 and a mean seasonal cycle amplitude difference across all regions of -0.84 ppb. | |||||
BibTeX:
@article{parker20a,
author = {Parker, Robert J. and Webb, Alex and Boesch, Hartmut and Somkuti, Peter and Guillo, Rocio Barrio and Di Noia, Antonio and Kalaitzi, Nikoleta and Anand, Jasdeep S. and Bergamaschi, Peter and Chevallier, Frederic and Palmer, I, Paul and Feng, Liang and Deutscher, Nicholas M. and Feist, Dietrich G. and Griffith, David W. T. and Hase, Frank and Kivi, Rigel and Morino, Isamu and Notholt, Justus and Oh, Young-Suk and Ohyama, Hirofumi and Petri, Christof and Pollard, David F. and Roehl, Coleen and Sha, Mahesh K. and Shiomi, Kei and Strong, Kimberly and Sussmann, Ralf and Te, Yao and Velazco, Voltaire A. and Warneke, Thorsten and Wennberg, Paul O. and Wunch, Debra},
title = {A decade of GOSAT Proxy satellite CH4 observations},
journal = {EARTH SYSTEM SCIENCE DATA},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {12},
number = {4},
pages = {3383--3412},
note = {Query date: 2021-04-02 15:20:04},
url = {https://essd.copernicus.org/articles/12/3383/2020/},
doi = {https://doi.org/10.5194/essd-12-3383-2020}
}
|
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| Patra, P.K., Crisp, D., Kaiser, J.W., Wunch, D., Saeki, T., Ichii, K., Sekiya, T., Wennberg, P.O., Feist, D.G., Pollard, D.F., Griffith, D.W.T., Velazco, V.A., De Maziere, M., Sha, M.K., Roehl, C., Chatterjee, A. and Ishijima, K. | The Orbiting Carbon Observatory (OCO-2) tracks 2-3 peta-gram increase in carbon release to the atmosphere during the 2014-2016 El Nino | {2017} | SCIENTIFIC REPORTS Vol. {7} |
article | DOI |
| Abstract: The powerful El Nino event of 2015-2016 - the third most intense since the 1950s - has exerted a large impact on the Earth's natural climate system. The column-averaged CO2 dry-air mole fraction (XCO2) observations from satellites and ground-based networks are analyzed together with in situ observations for the period of September 2014 to October 2016. From the differences between satellite (OCO-2) observations and simulations using an atmospheric chemistry-transport model, we estimate that, relative to the mean annual fluxes for 2014, the most recent El Nino has contributed to an excess CO2 emission from the Earth's surface (land + ocean) to the atmosphere in the range of 2.4 +/- 0.2 PgC (1 Pg = 10(15) g) over the period of July 2015 to June 2016. The excess CO2 flux is resulted primarily from reduction in vegetation uptake due to drought, and to a lesser degree from increased biomass burning. It is about the half of the CO2 flux anomaly (range: 4.4-6.7 PgC) estimated for the 1997/1998 El Nino. The annual total sink is estimated to be 3.9 +/- 0.2 PgC for the assumed fossil fuel emission of 10.1 PgC. The major uncertainty in attribution arise from error in anthropogenic emission trends, satellite data and atmospheric transport. |
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BibTeX:
@article{patra17a,
author = {Patra, Prabir K. and Crisp, David and Kaiser, Johannes W. and Wunch, Debra and Saeki, Tazu and Ichii, Kazuhito and Sekiya, Takashi and Wennberg, Paul O. and Feist, Dietrich G. and Pollard, David F. and Griffith, David W. T. and Velazco, Voltaire A. and De Maziere, M. and Sha, Mahesh K. and Roehl, Coleen and Chatterjee, Abhishek and Ishijima, Kentaro},
title = {The Orbiting Carbon Observatory (OCO-2) tracks 2-3 peta-gram increase in carbon release to the atmosphere during the 2014-2016 El Nino},
journal = {SCIENTIFIC REPORTS},
year = {2017},
volume = {7},
doi = {https://doi.org/10.1038/s41598-017-13459-0}
}
|
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| Paustian, K., Lehmann, J., Ogle, S., Reay, D., Robertson, G.P. and Smith, P. | Climate-smart soils | {2016} | NATURE Vol. {532}({7597}), pp. 49-57 |
article | DOI |
| Abstract: Soils are integral to the function of all terrestrial ecosystems and to food and fibre production. An overlooked aspect of soils is their potential to mitigate greenhouse gas emissions. Although proven practices exist, the implementation of soil-based greenhouse gas mitigation activities are at an early stage and accurately quantifying emissions and reductions remains a substantial challenge. Emerging research and information technology developments provide the potential for a broader inclusion of soils in greenhouse gas policies. Here we highlight `state of the art' soil greenhouse gas research, summarize mitigation practices and potentials, identify gaps in data and understanding and suggest ways to close such gaps through new research, technology and collaboration. |
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BibTeX:
@article{paustian16a,
author = {Paustian, Keith and Lehmann, Johannes and Ogle, Stephen and Reay, David and Robertson, G. Philip and Smith, Pete},
title = {Climate-smart soils},
journal = {NATURE},
year = {2016},
volume = {532},
number = {7597},
pages = {49--57},
doi = {https://doi.org/10.1038/nature17174}
}
|
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| Pei, Z., Han, G., Ma, X., Shi, T. and Gong, W. | A Method for Estimating the Background Column Concentration of CO2 Using the Lagrangian Approach | 2022 | IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Vol. 60 |
article | DOI |
| Abstract: With the rapid growth of greenhouse gas (GHG) monitoring satellites, more and more studies focused on the issue of inversion/optimization of carbon dioxide (CO2) fluxes using satellite-derived XCO2 observations in recent years. A common and critical challenge in this framework is the separation of background and anomalies from XCO2 observations, which directly affect the performance of the CO2 fluxes' inversion. We proposed a novel method to accurately extract background XCO2 from satellite observations. A series of observing system simulation experiments (OSSEs) were performed to test the performance of the method. We found that the bias and uncertainty of the background concentration are below 0.01 and 0.05 ppm in the given cases, respectively. Based on this method, we selected five overpasses from 2014 to 2016 to demonstrate a regional-scale flux inversion near Riyadh. The comparison with the two previous methods shows that the posterior simulated XCO2 by the method proposed in this article can match better with the observed XCO2 from Orbiting Carbon Observatory-2 (OCO-2). |
|||||
BibTeX:
@article{pei22a,
author = {Pei, Zhipeng and Han, Ge and Ma, Xin and Shi, Tianqi and Gong, Wei},
title = {A Method for Estimating the Background Column Concentration of CO2 Using the Lagrangian Approach},
journal = {IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING},
year = {2022},
volume = {60},
doi = {https://doi.org/10.1109/TGRS.2022.3176134}
}
|
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| Peiro, H., Crowell, S., Schuh, A., Baker, D.F., O'Dell, C., Jacobson, A.R., Chevallier, F., Liu, J., Eldering, A., Crisp, D., Deng, F., Weir, B., Basu, S., Johnson, M.S., Philip, S. and Baker, I. | Four years of global carbon cycle observed from the Orbiting Carbon Observatory 2 (OCO-2) version 9 and in situ data and comparison to OCO-2 version 7 | 2022 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 22(2), pp. 1097-1130 |
article | DOI |
| Abstract: The Orbiting Carbon Observatory 2 (OCO-2) satellite has been providing information to estimate carbon dioxide (CO2) fluxes at global and regional scales since 2014 through the combination of CO2 retrievals with top-down atmospheric inversion methods. Column average CO2 dry-air mole fraction retrievals have been constantly improved. A bias correction has been applied in the OCO-2 version 9 retrievals compared to the previousOCO-2 version 7r improving data accuracy and coverage. We study an ensemble of 10 atmospheric inversions all characterized by different transport models, data assimilation algorithms, and prior fluxes using first OCO-2 v7 in 2015-2016 and then OCO-2 version 9 land observations for the longer period 2015-2018. Inversions assimilating in situ (IS) measurements have also been used to provide a baseline against which the satellite-driven results are compared. The time series at different scales (going from global to regional scales) of the models emissions are analyzed and compared to each experiment using either OCO-2 or IS data. We then evaluate the inversion ensemble based on the dataset from the Total Carbon Column Observing Network (TCCON), aircraft, and in situ observations, all independent from assimilated data. While we find a similar constraint of global total carbon emissions between the ensemble spread using IS and both OCO-2 retrievals, differences between the two retrieval versions appear over regional scales and particularly in tropical Africa. A difference in the carbon budget between v7 and v9 is found over this region, which seems to show the impact of corrections applied in retrievals. However, the lack of data in the tropics limits our conclusions, and the estimation of carbon emissions over tropical Africa require further analysis. |
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BibTeX:
@article{peiro22a,
author = {Peiro, Helene and Crowell, Sean and Schuh, Andrew and Baker, David F. and O'Dell, Chris and Jacobson, Andrew R. and Chevallier, Frederic and Liu, Junjie and Eldering, Annmarie and Crisp, David and Deng, Feng and Weir, Brad and Basu, Sourish and Johnson, Matthew S. and Philip, Sajeev and Baker, Ian},
title = {Four years of global carbon cycle observed from the Orbiting Carbon Observatory 2 (OCO-2) version 9 and in situ data and comparison to OCO-2 version 7},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2022},
volume = {22},
number = {2},
pages = {1097-1130},
doi = {https://doi.org/10.5194/acp-22-1097-2022}
}
|
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| Peng, C., Guiot, J., Wu, H., Jiang, H. and Luo, Y. | Integrating models with data in ecology and palaeoecology: advances towards a model-data fusion approach | {2011} | ECOLOGY LETTERS Vol. {14}({5}), pp. 522-536 |
article | DOI |
| Abstract: P>It is increasingly being recognized that global ecological research requires novel methods and strategies in which to combine process-based ecological models and data in cohesive, systematic ways. Model-data fusion (MDF) is an emerging area of research in ecology and palaeoecology. It provides a new quantitative approach that offers a high level of empirical constraint over model predictions based on observations using inverse modelling and data assimilation (DA) techniques. Increasing demands to integrate model and data methods in the past decade has led to MDF utilization in palaeoecology, ecology and earth system sciences. This paper reviews key features and principles of MDF and highlights different approaches with regards to DA. After providing a critical evaluation of the numerous benefits of MDF and its current applications in palaeoecology (i.e. palaeoclimatic reconstruction, palaeovegetation and palaeocarbon storage) and ecology (i.e. parameter and uncertainty estimation, model error identification, remote sensing and ecological forecasting), the paper discusses method limitations, current challenges and future research direction. In the ongoing data-rich era of today's world, MDF could become an important diagnostic and prognostic tool in which to improve our understanding of ecological processes while testing ecological theory and hypotheses and forecasting changes in ecosystem structure, function and services. |
|||||
BibTeX:
@article{peng11a,
author = {Peng, Changhui and Guiot, Joel and Wu, Haibin and Jiang, Hong and Luo, Yiqi},
title = {Integrating models with data in ecology and palaeoecology: advances towards a model-data fusion approach},
journal = {ECOLOGY LETTERS},
year = {2011},
volume = {14},
number = {5},
pages = {522--536},
doi = {https://doi.org/10.1111/j.1461-0248.2011.01603.x}
}
|
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| Peng, Z., Zhang, M., Kou, X., Tian, X. and Ma, X. | A regional carbon data assimilation system and its preliminary evaluation in East Asia | {2015} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {15}({2}), pp. 1087-1104 |
article | DOI |
| Abstract: In order to optimize surface CO2 fluxes at grid scales, a regional surface CO2 flux inversion system (Carbon Flux Inversion system and Community Multi-scale Air Quality, CFI-CMAQ) has been developed by applying the ensemble Kalman filter (EnKF) to constrain the CO2 concentrations and applying the ensemble Kalman smoother (EnKS) to optimize the surface CO2 fluxes. The smoothing operator is associated with the atmospheric transport model to constitute a persistence dynamical model to forecast the surface CO2 flux scaling factors. In this implementation, the ``signal-to-noise'' problem can be avoided; plus, any useful observed information achieved by the current assimilation cycle can be transferred into the next assimilation cycle. Thus, the surface CO2 fluxes can be optimized as a whole at the grid scale in CFI-CMAQ. The performance of CFI-CMAQ was quantitatively evaluated through a set of Observing System Simulation Experiments (OSSEs) by assimilating CO2 retrievals from GOSAT (Greenhouse Gases Observing Satellite). The results showed that the CO2 concentration assimilation using EnKF could constrain the CO2 concentration effectively, illustrating that the simultaneous assimilation of CO2 concentrations can provide convincing CO2 initial analysis fields for CO2 flux inversion. In addition, the CO2 flux optimization using EnKS demonstrated that CFI-CMAQ could, in general, reproduce true fluxes at grid scales with acceptable bias. Two further sets of numerical experiments were conducted to investigate the sensitivities of the inflation factor of scaling factors and the smoother window. The results showed that the ability of CFI-CMAQ to optimize CO2 fluxes greatly relied on the choice of the inflation factor. However, the smoother window had a slight influence on the optimized results. CFI-CMAQ performed very well even with a short lag-window (e.g. 3 days). |
|||||
BibTeX:
@article{peng15a,
author = {Peng, Z. and Zhang, M. and Kou, X. and Tian, X. and Ma, X.},
title = {A regional carbon data assimilation system and its preliminary evaluation in East Asia},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2015},
volume = {15},
number = {2},
pages = {1087--1104},
doi = {https://doi.org/10.5194/acp-15-1087-2015}
}
|
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| Peng, W. | A METHOD FOR THE QUANTIFICATION OF SPATIAL FLUXES AND ASSOCIATED UNCERTAINTY OVER HETEROGENEOUS AGRICULTURAL LANDSCAPE | 2015 | School: The University of Alabama | phdthesis | URL |
| Abstract: Aircraft based measurement of surface exchange is now a widely used approach for determining fluxes. Since it requires 3-5km averaging length to generate meaningful fluxes, it is challenging to relate obtained flux signals to a single land cover type in heterogeneous … | |||||
BibTeX:
@phdthesis{peng15b,
author = {Wei Peng},
title = {A METHOD FOR THE QUANTIFICATION OF SPATIAL FLUXES AND ASSOCIATED UNCERTAINTY OVER HETEROGENEOUS AGRICULTURAL LANDSCAPE},
school = {The University of Alabama},
year = {2015},
url = {http://ir.ua.edu/handle/123456789/2977}
}
|
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| Peng, Z., Liu, Z., Chen, D. and Ban, J. | Improving PM2.5 forecast over China by the joint adjustment of initial conditions and source emissions with an ensemble Kalman filter | {2017} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {17}({7}), pp. 4837-4855 |
article | DOI |
| Abstract: In an attempt to improve the forecasting of atmospheric aerosols, the ensemble square root filter algorithm was extended to simultaneously optimize the chemical initial conditions (ICs) and emission input. The forecast model, which was expanded by combining the Weather Research and Forecasting with Chemistry (WRF-Chem) model and a forecast model of emission scaling factors, generated both chemical concentration fields and emission scaling factors. The forecast model of emission scaling factors was developed by using the ensemble concentration ratios of the WRF-Chem forecast chemical concentrations and also the time smoothing operator. Hourly surface fine particulate matter (PM2.5) observations were assimilated in this system over China from 5 to 16 October 2014. A series of 48 h forecasts was then carried out with the optimized initial conditions and emissions on each day at 00:00UTC and a control experiment was performed without data assimilation. In addition, we also performed an experiment of pure assimilation chemical ICs and the corresponding 48 h forecasts experiment for comparison. The results showed that the forecasts with the optimized initial conditions and emissions typically outperformed those from the control experiment. In the Yangtze River delta (YRD) and the Pearl River delta (PRD) regions, large reduction of the root-mean-square errors (RMSEs) was obtained for almost the entire 48 h forecast range attributed to assimilation. In particular, the relative reduction in RMSE due to assimilation was about 37.5% at nighttime when WRF-Chem performed comparatively worse. In the Beijing-Tianjin-Hebei (JJJ) region, relatively smaller improvements were achieved in the first 24 h forecast but then no improvements were achieved afterwards. Comparing to the forecasts with only the optimized ICs, the forecasts with the joint adjustment were always much better during the night in the PRD and YRD regions. However, they were very similar during daytime in both regions. Also, they performed similarly for almost the entire 48 h forecast range in the JJJ region. |
|||||
BibTeX:
@article{peng17a,
author = {Peng, Zhen and Liu, Zhiquan and Chen, Dan and Ban, Junmei},
title = {Improving PM2.5 forecast over China by the joint adjustment of initial conditions and source emissions with an ensemble Kalman filter},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2017},
volume = {17},
number = {7},
pages = {4837--4855},
doi = {https://doi.org/10.5194/acp-17-4837-2017}
}
|
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| Perez, I.A., Luisa Sanchez, M., Angeles Garcia, M., Pardo, N. and Fernandez-Duque, B. | The influence of meteorological variables on CO2 and CH4 trends recorded at a semi-natural station | {2018} | JOURNAL OF ENVIRONMENTAL MANAGEMENT Vol. {209}, pp. {37-45} |
article | DOI URL |
| Abstract: CO2 and CH4 evolution is usually linked with sources, sinks and their changes. However, this study highlights the role of meteorological variables. It aims to quantify their contribution to the trend of these greenhouse gases and to determine which contribute most. Six years of measurements at a semi-natural site in northern Spain were considered. Three sections are established: the first focuses on monthly deciles, the second explores the relationship between pairs of meteorological variables, and the third investigates the relationship between meteorological variables and changes in CO2 and CH4. In the first section, monthly outliers were more marked for CO2 than for CH4. The evolution of monthly deciles was fitted to three simple expressions, linear, quadratic and exponential. The linear and exponential are similar, whereas the quadratic evolution is the most flexible since it provided a variable rate of concentration change and a better fit. With this last evolution, a decrease in the change rate was observed for low CO2 deciles, whereas an increasing change rate prevailed for the rest and was more accentuated for CH4. In the second section, meteorological variables were provided by a trajectory model. Backward trajectories from 1-day prior to reaching the measurement site were used to calculate distance and direction averages as well as the recirculation factor. Terciles of these variables were determined in order to establish three intervals with low, medium and high values. These intervals were used to classify the variables following their interval widths and skewnesses. The best correlation between pairs of meteorological variables was observed for the average distance, in particular with horizontal wind speed. Sinusoidal relationships with the average direction were obtained for average distance and for vertical wind speed. Finally, in the third section, the quadratic evolution was considered in each interval of all the meteorological variables. As regards the main result, the greatest increases were obtained for high potential temperature for both gases followed by low and medium boundary layer height for CO2 and CH4, respectively. Combining both meteorological variables provided increases of 22 +/- 9 and 0.070 +/- 0.019 ppm for CO2 and CH4, respectively, although the number of observations affected is small, around 7%. (C) 2017 Elsevier Ltd. All rights reserved. | |||||
BibTeX:
@article{perez18a,
author = {Perez, Isidro A. and Luisa Sanchez, M. and Angeles Garcia, M. and Pardo, Nuria and Fernandez-Duque, Beatriz},
title = {The influence of meteorological variables on CO2 and CH4 trends recorded at a semi-natural station},
journal = {JOURNAL OF ENVIRONMENTAL MANAGEMENT},
publisher = {ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD},
year = {2018},
volume = {209},
pages = {37--45},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S0301479717312008},
doi = {https://doi.org/10.1016/j.jenvman.2017.12.028}
}
|
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| Peters, W., Jacobson, A.R., Sweeney, C., Andrews, A.E., Conway, T.J., Masarie, K., Miller, J.B., Bruhwiler, L.M.P., Petron, G., Hirsch, A.I., Worthy, D.E.J., van der Werf, G.R., Randerson, J.T., Wennberg, P.O., Krol, M.C. and Tans, P.P. | An atmospheric perspective on North American carbon dioxide exchange: CarbonTracker [BibTeX] |
{2007} | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Vol. {104}({48}), pp. 18925-18930 |
article | DOI |
BibTeX:
@article{peters07a,
author = {Peters, Wouter and Jacobson, Andrew R. and Sweeney, Colm and Andrews, Arlyn E. and Conway, Thomas J. and Masarie, Kenneth and Miller, John B. and Bruhwiler, Lori M. P. and Petron, Gabrielle and Hirsch, Adam I. and Worthy, Douglas E. J. and van der Werf, Guido R. and Randerson, James T. and Wennberg, Paul O. and Krol, Maarten C. and Tans, Pieter P.},
title = {An atmospheric perspective on North American carbon dioxide exchange: CarbonTracker},
journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
year = {2007},
volume = {104},
number = {48},
pages = {18925--18930},
doi = {https://doi.org/10.1073/pnas.0708986104}
}
|
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| Peters, W., Krol, M.C., van der Werf, G.R., Houweling, S., Jones, C.D., Hughes, J., Schaefer, K., Masarie, K.A., Jacobson, A.R., Miller, J.B., Cho, C.H., Ramonet, M., Schmidt, M., Ciattaglia, L., Apadula, F., Helta, D., Meinhardt, F., di Sarra, A.G., Piacentino, S., Sferlazzo, D., Aalto, T., Hatakka, J., Strom, J., Haszpra, L., Meijer, H.A.J., van der Laan, S., Neubert, R.E.M., Jordan, A., Rodo, X., Morgui, J.A., Vermeulen, A.T., Popa, E., Rozanski, K., Zimnoch, M., Manning, A.C., Leuenberger, M., Uglietti, C., Dolman, A.J., Ciais, P., Heimann, M. and Tans, P.P. | Seven years of recent European net terrestrial carbon dioxide exchange constrained by atmospheric observations | {2010} | GLOBAL CHANGE BIOLOGY Vol. {16}({4}), pp. 1317-1337 |
article | DOI |
| Abstract: We present an estimate of net ecosystem exchange (NEE) of CO2 in Europe for the years 2001-2007. It is derived with a data assimilation that uses a large set of atmospheric CO2 mole fraction observations (similar to 70 000) to guide relatively simple descriptions of terrestrial and oceanic net exchange, while fossil fuel and fire emissions are prescribed. Weekly terrestrial sources and sinks are optimized (i.e., a flux inversion) for a set of 18 large ecosystems across Europe in which prescribed climate, weather, and surface characteristics introduce finer scale gradients. We find that the terrestrial biosphere in Europe absorbed a net average of -165 Tg C yr-1 over the period considered. This uptake is predominantly in non-EU countries, and is found in the northern coniferous (-94 Tg C yr-1) and mixed forests (-30 Tg C yr-1) as well as the forest/field complexes of eastern Europe (-85 Tg C yr-1). An optimistic uncertainty estimate derived using three biosphere models suggests the uptake to be in a range of -122 to -258 Tg C yr-1, while a more conservative estimate derived from the a-posteriori covariance estimates is -165 +/- 437 Tg C yr-1. Note, however, that uncertainties are hard to estimate given the nature of the system and are likely to be significantly larger than this. Interannual variability in NEE includes a reduction in uptake due to the 2003 drought followed by 3 years of more than average uptake. The largest anomaly of NEE occurred in 2005 concurrent with increased seasonal cycles of observed CO2. We speculate these changes to result from the strong negative phase of the North Atlantic Oscillation in 2005 that lead to favorable summer growth conditions, and altered horizontal and vertical mixing in the atmosphere. All our results are available through http://www.carbontracker.eu. |
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BibTeX:
@article{peters10a,
author = {Peters, W. and Krol, M. C. and van der Werf, G. R. and Houweling, S. and Jones, C. D. and Hughes, J. and Schaefer, K. and Masarie, K. A. and Jacobson, A. R. and Miller, J. B. and Cho, C. H. and Ramonet, M. and Schmidt, M. and Ciattaglia, L. and Apadula, F. and Helta, D. and Meinhardt, F. and di Sarra, A. G. and Piacentino, S. and Sferlazzo, D. and Aalto, T. and Hatakka, J. and Strom, J. and Haszpra, L. and Meijer, H. A. J. and van der Laan, S. and Neubert, R. E. M. and Jordan, A. and Rodo, X. and Morgui, J. -A. and Vermeulen, A. T. and Popa, E. and Rozanski, K. and Zimnoch, M. and Manning, A. C. and Leuenberger, M. and Uglietti, C. and Dolman, A. J. and Ciais, P. and Heimann, M. and Tans, P. P.},
title = {Seven years of recent European net terrestrial carbon dioxide exchange constrained by atmospheric observations},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2010},
volume = {16},
number = {4},
pages = {1317--1337},
doi = {https://doi.org/10.1111/j.1365-2486.2009.02078.x}
}
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| Peters, C.N., Bennartz, R. and Hornberger, G.M. | Satellite-derived methane emissions from inundation in Bangladesh | {2017} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {122}({5}), pp. 1137-1155 |
article | DOI |
| Abstract: The uncertainty in methane (CH4) source strength of rice fields and wetlands is particularly high in South Asia CH4 budgets. We used satellite observations of CH4 column mixing ratios from Atmospheric Infrared Sounder (AIRS), Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), and Greenhouse Gases Observing Satellite (GOSAT) to estimate the contribution of Bangladesh emissions to atmospheric CH4 concentrations. Using satellite-derived inundation area as a proxy for source area, we developed a simple inverse advection model that estimates average annual CH4 surface fluxes to be 4, 9, and 19mgCH(4)m(-2)h(-1) in AIRS, SCIAMACHY, and GOSAT, respectively. Despite this variability, our flux estimates varied over a significantly narrower range than reported values for CH4 surface fluxes from a survey of 32 studies reporting ground-based observations between 0 and 260mgCH(4)m(-2)h(-1). Upscaling our satellite-derived surface flux estimates, we estimated total annual CH4 emissions for Bangladesh to be 1.33.2, 1.82.0, 3.11.6Tgyr(-1), depending on the satellite. Our estimates of total emissions are in line with the median of total emission values for Bangladesh reported in earlier studies. Plain Language Summary The extent of methane emissions from flooded areas, such as wetlands and rice paddies, is not well understood, particularly in South Asia. This study uses satellite observations of atmospheric methane and flooding to explore seasonal fluctuation in methane emissions from Bangladesh. Our findings suggest methane emissions similar to previously thought. |
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BibTeX:
@article{peters17a,
author = {Peters, C. N. and Bennartz, R. and Hornberger, G. M.},
title = {Satellite-derived methane emissions from inundation in Bangladesh},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2017},
volume = {122},
number = {5},
pages = {1137--1155},
doi = {https://doi.org/10.1002/2016JG003740}
}
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| Peters, W., van der Velde, I.R., van Schaik, E., Miller, J.B., Ciais, P., Duarte, H.F., van der Laan-Luijkx, I.T., van der Molen, M.K., Scholze, M., Schaefer, K., Vidale, P.L., Verhoef, A., Wårlind, D., Zhu, D., Tans, P.P., Vaughn, B. and White, J.W.C. | Increased water-use efficiency and reduced CO 2 uptake by plants during droughts at a continental scale [BibTeX] |
2018 | NATURE GEOSCIENCE Vol. 11, pp. 744-748 |
article | URL |
BibTeX:
@article{peters18a,
author = {Peters, Wouter and van der Velde, Ivar R. and van Schaik, Erik and Miller, John B. and Ciais, Philippe and Duarte, Henrique F. and van der Laan-Luijkx, Ingrid T. and van der Molen, Michiel K. and Scholze, Marko and Schaefer, Kevin and Vidale, Pier Luigi and Verhoef, Anne and Wårlind, David and Zhu, Dan and Tans, Pieter P. and Vaughn, Bruce and White, James W. C.},
title = {Increased water-use efficiency and reduced CO 2 uptake by plants during droughts at a continental scale},
journal = {NATURE GEOSCIENCE},
year = {2018},
volume = {11},
pages = {744-748},
url = {https://www.nature.com/articles/s41561-018-0212-7}
}
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| Peylin, P., Law, R.M., Gurney, K.R., Chevallier, F., Jacobson, A.R., Maki, T., Niwa, Y., Patra, P.K., Peters, W., Rayner, P.J., Roedenbeck, C., van der Laan-Luijkx, I.T. and Zhang, X. | Global atmospheric carbon budget: results from an ensemble of atmospheric CO2 inversions | {2013} | BIOGEOSCIENCES Vol. {10}({10}), pp. 6699-6720 |
article | DOI |
| Abstract: Atmospheric CO2 inversions estimate surface carbon fluxes from an optimal fit to atmospheric CO2 measurements, usually including prior constraints on the flux estimates. Eleven sets of carbon flux estimates are compared, generated by different inversions systems that vary in their inversions methods, choice of atmospheric data, transport model and prior information. The inversions were run for at least 5 yr in the period between 1990 and 2010. Mean fluxes for 2001-2004, seasonal cycles, interannual variability and trends are compared for the tropics and northern and southern extra-tropics, and separately for land and ocean. Some continental/basin-scale subdivisions are also considered where the atmospheric network is denser. Four-year mean fluxes are reasonably consistent across inversions at global/latitudinal scale, with a large total (land plus ocean) carbon uptake in the north (-3.4 Pg C yr(-1) (+/- 0.5 Pg C yr(-1) standard deviation), with slightly more uptake over land than over ocean), a significant although more variable source over the tropics (1.6 +/- 0.9 Pg C yr(-1)) and a compensatory sink of similar magnitude in the south (-1.4 +/- 0.5 Pg C yr(-1)) corresponding mainly to an ocean sink. Largest differences across inversions occur in the balance between tropical land sources and southern land sinks. Interannual variability (IAV) in carbon fluxes is larger for land than ocean regions (standard deviation around 1.06 versus 0.33 Pg C yr(-1) for the 1996-2007 period), with much higher consistency among the inversions for the land. While the tropical land explains most of the IAV (standard deviation similar to 0.65 Pg C yr(-1)), the northern and southern land also contribute (standard deviation similar to 0.39 Pg C yr(-1)). Most inversions tend to indicate an increase of the northern land carbon uptake from late 1990s to 2008 (around 0.1 Pg C yr(-1)), predominantly in North Asia. The mean seasonal cycle appears to be well constrained by the atmospheric data over the northern land (at the continental scale), but still highly dependent on the prior flux seasonality over the ocean. Finally we provide recommendations to interpret the regional fluxes, along with the uncertainty estimates. |
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BibTeX:
@article{peylin13a,
author = {Peylin, P. and Law, R. M. and Gurney, K. R. and Chevallier, F. and Jacobson, A. R. and Maki, T. and Niwa, Y. and Patra, P. K. and Peters, W. and Rayner, P. J. and Roedenbeck, C. and van der Laan-Luijkx, I. T. and Zhang, X.},
title = {Global atmospheric carbon budget: results from an ensemble of atmospheric CO2 inversions},
journal = {BIOGEOSCIENCES},
year = {2013},
volume = {10},
number = {10},
pages = {6699--6720},
doi = {https://doi.org/10.5194/bg-10-6699-2013}
}
|
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| Philip, S., Johnson, M.S., Potter, C., Genovesse, V., Baker, D.F., Haynes, K.D., Henze, D.K., Liu, J. and Poulter, B. | Prior biosphere model impact on global terrestrial CO2 fluxes estimated from OCO-2 retrievals | {2019} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {19}({20}), pp. {13267-13287} |
article | DOI URL |
| Abstract: This study assesses the impact of different state of the art global biospheric CO2 flux models, when applied as prior information, on inverse model ``top-down'' estimates of terrestrial CO2 fluxes obtained when assimilating Orbiting Carbon Observatory 2 (000-2) observations. This is done with a series of observing system simulation experiments (OSSEs) using synthetic CO2 column-average dry air mole fraction (XCO2) retrievals sampled at the OCO-2 satellite spatiotemporal frequency. The OSSEs utilized a 4-D variational (4D-Var) assimilation system with the GEOS-Chem global chemical transport model (CTM) to estimate CO2 net ecosystem exchange (NEE) fluxes using synthetic OCO-2 observations. The impact of biosphere models in inverse model estimates of NEE is quantified by conducting OSSEs using the NASA-CASA, CASA-GFED, SiB-4, and LPJ models as prior estimates and using NEE from the multi-model ensemble mean of the Multiscale Synthesis and Terrestrial Model Intercomparison Project as the ``truth''. Results show that the assimilation of simulated XCO2 retrievals at OCO-2 observing modes over land results in posterior NEE estimates which generally reproduce ``true'' NEE globally and over terrestrial TransCom-3 regions that are well-sampled. However, we find larger spread among pos- terior NEE estimates, when using different prior NEE fluxes, in regions and seasons that have limited OCO-2 observational coverage and a large range in ``bottom-up'' NEE fluxes. Seasonally averaged posterior NEE estimates had standard deviations (SD) of similar to 10 % to similar to 50 % of the multi-modelmean NEE for different TransCom-3 land regions with significant NEE fluxes (regions/seasons with a NEE flux >= 0.5 PgC yr(-1)). On a global average, the seasonally averaged residual impact of the prior model NEE assumption on the posterior NEE spread is similar to 10 %-20 % of the posterior NEE mean. Additional OCO-2 OSSE simulations demonstrate that posterior NEE estimates are also sensitive to the assumed prior NEE flux uncertainty statistics, with spread in posterior NEE estimates similar to those when using variable prior model NEE fluxes. In fact, the sensitivity of posterior NEE estimates to prior error statistics was larger than prior flux values in some regions/times in the tropics and Southern Hemisphere where sufficient OCO-2 data were available and large differences between the prior and truth were evident. Overall, even with the availability of spatiotemporally dense 000-2 data, noticeable residual differences (up to similar to 20 %-30 % globally and 50 % regionally) in posterior NEE flux estimates remain that were caused by the choice of prior model flux values and the specification of prior flux uncertainties. | |||||
BibTeX:
@article{philip19a,
author = {Philip, Sajeev and Johnson, Matthew S. and Potter, Christopher and Genovesse, Vanessa and Baker, David F. and Haynes, Katherine D. and Henze, Daven K. and Liu, Junjie and Poulter, Benjamin},
title = {Prior biosphere model impact on global terrestrial CO2 fluxes estimated from OCO-2 retrievals},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {19},
number = {20},
pages = {13267--13287},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/19/13267/2019/},
doi = {https://doi.org/10.5194/acp-19-13267-2019}
}
|
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| Philip, S., Johnson, M.S., Baker, D.F., Basu, S., Tiwari, Y.K., Indira, N.K., Ramonet, M. and Poulter, B. | OCO-2 Satellite-Imposed Constraints on Terrestrial Biospheric CO2 Fluxes Over South Asia | 2022 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 127(3) |
article | DOI |
| Abstract: The spatiotemporal variability of terrestrial biospheric carbon dioxide (CO2) fluxes over South Asia has large uncertainty. The Orbiting Carbon Observatory 2 (OCO-2) satellite provides much-needed retrievals of column-average CO2 on a global-scale, with the highest sensitivity to surface CO2 fluxes and spatiotemporal resolution available to-date. This study conducted global inverse model simulations, assimilating in situ (IS) data and OCO-2 retrievals, to assess optimized CO2 net ecosystem exchange (NEE) fluxes for South Asia. Annual Net Biome Exchange (NBE = NEE + biomass burning) fluxes over South Asia were estimated to be near neutral (0.04 +/- 0.14 PgC yr(-1)) using both IS and OCO-2 observations. The most robust result found by assimilating OCO-2 observations was the constraint imposed on the seasonal cycle of NBE fluxes. The amplitude of the seasonal cycle of NEE was found to be larger than previously assumed. The OCO-2 inversion led to an NBE seasonal amplitude of 0.34 PgC month(-1), which was larger compared to IS constrained NBE (0.19 PgC month(-1)) and MsTMIP ensemble mean NEE (0.16 PgC month(-1)). Moreover, OCO-2 data imposed a phase shift in the NBE seasonal cycle predicted by the prior model. The larger magnitude of NEE seasonality, and phase shift, simulated when assimilating OCO-2 observations are in general agreement with previous studies assimilating regional aircraft observations in addition to global IS observations. This result suggests that OCO-2 provides valuable data that allows for the estimate of NBE on a regional scale in a similar manner as regional in situ aircraft networks. Plain Language Summary The terrestrial biosphere plays a significant role in the global carbon budget. As biosphere-atmosphere exchange is one of the largest sources of uncertainty in the global carbon cycle, it is important that we better understand the sources and sinks of biospheric carbon dioxide (CO2). A major limitation for estimating CO2 fluxes from the terrestrial biosphere has historically been the scarcity of measurement data. However, to alleviate this issue, NASA's Orbiting Carbon Observatory 2 (OCO-2) satellite was launched in 2014 with the goal to improve our understanding about the regional exchange of CO2 between the terrestrial biosphere and atmosphere. This study applied OCO-2 data focusing on South Asia, a region with highly uncertain spatiotemporal variability of terrestrial biospheric fluxes. When using OCO-2 data in this study, a larger seasonal amplitude of biospheric CO2 fluxes was estimated compared to what has previously been assumed for this region. A noticeable difference in the temporal variability of the CO2 flux seasonality was also determined when using satellite data. The results of this study suggest that OCO-2 provides data sufficient for estimating biospheric CO2 fluxes at a regional scale in a similar manner as regional aircraft networks. |
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BibTeX:
@article{philip22a,
author = {Philip, Sajeev and Johnson, Matthew S. and Baker, David F. and Basu, Sourish and Tiwari, Yogesh K. and Indira, Nuggehalli K. and Ramonet, Michel and Poulter, Benjamin},
title = {OCO-2 Satellite-Imposed Constraints on Terrestrial Biospheric CO2 Fluxes Over South Asia},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2022},
volume = {127},
number = {3},
doi = {https://doi.org/10.1029/2021JD035035}
}
|
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| Piao, S.L., Ito, A., Li, S.G., Huang, Y., Ciais, P., Wang, X.H., Peng, S.S., Nan, H.J., Zhao, C., Ahlstrom, A., Andres, R.J., Chevallier, F., Fang, J.Y., Hartmann, J., Huntingford, C., Jeong, S., Levis, S., Levy, P.E., Li, J.S., Lomas, M.R., Mao, J.F., Mayorga, E., Mohammat, A., Muraoka, H., Peng, C.H., Peylin, P., Poulter, B., Shen, Z.H., Shi, X., Sitch, S., Tao, S., Tian, H.Q., Wu, X.P., Xu, M., Yu, G.R., Viovy, N., Zaehle, S., Zeng, N. and Zhu, B. | The carbon budget of terrestrial ecosystems in East Asia over the last two decades | {2012} | BIOGEOSCIENCES Vol. {9}({9}), pp. 3571-3586 |
article | DOI |
| Abstract: This REgional Carbon Cycle Assessment and Processes regional study provides a synthesis of the carbon balance of terrestrial ecosystems in East Asia, a region comprised of China, Japan, North and South Korea, and Mongolia. We estimate the current terrestrial carbon balance of East Asia and its driving mechanisms during 1990-2009 using three different approaches: inventories combined with satellite greenness measurements, terrestrial ecosystem carbon cycle models and atmospheric inversion models. The magnitudes of East Asia's terrestrial carbon sink from these three approaches are comparable: -0.293 +/- 0.033 PgC yr(-1) from inventory-remote sensing model-data fusion approach, -0.413 +/- 0.141 PgC yr(-1)(not considering biofuel emissions) or -0.224 +/- 0.141 PgC yr(-1) (considering biofuel emissions) for carbon cycle models, and -0.270 +/- 0.507 PgC yr(-1) for atmospheric inverse models. Here and in the following, the numbers behind +/- signs are standard deviations. The ensemble of ecosystem modeling based analyses further suggests that at the regional scale, climate change and rising atmospheric CO2 together resulted in a carbon sink of -0.289 +/- 0.135 PgC yr(-1), while land-use change and nitrogen deposition had a contribution of -0.013 +/- 0.029 PgC yr(-1) and -0.107 +/- 0.025 PgC yr(-1), respectively. Although the magnitude of climate change effects on the carbon balance varies among different models, all models agree that in response to climate change alone, southern China experienced an increase in carbon storage from 1990 to 2009, while northern East Asia including Mongolia and north China showed a decrease in carbon storage. Overall, our results suggest that about 13-27% of East Asia's CO2 emissions from fossil fuel burning have been offset by carbon accumulation in its terrestrial territory over the period from 1990 to 2009. The underlying mechanisms of carbon sink over East Asia still remain largely uncertain, given the diversity and intensity of land management processes, and the regional conjunction of many drivers such as nutrient deposition, climate, atmospheric pollution and CO2 changes, which cannot be considered as independent for their effects on carbon storage. |
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BibTeX:
@article{piao12a,
author = {Piao, S. L. and Ito, A. and Li, S. G. and Huang, Y. and Ciais, P. and Wang, X. H. and Peng, S. S. and Nan, H. J. and Zhao, C. and Ahlstrom, A. and Andres, R. J. and Chevallier, F. and Fang, J. Y. and Hartmann, J. and Huntingford, C. and Jeong, S. and Levis, S. and Levy, P. E. and Li, J. S. and Lomas, M. R. and Mao, J. F. and Mayorga, E. and Mohammat, A. and Muraoka, H. and Peng, C. H. and Peylin, P. and Poulter, B. and Shen, Z. H. and Shi, X. and Sitch, S. and Tao, S. and Tian, H. Q. and Wu, X. P. and Xu, M. and Yu, G. R. and Viovy, N. and Zaehle, S. and Zeng, N. and Zhu, B.},
title = {The carbon budget of terrestrial ecosystems in East Asia over the last two decades},
journal = {BIOGEOSCIENCES},
year = {2012},
volume = {9},
number = {9},
pages = {3571--3586},
doi = {https://doi.org/10.5194/bg-9-3571-2012}
}
|
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| Pickett-Heaps, C.A., Rayner, P.J., Law, R.M., Ciais, P., Patra, P.K., Bousquet, P., Peylin, P., Maksyutov, S., Marshall, J., Roedenbeck, C., Langenfelds, R.L., Steele, L.P., Francey, R.J., Tans, P. and Sweeney, C. | Atmospheric CO2 inversion validation using vertical profile measurements: Analysis of four independent inversion models | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: We present the results of a validation of atmospheric inversions of CO2 fluxes using four transport models. Each inversion uses data primarily from surface stations, combined with an atmospheric transport model, to estimate surface fluxes. The validation (or model evaluation) consists of running these optimized fluxes through the forward model and comparing the simulated concentrations with airborne concentration measurements. We focus on profiles from Cape Grim, Tasmania, and Carr, Colorado, while using other profile sites to test the generality of the comparison. Fits to the profiles are generally worse than to the surface data from the inversions and worse than the expected model-data mismatch. Thus inversion estimates are generally not consistent with the profile measurements. The TM3 model does better by some measures than the other three models. Models perform better over Tasmania than Colorado, and other profile sites bear out a general improvement from north to south and from continental to marine locations. There are also errors in the interannual variability of the fit, consistent in time and common across models. This suggests real variations in sources visible to the profile but not the surface measurements. |
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BibTeX:
@article{pickett-heaps11a,
author = {Pickett-Heaps, C. A. and Rayner, P. J. and Law, R. M. and Ciais, P. and Patra, P. K. and Bousquet, P. and Peylin, P. and Maksyutov, S. and Marshall, J. and Roedenbeck, C. and Langenfelds, R. L. and Steele, L. P. and Francey, R. J. and Tans, P. and Sweeney, C.},
title = {Atmospheric CO2 inversion validation using vertical profile measurements: Analysis of four independent inversion models},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2010JD014887}
}
|
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| Pilcher, D.J., Naiman, D.M., Cross, J.N., Hermann, A.J., Siedlecki, S.A., Gibson, G.A. and Mathis, J.T. | Modeled Effect of Coastal Biogeochemical Processes, Climate Variability, and Ocean Acidification on Aragonite Saturation State in the Bering Sea | {2019} | FRONTIERS IN MARINE SCIENCE Vol. {5} |
article | DOI URL |
| Abstract: The Bering Sea is highly vulnerable to ocean acidification (OA) due to naturally cold, poorly buffered waters and ocean mixing processes. Harsh weather conditions within this rapidly changing, geographically remote environment have limited the quantity of carbon chemistry data, thereby hampering efforts to understand underlying spatial-temporal variability and detect long-term trends. We add carbonate chemistry to a regional biogeochemical model of the Bering Sea to explore the underlying mechanisms driving carbon dynamics over a decadal hindcast (2003-2012). The results illustrate that coastal processes generate considerable spatial variability in the biogeochemistry and vulnerability of Bering Sea shelf water to OA. Substantial seasonal biological productivity maintains high supersaturation of aragonite on the outer shelf, whereas riverine freshwater runoff loaded with allochthonous carbon decreases aragonite saturation states (Omega(Arag)) to values below 1 on the inner shelf. Over the entire 2003-2012 model hindcast, annual surface Omega(Arag) decreases by 0.025 - 0.04 units/year due to positive trends in the partial pressure of carbon dioxide (pCO(2)) in surface waters and dissolved inorganic carbon (DIC). Variability in this trend is driven by an increase in fall phytoplankton productivity and shelf carbon uptake, occurring during a transition from a relatively warm (2003-2005) to cold (2010-2012) temperature regime. Our results illustrate how local biogeochemical processes and climate variability can modify projected rates of OA within a coastal shelf system. | |||||
BibTeX:
@article{pilcher19a,
author = {Pilcher, Darren J. and Naiman, Danielle M. and Cross, Jessica N. and Hermann, Albert J. and Siedlecki, Samantha A. and Gibson, Georgina A. and Mathis, Jeremy T.},
title = {Modeled Effect of Coastal Biogeochemical Processes, Climate Variability, and Ocean Acidification on Aragonite Saturation State in the Bering Sea},
journal = {FRONTIERS IN MARINE SCIENCE},
publisher = {FRONTIERS MEDIA SA},
year = {2019},
volume = {5},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.frontiersin.org/articles/10.3389/fmars.2018.00508/full?&utm_source=Email_to_authors_&utm_medium=Email&utm_content=T1_11.5e1_author&utm_campaign=Email_publication&field=&journalName=Frontiers_in_Marine_Science&id=410905},
doi = {https://doi.org/10.3389/fmars.2018.00508}
}
|
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| Pillai, D., Gerbig, C., Marshall, J., Ahmadov, R., Kretschmer, R., Koch, T. and Karstens, U. | High resolution modeling of CO2 over Europe: implications for representation errors of satellite retrievals | {2010} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {10}({1}), pp. 83-94 |
article | DOI |
| Abstract: Satellite retrievals for column CO2 with better spatial and temporal sampling are expected to improve the current surface flux estimates of CO2 via inverse techniques. However, the spatial scale mismatch between remotely sensed CO2 and current generation inverse models can induce representation errors, which can cause systematic biases in flux estimates. This study is focused on estimating these representation errors associated with utilization of satellite measurements in global models with a horizontal resolution of about 1 degree or less. For this we used simulated CO2 from the high resolution modeling framework WRF-VPRM, which links CO2 fluxes from a diagnostic biosphere model to a weather forecasting model at 10x10 km(2) horizontal resolution. Sub-grid variability of column averaged CO2, i.e. the variability not resolved by global models, reached up to 1.2 ppm with a median value of 0.4 ppm. Statistical analysis of the simulation results indicate that orography plays an important role. Using sub-grid variability of orography and CO2 fluxes as well as resolved mixing ratio of CO2, a linear model can be formulated that could explain about 50% of the spatial patterns in the systematic (bias or correlated error) component of representation error in column and near-surface CO2 during day- and night-times. These findings give hints for a parameterization of representation error which would allow for the representation error to taken into account in inverse models or data assimilation systems. |
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BibTeX:
@article{pillai10a,
author = {Pillai, D. and Gerbig, C. and Marshall, J. and Ahmadov, R. and Kretschmer, R. and Koch, T. and Karstens, U.},
title = {High resolution modeling of CO2 over Europe: implications for representation errors of satellite retrievals},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2010},
volume = {10},
number = {1},
pages = {83--94},
doi = {https://doi.org/10.5194/acp-10-83-2010}
}
|
|||||
| Pilon, L., Berberoglu, H. and Kandilian, R. | Radiation transfer in photobiological carbon dioxide fixation and fuel production by microalgae | {2011} | JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER Vol. {112}({17}), pp. 2639-2660 |
article | DOI |
| Abstract: Solar radiation is the energy source driving the metabolic activity of microorganisms able to photobiologically fixate carbon dioxide and convert solar energy into biofuels. Thus, careful radiation transfer analysis must be conducted in order to design and operate efficient photobioreactors. This review paper first introduces light harvesting mechanisms used by microorganisms as well as photosynthesis and photobiological fuel production. It then provides a thorough and critical review of both experimental and modeling efforts focusing on radiation transfer in microalgae suspension. Experimental methods to determine the radiation characteristics of microalgae are presented. Methods for solving the radiation transfer equation in photobioreactors with or without bubbles are also discussed. Sample measurements and numerical solutions are provided. Finally, novel strategies for achieving optimum light delivery and maximizing sunlight utilization in photobioreactors are discussed including genetic engineering of microorganisms with truncated chlorophyll antenna. (C) 2011 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{pilon11a,
author = {Pilon, Laurent and Berberoglu, Halil and Kandilian, Razmig},
title = {Radiation transfer in photobiological carbon dioxide fixation and fuel production by microalgae},
journal = {JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER},
year = {2011},
volume = {112},
number = {17},
pages = {2639--2660},
doi = {https://doi.org/10.1016/j.jqsrt.2011.07.004}
}
|
|||||
| Pino, D., Kaikkonen, J.P. and de Arellano, J.V.-G. | Quantifying the uncertainties of advection and boundary layer dynamics on the diurnal carbon dioxide budget | {2013} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {118}({16}), pp. 9376-9392 |
article | DOI |
| Abstract: We investigate the uncertainties in the carbon dioxide (CO2) mixing ratio and inferred surface flux associated with boundary layer processes and advection by using mixed-layer theory. By extending the previous analysis presented by Pino et al. (2012), new analytical expressions are derived to quantify the uncertainty of CO2 mixing ratio or surface flux associated to, among others, boundary layer depth, early morning CO2 mixing ratio at the mixed layer or at the free atmosphere; or CO2 advection. We identify and calculate two sorts of uncertainties associated to the CO2 mixing ratio and surface flux: instantaneous and past (due to advection). The numerical experiments are guided and constrained by meteorological and CO2 observations taken at the Cabauw 213 m tower. We select 2 days (25 September 2003 and 12 March 2004) with a well-defined convective boundary layer but different CO2 advection contributions. Our sensitivity analysis shows that uncertainty of the CO2 advection in the boundary layer due to instantaneous uncertainties represents at 1600 LT on 12 March 2004 a contribution of 2ppm and 0.072 mg m(-2)s(-1) in the uncertainty of the CO2 mixing ratio and inferred surface flux, respectively. Taking into account that the monthly averaged minimum CO2 surface flux for March 2004 was -0.55 mg m(-2)s(-1), the error on the surface flux is on the order of 10%. By including CO2 advection in the analytical expressions, we demonstrate that the uncertainty of the CO2 mixing ratio or surface flux also depends on the past uncertainties of the boundary layer depth. |
|||||
BibTeX:
@article{pino13a,
author = {Pino, D. and Kaikkonen, J. -P. and de Arellano, J. Vila-Guerau},
title = {Quantifying the uncertainties of advection and boundary layer dynamics on the diurnal carbon dioxide budget},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2013},
volume = {118},
number = {16},
pages = {9376--9392},
doi = {https://doi.org/10.1002/jgrd.50677}
}
|
|||||
| Pliutau, D. and Prasad, N.S. | Simulation framework to estimate the performance of CO2 and O-2 sensing from space and airborne platforms for the ASCENDS mission requirements analysis | {2012} | Vol. {8379}LASER RADAR TECHNOLOGY AND APPLICATIONS XVII |
inproceedings | DOI |
| Abstract: The Active Sensing of CO2 Emissions over Nights Days and Seasons (ASCENDS) mission recommended by the NRC Decadal Survey has a desired accuracy of 0.3% in carbon dioxide mixing ratio (XCO2) retrievals requiring careful selection and optimization of the instrument parameters. NASA Langley Research Center (LaRC) is investigating 1.57 micron carbon dioxide as well as the 1.26-1.27 micron oxygen bands for our proposed ASCENDS mission requirements investigation. Simulation studies are underway for these bands to select optimum instrument parameters. The simulations are based on a multi-wavelength lidar modeling framework being developed at NASA LaRC to predict the performance of CO2 and O-2 sensing from space and airborne platforms. The modeling framework consists of a lidar simulation module and a line-by-line calculation component with interchangeable lineshape routines to test the performance of alternative lineshape models in the simulations. As an option the line-by-line radiative transfer model (LBLRTM) program may also be used for line-by-line calculations. The modeling framework is being used to perform error analysis, establish optimum measurement wavelengths as well as to identify the best lineshape models to be used in CO2 and O-2 retrievals. Several additional programs for HITRAN database management and related simulations are planned to be included in the framework. The description of the modeling framework with selected results of the simulation studies for CO2 and O-2 sensing is presented in this paper. | |||||
BibTeX:
@inproceedings{pliutau12a,
author = {Pliutau, Denis and Prasad, Narasimha S.},
title = {Simulation framework to estimate the performance of CO2 and O-2 sensing from space and airborne platforms for the ASCENDS mission requirements analysis},
booktitle = {LASER RADAR TECHNOLOGY AND APPLICATIONS XVII},
publisher = {SPIE-INT SOC OPTICAL ENGINEERING},
year = {2012},
volume = {8379},
note = {Conference on Laser Radar Technology and Applications XVII, Baltimore, MD, APR 24-26, 2012},
doi = {https://doi.org/10.1117/12.919476}
}
|
|||||
| Polavarapu, S.M., Neish, M., Tanguay, M., Girard, C., de Grandpre, J., Semeniuk, K., Gravel, S., Ren, S., Roche, S., Chan, D. and Strong, K. | Greenhouse gas simulations with a coupled meteorological and transport model: the predictability of CO2 | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({18}), pp. 12005-12038 |
article | DOI |
| Abstract: A new model for greenhouse gas transport has been developed based on Environment and Climate Change Canada's operational weather and environmental prediction models. When provided with realistic posterior fluxes for CO2, the CO2 simulations compare well to NOAA's Carbon-Tracker fields and to near-surface continuous measurements, columns from the Total Carbon Column Observing Network (TCCON) and NOAA aircraft profiles. This coupled meteorological and tracer transport model is used to study the predictability of CO2. Predictability concerns the quantification of model forecast errors and thus of transport model errors. CO2 predictions are used to compute model-data mismatches when solving flux inversion problems and the quality of such predictions is a major concern. Here, the loss of meteorological predictability due to uncertain meteorological initial conditions is shown to impact CO2 predictability. The predictability of CO2 is shorter than that of the temperature field and increases near the surface and in the lower stratosphere. When broken down into spatial scales, CO2 predictability at the very largest scales is mainly due to surface fluxes but there is also some sensitivity to the land and ocean surface forcing of meteorological fields. The predictability due to the land and ocean surface is most evident in boreal summer when biospheric uptake produces large spatial gradients in the CO2 field. This is a newly identified source of uncertainty in CO2 predictions but it is expected to be much less significant than uncertainties in fluxes. However, it serves as an upper limit for the more important source of transport error and loss of predictability, which is due to uncertain meteorological analyses. By isolating this component of transport error, it is demonstrated that CO2 can only be defined on large spatial scales due to the presence of meteorological uncertainty. Thus, for a given model, there is a spatial scale below which fluxes cannot be inferred simply due to the fact that meteorological analyses are imperfect. These unresolved spatial scales correspond to small scales near the surface but increase with altitude. By isolating other components of transport error, the largest or limiting error can be identified. For example, a model error due to the lack of convective tracer transport was found to impact transport error on the very largest (wavenumbers less than 5) spatial scales. Thus for wavenumbers greater than 5, transport model error due to meteorological analysis uncertainty is more important for our model than the lack of convective tracer transport. |
|||||
BibTeX:
@article{polavarapu16a,
author = {Polavarapu, Saroja M. and Neish, Michael and Tanguay, Monique and Girard, Claude and de Grandpre, Jean and Semeniuk, Kirill and Gravel, Sylvie and Ren, Shuzhan and Roche, Sebastien and Chan, Douglas and Strong, Kimberly},
title = {Greenhouse gas simulations with a coupled meteorological and transport model: the predictability of CO2},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {18},
pages = {12005--12038},
doi = {https://doi.org/10.5194/acp-16-12005-2016}
}
|
|||||
| Polavarapu, S.M., Deng, F., Byrne, B., Jones, D.B.A. and Neish, M. | A comparison of posterior atmospheric CO2 adjustments obtained from in situ and GOSAT constrained flux inversions | {2018} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {18}({16}), pp. {12011-12044} |
article | |
| Abstract: Posterior fluxes obtained from inverse modelling are difficult to verify because there is no dense network of flux measurements available to evaluate estimates against. Here we present a new diagnostic to evaluate structures in posterior fluxes. First, we simulate the change in atmospheric CO2 fields between posterior and prior fluxes, referred to as the posterior atmospheric adjustments due to updated fluxes (PAAFs). Second, we calculate the uncertainty in atmospheric CO2 fields due solely to uncertainty in the meteorological fields, referred to as the posterior atmospheric adjustments due to imperfect meteorology (PAAMs). We argue that PAAF can only be considered robust if it exceeds PAAM, that is, the changes in atmospheric CO2 between the posterior and prior fluxes should at least exceed atmospheric CO2 changes arising from imperfect meteorology. This diagnostic is applied to two CO2 flux inversions: one which assimilates observations from the in situ CO2 network and the other which assimilates observations from the Greenhouse Gases Observing SATellite (GOSAT). On the global scale, PAAF in the troposphere reflects northern extratropical fluxes, whereas stratospheric adjustments primarily reflect tropical fluxes. In general, larger spatiotemporal variations in PAAF are obtained for the GOSAT inversion than for the in situ inversion. Zonal standard deviations of the PAAF exceed the PAAM through most of the year when GOSAT observations are used, but the minimum value is exceeded only in boreal summer when in situ observations are used. Zonal spatial structures in GOSAT-based PAAF exceed PAAM throughout the year in the tropics and through most of the year in the northern extratropics, suggesting GOSAT flux inversions can constrain zonal asymmetries in fluxes. However, we cannot discount the possibility that these structures are influenced by biases in GOSAT retrievals. Verification of such spatial structures will require a dense network of independent observations. Because PAAF depends on the choice of prior fluxes, the comparison with PAAM is system dependent and thus can be used to monitor a given assimilation system's behaviour. |
|||||
BibTeX:
@article{polavarapu18a,
author = {Polavarapu, Saroja M. and Deng, Feng and Byrne, Brendan and Jones, Dylan B. A. and Neish, Michael},
title = {A comparison of posterior atmospheric CO2 adjustments obtained from in situ and GOSAT constrained flux inversions},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2018},
volume = {18},
number = {16},
pages = {12011-12044}
}
|
|||||
| Pradhan, R., Goroshi, S. and Singh, R.P. | SPATIAL AND SEASONAL CHARACTERIZATION OF TERRESTRIAL BIOSPHERIC CARBON FLUX OVER INDIA USING GOSAT DATA | {2014} | Vol. {40-8}ISPRS TECHNICAL COMMISSION VIII SYMPOSIUM, pp. 617-621 |
inproceedings | DOI |
| Abstract: Carbon plays a crucial role in determining the ecosystem balance and slight changes in its concentration in the atmosphere can have significant impacts. The launch of JAXA's GOSAT (Greenhouse gases Observing SATellite) in 2009 has started a new era of high accuracy CO2 concentration and flux measurements from space borne sensors. This paper reports the spatial and temporal variability of terrestrial biospheric carbon fluxes over the agro-climatic zones of India derived using GOSAT data for the period June 2009 to October 2011. The country averaged biospheric carbon flux varied from -0.47 (October) to 0.37 (April) gC m(-2) day(-1). Maximum variability in fluxes was observed for the North-Eastern region (-2.18 to + 1.38 gC m(-2) day(-1)) whereas the dry region of Rajasthan showed extremely low values (-0.1 to + 0.1 gC m(-2) day(-1)). The temporal variation in flux values was compared to averaged NDVI for each zone and indicated that growing season corresponds to more sequestration of carbon from the atmosphere. We compared GOSAT derived biospheric flux with Carbon Tracker (CT) data and observed that the two values show good agreement for all months except June and July. This study provides new estimates of biospheric carbon flux using satellite data driven models to better understand the carbon dynamics associated with terrestrial biosphere over India. |
|||||
BibTeX:
@inproceedings{pradhan14a,
author = {Pradhan, Rohit and Goroshi, Sheshakumar and Singh, Raghavendra P.},
title = {SPATIAL AND SEASONAL CHARACTERIZATION OF TERRESTRIAL BIOSPHERIC CARBON FLUX OVER INDIA USING GOSAT DATA},
booktitle = {ISPRS TECHNICAL COMMISSION VIII SYMPOSIUM},
year = {2014},
volume = {40-8},
pages = {617--621},
note = {ISPRS Technical Commission VIII Symposium, Hyderabad, INDIA, DEC 09-12, 2014},
doi = {https://doi.org/10.5194/isprsarchives-XL-8-617-2014}
}
|
|||||
| Pu, J., Xu, H., Kang, L. and Ma, Q. | Characteristics of Atmopsheric CO2 Concentration and Variation of Carbon Source & Sink at Lin'an Regional Background Station [BibTeX] |
2011 | Environmental Science Vol. 32(8) |
article | |
BibTeX:
@article{pu11a,
author = {Pu, Jingjiao and Xu, Honghui and Kang, Lili and Ma, Qianli},
title = {Characteristics of Atmopsheric CO2 Concentration and Variation of Carbon Source & Sink at Lin'an Regional Background Station},
journal = {Environmental Science},
year = {2011},
volume = {32},
number = {8}
}
|
|||||
| Qiu, B., Chen, J.M., Ju, W., Zhang, Q. and Zhang, Y. | Simulating emission and scattering of solar-induced chlorophyll fluorescence at far-red band in global vegetation with different canopy structures | {2019} | REMOTE SENSING OF ENVIRONMENT Vol. {233} |
article | DOI URL |
| Abstract: Recent satellite retrieval of solar-induced fluorescence (SIF) has provided promising information for constraining carbon flux simulation with terrestrial biosphere models (TBMs). For this purpose, it is necessary to implement a SIF model in TBMs. SIF emerging from leaves generally undergoes multiple scattering processes within a canopy. However, it remains unclear how canopy scattering impacts observed SIF, which is used to constrain regional and global GPP modeling. Here, we developed an efficient scheme to account for the canopy scattering in a SIF model. Then we coupled this mechanistic representation of SIF to Boreal Ecosystem Productivity Simulator (BEPS) and evaluated the new model (BEPS-SIF) simulations with ground and satellite-based SIF measurements. The results showed that BEPS-SIF reproduced global patterns of SIF observed by a satellite sensor and captured the seasonality of SIF reasonably well over different regions. The canopy scattering effects on the relationship between SIF and gross primary productivity (GPP) were also examined at the global scale using the BEPS-SIF model. We confirmed that SIF emitted from leaves was more directly linked to GPP globally than the observed canopy-leaving SIF, with higher improvements of the coefficient of determination (R-2) in dense vegetated regions and lower improvements of R-2 in sparse vegetated regions. This study highlights the importance of implementing the canopy scattering effect in a fluorescence model of TBMs and the need to account for this effect in the use of satellite SIF data for constraining global GPP modeling. | |||||
BibTeX:
@article{qiu19a,
author = {Qiu, Bo and Chen, Jing M. and Ju, Weimin and Zhang, Qian and Zhang, Yongguang},
title = {Simulating emission and scattering of solar-induced chlorophyll fluorescence at far-red band in global vegetation with different canopy structures},
journal = {REMOTE SENSING OF ENVIRONMENT},
publisher = {ELSEVIER SCIENCE INC},
year = {2019},
volume = {233},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S003442571930392X},
doi = {https://doi.org/10.1016/j.rse.2019.111373}
}
|
|||||
| Quadri, P. | Local Habitat Modulation of Climate Change Effects on High-Altitude Tropical Conifers and Temporal and Geographic Variation in the Effects of Heritage Conservation … | 2018 | School: UNIVERSITY OF CALIFORNIA | phdthesis | URL |
| Abstract: Species in tropical mountains are more vulnerable to climate change than species elsewhere because their adaptations are more tightly coupled to their habitats and because tropical high elevations seem to be warming faster than the rest of the planet. However, the … | |||||
BibTeX:
@phdthesis{quadri18a,
author = {Paulo Quadri},
title = {Local Habitat Modulation of Climate Change Effects on High-Altitude Tropical Conifers and Temporal and Geographic Variation in the Effects of Heritage Conservation …},
school = {UNIVERSITY OF CALIFORNIA},
year = {2018},
url = {https://escholarship.org/uc/item/271102nt}
}
|
|||||
| Quadri, P., Silva, L.C.R. and Zavaleta, E.S. | Climate-induced reversal of tree growth patterns at a tropical treeline | 2021 | SCIENCE ADVANCES Vol. 7(22) |
article | DOI |
| Abstract: Globally, cold-limited trees and forests are expected to experience growth acceleration as a direct response to warming temperatures. However, thresholds of temperature limitation may vary substantially with local environmental conditions, leading to heterogeneous responses in tree ecophysiology. We used dendroecological and isotopic methods to quantify shifting tree growth and resource use over the past 143 years across topographic aspects in a high-elevation forest of central Mexico. Trees on south-facing slopes (SFS) grew faster than those on north-facing slopes (NFS) until the mid-20th century, when this pattern reversed notably with marked growth rate declines on SFS and increases on NFS. Stable isotopes of carbon, oxygen, and carbon-to-nitrogen ratios suggest that this reversal is linked to interactions between CO2 stimulation of photosynthesis and water or nitrogen limitation. Our findings highlight the importance of incorporating landscape processes and habitat heterogeneity in predictions of tree growth responses to global environmental change. |
|||||
BibTeX:
@article{quadri21a,
author = {Quadri, Paulo and Silva, Lucas C. R. and Zavaleta, Erika S.},
title = {Climate-induced reversal of tree growth patterns at a tropical treeline},
journal = {SCIENCE ADVANCES},
year = {2021},
volume = {7},
number = {22},
doi = {https://doi.org/10.1126/sciadv.abb7572}
}
|
|||||
| Le Quéré, C., Canadell, J.G., Ciais, P., Dhakal, S., Patwardhan, A., Raupach, M.R. and Young, O.R. | An International Carbon Office to assist policy-based science [BibTeX] |
2010 | Current Opinion in Environmental Sustainability Vol. 2(4), pp. 297-300 |
article | |
BibTeX:
@article{quere10a,
author = {Le Quéré, Corinne and Canadell, Josep G and Ciais, Philippe and Dhakal, Shobhakar and Patwardhan, Anand and Raupach, Michael R and Young, Oran R},
title = {An International Carbon Office to assist policy-based science},
journal = {Current Opinion in Environmental Sustainability},
year = {2010},
volume = {2},
number = {4},
pages = {297--300}
}
|
|||||
| Raczka, B.M., Davis, K.J., Huntzinger, D., Neilson, R.P., Poulter, B., Richardson, A.D., Xiao, J., Baker, I., Ciais, P., Keenan, T.F., Law, B., Post, W.M., Ricciuto, D., Schaefer, K., Tian, H., Tomelleri, E., Verbeeck, H. and Viovy, N. | Evaluation of continental carbon cycle simulations with North American flux tower observations | {2013} | ECOLOGICAL MONOGRAPHS Vol. {83}({4}), pp. 531-556 |
article | DOI |
| Abstract: Terrestrial biosphere models can help identify physical processes that control carbon dynamics, including land-atmosphere CO2 fluxes, and have great potential to predict the terrestrial ecosystem response to changing climate. The skill of models that provide continental-scale carbon flux estimates, however, remains largely untested. This paper evaluates the performance of continental-scale flux estimates from 17 models against observations from 36 North American flux towers. Fluxes extracted from regional model simulations were compared with co-located flux tower observations at monthly and annual time increments. Site-level model simulations were used to help interpret sources of the mismatch between the regional simulations and site-based observations. On average, the regional model runs overestimated the annual gross primary productivity (5%) and total respiration (15%), and they significantly underestimated the annual net carbon uptake (64%) during the time period 2000-2005. Comparison with site-level simulations implicated choices specific to regional model simulations as contributors to the gross flux biases, but not the net carbon uptake bias. The models performed the best at simulating carbon exchange at deciduous broadleaf sites, likely because a number of models used prescribed phenology to simulate seasonal fluxes. The models did not perform as well for crop, grass, and evergreen sites. The regional models matched the observations most closely in terms of seasonal correlation and seasonal magnitude of variation, but they have very little skill at interannual correlation and minimal skill at interannual magnitude of variability. The comparison of site vs. regional-level model runs demonstrated that (1) the interannual correlation is higher for site-level model runs, but the skill remains low; and (2) the underestimation of year-to-year variability for all fluxes is an inherent weakness of the models. The best-performing regional models that did not use flux tower calibration were CLM-CN, CASA-GFEDv2, and SIB3.1. Two flux tower calibrated, empirical models, EC-MOD and MOD17 broken vertical bar, performed as well as the best process-based models. This suggests that (1) empirical, calibrated models can perform as well as complex, process-based models and (2) combining process-based model structure with relevant constraining data could significantly improve model performance. |
|||||
BibTeX:
@article{raczka13a,
author = {Raczka, Brett M. and Davis, Kenneth J. and Huntzinger, Deborah and Neilson, Ronald P. and Poulter, Benjamin and Richardson, Andrew D. and Xiao, Jingfeng and Baker, Ian and Ciais, Philippe and Keenan, Trevor F. and Law, Beverly and Post, Wilfred M. and Ricciuto, Daniel and Schaefer, Kevin and Tian, Hanqin and Tomelleri, Enrico and Verbeeck, Hans and Viovy, Nicolas},
title = {Evaluation of continental carbon cycle simulations with North American flux tower observations},
journal = {ECOLOGICAL MONOGRAPHS},
year = {2013},
volume = {83},
number = {4},
pages = {531--556},
doi = {https://doi.org/10.1890/12-0893.1}
}
|
|||||
| Rajan, N., Maas, S.J. and Cui, S. | Extreme Drought Effects on Carbon Dynamics of a Semiarid Pasture | {2013} | AGRONOMY JOURNAL Vol. {105}({6}), pp. 1749-1760 |
article | DOI |
| Abstract: Environmental and management factors are critical in determining the C source or sink status of agroecosystems. Information on the C dynamics of an ecosystem from source to sink and vice versa are critical in determining the role of that ecosystem in regional and global C balances. We investigated the impact of the 2011 mega-drought on seasonal changes in net CO2 exchange of a WW-B. Dahl Old World bluestem [Bothriochloa bladhii (Retz) S.T. Blake] pasture in the Texas High Plains and compared the results with those from 2010, a hydrologically wet year. Carbon dioxide flux between the vegetation and atmosphere was measured using an eddy covariance flux tower. Our results indicate that net ecosystem exchange, ecosystem respiration, and gross primary production for this agroecosystem were strongly affected by environmental variables and grazing. During the period of measurement in 2010 (Days of the Year 152-365), the pasture accumulated 164 g C m(-2) and was a net C sink. During the same period in 2011, the severe drought changed the dynamics of the pasture from a C sink to a source, with a net cumulative loss of 142 g C m(-2). Ecosystem respiration was an exponential function of soil temperature in both years. When extreme water-limiting days were excluded, the exponential model explained 90% of the variation in ecosystem respiration in 2011 and 92% of the variation in ecosystem respiration in 2010. Incorporating the results from our study with ecosystem models can improve our understanding of the contributions of managed pastures to regional C balances. |
|||||
BibTeX:
@article{rajan13a,
author = {Rajan, Nithya and Maas, Stephan J. and Cui, Song},
title = {Extreme Drought Effects on Carbon Dynamics of a Semiarid Pasture},
journal = {AGRONOMY JOURNAL},
year = {2013},
volume = {105},
number = {6},
pages = {1749--1760},
doi = {https://doi.org/10.2134/agronj2013.0112}
}
|
|||||
| Rastogi, B., Miller, J.B., Trudeau, M., Andrews, A.E., Hu, L., Mountain, M., Nehrkorn, T., Baier, B., McKain, K., Mund, J., Guan, K. and Alden, C.B. | Evaluating consistency between total column CO2 retrievals from OCO-2 and the in situ network over North America: implications for carbon flux estimation | 2021 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 21(18), pp. 14385-14401 |
article | DOI |
| Abstract: Feedbacks between the climate system and the carbon cycle represent a key source of uncertainty in model projections of Earth's climate, in part due to our inability to directly measure large-scale biosphere-atmosphere carbon fluxes. In situ measurements of the CO2 mole fraction from surface flasks, towers, and aircraft are used in inverse models to infer fluxes, but measurement networks remain sparse, with limited or no coverage over large parts of the planet. Satellite retrievals of total column CO2 (X-CO2), such as those from NASA's Orbiting Carbon Observatory-2 (OCO-2), can potentially provide unprecedented global information about CO2 spatiotemporal variability. However, for use in inverse modeling, data need to be extremely stable, highly precise, and unbiased to distinguish abundance changes emanating from surface fluxes from those associated with variability in weather. Systematic errors in X-CO2 have been identified and, while bias correction algorithms are applied globally, inconsistencies persist at regional and smaller scales that may complicate or confound flux estimation. To evaluate X-CO2 retrievals and assess potential biases, we compare OCO-2 v10 retrievals with in situ data-constrained X-CO2 simulations over North America estimated using surface fluxes and boundary conditions optimized with observations that are rigorously calibrated relative to the World Meteorological Organization X2007 CO2 scale. Systematic errors in simulated atmospheric transport are independently evaluated using unassimilated aircraft and AirCore profiles. We find that the global OCO-2 v10 bias correction shifts the distribution of retrievals closer to the simulated X-CO2, as intended. Comparisons between bias-corrected and simulated X-CO2 reveal differences that vary seasonally. Importantly, the difference between simulations and retrievals is of the same magnitude as the imprint of recent surface flux in the total column. This work demonstrates that systematic errors in OCO-2 v10 retrievals of X-CO2 over land can be large enough to confound reliable surface flux estimation and that further improvements in retrieval and bias correction techniques are essential. Finally, we show that independent observations, especially vertical profile data, such as those from the National Oceanic and Atmospheric Administration aircraft and AirCore programs are critical for evaluating errors in both satellite retrievals and carbon cycle models. |
|||||
BibTeX:
@article{rastogi21a,
author = {Rastogi, Bharat and Miller, John B. and Trudeau, Micheal and Andrews, Arlyn E. and Hu, Lei and Mountain, Marikate and Nehrkorn, Thomas and Baier, Bianca and McKain, Kathryn and Mund, John and Guan, Kaiyu and Alden, Caroline B.},
title = {Evaluating consistency between total column CO2 retrievals from OCO-2 and the in situ network over North America: implications for carbon flux estimation},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2021},
volume = {21},
number = {18},
pages = {14385-14401},
doi = {https://doi.org/10.5194/acp-21-14385-2021}
}
|
|||||
| Reed, Z.D., Sperling, B., van Zee, R.D., Whetstone, J.R., Gillis, K.A. and Hodges, J.T. | Photoacoustic spectrometer for accurate, continuous measurements of atmospheric carbon dioxide concentration | {2014} | APPLIED PHYSICS B-LASERS AND OPTICS Vol. {117}({2}), pp. 645-657 |
article | DOI |
| Abstract: We have developed a portable photoacoustic spectrometer that offers routine, precise and accurate measurements of the molar concentration of atmospheric carbon. The temperature-controlled spectrometer continuously samples dried atmospheric air and employs an intensity-modulated distributed feedback laser and fiber amplifier operating near 1.57 A mu m. For measurements of carbon dioxide in air, we demonstrate a measurement precision (60-s averaging time) of 0.15 A mu mol mol(-1) and achieve a standard uncertainty of 0.8 A mu mol mol(-1) by calibrating the analyzer response in terms of certified gas mixtures. We also investigate how water vapor affects the photoacoustic signal by promoting collisional relaxation of the carbon dioxide. |
|||||
BibTeX:
@article{reed14a,
author = {Reed, Zachary D. and Sperling, Brent and van Zee, Roger D. and Whetstone, James R. and Gillis, Keith A. and Hodges, Joseph T.},
title = {Photoacoustic spectrometer for accurate, continuous measurements of atmospheric carbon dioxide concentration},
journal = {APPLIED PHYSICS B-LASERS AND OPTICS},
year = {2014},
volume = {117},
number = {2},
pages = {645--657},
doi = {https://doi.org/10.1007/s00340-014-5878-y}
}
|
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| Rella, C.W., Chen, H., Andrews, A.E., Filges, A., Gerbig, C., Hatakka, J., Karion, A., Miles, N.L., Richardson, S.J., Steinbacher, M., Sweeney, C., Wastine, B. and Zellweger, C. | High accuracy measurements of dry mole fractions of carbon dioxide and methane in humid air | {2013} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {6}({3}), pp. 837-860 |
article | DOI |
| Abstract: Traditional techniques for measuring the mole fractions of greenhouse gases in the well-mixed atmosphere have required dry sample gas streams (dew point < -25 degrees C) to achieve the inter-laboratory compatibility goals set forth by the Global Atmosphere Watch programme of the World Meteorological Organisation (WMO/GAW) for carbon dioxide (+/- 0.1 ppm in the Northern Hemisphere and +/- 0.05 ppm in the Southern Hemisphere) and methane (+/- 2 ppb). Drying the sample gas to low levels of water vapour can be expensive, time-consuming, and/or problematic, especially at remote sites where access is difficult. Recent advances in optical measurement techniques, in particular cavity ring down spectroscopy, have led to the development of greenhouse gas analysers capable of simultaneous measurements of carbon dioxide, methane and water vapour. Unlike many older technologies, which can suffer from significant uncorrected interference from water vapour, these instruments permit accurate and precise greenhouse gas measurements that can meet the WMO/GAW inter-laboratory compatibility goals (WMO, 2011a) without drying the sample gas. In this paper, we present laboratory methodology for empirically deriving the water vapour correction factors, and we summarise a series of in-situ validation experiments comparing the measurements in humid gas streams to well-characterised dry-gas measurements. By using the manufacturer-supplied correction factors, the dry-mole fraction measurements have been demonstrated to be well within the GAW compatibility goals up to a water vapour concentration of at least 1%. By determining the correction factors for individual instruments once at the start of life, this water vapour concentration range can be extended to at least 2% over the life of the instrument, and if the correction factors are determined periodically over time, the evidence suggests that this range can be extended up to and even above 4% water vapour concentrations. |
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BibTeX:
@article{rella13a,
author = {Rella, C. W. and Chen, H. and Andrews, A. E. and Filges, A. and Gerbig, C. and Hatakka, J. and Karion, A. and Miles, N. L. and Richardson, S. J. and Steinbacher, M. and Sweeney, C. and Wastine, B. and Zellweger, C.},
title = {High accuracy measurements of dry mole fractions of carbon dioxide and methane in humid air},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2013},
volume = {6},
number = {3},
pages = {837--860},
doi = {https://doi.org/10.5194/amt-6-837-2013}
}
|
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| Reuter, M., Buchwitz, M., Schneising, O., Heymann, J., Bovensmann, H. and Burrows, J.P. | A method for improved SCIAMACHY CO2 retrieval in the presence of optically thin clouds | {2010} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {3}({1}), pp. 209-232 |
article | DOI |
| Abstract: An optimal estimation based retrieval scheme for satellite based retrievals of XCO2 ( the dry air column averaged mixing ratio of atmospheric CO2) is presented enabling accurate retrievals also in the presence of thin clouds. The proposed method is designed to analyze near-infrared nadir measurements of the SCIAMACHY instrument in the CO2 absorption band at 1580 nm and in the O-2-A absorption band at around 760nm. The algorithm accounts for scattering in an optically thin cirrus cloud layer and at aerosols of a default profile. The scattering information is mainly obtained from the O-2-A band and a merged fit windows approach enables the transfer of information between the O-2-A and the CO2 band. Via the optimal estimation technique, the algorithm is able to account for a priori information to further constrain the inversion. Test scenarios of simulated SCIAMACHY sun-normalized radiance measurements are analyzed in order to specify the quality of the proposed method. In contrast to existing algorithms for SCIAMACHY retrievals, the systematic errors due to cirrus clouds with optical thicknesses up to 1.0 are reduced to values below 4ppm for most of the analyzed scenarios. This shows that the proposed method has the potential to reduce uncertainties of SCIAMACHY retrieved XCO2 making this data product potentially useful for surface flux inverse modeling. |
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BibTeX:
@article{reuter10a,
author = {Reuter, M. and Buchwitz, M. and Schneising, O. and Heymann, J. and Bovensmann, H. and Burrows, J. P.},
title = {A method for improved SCIAMACHY CO2 retrieval in the presence of optically thin clouds},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2010},
volume = {3},
number = {1},
pages = {209--232},
doi = {https://doi.org/10.5194/amt-3-209-2010}
}
|
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| Reuter, M., Bovensmann, H., Buchwitz, M., Burrows, J.P., Connor, B.J., Deutscher, N.M., Griffith, D.W.T., Heymann, J., Keppel-Aleks, G., Messerschmidt, J., Notholt, J., Petri, C., Robinson, J., Schneising, O., Sherlock, V., Velazco, V., Warneke, T., Wennberg, P.O. and Wunch, D. | Retrieval of atmospheric CO2 with enhanced accuracy and precision from SCIAMACHY: Validation with FTS measurements and comparison with model results | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: The Bremen Optimal Estimation differential optical absorption spectroscopy (DOAS) (BESD) algorithm for satellite based retrievals of XCO2 (the column-average dry-air mole fraction of atmospheric CO2) has been applied to Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) data. It uses measurements in the O-2-A absorption band to correct for scattering of undetected clouds and aerosols. Comparisons with precise and accurate ground-based Fourier transform spectrometer (FTS) measurements at four Total Carbon Column Observing Network (TCCON) sites have been used to quantify the quality of the new SCIAMACHY XCO2 data set. Additionally, the results have been compared to NOAA's assimilation system CarbonTracker. The comparisons show that the new retrieval meets the expectations from earlier theoretical studies. We find no statistically significant regional XCO2 biases between SCIAMACHY and the FTS instruments. However, the standard error of the systematic differences is in the range of 0.2 ppm and 0.8 ppm. The XCO2 single-measurement precision of 2.5 ppm is similar to theoretical estimates driven by instrumental noise. There are no significant differences found for the year-to-year increase as well as for the average seasonal amplitude between SCIAMACHY XCO2 and the collocated FTS measurements. Comparison of the year-to-year increase and also of the seasonal amplitude of CarbonTracker exhibit significant differences with the corresponding FTS values at Darwin. Here the differences between SCIAMACHY and CarbonTracker are larger than the standard error of the SCIAMACHY values. The difference of the seasonal amplitude exceeds the significance level of 2 standard errors. Therefore, our results suggest that SCIAMACHY may provide valuable additional information about XCO2, at least in regions with a low density of in situ measurements. |
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BibTeX:
@article{reuter11a,
author = {Reuter, M. and Bovensmann, H. and Buchwitz, M. and Burrows, J. P. and Connor, B. J. and Deutscher, N. M. and Griffith, D. W. T. and Heymann, J. and Keppel-Aleks, G. and Messerschmidt, J. and Notholt, J. and Petri, C. and Robinson, J. and Schneising, O. and Sherlock, V. and Velazco, V. and Warneke, T. and Wennberg, P. O. and Wunch, D.},
title = {Retrieval of atmospheric CO2 with enhanced accuracy and precision from SCIAMACHY: Validation with FTS measurements and comparison with model results},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2010JD015047}
}
|
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| Reuter, M., Buchwitz, M., Schneising, O., Hase, F., Heymann, J., Guerlet, S., Cogan, A.J., Bovensmann, H. and Burrows, J.P. | A simple empirical model estimating atmospheric CO2 background concentrations | {2012} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {5}({6}), pp. 1349-1357 |
article | DOI |
| Abstract: A simple empirical CO2 model (SECM) is presented to estimate column-average dry-air mole fractions of atmospheric CO2 (XCO2) as well as mixing ratio profiles. SECM is based on a simple equation depending on 17 empirical parameters, latitude, and date. The empirical parameters have been determined by least squares fitting to NOAA's (National Oceanic and Atmospheric Administration) assimilation system CarbonTracker version 2010 (CT2010). Comparisons with TCCON (total carbon column observing network) FTS (Fourier transform spectrometer) measurements show that SECM XCO2 agrees quite well with reality. The synthetic XCO2 values have a standard error of 1.39 ppm and systematic station-to-station biases of 0.46 ppm. Typical column averaging kernels of the TCCON FTS, a SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY), and two GOSAT (Greenhouse gases Observing SATellite) XCO2 retrieval algorithms have been used to assess the smoothing error introduced by using SECM profiles instead of CT2010 profiles as a priori. The additional smoothing error amounts to 0.17 ppm for a typical SCIAMACHY averaging kernel and is most times much smaller for the other instruments (e.g. 0.05 ppm for a typical TCCON FTS averaging kernel). Therefore, SECM is well suited to provide a priori information for state-of-the-art ground-based (FTS) and satellite-based (GOSAT, SCIAMACHY) XCO2 retrievals. Other potential applications are: (i) near real-time processing systems (that cannot make use of models like CT2010 operated in delayed mode), (ii) `CO2 proxy' methods for XCH4 retrievals (as correction for the XCO2 background), and (iii) observing system simulation experiments especially for future satellite missions. |
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BibTeX:
@article{reuter12a,
author = {Reuter, M. and Buchwitz, M. and Schneising, O. and Hase, F. and Heymann, J. and Guerlet, S. and Cogan, A. J. and Bovensmann, H. and Burrows, J. P.},
title = {A simple empirical model estimating atmospheric CO2 background concentrations},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2012},
volume = {5},
number = {6},
pages = {1349--1357},
doi = {https://doi.org/10.5194/amt-5-1349-2012}
}
|
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| Reuter, M., Bovensmann, H., Buchwitz, M., Burrows, J.P., Deutscher, N.M., Heymann, J., Rozanov, A., Schneising, O., Suto, H., Toon, G.C. and Warneke, T. | On the potential of the 2041-2047 nm spectral region for remote sensing of atmospheric CO2 isotopologues | {2012} | JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER Vol. {113}({16}), pp. 2009-2017 |
article | DOI |
| Abstract: Pressing open questions about the carbon cycle can be addressed with precise measurements of the three most abundant CO2 isotopologues (OCO)-O-16-C-12-O-16, (OCO)-O-16-C-13-O-16, and (OCO)-O-16-C-12-O-18. Such measurements can, e.g., help to further constrain oceanic and biospheric net fluxes or to differentiate between the gross biospheric fluxes photosynthesis and respiration. The 2041-2047 nm (about 4885-4900 cm(-1)) spectral region contains separated absorption lines of the three most abundant CO2 isotopologues. Their spectral properties make this spectral region well suited for the use of a light path proxy method for the retrieval of delta C-13 and delta O-18 (the ratio of heavier to lighter isotopologues relative to a standard). An optimal estimation based light path proxy retrieval for delta C-13 and delta O-18 has been set up, applicable to GOSAT (Greenhouse gases Observing Satellite) and ground-based FTS (Fourier transform spectrometer) measurements. Initial results show that it is possible to retrieve delta C-13 and delta O-18 from ground-based FTS instruments with a precision of 0.6-1.6 parts per thousand and from GOSAT with a precision of about 30 parts per thousand. Comparison of the achievable precision with the expected atmospheric signals shows that ground-based FTS remote sensing measurements have the potential to gain valuable information on delta C-13 and delta O-18 if averaging a sufficient number of measurements. It seems unlikely that this applies also to GOSAT because of the lower precision and a conceptual larger sensitivity to scattering related errors in satellite viewing geometry. (C) 2012 Elsevier Ltd. All rights reserved. |
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BibTeX:
@article{reuter12b,
author = {Reuter, M. and Bovensmann, H. and Buchwitz, M. and Burrows, J. P. and Deutscher, N. M. and Heymann, J. and Rozanov, A. and Schneising, O. and Suto, H. and Toon, G. C. and Warneke, T.},
title = {On the potential of the 2041-2047 nm spectral region for remote sensing of atmospheric CO2 isotopologues},
journal = {JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER},
year = {2012},
volume = {113},
number = {16},
pages = {2009--2017},
doi = {https://doi.org/10.1016/j.jqsrt.2012.07.013}
}
|
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| Reuter, M., Boesch, H., Bovensmann, H., Bril, A., Buchwitz, M., Butz, A., Burrows, J.P., O'Dell, C.W., Guerlet, S., Hasekamp, O., Heymann, J., Kikuchi, N., Oshchepkov, S., Parker, R., Pfeifer, S., Schneising, O., Yokota, T. and Yoshida, Y. | A joint effort to deliver satellite retrieved atmospheric CO2 concentrations for surface flux inversions: the ensemble median algorithm EMMA | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({4}), pp. 1771-1780 |
article | DOI |
| Abstract: We analyze an ensemble of seven XCO2 retrieval algorithms for SCIAMACHY (scanning imaging absorption spectrometer of atmospheric chartography) and GOSAT (greenhouse gases observing satellite). The ensemble spread can be interpreted as regional uncertainty and can help to identify locations for new TCCON (total carbon column observing network) validation sites. Additionally, we introduce the ensemble median algorithm EMMA combining individual soundings of the seven algorithms into one new data set. The ensemble takes advantage of the algorithms' independent developments. We find ensemble spreads being often < 1 ppm but rising up to 2 ppm especially in the tropics and East Asia. On the basis of gridded monthly averages, we compare EMMA and all individual algorithms with TCCON and CarbonTracker model results (potential outliers, north/south gradient, seasonal (peak-to-peak) amplitude, standard deviation of the difference). Our findings show that EMMA is a promising candidate for inverse modeling studies. Compared to CarbonTracker, the satellite retrievals find consistently larger north/south gradients (by 0.3-0.9 ppm) and seasonal amplitudes (by 1.5-2.0 ppm). |
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BibTeX:
@article{reuter13a,
author = {Reuter, M. and Boesch, H. and Bovensmann, H. and Bril, A. and Buchwitz, M. and Butz, A. and Burrows, J. P. and O'Dell, C. W. and Guerlet, S. and Hasekamp, O. and Heymann, J. and Kikuchi, N. and Oshchepkov, S. and Parker, R. and Pfeifer, S. and Schneising, O. and Yokota, T. and Yoshida, Y.},
title = {A joint effort to deliver satellite retrieved atmospheric CO2 concentrations for surface flux inversions: the ensemble median algorithm EMMA},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {4},
pages = {1771--1780},
doi = {https://doi.org/10.5194/acp-13-1771-2013}
}
|
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| Reuter, M., Buchwitz, M., Hilboll, A., Richter, A., Schneising, O., Hilker, M., Heymann, J., Bovensmann, H. and Burrows, J.P. | Decreasing emissions of NOx relative to CO2 in East Asia inferred from satellite observations | {2014} | NATURE GEOSCIENCE Vol. {7}({11}), pp. 792-795 |
article | DOI |
| Abstract: At present, global CO2 emission inventories are mainly based on bottom-up estimates that rely, for example, on reported fossil fuel consumptions and fuel types(1,2). The associated uncertainties propagate into the CO2-to-NOx emission ratios that are used in pollution prediction and monitoring(3), as well as into biospheric carbon fluxes derived by inverse models(4). Here we analyse simultaneous and co-located satellite retrievals from SCIAMACHY (ref. 5; SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY) of the column-average dry-air mole fraction of CO2 (refs 6,7) and NO2 (refs 8-10) for the years 2003-2011 to provide a top-down estimate of trends in emissions and in the ratio between CO2 and NOx emissions. Our analysis shows that the CO2-to-NOx emission ratio has increased by 4.2 +/- 1.7% yr(-1) in East Asia. In this region, we find a large positive trend of CO2 emissions (9.8 +/- 1.7% yr(-1)), which we largely attribute to the growing Chinese economy. This trend exceeds the positive trend of NOx emissions (5.8 +/- 0.9% yr(-1)). Our findings suggest that the recently installed and renewed technology in East Asia, such as power plants, transportation and so on, is cleaner in terms of NOx emissions than the old infrastructure, and roughly matches relative emission levels in North America and Europe. |
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BibTeX:
@article{reuter14a,
author = {Reuter, M. and Buchwitz, M. and Hilboll, A. and Richter, A. and Schneising, O. and Hilker, M. and Heymann, J. and Bovensmann, H. and Burrows, J. P.},
title = {Decreasing emissions of NOx relative to CO2 in East Asia inferred from satellite observations},
journal = {NATURE GEOSCIENCE},
year = {2014},
volume = {7},
number = {11},
pages = {792--795},
doi = {https://doi.org/10.1038/NGEO2257}
}
|
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| Reuter, M., Buchwitz, M., Hilker, M., Heymann, J., Schneising, O., Pillai, D., Bovensmann, H., Burrows, J.P., Boesch, H., Parker, R., Butz, A., Hasekamp, O., O'Dell, C.W., Yoshida, Y., Gerbig, C., Nehrkorn, T., Deutscher, N.M., Warneke, T., Notholt, J., Hase, F., Kivi, R., Sussmann, R., Machida, T., Matsueda, H. and Sawa, Y. | Satellite-inferred European carbon sink larger than expected | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({24}), pp. 13739-13753 |
article | DOI |
| Abstract: Current knowledge about the European terrestrial biospheric carbon sink, from the Atlantic to the Urals, relies upon bottom-up inventory and surface flux inverse model estimates (e.g. 0.27 +/- 0.16 GtCa(-1) for 2000-2005 (Schulze et al., 2009), 0.17 +/- 0.44 GtCa(-1) for 2001-2007 (Peters et al., 2010), 0.45 +/- 0.40 GtCa(-1) for 2010 (Chevallier et al., 2014), 0.40 +/- 0.42 GtCa(-1) for 2001-2004 (Peylin et al., 2013)). Inverse models assimilate in situ CO2 atmospheric concentrations measured by surface-based air sampling networks. The intrinsic sparseness of these networks is one reason for the relatively large flux uncertainties (Peters et al., 2010; Bruhwiler et al., 2011). Satellite-based CO2 measurements have the potential to reduce these uncertainties (Miller et al., 2007; Chevallier et al., 2007). Global inversion experiments using independent models and independent GOSAT satellite data products consistently derived a considerably larger European sink (1.0-1.3 GtCa(-1) for 09/2009-08/2010 (Basu et al., 2013), 1.2-1.8 GtCa(-1) in 2010 (Chevallier et al., 2014)). However, these results have been considered unrealistic due to potential retrieval biases and/or transport errors (Chevallier et al., 2014) or have not been discussed at all (Basu et al., 2013; Takagi et al., 2014). Our analysis comprises a regional inversion approach using STILT (Gerbig et al., 2003; Lin et al., 2003) short-range (days) particle dispersion modelling, rendering it insensitive to large-scale retrieval biases and less sensitive to long-range transport errors. We show that the satellite-derived European terrestrial carbon sink is indeed much larger (1.02 +/- 0.30 GtCa(-1) in 2010) than previously expected. This is qualitatively consistent among an ensemble of five different inversion set-ups and five independent satellite retrievals (BESD (Reuter et al., 2011) 2003-2010, ACOS (O'Dell et al., 2012) 2010, UoL-FP (Cogan et al., 2012) 2010, RemoTeC (Butz et al., 2011) 2010, and NIES (Yoshida et al., 2013) 2010) using data from two different instruments (SCIAMACHY (Bovensmann et al., 1999) and GOSAT (Kuze et al., 2009)). The difference to in situ based inversions (Peylin et al., 2013), whilst large with respect to the mean reported European carbon sink (0.4 GtCa(-1) for 2001-2004), is similar in magnitude to the reported uncertainty (0.42 GtCa(-1)). The highest gain in information is obtained during the growing season when satellite observation conditions are advantageous, a priori uncertainties are largest, and the surface sink maximises; during the dormant season, the results are dominated by the a priori. Our results provide evidence that the current understanding of the European carbon sink has to be revisited. |
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BibTeX:
@article{reuter14b,
author = {Reuter, M. and Buchwitz, M. and Hilker, M. and Heymann, J. and Schneising, O. and Pillai, D. and Bovensmann, H. and Burrows, J. P. and Boesch, H. and Parker, R. and Butz, A. and Hasekamp, O. and O'Dell, C. W. and Yoshida, Y. and Gerbig, C. and Nehrkorn, T. and Deutscher, N. M. and Warneke, T. and Notholt, J. and Hase, F. and Kivi, R. and Sussmann, R. and Machida, T. and Matsueda, H. and Sawa, Y.},
title = {Satellite-inferred European carbon sink larger than expected},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {24},
pages = {13739--13753},
doi = {https://doi.org/10.5194/acp-14-13739-2014}
}
|
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| Reuter, M., Buchwitz, M., Schneising, O., Noel, S., Rozanov, V., Bovensmann, H. and Burrows, J.P. | A Fast Atmospheric Trace Gas Retrieval for Hyperspectral Instruments Approximating Multiple ScatteringPart 1: Radiative Transfer and a Potential OCO-2 XCO2 Retrieval Setup | {2017} | REMOTE SENSING Vol. {9}({11}) |
article | DOI |
| Abstract: Satellite retrievals of the atmospheric dry-air column-average mole fraction of CO2 (XCO2) based on hyperspectral measurements in appropriate near (NIR) and short wave infrared (SWIR) O2 and CO2 absorption bands can help to answer important questions about the carbon cycle but the precision and accuracy requirements for XCO2 data products are demanding. Multiple scattering of light at aerosols and clouds can be a significant error source for XCO2 retrievals. Therefore, so called full physics retrieval algorithms were developed aiming to minimize scattering related errors by explicitly fitting scattering related properties such as cloud water/ ice content, aerosol optical thickness, cloud height, etc. However, the computational costs for multiple scattering radiative transfer (RT) calculations can be immense. Processing all data of the Orbiting Carbon Observatory-2 (OCO-2) can require up to thousands of CPU cores and the next generation of CO2 monitoring satellites will produce at least an order of magnitude more data. Here we introduce the Fast atmOspheric traCe gAs retrievaL FOCAL including a scalar RT model which approximates multiple scattering effects with an analytic solution of the RT problem of an isotropic scattering layer and a Lambertian surface. The computational performance is similar to an absorption only model and currently determined by the convolution of the simulated spectra with the instrumental line shape function (ILS). We assess FOCAL's quality by confronting it with accurate multiple scattering vector RT simulations using SCIATRAN. The simulated scenarios do not cover all possible geophysical conditions but represent, among others, some typical cloud and aerosol scattering scenarios with optical thicknesses of up to 0.7 which have the potential to survive the pre-processing of a XCO2 algorithm for real OCO-2 measurements. Systematic errors of XCO2 range from 2.5 ppm (6.3%) to 3.0ppm (7.6%) and are usually smaller than 0.3ppm (0.8%). The stochastic uncertainty of XCO2 is typically about 1.0ppm (2.5%). FOCAL simultaneously retrieves the dry-air column-average mole fraction ofH2O (XH2O) and the solar induced chlorophyll fluorescence at 760nm (SIF). Systematic and stochastic errors of XH2O are most times smaller than 6ppm and 9 ppm, respectively. The systematic SIF errors are always below 0.02mW/ m2/ sr/ nm, i. e., it can be expected that instrumental or forward model effects causing an in-filling of the used Fraunhofer lines will dominate the systematic errors when analyzing actually measured data. The stochastic uncertainty of SIF is usually below 0.3mW/ m2/ sr/ nm. Without understating the importance of analyzing synthetic measurements as presented here, the actual retrieval performance can only be assessed by analyzing measured data which is subject to part 2 of this publication. |
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BibTeX:
@article{reuter17a,
author = {Reuter, Maximilian and Buchwitz, Michael and Schneising, Oliver and Noel, Stefan and Rozanov, Vladimir and Bovensmann, Heinrich and Burrows, John P.},
title = {A Fast Atmospheric Trace Gas Retrieval for Hyperspectral Instruments Approximating Multiple ScatteringPart 1: Radiative Transfer and a Potential OCO-2 XCO2 Retrieval Setup},
journal = {REMOTE SENSING},
year = {2017},
volume = {9},
number = {11},
doi = {https://doi.org/10.3390/rs9111159}
}
|
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| Reuter, M., Buchwitz, M., Schneising, O., Noeel, S., Bovensmann, H., Burrows, J.P., Boesch, H., Di Noia, A., Anand, J., Parker, R.J., Somkuti, P., Wu, L., Hasekamp, O.P., Aben, I., Kuze, A., Suto, H., Shiomi, K., Yoshida, Y., Morino, I., Crisp, D., O'Dell, C.W., Notholt, J., Petri, C., Warneke, T., Velazco, V.A., Deutscher, N.M., Griffith, D.W.T., Kivi, R., Pollard, D.F., Hase, F., Sussmann, R., Te V, Y., Strong, K., Roche, S., Sha, M.K., De Maziere, M., Feist, D.G., Iraci, L.T., Roehl, C.M., Retscher, C. and Schepers, D. | Ensemble-based satellite-derived carbon dioxide and methane column-averaged dry-air mole fraction data sets (2003-2018) for carbon and climate applications | {2020} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {13}({2}), pp. {789-819} |
article | DOI URL |
| Abstract: Satellite retrievals of column-averaged dry-air mole fractions of carbon dioxide (CO2) and methane (CH4), denoted XCO2 and XCH4, respectively, have been used in recent years to obtain information on natural and anthropogenic sources and sinks and for other applications such as comparisons with climate models. Here we present new data sets based on merging several individual satellite data products in order to generate consistent long-term climate data records (CDRs) of these two Essential Climate Variables (ECVs). These ECV CDRs, which cover the time period 2003-2018, have been generated using an ensemble of data products from the satellite sensors SCIAMACHY/ENVISAT and TANSO-FTS/GOSAT and (for XCO2) for the first time also including data from the Orbiting Carbon Observatory 2 (OCO-2) satellite. Two types of products have been generated: (i) Level 2 (L2) products generated with the latest version of the ensemble median algorithm (EMMA) and (ii) Level 3 (L3) products obtained by gridding the corresponding L2 EMMA products to obtain a monthly 5 degrees x 5 degrees data product in Obs4MIPs (Observations for Model Inter-comparisons Project) format. The L2 products consist of daily NetCDF (Network Common Data Form) files, which contain in addition to the main parameters, i.e., XCO2 or XCH4, corresponding uncertainty estimates for random and potential systematic uncertainties and the averaging kernel for each single (quality-filtered) satellite observation. We describe the algorithms used to generate these data products and present quality assessment results based on comparisons with Total Carbon Column Observing Network (TC-CON) ground-based retrievals. We found that the XCO2 Level 2 data set at the TCCON validation sites can be characterized by the following figures of merit (the corresponding values for the Level 3 product are listed in brackets) single-observation random error (1 sigma): 1.29 ppm (monthly: 1.18 ppm); global bias: 0.20 ppm (0.18 ppm); and spatiotemporal bias or relative accuracy (1 sigma): 0.66 ppm (0.70 ppm). The corresponding values for the XCH4 products are single-observation random error (1 sigma): 17.4 ppb (monthly: 8.7 ppb); global bias: 2.0 ppb (2.9 ppb); and spatiotemporal bias (1 sigma): 5.0 ppb (4.9 ppb). It has also been found that the data products exhibit very good long-term stability as no significant long-term bias trend has been identified. The new data sets have also been used to derive annual XCO2 and XCH4 growth rates, which are in reasonable to good agreement with growth rates from the National Oceanic and Atmospheric Administration (NOAA) based on marine surface observations. | |||||
BibTeX:
@article{reuter20a,
author = {Reuter, Maximilian and Buchwitz, Michael and Schneising, Oliver and Noeel, Stefan and Bovensmann, Heinrich and Burrows, John P. and Boesch, Hartmut and Di Noia, Antonio and Anand, Jasdeep and Parker, Robert J. and Somkuti, Peter and Wu, Lianghai and Hasekamp, Otto P. and Aben, Ilse and Kuze, Akihiko and Suto, Hiroshi and Shiomi, Kei and Yoshida, Yukio and Morino, Isamu and Crisp, David and O'Dell, Christopher W. and Notholt, Justus and Petri, Christof and Warneke, Thorsten and Velazco, Voltaire A. and Deutscher, Nicholas M. and Griffith, David W. T. and Kivi, Rigel and Pollard, David F. and Hase, Frank and Sussmann, Ralf and Te, V, Yao and Strong, Kimberly and Roche, Sebastien and Sha, Mahesh K. and De Maziere, Martine and Feist, Dietrich G. and Iraci, Laura T. and Roehl, Coleen M. and Retscher, Christian and Schepers, Dinand},
title = {Ensemble-based satellite-derived carbon dioxide and methane column-averaged dry-air mole fraction data sets (2003-2018) for carbon and climate applications},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {13},
number = {2},
pages = {789--819},
note = {Query date: 2021-04-02 15:20:04},
url = {https://amt.copernicus.org/articles/13/789/2020/},
doi = {https://doi.org/10.5194/amt-13-789-2020}
}
|
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| Rieker, G.B., Giorgetta, F.R., Swann, W.C., Kofler, J., Zolot, A.M., Sinclair, L.C., Baumann, E., Cromer, C., Petron, G., Sweeney, C., Tans, P.P., Coddington, I. and Newbury, N.R. | Frequency-comb-based remote sensing of greenhouse gases over kilometer air paths | {2014} | OPTICA Vol. {1}({5}), pp. 290-298 |
article | DOI |
| Abstract: Increasing our understanding of regional greenhouse gas transport, sources, and sinks requires accurate, precise, continuous measurements of small gas enhancements over long ranges. We demonstrate a coherent dual frequency-comb spectroscopy technique capable of achieving these goals. Spectra are acquired spanning 5990 to 6260 cm(-1) (1600-1670 nm) covering similar to 700 absorption features from CO2, CH4, H2O, HDO, and (CO2)-C-13, across a 2 km path. The spectra have sub-1-kHz frequency accuracy, no instrument lineshape, and a 0.0033 cm(-1) point spacing. They are fit with different absorption models to yield dry-air mole fractions of greenhouse gases. These results are compared with a point sensor under well-mixed conditions to evaluate the accuracy of models critical to global satellite-based trace gas monitoring. Under heterogeneous conditions, time-resolved data demonstrate tracking of small variations in mole fractions, with a precision <1 ppm for CO2 and <3 ppb for CH4 in 5 min. Portable systems could enable regional monitoring. (C) 2014 Optical Society of America |
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BibTeX:
@article{rieker14a,
author = {Rieker, G. B. and Giorgetta, F. R. and Swann, W. C. and Kofler, J. and Zolot, A. M. and Sinclair, L. C. and Baumann, E. and Cromer, C. and Petron, G. and Sweeney, C. and Tans, P. P. and Coddington, I. and Newbury, N. R.},
title = {Frequency-comb-based remote sensing of greenhouse gases over kilometer air paths},
journal = {OPTICA},
year = {2014},
volume = {1},
number = {5},
pages = {290--298},
doi = {https://doi.org/10.1364/OPTICA.1.000290}
}
|
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| Riley, W.J., Biraud, S.C., Torn, M.S., Fischer, M.L., Billesbach, D.P. and Berry, J.A. | Regional CO2 and latent heat surface fluxes in the Southern Great Plains: Measurements, modeling, and scaling | {2009} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {114} |
article | DOI |
| Abstract: Characterizing net ecosystem exchanges (NEE) of CO2 and sensible and latent heat fluxes in heterogeneous landscapes is difficult, yet critical given expected changes in climate and land use. We report here a measurement and modeling study designed to improve our understanding of surface to atmosphere gas exchanges under very heterogeneous land cover in the mostly agricultural U.S. Southern Great Plains (SGP). We combined three years of site-level, eddy covariance measurements in several of the dominant land cover types with regional-scale climate data from the distributed Mesonet stations and Next Generation Weather Radar precipitation measurements to calibrate a land surface model of trace gas and energy exchanges (isotope-enabled land surface model (ISOLSM)). Yearly variations in vegetation cover distributions were estimated from Moderate Resolution Imaging Spectroradiometer normalized difference vegetation index and compared to regional and subregional vegetation cover type estimates from the U.S. Department of Agriculture census. We first applied ISOLSM at a 250 m spatial scale to account for vegetation cover type and leaf area variations that occur on hundred meter scales. Because of computational constraints, we developed a subsampling scheme within 10 km ``macrocells'' to perform these high-resolution simulations. We estimate that the Atmospheric Radiation Measurement Climate Research Facility SGP region net CO2 exchange with the local atmosphere was -240, -340, and -270 gC m(-2) yr(-1) (positive toward the atmosphere) in 2003, 2004, and 2005, respectively, with large seasonal variations. We also performed simulations using two scaling approaches at resolutions of 10, 30, 60, and 90 km. The scaling approach applied in current land surface models led to regional NEE biases of up to 50 and 20% in weekly and annual estimates, respectively. An important factor in causing these biases was the complex leaf area index (LAI) distribution within cover types. Biases in predicted weekly average regional latent heat fluxes were smaller than for NEE, but larger than for either ecosystem respiration or assimilation alone. However, spatial and diurnal variations of hundreds of W m(-2) in latent heat fluxes were common. We conclude that, in this heterogeneous system, characterizing vegetation cover type and LAI at the scale of spatial variation are necessary for accurate estimates of bottom-up, regional NEE and surface energy fluxes. |
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BibTeX:
@article{riley09a,
author = {Riley, W. J. and Biraud, S. C. and Torn, M. S. and Fischer, M. L. and Billesbach, D. P. and Berry, J. A.},
title = {Regional CO2 and latent heat surface fluxes in the Southern Great Plains: Measurements, modeling, and scaling},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2009},
volume = {114},
doi = {https://doi.org/10.1029/2009JG001003}
}
|
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| Rivier, L., Peylin, P., Ciais, P., Gloor, M., Rodenbeck, C., Geels, C., Karstens, U., Bousquet, P., Brandt, J., Heimann, M. and Experimentalists, A. | European CO2 fluxes from atmospheric inversions using regional and global transport models | {2010} | CLIMATIC CHANGE Vol. {103}({1-2}), pp. 93-115 |
article | DOI |
| Abstract: Approximately half of human-induced carbon dioxide (CO2) emissions are taken up by the land and ocean, and the rest stays in the atmosphere, increasing the global concentration and acting as a major greenhouse-gas (GHG) climate-forcing element. Although GHG mitigation is now in the political arena, the exact spatial distribution of the land sink is not well known. In this paper, an estimation of mean European net ecosystem exchange (NEE) carbon fluxes for the period 1998-2001 is performed with three mesoscale and two global transport models, based on the integration of atmospheric CO2 measurements into the same Bayesian synthesis inverse approach. A special focus is given to sub-continental regions of Europe making use of newly available CO2 concentration measurements in this region. Inverse flux estimates from the five transport models are compared with independent flux estimates from four ecosystem models. All inversions detect a strong annual carbon sink in the southwestern part of Europe and a source in the northeastern part. Such a dipole, although robust with respect to the network of stations used, remains uncertain and still to be confirmed with independent estimates. Comparison of the seasonal variations of the inversion-based net land biosphere fluxes (NEP) with the NEP predicted by the ecosystem models indicates a shift of the maximum uptake period, from June in the ecosystem models to July in the inversions. This study thus improves on the understanding of the carbon cycle at sub-continental scales over Europe, demonstrating that the methodology for understanding regional carbon cycle is advancing, which increases its relevance in terms of issues related to regional mitigation policies. |
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BibTeX:
@article{rivier10a,
author = {Rivier, L. and Peylin, Ph and Ciais, Ph and Gloor, M. and Rodenbeck, C. and Geels, C. and Karstens, U. and Bousquet, Ph and Brandt, J. and Heimann, M. and Aerocarb Experimentalists},
title = {European CO2 fluxes from atmospheric inversions using regional and global transport models},
journal = {CLIMATIC CHANGE},
year = {2010},
volume = {103},
number = {1-2},
pages = {93--115},
doi = {https://doi.org/10.1007/s10584-010-9908-4}
}
|
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| Robbins, L.L., Daly, K.L., Barbero, L., Wanninkhof, R., He, R., Zong, H., Lisle, J.T., Cai, W.J. and Smith, C.G. | Spatial and Temporal Variability of pCO(2), Carbon Fluxes, and Saturation State on the West Florida Shelf | {2018} | JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS Vol. {123}({9}), pp. {6174-6188} |
article | DOI |
| Abstract: The West Florida Shelf (WFS) is a source of uncertainty for the Gulf of Mexico carbon budget. Data from the synthesis of approximately 135,000 pCO(2) values from 97 cruises from the WFS show that the shelf waters fluctuate between being a weak source to a weak sink of carbon. Overall, the shelf acts as a weak source of CO2 at 0.321.5mol m(-2) yr(-1). Subregions, however, reveal slightly different trends, where surface waters associated with 40-200-m isobath in the northern and southern WFS are generally weak sinks all year, except for summer when they act as sources of CO2. Conversely, nearshore waters (<40m) are a source of CO2, particularly the southern shallow waters, which are a source all year round. The pCO(2) of seawater has been increasing at a rate of approximately 4.37atm/year as compared to atmospheric pCO(2) which has increased at a rate of about 1.7atm per year from 1996 to 2016. The annual CO2 flux has increased from -0.78 to 0.92mol m(-2) yr(-1) on the shelf from 1996-2016. The WFS is emitting 9.23Tg C/year, with the southern nearshore region emitting the most at 9.01Tg C/year and the northern region acting as a sink of -1.96Tg C/year. Aragonite saturation state on the WFS shows seasonal and geographic trends with values ranging from 2 to 5. Lowest values are found in winter associated with subregion <40-m isobath. The West Florida Shelf (WFS) is a source of uncertainty for determining the Gulf of Mexico carbon budget and how surface waters are being affected by increasing atmospheric carbon dioxide (CO2) levels. Little is known about the WFS trends of the seawater partial pressure of carbon dioxide (pCO(2)) over the last decades; much of the uncertainty stems from lack of data. In order to address some of this uncertainty, approximately 135,000 pCO(2) values collected on 97 research cruises between 1996 and 2016 were analyzed and show that the shelf waters have changed from being a weak sink to weak source of CO2 to the atmosphere. Further, data was divided into four geographical subregions. Offshore surface waters absorb CO2, whereas nearshore surface waters emit CO2 to the atmosphere. Importantly, pCO(2) of the nearshore seawater has been increasing at a rate approximately 2.5 times faster than atmospheric pCO(2) over the past 20years. These data indicate that factors in addition to the atmosphere CO2 are influencing increases in nearshore seawater. Additionally, WFS aragonite saturation state, often used to monitor ocean acidification conditions, shows seasonal and geographic trends, with year-round supersaturated values ranging from 2 to 5. |
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BibTeX:
@article{robbins18a,
author = {Robbins, L. L. and Daly, K. L. and Barbero, L. and Wanninkhof, R. and He, R. and Zong, H. and Lisle, J. T. and Cai, W. -J. and Smith, C. G.},
title = {Spatial and Temporal Variability of pCO(2), Carbon Fluxes, and Saturation State on the West Florida Shelf},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS},
year = {2018},
volume = {123},
number = {9},
pages = {6174-6188},
doi = {https://doi.org/10.1029/2018JC014195}
}
|
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| Robinson, D.T., Brown, D.G. and Currie, W.S. | Modelling carbon storage in highly fragmented and human-dominated landscapes: Linking land-cover patterns and ecosystem models | {2009} | ECOLOGICAL MODELLING Vol. {220}({9-10}), pp. 1325-1338 |
article | DOI |
| Abstract: To extend coupled human-environment systems research and include the ecological effects of land-use and land-cover change and policy scenarios, we present an analysis of the effects of forest patch size and shape and landscape pattern on carbon storage estimated by BIOME-BGC. We evaluate the effects of including within-patch and landscape-scale heterogeneity in air temperature on carbon estimates using two modelling experiments. In the first, we combine fieldwork, spatial analysis, and BIOME-BGC at a 15-m resolution to estimate carbon storage in the highly fragmented and human-dominated landscape of Southeastern Michigan, USA. In the second, we perform the same analysis on 12 hypothetical landscapes that differ only in their degree of fragmentation. For each experiment we conduct four air-temperature treatments, three guided by field-based data and one empirically informed by local National Weather Service station data. The three field data sets were measured (1) exterior to a forest patch, (2) from the patch edge inward to 60 m on east-, south-, and west-facing aspects, separately, and (3) interior to that forest patch. Our field-data analysis revealed a decrease in maximum air temperature from the forest patch edge to a depth of 80 m. Within-patch air-temperature values were significantly different (alpha = 0.01) among transects (c.v. = 13.28) and for all measurement locations (c.v. = 30.58). Results from the first experiment showed that the interior treatment underestimated carbon storage by similar to 8000 Mg C and the exterior treatment overestimated carbon storage by 30,000 Mg C within Dundee Township, Southeastern Michigan, when compared to a treatment that included within-patch heterogeneity. in the second experiment we found a logarithmic increase in carbon storage with increasing fragmentation (r(2) = 0.91). While a number of other processes (e.g. altered disturbance frequency or severity) remain to be included in future experiments, this combined field and modelling study clearly demonstrated that the inclusion of within-patch and landscape heterogeneity, and landscape fragmentation, each have a strong effect on forest carbon cycling and storage as simulated by a widely used ecosystem process model. (C) 2009 Elsevier B.V. All rights reserved. |
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BibTeX:
@article{robinson09a,
author = {Robinson, D. T. and Brown, D. G. and Currie, W. S.},
title = {Modelling carbon storage in highly fragmented and human-dominated landscapes: Linking land-cover patterns and ecosystem models},
journal = {ECOLOGICAL MODELLING},
year = {2009},
volume = {220},
number = {9-10},
pages = {1325--1338},
note = {Euopean Conference on Ecological Modelling, Trieste, ITALY, 2007},
doi = {https://doi.org/10.1016/j.ecolmodel.2009.02.020}
}
|
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| Robinson, D.T. | Effects of land-use policy, forest fragmentation, and residential parcel size on land-cover and carbon storage in Southeastern Michigan [BibTeX] |
2009 | School: University of Michigan | phdthesis | |
BibTeX:
@phdthesis{robinson09b,
author = {Robinson, Derek Thomas},
title = {Effects of land-use policy, forest fragmentation, and residential parcel size on land-cover and carbon storage in Southeastern Michigan},
school = {University of Michigan},
year = {2009}
}
|
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| Robinson, T.D. | MODELING THE INFRARED SPECTRUM OF THE EARTH-MOON SYSTEM: IMPLICATIONS FOR THE DETECTION AND CHARACTERIZATION OF EARTHLIKE EXTRASOLAR PLANETS AND THEIR MOONLIKE COMPANIONS | {2011} | ASTROPHYSICAL JOURNAL Vol. {741}({1}) |
article | DOI |
| Abstract: The Moon maintains large surface temperatures on its illuminated hemisphere and can contribute significant amounts of flux to spatially unresolved thermal infrared (IR) observations of the Earth-Moon system, especially at wavelengths where Earth's atmosphere is absorbing. In this paper we investigate the effects of an unresolved companion on IR observations of Earthlike exoplanets. For an extrasolar twin Earth-Moon system observed at full phase at IR wavelengths, the Moon consistently comprises about 20% of the total signal, approaches 30% of the signal in the 9.6 mu m ozone band and the 15 mu m carbon dioxide band, makes up as much as 80% of the signal in the 6.3 mu m water band, and more than 90% of the signal in the 4.3 mu m carbon dioxide band. These excesses translate to inferred brightness temperatures for Earth that are too large by 20-40 K and demonstrate that the presence of undetected satellites can have significant impacts on the spectroscopic characterization of exoplanets. The thermal flux contribution from an airless companion depends strongly on phase, implying that observations of exoplanets should be taken when the star-planet-observer angle (i.e., phase angle) is as large as feasibly possible if contributions from companions are to be minimized. We show that, by differencing IR observations of an Earth twin with a companion taken at both gibbous and crescent phases, Moonlike satellites may be detectable by future exoplanet characterization missions for a wide range of system inclinations. |
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BibTeX:
@article{robinson11a,
author = {Robinson, Tyler D.},
title = {MODELING THE INFRARED SPECTRUM OF THE EARTH-MOON SYSTEM: IMPLICATIONS FOR THE DETECTION AND CHARACTERIZATION OF EARTHLIKE EXTRASOLAR PLANETS AND THEIR MOONLIKE COMPANIONS},
journal = {ASTROPHYSICAL JOURNAL},
year = {2011},
volume = {741},
number = {1},
doi = {https://doi.org/10.1088/0004-637X/741/1/51}
}
|
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| Roche, S., Strong, K., Wunch, D., Mendonca, J., Sweeney, C., Baier, B., Biraud, S.C., Laughner, J.L., Toon, G.C. and Connor, B.J. | Retrieval of atmospheric CO2 vertical profiles from ground-based near-infrared spectra | 2021 | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. 14(4), pp. 3087-3118 |
article | DOI |
| Abstract: We evaluate vertical profile retrievals of CO2 from 0.02 cm(-1) resolution ground-based near-infrared solar absorption spectra with the GFIT2 algorithm, using improved spectroscopic line lists and line shapes. With these improvements, CO2 profiles were obtained from sequential retrievals in five spectral windows with different vertical sensitivities using synthetic and real spectra. A sensitivity study using synthetic spectra shows that the leading source of uncertainty in the retrieved CO2 profiles is the error in the a priori temperature profile, even with 3-hourly reanalysis a priori profiles. A 2 degrees C error in the temperature profile in the lower troposphere between 0.6 and 0.85 atm causes deviations in the retrieved CO2 profiles that are larger than the typical vertical variations of CO2. To distinguish the effect of errors in the a priori meteorology and trace gas concentration profiles from those in the instrument alignment and spectroscopic parameters, we retrieve CO2 profiles from atmospheric spectra while using an a priori profile built from coincident AirCore, radiosonde, and surface in situ measurements at the Lamont, Oklahoma (USA), Total Carbon Column Observing Network station. In those cases, the deviations in retrieved CO2 profiles are also larger than typical vertical variations of CO2, suggesting that remaining errors in the forward model limit the accuracy of the retrieved profiles. Implementing a temperature retrieval or correction and quantifying and model- ing an imperfect instrument alignment are critical to improve CO2 profile retrievals. Without significant advances in modeling imperfect instrument alignment, and improvements in the accuracy of the temperature profile, the CO2 profile retrieval with GFIT2 presents no clear advantage over scaling retrievals for the purpose of ascertaining the total column. |
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BibTeX:
@article{roche21a,
author = {Roche, Sebastien and Strong, Kimberly and Wunch, Debra and Mendonca, Joseph and Sweeney, Colm and Baier, Bianca and Biraud, Sebastien C. and Laughner, Joshua L. and Toon, Geoffrey C. and Connor, Brian J.},
title = {Retrieval of atmospheric CO2 vertical profiles from ground-based near-infrared spectra},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2021},
volume = {14},
number = {4},
pages = {3087-3118},
doi = {https://doi.org/10.5194/amt-14-3087-2021}
}
|
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| Rochoux, M.C., Ricci, S., Lucor, D., Cuenot, B. and Trouve, A. | Towards predictive data-driven simulations of wildfire spread - Part I: Reduced-cost Ensemble Kalman Filter based on a Polynomial Chaos surrogate model for parameter estimation | {2014} | NATURAL HAZARDS AND EARTH SYSTEM SCIENCES Vol. {14}({11}), pp. 2951-2973 |
article | DOI |
| Abstract: This paper is the first part in a series of two articles and presents a data-driven wildfire simulator for forecasting wildfire spread scenarios, at a reduced computational cost that is consistent with operational systems. The prototype simulator features the following components: an Eulerian front propagation solver FIREFLY that adopts a regional-scale modeling viewpoint, treats wildfires as surface propagating fronts, and uses a description of the local rate of fire spread (ROS) as a function of environmental conditions based on Rothermel's model; a series of airborne-like observations of the fire front positions; and a data assimilation (DA) algorithm based on an ensemble Kalman filter (EnKF) for parameter estimation. This stochastic algorithm partly accounts for the nonlinearities between the input parameters of the semi-empirical ROS model and the fire front position, and is sequentially applied to provide a spatially uniform correction to wind and biomass fuel parameters as observations become available. A wildfire spread simulator combined with an ensemble-based DA algorithm is therefore a promising approach to reduce uncertainties in the forecast position of the fire front and to introduce a paradigm-shift in the wildfire emergency response. In order to reduce the computational cost of the EnKF algorithm, a surrogate model based on a polynomial chaos (PC) expansion is used in place of the forward model FIREFLY in the resulting hybrid PC-EnKF algorithm. The performance of EnKF and PC-EnKF is assessed on synthetically generated simple configurations of fire spread to provide valuable information and insight on the benefits of the PC-EnKF approach, as well as on a controlled grassland fire experiment. The results indicate that the proposed PC-EnKF algorithm features similar performance to the standard EnKF algorithm, but at a much reduced computational cost. In particular, the re-analysis and forecast skills of DA strongly relate to the spatial and temporal variability of the errors in the ROS model parameters. |
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BibTeX:
@article{rochoux14a,
author = {Rochoux, M. C. and Ricci, S. and Lucor, D. and Cuenot, B. and Trouve, A.},
title = {Towards predictive data-driven simulations of wildfire spread - Part I: Reduced-cost Ensemble Kalman Filter based on a Polynomial Chaos surrogate model for parameter estimation},
journal = {NATURAL HAZARDS AND EARTH SYSTEM SCIENCES},
year = {2014},
volume = {14},
number = {11},
pages = {2951--2973},
doi = {https://doi.org/10.5194/nhess-14-2951-2014}
}
|
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| Rodway, J.E. | Implementation and Evaluation of Spatiotemporal Prediction Algorithms and Prediction of Spatially Distributed Greenhouse Gas Inventories [BibTeX] |
2011 | School: University of Alberta | phdthesis | |
BibTeX:
@phdthesis{rodway11a,
author = {Rodway, James EA},
title = {Implementation and Evaluation of Spatiotemporal Prediction Algorithms and Prediction of Spatially Distributed Greenhouse Gas Inventories},
school = {University of Alberta},
year = {2011}
}
|
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| Roedenbeck, C., Gerbig, C., Trusilova, K. and Heimann, M. | A two-step scheme for high-resolution regional atmospheric trace gas inversions based on independent models | {2009} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {9}({14}), pp. 5331-5342 |
article | |
| Abstract: Mixing ratio measurements of atmospheric tracers like CO2 can be used to estimate regional surface-air tracer fluxes using inverse methods, involving a numerical transport model. Currently available transport models are either global but rather coarse, or more accurate but only over a limited spatial and temporal domain. To obtain higher-resolution flux estimates within a region of interest, existing studies use zoomed or coupled models. The two-step scheme developed here uses global and regional models sequentially in separate inversion steps, coupled only via the data vector. This provides a nested atmospheric inversion scheme without the necessity of a direct coupled model implementation. For example, the scheme allows an easy nesting of Lagrangian models with their potential of very high resolution into global inversions based on Eulerian models. |
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BibTeX:
@article{roedenbeck09a,
author = {Roedenbeck, C. and Gerbig, C. and Trusilova, K. and Heimann, M.},
title = {A two-step scheme for high-resolution regional atmospheric trace gas inversions based on independent models},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2009},
volume = {9},
number = {14},
pages = {5331--5342}
}
|
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| Ross, A. | GOSAT measurements of wildfire emissions [BibTeX] |
2012 | School: UNIVERSITY OF LONDON | mastersthesis | |
BibTeX:
@mastersthesis{ross12a,
author = {Ross, Adrian},
title = {GOSAT measurements of wildfire emissions},
school = {UNIVERSITY OF LONDON},
year = {2012}
}
|
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| Rosso, I., Mazloff, M.R., Verdy, A. and Talley, L.D. | Space and time variability of the Southern Ocean carbon budget | {2017} | JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS Vol. {122}({9}), pp. 7407-7432 |
article | DOI |
| Abstract: The upper ocean dissolved inorganic carbon (DIC) concentration is regulated by advective and diffusive transport divergence, biological processes, freshwater, and air-sea CO2 fluxes. The relative importance of these mechanisms in the Southern Ocean is uncertain, as year-round observations in this area have been limited. We use a novel physical-biogeochemical state estimate of the Southern Ocean to construct a closed DIC budget of the top 650 m and investigate the spatial and temporal variability of the different components of the carbon system. The dominant mechanisms of variability in upper ocean DIC depend on location and time and space scales considered. Advective transport is the most influential mechanism and governs the local DIC budget across the 10 day-5 year timescales analyzed. Diffusive effects are nearly negligible. The large-scale transport structure is primarily set by upwelling and downwelling, though both the lateral ageostrophic and geostrophic transports are significant. In the Antarctic Circumpolar Current, the carbon budget components are also influenced by the presence of topography and biological hot spots. In the subtropics, evaporation and air-sea CO2 flux primarily balances the sink due to biological production and advective transport. Finally, in the subpolar region sea ice processes, which change the seawater volume and thus the DIC concentration, compensate the large impact of the advective transport and modulate the timing of biological activity and air-sea CO2 flux. |
|||||
BibTeX:
@article{rosso17a,
author = {Rosso, Isabella and Mazloff, Matthew R. and Verdy, Ariane and Talley, Lynne D.},
title = {Space and time variability of the Southern Ocean carbon budget},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS},
year = {2017},
volume = {122},
number = {9},
pages = {7407--7432},
doi = {https://doi.org/10.1002/2016JC012646}
}
|
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| Rowe, P.M., Walden, V.P., Brandt, R.E., Town, M.S., Hudson, S.R. and Neshyba, S. | Evaluation of Temperature-Dependent Complex Refractive Indices of Supercooled Liquid Water Using Downwelling Radiance and In-Situ Cloud Measurements at South Pole | 2022 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 127(1) |
article | DOI |
| Abstract: Clouds have a large effect on the radiation budget and represent a major source of uncertainty in climate models. Supercooled liquid clouds can exist at temperatures as low as 235 K, and the radiative effect of these clouds depends on the complex refractive index (CRI) of liquid water. Laboratory measurements have demonstrated that the liquid-water CRI is temperature-dependent, but corroboration with field measurements is difficult. Here we present measurements of the downwelling infrared radiance and in-situ measurements of supercooled liquid water in a cloud at temperatures as low as 240 K, made at South Pole Station in 2001. These results demonstrate that including the temperature dependence of the liquid-water CRI is essential for accurate calculations of radiative transfer through supercooled liquid clouds. Furthermore, we show that when cloud properties are retrieved from infrared radiances (using the spectral range 500-1,200 cm(-1)) spurious ice may be retrieved if the 300 K CRI is used for cold liquid clouds (similar to 240 K). These results have implications for radiative transfer in climate models as well as for retrievals of cloud properties from infrared radiance spectra. |
|||||
BibTeX:
@article{rowe22a,
author = {Rowe, Penny M. and Walden, Von P. and Brandt, Richard E. and Town, Michael S. and Hudson, Stephen R. and Neshyba, Steven},
title = {Evaluation of Temperature-Dependent Complex Refractive Indices of Supercooled Liquid Water Using Downwelling Radiance and In-Situ Cloud Measurements at South Pole},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2022},
volume = {127},
number = {1},
doi = {https://doi.org/10.1029/2021JD035182}
}
|
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| Saito, R., Tanaka, T., Hara, H., Oguma, H., Takamura, T., Kuze, H. and Yokota, T. | Aircraft and ground-based observations of boundary layer CO2 concentration in anticyclonic synoptic condition | {2009} | GEOPHYSICAL RESEARCH LETTERS Vol. {36} |
article | DOI |
| Abstract: Concentrations of atmospheric CO2 and aerosol were measured in a field campaign conducted in winter 2006 around Mt. Tsukuba, Japan using ground-based CO2 analyzers, a lidar, and sky radiometers as well as CO2 analyzers onboard an aircraft. Vertical measurements revealed occasional similarity between the profiles of CO2 and aerosol concentrations, though their temporal variations are not always coordinated because of the effects of local sources or sinks. A sudden increase of downward winds, due to the approach of an anticyclonic synoptic flow, resulted in a rapid decrease in both the CO2 and aerosol concentrations in the boundary layer. These observation results have demonstrated that simultaneous measurements with airborne and ground-based instruments set on the summit/foot of a mountain are useful for the study of variability of CO2 concentration in the boundary layer. Citation: Saito, R., T. Tanaka, H. Hara, H. Oguma, T. Takamura, H. Kuze, and T. Yokota (2009), Aircraft and ground-based observations of boundary layer CO2 concentration in anticyclonic synoptic condition, Geophys. Res. Lett., 36, L07807, doi: 10.1029/2008GL037037. |
|||||
BibTeX:
@article{saito09a,
author = {Saito, Ryu and Tanaka, Tomoaki and Hara, Hiroshi and Oguma, Hiroyuki and Takamura, Tamio and Kuze, Hiroaki and Yokota, Tatsuya},
title = {Aircraft and ground-based observations of boundary layer CO2 concentration in anticyclonic synoptic condition},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2009},
volume = {36},
doi = {https://doi.org/10.1029/2008GL037037}
}
|
|||||
| Saito, R., Houweling, S., Patra, P.K., Belikov, D., Lokupitiya, R., Niwa, Y., Chevallier, F., Saeki, T. and Maksyutov, S. | TransCom satellite intercomparison experiment: Construction of a bias corrected atmospheric CO2 climatology | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: A model-based three-dimensional (3-D) climatology of atmospheric CO2 concentrations has been constructed for the analysis of satellite observations, as a priori information in retrieval calculations, and for preliminary evaluation of remote sensing products. The locations of ground-based instruments and the coverage of aircraft in situ measurements are limited and do not represent the full atmospheric column, which is a primary requirement for the validation of satellite data. To address this problem, we have developed a method for constructing a 3-D CO2 climatology from the surface up to approximately 30 km by combining information from in situ measurements and several transport models. The model-simulated CO2 concentrations have been generated in the framework of the TransCom satellite experiment. The spatial and temporal biases of the transport-model-derived data set have been corrected using in situ CO2 measurements in the troposphere and in situ profiles of the mean age of air in the stratosphere. The constructed multimodel mean CO2 climatology represents the seasonal cycle and the inter-hemispheric gradient better than each transport model. Our approach performs well near the surface and in regions where the observational network is relatively dense. The column-mean CO2 of the constructed climatology was reduced by similar to 1 ppm from that of a single transport models, consistent with model validation against measurements of the CO2 total column. |
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BibTeX:
@article{saito11a,
author = {Saito, Ryu and Houweling, Sander and Patra, Prabir K. and Belikov, Dmitry and Lokupitiya, Ravindra and Niwa, Yosuke and Chevallier, Frederic and Saeki, Tazu and Maksyutov, Shamil},
title = {TransCom satellite intercomparison experiment: Construction of a bias corrected atmospheric CO2 climatology},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2011JD016033}
}
|
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| Saitoh, N., Kimoto, S., Sugimura, R., Imasu, R., Kawakami, S., Shiomi, K., Kuze, A., Machida, T., Sawa, Y. and Matsueda, H. | Algorithm update of the GOSAT/TANSO-FTS thermal infrared CO2 product (version 1) and validation of the UTLS CO2 data using CONTRAIL … [BibTeX] |
2016 | Atmospheric Measurement Techniques Vol. 9(5), pp. 2119-2134 |
article | |
BibTeX:
@article{saitoh16a,
author = {Saitoh, Naoko and Kimoto, Shuhei and Sugimura, Ryo and Imasu, Ryoichi and Kawakami, Shuji and Shiomi, Kei and Kuze, Akihiko and Machida, Toshinobu and Sawa, Yousuke and Matsueda, Hidekazu},
title = {Algorithm update of the GOSAT/TANSO-FTS thermal infrared CO2 product (version 1) and validation of the UTLS CO2 data using CONTRAIL …},
journal = {Atmospheric Measurement Techniques},
year = {2016},
volume = {9},
number = {5},
pages = {2119--2134}
}
|
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| Samaddar, A., Feng, S., Lauvaux, T., Barkley, Z.R., Pal, S. and Davis, K.J. | Carbon Dioxide Distribution, Origins, and Transport Along a Frontal Boundary During Summer in Mid-Latitudes | 2021 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 126(9) |
article | DOI |
| Abstract: Synoptic weather systems are a major driver of spatial gradients in atmospheric CO2 mole fractions. During frontal passages, air masses from different regions meet at the frontal boundary creating significant gradients in CO2 mole fractions. We quantitatively describe the atmospheric transport of CO2 mole fractions during a mid-latitude cold front passage and explore the impact of various sources of CO2. We focus here on a cold front passage over Lincoln, Nebraska on August 4th, 2016 observed by aircraft during the Atmospheric Carbon and Transport-America campaign. A band of air with elevated CO2 was located along the frontal boundary. Observed and simulated differences in CO2 across the front were as high as 25 ppm. Numerical simulations using Weather Research and Forecasting Model with Chemistry at cloud resolving resolutions (3 km), coupled with CO2 surface fluxes and boundary conditions from CarbonTracker (CT-NRTv2017x), were performed to explore atmospheric transport at the front. Model results demonstrate that the frontal CO2 difference in the upper troposphere can be explained largely by inflow from outside of North America. This difference is modified in the atmospheric boundary layer and lower troposphere by continental surface fluxes, dominated in this case by biogenic and fossil fuel fluxes. Horizontal and vertical advection are found to be responsible for the transport of CO2 mole fractions along the frontal boundary. We show that cold front passages lead to large CO2 transport events including a significant contribution from vertical advection, and that midcontinent frontal boundaries are formed from a complex mixture of CO2 sources. |
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BibTeX:
@article{samaddar21a,
author = {Samaddar, Arkayan and Feng, Sha and Lauvaux, Thomas and Barkley, Zachary R. and Pal, Sandip and Davis, Kenneth J.},
title = {Carbon Dioxide Distribution, Origins, and Transport Along a Frontal Boundary During Summer in Mid-Latitudes},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2021},
volume = {126},
number = {9},
doi = {https://doi.org/10.1029/2020JD033118}
}
|
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| Sanaullah, M., Afzal, T., Shahzad, T. and Wakeel, A. | Carbon Sequestration for Sustainable Agriculture | 2019 | book | URL | |
| Abstract: The climate of earth has been experiencing an unprecedented change possibly due to the rapidly increasing amount of greenhouse gases (GHGs) in the atmosphere. If the release of GHGs into atmosphere continued at current rate, global warming will make the earth's … | |||||
BibTeX:
@book{sanaullah19a,
author = {Muhammad Sanaullah and Tahseen Afzal and Tanvir Shahzad and Abdul Wakeel},
title = {Carbon Sequestration for Sustainable Agriculture},
publisher = {SPRINGER},
year = {2019},
url = {https://link.springer.com/chapter/10.1007/978-3-030-23169-9_15}
}
|
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| Sargent, M., Barrera, Y., Nehrkorn, T., Hutyra, L.R., Gately, C.K., Jones, T., McKain, K., Sweeney, C., Hegarty, J., Hardiman, B. and Wofsy, S.C. | Anthropogenic and biogenic CO2 fluxes in the Boston urban region | {2018} | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Vol. {115}({29}), pp. {7491-7496} |
article | DOI |
| Abstract: With the pending withdrawal of the United States from the Paris Climate Accord, cities are now leading US actions toward reducing greenhouse gas emissions. Implementing effective mitigation strategies requires the ability to measure and track emissions over time and at various scales. We report CO2 emissions in the Boston, MA, urban region from September 2013 to December 2014 based on atmospheric observations in an inverse model framework. Continuous atmospheric measurements of CO2 from five sites in and around Boston were combined with a high-resolution bottom-up CO2 emission inventory and a Lagrangian particle dispersion model to determine regional emissions. Our model-measurement framework incorporates emissions estimates from submodels for both anthropogenic and biological CO2 fluxes, and development of a CO2 concentration curtain at the boundary of the study region based on a combination of tower measurements and modeled vertical concentration gradients. We demonstrate that an emission inventory with high spatial and temporal resolution and the inclusion of urban biological fluxes are both essential to accurately modeling annual CO2 fluxes using surface measurement networks. We calculated annual average emissions in the Boston region of 0.92 kg C.m(-2).y(-1) (95% confidence interval: 0.79 to 1.06), which is 14% higher than the Anthropogenic Carbon Emissions System inventory. Based on the capability of the model-measurement approach demonstrated here, our framework should be able to detect changes in CO2 emissions of greater than 18%, providing stakeholders with critical information to assess mitigation efforts in Boston and surrounding areas. |
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BibTeX:
@article{sargent18a,
author = {Sargent, Maryann and Barrera, Yanina and Nehrkorn, Thomas and Hutyra, Lucy R. and Gately, Conor K. and Jones, Taylor and McKain, Kathryn and Sweeney, Colm and Hegarty, Jennifer and Hardiman, Brady and Wofsy, Steven C.},
title = {Anthropogenic and biogenic CO2 fluxes in the Boston urban region},
journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
year = {2018},
volume = {115},
number = {29},
pages = {7491-7496},
doi = {https://doi.org/10.1073/pnas.1803715115}
}
|
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| Sarkar, S. | Phenology and carbon fixing: a satellite-based study over Continental USA | {2018} | INTERNATIONAL JOURNAL OF REMOTE SENSING Vol. {39}({1}), pp. 1-16 |
article | DOI |
| Abstract: Global climate change has led to concerns about its impact on our biosphere and vegetation. Any impact of climate on vegetation can manifest in terms of changes in plant growth characteristics, its health and timing of different vegetative phenomena, such as germination, bud burst, maturity, etc. The duration and changes in the timing of plant growth stages can in turn impact the global carbon cycle. Similarly any change in plant productivity, because of changing climate will alter the carbon flux pattern by changing the overall biological flux being added or taken away from the atmosphere. We have used satellite data to study spatiotemporal changes in the plant phenology and plant productivity over the Continental USA (CONUS) to get an overall understanding of the evolution of these metrics over the past decade. Our study reveals that the prairies situated in the heartland of CONUS have become an increasingly important player in determining any changes in vegetation induced carbon source/sink patterns. The northern Great Plains has shown increased fixation of carbon in recent years, while the southern Plains has become a carbon source. This has been largely driven by changes in recent weather patterns where the northern plains have seen an increasingly cooler and wetter growing season whereas the southern plains have at the same time seen increased aridity, especially since 2011. This is also reflected in increasing growing season greenness values over the northern Plains and the opposite over the southern Plains. The gradual changing pattern of land biological fluxes over CONUS, as documented in this paper will likely be of interest to climate modellers as they seek to better understand the interaction between global carbon balance and climate change. |
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BibTeX:
@article{sarkar18a,
author = {Sarkar, S.},
title = {Phenology and carbon fixing: a satellite-based study over Continental USA},
journal = {INTERNATIONAL JOURNAL OF REMOTE SENSING},
year = {2018},
volume = {39},
number = {1},
pages = {1--16},
doi = {https://doi.org/10.1080/01431161.2017.1378457}
}
|
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| Sarma, V.V.S.S., Lenton, A., Law, R.M., Metzl, N., Patra, P.K., Doney, S., Lima, I.D., Dlugokencky, E., Ramonet, M. and Valsala, V. | Sea-air CO2 fluxes in the Indian Ocean between 1990 and 2009 | {2013} | BIOGEOSCIENCES Vol. {10}({11}), pp. 7035-7052 |
article | DOI |
| Abstract: The Indian Ocean (44 degrees S-30 degrees N) plays an important role in the global carbon cycle, yet it remains one of the most poorly sampled ocean regions. Several approaches have been used to estimate net sea-air CO2 fluxes in this region: interpolated observations, ocean biogeochemical models, atmospheric and ocean inversions. As part of the RECCAP (REgional Carbon Cycle Assessment and Processes) project, we combine these different approaches to quantify and assess the magnitude and variability in Indian Ocean sea-air CO2 fluxes between 1990 and 2009. Using all of the models and inversions, the median annual mean sea-air CO2 uptake of -0.37 +/- 0.06 PgC yr(-1) is consistent with the -0.24 +/- 0.12 PgC yr(-1) calculated from observations. The fluxes from the southern Indian Ocean (18-44 degrees S; -0.43 +/- 0.07 PgC yr(-1)) are similar in magnitude to the annual uptake for the entire Indian Ocean. All models capture the observed pattern of fluxes in the Indian Ocean with the following exceptions: underestimation of upwelling fluxes in the northwestern region (off Oman and Somalia), overestimation in the northeastern region (Bay of Bengal) and underestimation of the CO2 sink in the subtropical convergence zone. These differences were mainly driven by lack of atmospheric CO2 data in atmospheric inversions, and poor simulation of monsoonal currents and freshwater discharge in ocean biogeochemical models. Overall, the models and inversions do capture the phase of the observed seasonality for the entire Indian Ocean but overestimate the magnitude. The predicted sea-air CO2 fluxes by ocean biogeochemical models (OBGMs) respond to seasonal variability with strong phase lags with reference to climatological CO2 flux, whereas the atmospheric inversions predicted an order of magnitude higher seasonal flux than OBGMs. The simulated interannual variability by the OBGMs is weaker than that found by atmospheric inversions. Prediction of such weak interannual variability in CO2 fluxes by atmospheric inversions was mainly caused by a lack of atmospheric data in the Indian Ocean. The OBGM models suggest a small strengthening of the sink over the period 1990-2009 of -0.01 PgC decade(-1) . This is inconsistent with the observations in the southwestern Indian Ocean that shows the growth rate of oceanic pCO(2) was faster than the observed atmospheric CO2 growth, a finding attributed to the trend of the Southern Annular Mode (SAM) during the 1990s. |
|||||
BibTeX:
@article{sarma13a,
author = {Sarma, V. V. S. S. and Lenton, A. and Law, R. M. and Metzl, N. and Patra, P. K. and Doney, S. and Lima, I. D. and Dlugokencky, E. and Ramonet, M. and Valsala, V.},
title = {Sea-air CO2 fluxes in the Indian Ocean between 1990 and 2009},
journal = {BIOGEOSCIENCES},
year = {2013},
volume = {10},
number = {11},
pages = {7035--7052},
doi = {https://doi.org/10.5194/bg-10-7035-2013}
}
|
|||||
| Saunois, M., Bousquet, P., Poulter, B., Peregon, A., Ciais, P., Canadell, J.G., Dlugokencky, E.J., Etiope, G., Bastviken, D., Houweling, S., Janssens-Maenhout, G., Tubiello, F.N., Castaldi, S., Jackson, R.B., Alexe, M., Arora, V.K., Beerling, D.J., Bergamaschi, P., Blake, D.R., Brailsford, G., Brovkin, V., Bruhwiler, L., Crevoisier, C., Crill, P., Covey, K., Curry, C., Frankenberg, C., Gedney, N., Hoeglund-Isaksson, L., Ishizawa, M., Ito, A., Joos, F., Kim, H.-S., Kleinen, T., Krummel, P., Lamarque, J.-F., Langenfelds, R., Locatelli, R., Machida, T., Maksyutov, S., McDonald, K.C., Marshall, J., Melton, J.R., Morino, I., Naik, V., O'Doherty, S., Parmentier, F.-J.W., Patra, P.K., Peng, C., Peng, S., Peters, G.P., Pison, I., Prigent, C., Prinn, R., Ramonet, M., Riley, W.J., Saito, M., Santini, M., Schroeder, R., Simpson, I.J., Spahni, R., Steele, P., Takizawa, A., Thornton, B.F., Tian, H., Tohjima, Y., Viovy, N., Voulgarakis, A., van Weele, M., van der Werf, G.R., Weiss, R., Wiedinmyer, C., Wilton, D.J., Wiltshire, A., Worthy, D., Wunch, D., Xu, X., Yoshida, Y., Zhang, B., Zhang, Z. and Zhu, Q. | The global methane budget 2000-2012 | {2016} | EARTH SYSTEM SCIENCE DATA Vol. {8}({2}), pp. 697-751 |
article | DOI |
| Abstract: The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (similar to biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). For the 2003-2012 decade, global methane emissions are estimated by top-down inversions at 558 TgCH(4) yr(-1), range 540-568. About 60% of global emissions are anthropogenic (range 50-65 %). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP scenarios. Bottom-up approaches suggest larger global emissions (736 TgCH(4) yr(-1), range 596-884) mostly because of larger natural emissions from individual sources such as inland waters, natural wetlands and geological sources. Considering the atmospheric constraints on the top-down budget, it is likely that some of the individual emissions reported by the bottom-up approaches are overestimated, leading to too large global emissions. Latitudinal data from top-down emissions indicate a predominance of tropical emissions (similar to 64% of the global budget, <30 degrees N) as compared to mid (similar to 32 %, 30-60 degrees N) and high northern latitudes (similar to 4 %, 60-90 degrees N). Top-down inversions consistently infer lower emissions in China (similar to 58 TgCH(4) yr(-1), range 51-72, -14 %) and higher emissions in Africa (86 TgCH(4) yr(-1), range 73-108, + 19 %) than bottom-up values used as prior estimates. Overall, uncertainties for anthropogenic emissions appear smaller than those from natural sources, and the uncertainties on source categories appear larger for top-down inversions than for bottom-up inventories and models. The most important source of uncertainty on the methane budget is attributable to emissions from wetland and other inland waters. We show that the wetland extent could contribute 30-40% on the estimated range for wetland emissions. Other priorities for improving the methane budget include the following: (i) the development of process-based models for inland-water emissions, (ii) the intensification of methane observations at local scale (flux measurements) to constrain bottom-up land surface models, and at regional scale (surface networks and satellites) to constrain top-down inversions, (iii) improvements in the estimation of atmospheric loss by OH, and (iv) improvements of the transport models integrated in top-down inversions. The data presented here can be downloaded from the Carbon Dioxide Information Analysis Center (http://doi.org/10.3334/CDIAC/GLOBAL_METHANE_BUDGET_2016_V1.1) and the Global Carbon Project. |
|||||
BibTeX:
@article{saunois16a,
author = {Saunois, Marielle and Bousquet, Philippe and Poulter, Ben and Peregon, Anna and Ciais, Philippe and Canadell, Josep G. and Dlugokencky, Edward J. and Etiope, Giuseppe and Bastviken, David and Houweling, Sander and Janssens-Maenhout, Greet and Tubiello, Francesco N. and Castaldi, Simona and Jackson, Robert B. and Alexe, Mihai and Arora, Vivek K. and Beerling, David J. and Bergamaschi, Peter and Blake, Donald R. and Brailsford, Gordon and Brovkin, Victor and Bruhwiler, Lori and Crevoisier, Cyril and Crill, Patrick and Covey, Kristofer and Curry, Charles and Frankenberg, Christian and Gedney, Nicola and Hoeglund-Isaksson, Lena and Ishizawa, Misa and Ito, Akihiko and Joos, Fortunat and Kim, Heon-Sook and Kleinen, Thomas and Krummel, Paul and Lamarque, Jean-Francois and Langenfelds, Ray and Locatelli, Robin and Machida, Toshinobu and Maksyutov, Shamil and McDonald, Kyle C. and Marshall, Julia and Melton, Joe R. and Morino, Isamu and Naik, Vaishali and O'Doherty, Simon and Parmentier, Frans-Jan W. and Patra, Prabir K. and Peng, Changhui and Peng, Shushi and Peters, Glen P. and Pison, Isabelle and Prigent, Catherine and Prinn, Ronald and Ramonet, Michel and Riley, William J. and Saito, Makoto and Santini, Monia and Schroeder, Ronny and Simpson, Isobel J. and Spahni, Renato and Steele, Paul and Takizawa, Atsushi and Thornton, Brett F. and Tian, Hanqin and Tohjima, Yasunori and Viovy, Nicolas and Voulgarakis, Apostolos and van Weele, Michiel and van der Werf, Guido R. and Weiss, Ray and Wiedinmyer, Christine and Wilton, David J. and Wiltshire, Andy and Worthy, Doug and Wunch, Debra and Xu, Xiyan and Yoshida, Yukio and Zhang, Bowen and Zhang, Zhen and Zhu, Qiuan},
title = {The global methane budget 2000-2012},
journal = {EARTH SYSTEM SCIENCE DATA},
year = {2016},
volume = {8},
number = {2},
pages = {697--751},
doi = {https://doi.org/10.5194/essd-8-697-2016}
}
|
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| Scheelbeek, P.F.D., Bird, F.A., Tuomisto, H.L., Green, R., Harris, F.B., Joy, E.J.M., Chalabi, Z., Allen, E., Haines, A. and Dangour, A.D. | Effect of environmental changes on vegetable and legume yields and nutritional quality | {2018} | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Vol. {115}({26}), pp. {6804-6809} |
article | DOI |
| Abstract: Environmental changes threaten agricultural production, food security, and health. Previous reviews suggest that environmental changes will substantially affect future yields of starchy dietary staples. To date, no comprehensive global analysis of the impacts of environmental change on (nonstaple) vegetables and legumes-important constituents of healthy diets-has been reported. We systematically searched for articles published between 1975 and 2016 on the effects of ambient temperature, tropospheric carbon dioxide (CO2), and ozone (O-3) concentrations, water availability, and salinization on yields and nutritional quality of vegetables and legumes. We estimated mean effects of standardized environmental changes using observed exposure-response relationships and conducted meta-analyses where possible. We identified 174 relevant papers reporting 1,540 experiments. The mean (95% CI) reported yield changes for all vegetables and legumes combined were +22.0% (+11.6% to +32.5%) for a 250-ppm increase in CO2 concentration, -8.9% (-15.6% to -2.2%) for a 25% increase in O-3 concentration,-34.7% (-44.6% to -24.9%) for a 50% reduction in water availability, and -2.3% (-3.7% to -0.9%) for a 25% increase in salinity. In papers with baseline temperatures >20 degrees C, a 4 degrees C increase in temperature reduced mean yields by -31.5% (-41.4% to -21.5%). Impacts of environmental changes on nutritional quality were mixed. In a business-as-usual scenario, predicted changes in environmental exposures would lead to reductions in yields of non-staple vegetables and legumes. Where adaptation possibilities are limited, this may substantially change their global availability, affordability, and consumption in the mid to long term. Our results stress the importance of prioritizing agricultural developments, to minimize potential reductions in vegetable and legume yields and associated negative health effects. |
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BibTeX:
@article{scheelbeek18a,
author = {Scheelbeek, Pauline F. D. and Bird, Frances A. and Tuomisto, Hanna L. and Green, Rosemary and Harris, Francesca B. and Joy, Edward J. M. and Chalabi, Zaid and Allen, Elizabeth and Haines, Andy and Dangour, Alan D.},
title = {Effect of environmental changes on vegetable and legume yields and nutritional quality},
journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
year = {2018},
volume = {115},
number = {26},
pages = {6804-6809},
doi = {https://doi.org/10.1073/pnas.1800442115}
}
|
|||||
| Scheelbeek, P. and Alae-Carew, C. | Climate Change and Its Impact on Fruits, Vegetables, Legumes, Nuts, and Seeds: What is The Gap to Bridge? | 2021 | … of Climate Change: Case Studies of … | article | URL |
| Abstract: Our planet's environment is changing rapidly, and this poses an ever-increasing risk to human health and our food systems. Changes such as agricultural land degradation, water shortages, rising temperatures and changing rainfall patterns can affect yields and nutrient … | |||||
BibTeX:
@article{scheelbeek21a,
author = {P Scheelbeek and C Alae-Carew},
title = {Climate Change and Its Impact on Fruits, Vegetables, Legumes, Nuts, and Seeds: What is The Gap to Bridge?},
journal = {… of Climate Change: Case Studies of …},
publisher = {World Scientific},
year = {2021},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.worldscientific.com/doi/abs/10.1142/9789811213953_0015}
}
|
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| Schepers, D., Guerlet, S., Butz, A., Landgraf, J., Frankenberg, C., Hasekamp, O., Blavier, J.F., Deutscher, N.M., Griffith, D.W.T., Hase, F., Kyro, E., Morino, I., Sherlock, V., Sussmann, R. and Aben, I. | Methane retrievals from Greenhouse Gases Observing Satellite (GOSAT) shortwave infrared measurements: Performance comparison of proxy and physics retrieval algorithms | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {117} |
article | DOI |
| Abstract: We compare two conceptually different methods for determining methane column-averaged mixing ratios (X-CH4) from Greenhouse Gases Observing Satellite (GOSAT) shortwave infrared (SWIR) measurements. These methods account differently for light scattering by aerosol and cirrus. The proxy method retrieves a CO2 column which, in conjunction with prior knowledge on CO2 acts as a proxy for scattering effects. The physics-based method accounts for scattering by retrieving three effective parameters of a scattering layer. Both retrievals are validated on a 19-month data set using ground-based X-CH4 measurements at 12 stations of the Total Carbon Column Observing Network (TCCON), showing comparable performance: for the proxy retrieval we find station-dependent retrieval biases from -0.312% to 0.421% of X-CH4 with a standard deviation of 0.22% and a typical precision of 17 ppb. The physics method shows biases between -0.836% and -0.081% with a standard deviation of 0.24% and a precision similar to the proxy method. Complementing this validation we compared both retrievals with simulated methane fields from a global chemistry-transport model. This identified shortcomings of both retrievals causing biases of up to 1ings and provide a satisfying validation of any methane retrieval from space-borne SWIR measurements, in our opinion it is essential to further expand the network of TCCON stations. |
|||||
BibTeX:
@article{schepers12a,
author = {Schepers, D. and Guerlet, S. and Butz, A. and Landgraf, J. and Frankenberg, C. and Hasekamp, O. and Blavier, J. -F. and Deutscher, N. M. and Griffith, D. W. T. and Hase, F. and Kyro, E. and Morino, I. and Sherlock, V. and Sussmann, R. and Aben, I.},
title = {Methane retrievals from Greenhouse Gases Observing Satellite (GOSAT) shortwave infrared measurements: Performance comparison of proxy and physics retrieval algorithms},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2012JD017549}
}
|
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| Schepers, D., Butz, A., Hu, H., Hasekamp, O.P., Arnold, S.G., Schneider, M., Feist, D.G., Morino, I., Pollard, D., Aben, I. and Landgraf, J. | Methane and carbon dioxide total column retrievals from cloudy GOSAT soundings over the oceans | {2016} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {121}({9}), pp. 5031-5050 |
article | DOI |
| Abstract: We present a novel physics-based retrieval method to infer total column mixing ratios of methane (XCH4) and carbon dioxide (XCO2) from space-borne short-wavelength infrared (SWIR) Earth radiance observations over the cloud-covered ocean. In nadir observing geometry in the SWIR spectral range, backscattering at the ocean surface is negligible. Hence, space-borne radiance measurements of ocean scenes generally do not provide sufficient level to retrieve XCO2 and XCH4. Our approach specifically targets cloudy GOSAT ocean soundings to provide sufficient radiance signal in nadir soundings in ocean areas. Currently, exploiting space-borne SWIR soundings over oceans relies on soundings in Sun glint geometry, observing the specular solar reflection at the ocean surface. The glint observation mode requires cloud-free conditions and a suitable observation geometry, severely limiting their number and geographical coverage. The proposed method is based on the existing RemoTeC algorithm that is extensively used to retrieve CH4 and CO2 columns from GOSAT SWIR measurements over land. For ocean pixels, we describe light scattering by clouds and aerosols by a single-layer water cloud with Gaussian height distribution. We infer the height and the geometrical thickness of the cloud layer jointly with the droplet size and the number density and the column abundances of CO2, CH4, and H2O. The CO2 and CH4 column product is validated with ground-based total column measurements performed at eight stations from the TCCON network that are geographically close to an ocean coastline. For the TCCON site with the most robust statistics (Lauder, New Zealand), we find a retrieval bias of 0.36% for XCH4 combined with a standard deviation of retrieval errors of 1.12%. For XCO2, the bias is 0.51% combined with a standard deviation of 1.03%. Averaged over all TCCON sites, our retrievals are biased -0.01% for XCO2 and -0.32% for XCH4. The standard deviation of station biases amounts to 0.45% for XCO2 and 0.35% for XCH4. |
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BibTeX:
@article{schepers16a,
author = {Schepers, D. and Butz, A. and Hu, H. and Hasekamp, O. P. and Arnold, S. G. and Schneider, M. and Feist, D. G. and Morino, I. and Pollard, D. and Aben, I. and Landgraf, J.},
title = {Methane and carbon dioxide total column retrievals from cloudy GOSAT soundings over the oceans},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2016},
volume = {121},
number = {9},
pages = {5031--5050},
doi = {https://doi.org/10.1002/2015JD023389}
}
|
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| Schmidt, A., Rella, C.W., Goeckede, M., Hanson, C., Yang, Z. and Law, B.E. | Removing traffic emissions from CO2 time series measured at a tall tower using mobile measurements and transport modeling | {2014} | ATMOSPHERIC ENVIRONMENT Vol. {97}({SI}), pp. 94-108 |
article | DOI |
| Abstract: In recent years, measurements of atmospheric carbon dioxide with high precision and accuracy have become increasingly important for climate change research, in particular to inform terrestrial biosphere models. Anthropogenic carbon dioxide emissions from fossil fuel burning have long been recognized to contribute a significant portion of the carbon dioxide in the atmosphere. Here, we present an approach to remove the traffic related carbon dioxide emissions from mole fractions measured at a tall tower by using the corresponding carbon monoxide measurements in combination with footprint analyses and transport modeling. This technique improves the suitability of the CO2 data to be used in inverse modeling approaches of atmosphere-biosphere exchange that do not account for non-biotic portions of CO2. In our study region in Oregon, road traffic emissions are the biggest source of anthropogenic carbon dioxide and carbon monoxide. A three-day mobile campaign covering 1700 km of roads in northwestern Oregon was performed during summer of 2012 using a laser-based Cavity Ring-Down Spectrometer. The mobile measurements incorporated different roads including main highways, urban streets, and back-roads, largely within the typical footprint of a tall CO/CO2 observation tower in Oregon's Willamette Valley. For the first time, traffic related CO:CO2 emission ratios were measured directly at the sources during an on-road campaign under a variety of different driving conditions. An average emission ratio of 7.43 (+/- 1.80) ppb CO per ppm CO2 was obtained for the study region and applied to separate the traffic related portion of CO2 from the mole fraction time series. The road traffic related portion of the CO2 mole fractions measured at the tower site reached maximum values ranging from 9.8 to 12 ppm, depending on the height above the surface, during summer 2012. (C) 2014 Elsevier Ltd. All rights reserved. |
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BibTeX:
@article{schmidt14a,
author = {Schmidt, Andres and Rella, Chris W. and Goeckede, Mathias and Hanson, Chad and Yang, Zhenlin and Law, Beverly E.},
title = {Removing traffic emissions from CO2 time series measured at a tall tower using mobile measurements and transport modeling},
journal = {ATMOSPHERIC ENVIRONMENT},
year = {2014},
volume = {97},
number = {SI},
pages = {94--108},
doi = {https://doi.org/10.1016/j.atmosenv.2014.08.006}
}
|
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| Schneising, O., Buchwitz, M., Burrows, J.P., Bovensmann, H., Reuter, M., Notholt, J., Macatangay, R. and Warneke, T. | Three years of greenhouse gas column-averaged dry air mole fractions retrieved from satellite - Part 1: Carbon dioxide | {2008} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {8}({14}), pp. 3827-3853 |
article | DOI |
| Abstract: Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic greenhouse gases. SCIAMACHY on ENVISAT is the first satellite instrument whose measurements are sensitive to concentration changes of the two gases at all altitude levels down to the Earth's surface where the source/sink signals are largest. We have processed three years (2003-2005) of SCIAMACHY near-infrared nadir measurements to simultaneously retrieve vertical columns of CO2 (from the 1.58 mu m absorption band), CH4 (1.66 mu m) and oxygen (O-2 A-band at 0.76 mu m) using the scientific retrieval algorithm WFM-DOAS. We show that the latest version of WFM-DOAS, version 1.0, which is used for this study, has been significantly improved with respect to its accuracy compared to the previous versions while essentially maintaining its high processing speed (similar to 1 min per orbit, corresponding to similar to 6000 single measurements, and per gas on a standard PC). The greenhouse gas columns are converted to dry air column-averaged mole fractions, denoted XCO2 (in ppm) and XCH4 (in ppb), by dividing the greenhouse gas columns by simultaneously retrieved dry air columns. For XCO2 dry air columns are obtained from the retrieved O-2 columns. For XCH4 dry air columns are obtained from the retrieved CO2 columns because of better cancellation of light path related errors compared to using O-2 columns retrieved from the spectrally distant O-2 A-band. Here we focus on a discussion of the XCO2 data set. The XCH4 data set is discussed in a separate paper (Part 2). In order to assess the quality of the retrieved XCO2 we present comparisons with Fourier Transform Spectroscopy (FTS) XCO2 measurements at two northern hemispheric mid-latitude ground stations. To assess the quality globally, we present detailed comparisons with global XCO2 fields obtained from NOAA's CO2 assimilation system CarbonTracker. For the Northern Hemisphere we find good agreement with the reference data for the CO2 seasonal cycle and the CO2 annual increase. For the Southern Hemisphere, where significantly less data are available for averaging compared to the Northern Hemisphere, the CO2 annual increase is also in good agreement with CarbonTracker but the amplitude and phase of the seasonal cycle show systematic differences (up to several ppm) arising partially from the O-2 normalization most likely caused by unconsidered scattering effects due to subvisual cirrus clouds. The retrieved XCO2 regional pattern at monthly resolution over various regions show clear correlations with CarbonTracker but also significant differences. Typically the retrieved variability is about 4 ppm (1% of 380 ppm) higher but depending on time and location differences can reach or even exceed 8 ppm. Based on the error analysis and on the comparison with the reference data we conclude that the XCO2 data set can be characterized by a single measurement retrieval precision (random error) of 1-2%, a systematic low bias of about 1.5%, and by a relative accuracy of about 1-2% for monthly averages at a spatial resolution of about 7 degrees X 7 degrees. When averaging the SCIAMACHY XCO2 over all three years we find elevated CO2 over the highly populated region of western central Germany and parts of the Netherlands ('Rhine-Main area') reasonably well correlatd with EDGAR anthropogenic CO2 emissions. On average the regional enhancement is 2.7 ppm including an estimated contribution of 1-1.5 ppm due to aerosol related errors and sampling. |
|||||
BibTeX:
@article{schneising08a,
author = {Schneising, O. and Buchwitz, M. and Burrows, J. P. and Bovensmann, H. and Reuter, M. and Notholt, J. and Macatangay, R. and Warneke, T.},
title = {Three years of greenhouse gas column-averaged dry air mole fractions retrieved from satellite - Part 1: Carbon dioxide},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2008},
volume = {8},
number = {14},
pages = {3827--3853},
doi = {https://doi.org/10.5194/acp-8-3827-2008}
}
|
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| Schneising, O., Buchwitz, M., Burrows, J.P., Bovensmann, H., Bergamaschi, P. and Peters, W. | Three years of greenhouse gas column-averaged dry air mole fractions retrieved from satellite - Part 2: Methane | {2009} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {9}({2}), pp. 443-465 |
article | DOI |
| Abstract: Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic greenhouse gases. SCIAMACHY on ENVISAT is the first satellite instrument whose measurements are sensitive to concentration changes of the two gases at all altitude levels down to the Earth's surface where the source/sink signals are largest. We have processed three years (2003-2005) of SCIAMACHY near-infrared nadir measurements to simultaneously retrieve vertical columns of CO2 (from the 1.58 mu m absorption band), CH4 (1.66 mu m) and oxygen (O-2 A-band at 0.76 mu m) using the scientific retrieval algorithm WFM-DOAS. We show that the latest version of WFM-DOAS, version 1.0, which is used for this study, has been significantly improved with respect to its accuracy compared to the previous versions while essentially maintaining its high processing speed (similar to 1 min per orbit, corresponding to similar to 6000 single measurements, and per gas on a standard PC). The greenhouse gas columns are converted to dry air column-averaged mole fractions, denoted XCO2 (in ppm) and XCH4 (in ppb), by dividing the greenhouse gas columns by simultaneously retrieved dry air columns. For XCO2 dry air columns are obtained from the retrieved O-2 columns. For XCH4 dry air columns are obtained from the retrieved CO2 columns because of better cancellation of light path related errors compared to using O-2 columns retrieved from the spectrally distant O-2 A-band. Here we focus on a discussion of the XCH4 data set. The XCO2 data set is discussed in a separate paper (Part 1). For 2003 we present detailed comparisons with the TM5 model which has been optimally matched to highly accurate but sparse methane surface observations. After accounting for a systematic low bias of similar to 2% agreement with TM5 is typically within 1-2%. We investigated to what extent the SCIAMACHY XCH4 is influenced by the variability of atmospheric CO2 using global CO2 fields from NOAA's CO2 assimilation system CarbonTracker. We show that the CO2 corrected and uncorrected XCH4 spatio-temporal pattern are very similar but that agreement with TM5 is better for the CarbonTracker CO2 corrected XCH4. In line with previous studies (e. g., Frankenberg et al., 2005b) we find higher methane over the tropics compared to the model. We show that tropical methane is also higher when normalizing the CH4 columns with retrieved O-2 columns instead of CO2. In consistency with recent results of Frankenberg et al. (2008b) it is shown that the magnitude of the retrieved tropical methane is sensitive to the choice of the spectroscopic line parameters of water vapour. Concerning inter-annual variability we find similar methane spatio-temporal pattern for 2003 and 2004. For 2005 the retrieved methane shows significantly higher variability compared to the two previous years, most likely due to somewhat larger noise of the spectral measurements. |
|||||
BibTeX:
@article{schneising09a,
author = {Schneising, O. and Buchwitz, M. and Burrows, J. P. and Bovensmann, H. and Bergamaschi, P. and Peters, W.},
title = {Three years of greenhouse gas column-averaged dry air mole fractions retrieved from satellite - Part 2: Methane},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2009},
volume = {9},
number = {2},
pages = {443--465},
doi = {https://doi.org/10.5194/acp-9-443-2009}
}
|
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| Schneising, O., Buchwitz, M., Reuter, M., Heymann, J., Bovensmann, H. and Burrows, J.P. | Long-term analysis of carbon dioxide and methane column-averaged mole fractions retrieved from SCIAMACHY | {2011} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {11}({6}), pp. 2863-2880 |
article | DOI |
| Abstract: Carbon dioxide (CO(2)) and methane (CH(4)) are the two most important anthropogenic greenhouse gases contributing to global climate change. SCIAMACHY onboard ENVISAT (launch 2002) was the first and is now with TANSO onboard GOSAT (launch 2009) one of only two satellite instruments currently in space whose measurements are sensitive to CO(2) and CH(4) concentration changes in the lowest atmospheric layers where the variability due to sources and sinks is largest. We present long-term SCIAMACHY retrievals (2003-2009) of column-averaged dry air mole fractions of both gases (denoted XCO(2) and XCH(4)) derived from absorption bands in the near-infrared/shortwave-infrared (NIR/SWIR) spectral region focusing on large-scale features. The results are obtained using an upgraded version (v2) of the retrieval algorithm WFM-DOAS including several improvements, while simultaneously maintaining its high processing speed. The retrieved mole fractions are compared to global model simulations (CarbonTracker XCO(2) and TM5 XCH(4)) being optimised by assimilating highly accurate surface measurements from the NOAA/ESRL network and taking the SCIAMACHY averaging kernels into account. The comparisons address seasonal variations and long-term characteristics. The steady increase of atmospheric carbon dioxide primarily caused by the burning of fossil fuels can be clearly observed with SCIAMACHY globally. The retrieved global annual mean XCO(2) increase agrees with CarbonTracker within the error bars (1.80 +/- 0.13 ppm yr(-1) compared to 1.81 +/- 0.09 ppm yr(-1)). The amplitude of the XCO(2) seasonal cycle as retrieved by SCIAMACHY, which is 4.3 +/- 0.2 ppm for the Northern Hemisphere and 1.4 +/- 0.2 ppm for the Southern Hemisphere, is on average about 1 ppm larger than for CarbonTracker. An investigation of the boreal forest carbon uptake during the growing season via the analysis of longitudinal gradients shows good agreement between SCIAMACHY and CarbonTracker concerning the overall magnitude of the gradients and their annual variations. The analysis includes a discussion of the relative uptake strengths of the Russian and North American boreal forest regions. The retrieved XCH(4) results show that after years of stability, atmospheric methane has started to rise again in recent years which is consistent with surface measurements. The largest increase is observed for the tropics and northern mid- and high-latitudes amounting to about 7.5 +/- 1.5 ppb yr(-1) since 2007. Due care has been exercised to minimise the influence of detector degradation on the quantitative estimate of this anomaly. |
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BibTeX:
@article{schneising11a,
author = {Schneising, O. and Buchwitz, M. and Reuter, M. and Heymann, J. and Bovensmann, H. and Burrows, J. P.},
title = {Long-term analysis of carbon dioxide and methane column-averaged mole fractions retrieved from SCIAMACHY},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
volume = {11},
number = {6},
pages = {2863--2880},
doi = {https://doi.org/10.5194/acp-11-2863-2011}
}
|
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| Schneising, O., Bergamaschi, P., Bovensmann, H., Buchwitz, M., Burrows, J.P., Deutscher, N.M., Griffith, D.W.T., Heymann, J., Macatangay, R., Messerschmidt, J., Notholt, J., Rettinger, M., Reuter, M., Sussmann, R., Velazco, V.A., Warneke, T., Wennberg, P.O. and Wunch, D. | Atmospheric greenhouse gases retrieved from SCIAMACHY: comparison to ground-based FTS measurements and model results | {2012} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {12}({3}), pp. 1527-1540 |
article | DOI |
| Abstract: SCIAMACHY onboard ENVISAT (launched in 2002) enables the retrieval of global long-term column-averaged dry air mole fractions of the two most important anthropogenic greenhouse gases carbon dioxide and methane (denoted XCO2 and XCH4). In order to assess the quality of the greenhouse gas data obtained with the recently introduced v2 of the scientific retrieval algorithm WFM-DOAS, we present validations with ground-based Fourier Transform Spectrometer (FTS) measurements and comparisons with model results at eight Total Carbon Column Observing Network (TCCON) sites providing realistic error estimates of the satellite data. Such validation is a prerequisite to assess the suitability of data sets for their use in inverse modelling. It is shown that there are generally no significant differences between the carbon dioxide annual increases of SCIAMACHY and the assimilation system CarbonTracker (2.00 +/- 0.16 ppm yr(-1) compared to 1.94 +/- 0.03 ppm yr(-1) on global average). The XCO2 seasonal cycle amplitudes derived from SCIAMACHY are typically larger than those from TCCON which are in turn larger than those from CarbonTracker. The absolute values of the northern hemispheric TCCON seasonal cycle amplitudes are closer to SCIAMACHY than to CarbonTracker and the corresponding differences are not significant when compared with SCIAMACHY, whereas they can be significant for a subset of the analysed TCCON sites when compared with CarbonTracker. At Darwin we find discrepancies of the seasonal cycle derived from SCIAMACHY compared to the other data sets which can probably be ascribed to occurrences of undetected thin clouds. Based on the comparison with the reference data, we conclude that the carbon dioxide data set can be characterised by a regional relative precision (mean standard deviation of the differences) of about 2.2 ppm and a relative accuracy (standard deviation of the mean differences) of 1.1-1.2 ppm for monthly average composites within a radius of 500 km. For methane, prior to November 2005, the regional relative precision amounts to 12 ppb and the relative accuracy is about 3 ppb for monthly composite averages within the same radius. The loss of some spectral detector pixels results in a degradation of performance thereafter in the spectral range currently used for the methane column retrieval. This leads to larger scatter and lower XCH4 values are retrieved in the tropics for the subsequent time period degrading the relative accuracy. As a result, the overall relative precision is estimated to be 17 ppb and the relative accuracy is in the range of about 10-20 ppb for monthly averages within a radius of 500 km. The derived estimates show that the SCIAMACHY XCH4 data set before November 2005 is suitable for regional source/sink determination and regional-scale flux uncertainty reduction via inverse modelling worldwide. In addition, the XCO2 monthly data potentially provide valuable information in continental regions, where there is sparse sampling by surface flask measurements. |
|||||
BibTeX:
@article{schneising12a,
author = {Schneising, O. and Bergamaschi, P. and Bovensmann, H. and Buchwitz, M. and Burrows, J. P. and Deutscher, N. M. and Griffith, D. W. T. and Heymann, J. and Macatangay, R. and Messerschmidt, J. and Notholt, J. and Rettinger, M. and Reuter, M. and Sussmann, R. and Velazco, V. A. and Warneke, T. and Wennberg, P. O. and Wunch, D.},
title = {Atmospheric greenhouse gases retrieved from SCIAMACHY: comparison to ground-based FTS measurements and model results},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2012},
volume = {12},
number = {3},
pages = {1527--1540},
doi = {https://doi.org/10.5194/acp-12-1527-2012}
}
|
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| Schneising, O., Heymann, J., Buchwitz, M., Reuter, M., Bovensmann, H. and Burrows, J.P. | Anthropogenic carbon dioxide source areas observed from space: assessment of regional enhancements and trends | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({5}), pp. 2445-2454 |
article | DOI |
| Abstract: Urban areas, which are home to the majority of today's world population, are responsible for more than two-thirds of the global energy-related carbon dioxide emissions. Given the ongoing demographic growth and rising energy consumption in metropolitan regions particularly in the developing world, urban-based emissions are expected to further increase in the future. As a consequence, monitoring and independent verification of reported anthropogenic emissions is becoming more and more important. It is demonstrated using SCIAMACHY nadir measurements that anthropogenic CO2 emissions can be detected from space and that emission trends might be tracked using satellite observations. This is promising with regard to future satellite missions with high spatial resolution and wide swath imaging capability aiming at constraining anthropogenic emissions down to the point-source scale. By subtracting retrieved background values from those retrieved over urban areas we find significant CO2 enhancements for several anthropogenic source regions, namely 1.3 +/- 0.7 ppm for the Rhine-Ruhr metropolitan region and the Benelux, 1.1 +/- 0.5 ppm for the East Coast of the United States, and 2.4 +/- 0.9 ppm for the Yangtze River Delta. The order of magnitude of the enhancements is in agreement with what is expected for anthropogenic CO2 signals. The larger standard deviation of the retrieved Yangtze River Delta enhancement is due to a distinct positive trend of 0.3 +/- 0.2 ppmyr(-1), which is quantitatively consistent with anthropogenic emissions from the Emission Database for Global Atmospheric Research (EDGAR) in terms of percentual increase per year. Potential contributions to the retrieved CO2 enhancement by several error sources, e. g. aerosols, albedo, and residual biospheric signals due to heterogeneous seasonal sampling, are discussed and can be ruled out to a large extent. |
|||||
BibTeX:
@article{schneising13a,
author = {Schneising, O. and Heymann, J. and Buchwitz, M. and Reuter, M. and Bovensmann, H. and Burrows, J. P.},
title = {Anthropogenic carbon dioxide source areas observed from space: assessment of regional enhancements and trends},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {5},
pages = {2445--2454},
doi = {https://doi.org/10.5194/acp-13-2445-2013}
}
|
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| Schneising, O., Reuter, M., Buchwitz, M., Heymann, J., Bovensmann, H. and Burrows, J.P. | Terrestrial carbon sink observed from space: variation of growth rates and seasonal cycle amplitudes in response to interannual surface temperature variability | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({1}), pp. 133-141 |
article | DOI |
| Abstract: The terrestrial biosphere is currently acting as a net carbon sink on the global scale, exhibiting significant interannual variability in strength. To reliably predict the future strength of the land sink and its role in atmospheric CO2 growth, the underlying biogeochemical processes and their response to a changing climate need to be well understood. In particular, better knowledge of the impact of key climate variables such as temperature or precipitation on the biospheric carbon reservoir is essential. It is demonstrated using nearly a decade of SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) nadir measurements that years with higher temperatures during the growing season can be robustly associated with larger growth rates in atmospheric CO2 and smaller seasonal cycle amplitudes for northern mid-latitudes. We find linear relationships between warming and CO2 growth as well as seasonal cycle amplitude at the 98 % significance level. This suggests that the terrestrial carbon sink is less efficient at higher temperatures during the analysed time period. Unless the biosphere has the ability to adapt its carbon storage under warming conditions in the longer term, such a temperature response entails the risk of potential future sink saturation via a positive carbon-climate feedback. Quantitatively, the covariation between the annual CO2 growth rates derived from SCIAMACHY data and warm season surface temperature anomaly amounts to 1.25 +/- 0.32 ppm yr(-1) K-1 for the Northern Hemisphere, where the bulk of the terrestrial carbon sink is located. In comparison, this relationship is less pronounced in the Southern Hemisphere. The covariation of the seasonal cycle amplitudes retrieved from satellite measurements and temperature anomaly is -1.30 +/- 0.31 ppm K-1 for the north temperate zone. These estimates are consistent with those from the CarbonTracker data assimilated CO2 data product, indicating that the temperature dependence of the model surface fluxes is realistic. |
|||||
BibTeX:
@article{schneising14a,
author = {Schneising, O. and Reuter, M. and Buchwitz, M. and Heymann, J. and Bovensmann, H. and Burrows, J. P.},
title = {Terrestrial carbon sink observed from space: variation of growth rates and seasonal cycle amplitudes in response to interannual surface temperature variability},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {1},
pages = {133--141},
doi = {https://doi.org/10.5194/acp-14-133-2014}
}
|
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| Schuh, A.E., Denning, A.S., Uliasz, M. and Corbin, K.D. | Seeing the forest through the trees: Recovering large-scale carbon flux biases in the midst of small-scale variability | {2009} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {114} |
article | DOI |
| Abstract: This paper investigates the effect of fine-scale spatial variability in carbon fluxes upon regional carbon flux inversion estimates in North America using simulated data from 1 May through 31 August 2004 and a hypothetical sparse network of eight towers in North America. A suite of random smooth regional carbon flux patterns are created and then obscured with random fine-scale spatial flux ``noise'' to mimic the effect of fine-scale heterogeneity in carbon fluxes found in nature. Five hundred and forty grid-scale atmospheric inversions are run using the synthetic data. We find that, regardless of the particular fine spatial scale carbon fluxes used ( noise), the inversions can improve a priori carbon flux estimates significantly by capturing the large-scale regional flux patterns. We also find significant improvement in the root-mean-square error of the model are possible across a wide range of spatial decorrelation length scales. Errors associated with the inversion decrease as estimates are sought for larger and larger areas. Results show dramatic differences between postaggregated fine-scale inversion results and preaggregated coarse-scale inversion results confirming recent warnings about the ``preaggregation'' of inversion regions. |
|||||
BibTeX:
@article{schuh09a,
author = {Schuh, A. E. and Denning, A. S. and Uliasz, M. and Corbin, K. D.},
title = {Seeing the forest through the trees: Recovering large-scale carbon flux biases in the midst of small-scale variability},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2009},
volume = {114},
doi = {https://doi.org/10.1029/2008JG000842}
}
|
|||||
| Schuh, A. | Recovering spatially and temporally dynamic regional scale carbon flux estimates [BibTeX] |
2009 | School: Colorado State University | phdthesis | |
BibTeX:
@phdthesis{schuh09b,
author = {Andrew Schuh},
title = {Recovering spatially and temporally dynamic regional scale carbon flux estimates},
school = {Colorado State University},
year = {2009}
}
|
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| Schuh, A.E., Denning, A.S., Corbin, K.D., Baker, I.T., Uliasz, M., Parazoo, N., Andrews, A.E. and Worthy, D.E.J. | A regional high-resolution carbon flux inversion of North America for 2004 | {2010} | BIOGEOSCIENCES Vol. {7}({5}), pp. 1625-1644 |
article | DOI |
| Abstract: Resolving the discrepancies between NEE estimates based upon (1) ground studies and (2) atmospheric inversion results, demands increasingly sophisticated techniques. In this paper we present a high-resolution inversion based upon a regional meteorology model (RAMS) and an underlying biosphere (SiB3) model, both running on an identical 40 km grid over most of North America. Current operational systems like CarbonTracker as well as many previous global inversions including the Transcom suite of inversions have utilized inversion regions formed by collapsing biome-similar grid cells into larger aggregated regions. An extreme example of this might be where corrections to NEE imposed on forested regions on the east coast of the United States might be the same as that imposed on forests on the west coast of the United States while, in reality, there likely exist subtle differences in the two areas, both natural and anthropogenic. Our current inversion framework utilizes a combination of previously employed inversion techniques while allowing carbon flux corrections to be biome independent. Temporally and spatially high-resolution results utilizing biome-independent corrections provide insight into carbon dynamics in North America. In particular, we analyze hourly CO2 mixing ratio data from a sparse network of eight towers in North America for 2004. A prior estimate of carbon fluxes due to Gross Primary Productivity (GPP) and Ecosystem Respiration (ER) is constructed from the SiB3 biosphere model on a 40 km grid. A combination of transport from the RAMS and the Parameterized Chemical Transport Model (PCTM) models is used to forge a connection between upwind biosphere fluxes and downwind observed CO2 mixing ratio data. A Kalman filter procedure is used to estimate weekly corrections to biosphere fluxes based upon observed CO2. RMSE-weighted annual NEE estimates, over an ensemble of potential inversion parameter sets, show a mean estimate 0.57 Pg/yr sink in North America. We perform the inversion with two independently derived boundary inflow conditions and calculate jackknife-based statistics to test the robustness of the model results. We then compare final results to estimates obtained from the CarbonTracker inversion system and at the Southern Great Plains flux site. Results are promising, showing the ability to correct carbon fluxes from the biosphere models over annual and seasonal time scales, as well as over the different GPP and ER components. Additionally, the correlation of an estimated sink of carbon in the South Central United States with regional anomalously high precipitation in an area of managed agricultural and forest lands provides interesting hypotheses for future work. |
|||||
BibTeX:
@article{schuh10a,
author = {Schuh, A. E. and Denning, A. S. and Corbin, K. D. and Baker, I. T. and Uliasz, M. and Parazoo, N. and Andrews, A. E. and Worthy, D. E. J.},
title = {A regional high-resolution carbon flux inversion of North America for 2004},
journal = {BIOGEOSCIENCES},
year = {2010},
volume = {7},
number = {5},
pages = {1625--1644},
doi = {https://doi.org/10.5194/bg-7-1625-2010}
}
|
|||||
| Schuh, A.E., Lauvaux, T., West, T.O., Denning, A.S., Davis, K.J., Miles, N., Richardson, S., Uliasz, M., Lokupitiya, E., Cooley, D., Andrews, A. and Ogle, S. | Evaluating atmospheric CO2 inversions at multiple scales over a highly inventoried agricultural landscape | {2013} | GLOBAL CHANGE BIOLOGY Vol. {19}({5}), pp. 1424-1439 |
article | DOI |
| Abstract: An intensive regional research campaign was conducted by the North American Carbon Program (NACP) in 2007 to study the carbon cycle of the highly productive agricultural regions of the Midwestern United States. Forty-five different associated projects were conducted across five US agencies over the course of nearly a decade involving hundreds of researchers. One of the primary objectives of the intensive campaign was to investigate the ability of atmospheric inversion techniques to use highly calibrated CO2 mixing ratio data to estimate CO2 flux over the major croplands of the United States by comparing the results to an inventory of CO2 fluxes. Statistics from densely monitored crop production, consisting primarily of corn and soybeans, provided the backbone of a well studied bottom-up inventory flux estimate that was used to evaluate the atmospheric inversion results. Estimates were compared to the inventory from three different inversion systems, representing spatial scales varying from high resolution mesoscale (PSU), to continental (CSU) and global (CarbonTracker), coupled to different transport models and optimization techniques. The inversion-based mean CO2-C sink estimates were generally slightly larger, 820% for PSU, 1020% for CSU, and 21% for CarbonTracker, but statistically indistinguishable, from the inventory estimate of 135 TgC. While the comparisons show that the MCI region-wide C sink is robust across inversion system and spatial scale, only the continental and mesoscale inversions were able to reproduce the spatial patterns within the region. In general, the results demonstrate that inversions can recover CO2 fluxes at sub-regional scales with a relatively high density of CO2 observations and adequate information on atmospheric transport in the region. |
|||||
BibTeX:
@article{schuh13a,
author = {Schuh, Andrew E. and Lauvaux, Thomas and West, Tristram O. and Denning, A. Scott and Davis, Kenneth J. and Miles, Natasha and Richardson, Scott and Uliasz, Marek and Lokupitiya, Erandathie and Cooley, Daniel and Andrews, Arlyn and Ogle, Stephen},
title = {Evaluating atmospheric CO2 inversions at multiple scales over a highly inventoried agricultural landscape},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2013},
volume = {19},
number = {5},
pages = {1424--1439},
doi = {https://doi.org/10.1111/gcb.12141}
}
|
|||||
| Schuh, A.E., Jacobson, A.R., Basu, S., Weir, B., Baker, D., Bowman, K., Chevallier, F., Crowell, S., Davis, K.J., Deng, F., Denning, S., Feng, L., Jones, D., Liu, J. and Palmer I, P. | Quantifying the Impact of Atmospheric Transport Uncertainty on CO2 Surface Flux Estimates | {2019} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {33}({4}), pp. {484-500} |
article | DOI URL |
| Abstract: We show that transport differences between two commonly used global chemical transport models, GEOS-Chem and TM5, lead to systematic space-time differences in modeled distributions of carbon dioxide and sulfur hexafluoride. The distribution of differences suggests inconsistencies between the transport simulated by the models, most likely due to the representation of vertical motion. We further demonstrate that these transport differences result in systematic differences in surface CO2 flux estimated by a collection of global atmospheric inverse models using TM5 and GEOS-Chem and constrained by in situ and satellite observations. While the impact on inferred surface fluxes is most easily illustrated in the magnitude of the seasonal cycle of surface CO2 exchange, it is the annual carbon budgets that are particularly relevant for carbon cycle science and policy. We show that inverse model flux estimates for large zonal bands can have systematic biases of up to 1.7PgC/year due to large-scale transport uncertainty. These uncertainties will propagate directly into analysis of the annual meridional CO2 flux gradient between the tropics and northern midlatitudes, a key metric for understanding the location, and more importantly the processes, responsible for the annual global carbon sink. The research suggests that variability among transport models remains the largest source of uncertainty across global flux inversion systems and highlights the importance both of using model ensembles and of using independent constraints to evaluate simulated transport. | |||||
BibTeX:
@article{schuh19a,
author = {Schuh, Andrew E. and Jacobson, Andrew R. and Basu, Sourish and Weir, Brad and Baker, David and Bowman, Kevin and Chevallier, Frederic and Crowell, Sean and Davis, Kenneth J. and Deng, Feng and Denning, Scott and Feng, Lian and Jones, Dylan and Liu, Junjie and Palmer, I, Paul},
title = {Quantifying the Impact of Atmospheric Transport Uncertainty on CO2 Surface Flux Estimates},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2019},
volume = {33},
number = {4},
pages = {484--500},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GB006086},
doi = {https://doi.org/10.1029/2018GB006086}
}
|
|||||
| Schuh, A.E., Otte, M., Lauvaux, T. and Oda, T. | Far-field biogenic and anthropogenic emissions as a dominant source of variability in local urban carbon budgets: A global high-resolution model study with implications for satellite remote sensing | 2021 | REMOTE SENSING OF ENVIRONMENT Vol. 262 |
article | DOI |
| Abstract: With the launch of the Observing Carbon Observatories (OCO-2 and OCO-3), we have entered a new era of greenhouse gas (GHG) data collection where sub-city scale data can be collected at varying times across the entire globe. An increasing focus on quantifying urban emissions of GHGs from policy makers has begun to spur new research into how best to use this unique and very high resolution data set. While, historically, this line of research has been the domain of limited domain mesoscale and regional models, an increasing understanding and respect for boundary inflow uncertainty and bias has led people to search for an alternative modeling framework that both characterizes high frequency variability of CO2 in space and time as well as honor mass conservation requirements globally and be seamless with respect to boundaries. To monitor local anthropogenic emissions from space, the influence of atmospheric signals originating from outside the local area of interest needs to be quantified. In our first step towards building a comprehensive multi-scale CO2 inversion system, we use free running simulations of the Ocean Land Atmosphere Model (OLAM), a variable-resolution general circulation model, to explore the signal-to-noise statistics of anthropogenic urban emissions of CO2 versus the background inflow for approximately 40 of the largest cities across the globe. We show that signal-to-noise levels are much better in winter time than summer but also that the winter biological inflow is far from negligible, suggesting that the commonly held assumption that biology can be ignored in winter time urban emission estimates is probably incorrect. Simulated pressure-weighted column average CO2 (XCO2) is also used to evaluate the ability of fixed location XCO2 measurements to provide background inflow estimates. Results show why Los Angeles, a heavily instrumented and studied urban center, is likely one of the easiest cities to observe globally from space, despite its relatively complex meteorology. Lastly, we discuss challenges and possible research paths forward to continue to advance the notion of multi-scale global CO2 flux inversion systems capable of simultaneously optimizing local urban emissions and large-scale CO2 transport patterns. |
|||||
BibTeX:
@article{schuh21a,
author = {Schuh, Andrew E. and Otte, Martin and Lauvaux, Thomas and Oda, Tomohiro},
title = {Far-field biogenic and anthropogenic emissions as a dominant source of variability in local urban carbon budgets: A global high-resolution model study with implications for satellite remote sensing},
journal = {REMOTE SENSING OF ENVIRONMENT},
year = {2021},
volume = {262},
doi = {https://doi.org/10.1016/j.rse.2021.112473}
}
|
|||||
| Schwalm, C.R., Williams, C.A. and Schaefer, K. | Carbon consequences of global hydrologic change, 1948-2009 | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {116} |
article | DOI |
| Abstract: Eddy covariance data (FLUXNET) provide key insights into how carbon and water fluxes covary with climate and ecosystem states. Here we merge FLUXNET data with reanalyzed evaporative fraction and dynamic land cover to create monthly global carbon flux anomalies attributable to hydrologic change from 1948 to 2009. Changes in land cover had a relative influence of <1% with an absolute effect less than uncertainty. The lack of trend globally in Net Ecosystem Productivity (NEP) attributable to hydroclimatic change masked positive trends in North America and Australia and negative trends in Africa and Asia. This spatial pattern coincided with geographic variation in hydroclimate excluding the temperature-limited high latitudes. Global NEP anomalies due to hydroclimatic variability ranged from -2.1 to +2.3 Pg C yr(-1) relative to a global average sink of +2.8 Pg C yr(-1). Trends in hydroclimate-induced NEP anomalies exceeded the background mean sink in many regions. |
|||||
BibTeX:
@article{schwalm11a,
author = {Schwalm, Christopher R. and Williams, Christopher A. and Schaefer, Kevin},
title = {Carbon consequences of global hydrologic change, 1948-2009},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2011JG001674}
}
|
|||||
| Scott, R.L., Jenerette, G.D., Potts, D.L. and Huxman, T.E. | Effects of seasonal drought on net carbon dioxide exchange from a woody-plant-encroached semiarid grassland | {2009} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {114} |
article | DOI |
| Abstract: Annual precipitation in the central and southern warm-desert region of North America is distributed climatologically between summer and winter periods with two prominent dry periods between them. We used energy and carbon dioxide (CO2) fluxes from eddy covariance along with standard meteorological and soil moisture measurements at a semiarid savanna in southern Arizona, United States, to better understand the consequences of warm or cool season drought on ecosystem CO2 exchange in these bimodally forced water-limited regions. Over the last 100 years, this historic grassland has converted to a savanna by the encroachment of the native mesquite tree (Prosopis velutina Woot.). During each of the 4 years of observation (2004-2007), annual precipitation (P) was below average, but monsoon (July-September) P was both above and below average while cool-season (December-March) P was always less than average by varying degrees. The ecosystem was a net source of CO2 to the atmosphere, ranging from 14 to 95 g C m(-2) yr(-1) with the strength of the source increasing with decreasing precipitation. When the rainfall was closest to the long-term average in its distribution and amount, the ecosystem was essentially carbon neutral. Summer drought resulted in increased carbon losses due mainly to a shortening of the growing season and the length of time later in the season when photosynthetic gain exceeds respiration loss. Severe cool season drought led to decreased spring carbon uptake and seemingly enhanced summer respiration, resulting in conditions that led to the greatest annual net carbon loss. |
|||||
BibTeX:
@article{scott09a,
author = {Scott, Russell L. and Jenerette, G. Darrel and Potts, Daniel L. and Huxman, Travis E.},
title = {Effects of seasonal drought on net carbon dioxide exchange from a woody-plant-encroached semiarid grassland},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2009},
volume = {114},
doi = {https://doi.org/10.1029/2008JG000900}
}
|
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| Sharma, A., Bhunia, H.G. and Bajpai, P. | Studies of CO2 sequestration by Anabaena viriabilis in stirred tank batch type photobioreactor [BibTeX] |
2014 | School: Thapar University | mastersthesis | |
BibTeX:
@mastersthesis{sharma14a,
author = {Sharma, Abhishek and Bhunia, Haripada Guide and Bajpai, PK},
title = {Studies of CO2 sequestration by Anabaena viriabilis in stirred tank batch type photobioreactor},
school = {Thapar University},
year = {2014}
}
|
|||||
| Sheng, M., Lei, L., Zeng, Z.-C., Rao, W. and Zhang, S. | Detecting the Responses of CO2 Column Abundances to Anthropogenic Emissions from Satellite Observations of GOSAT and OCO-2 | 2021 | REMOTE SENSING Vol. 13(17) |
article | DOI |
| Abstract: The continuing increase in atmospheric CO2 concentration caused by anthropogenic CO2 emissions significantly contributes to climate change driven by global warming. Satellite measurements of long-term CO2 data with global coverage improve our understanding of global carbon cycles. However, the sensitivity of the space-borne measurements to anthropogenic emissions on a regional scale is less explored because of data sparsity in space and time caused by impacts from geophysical factors such as aerosols and clouds. Here, we used global land mapping column averaged dry-air mole fractions of CO2 (XCO2) data (Mapping-XCO2), generated from a spatio-temporal geostatistical method using GOSAT and OCO-2 observations from April 2009 to December 2020, to investigate the responses of XCO2 to anthropogenic emissions at both global and regional scales. Our results show that the long-term trend of global XCO2 growth rate from Mapping-XCO2, which is consistent with that from ground observations, shows interannual variations caused by the El Nino Southern Oscillation (ENSO). The spatial distributions of XCO2 anomalies, derived from removing background from the Mapping-XCO2 data, reveal XCO2 enhancements of about 1.5-3.5 ppm due to anthropogenic emissions and seasonal biomass burning in the wintertime. Furthermore, a clustering analysis applied to seasonal XCO2 clearly reveals the spatial patterns of atmospheric transport and terrestrial biosphere CO2 fluxes, which help better understand and analyze regional XCO2 changes that are associated with atmospheric transport. To quantify regional anomalies of CO2 emissions, we selected three representative urban agglomerations as our study areas, including the Beijing-Tian-Hebei region (BTH), the Yangtze River Delta urban agglomerations (YRD), and the high-density urban areas in the eastern USA (EUSA). The results show that the XCO2 anomalies in winter well capture the several-ppm enhancement due to anthropogenic CO2 emissions. For BTH, YRD, and EUSA, regional positive anomalies of 2.47 +/- 0.37 ppm, 2.20 +/- 0.36 ppm, and 1.38 +/- 0.33 ppm, respectively, can be detected during winter months from 2009 to 2020. These anomalies are slightly higher than model simulations from CarbonTracker-CO2. In addition, we compared the variations in regional XCO2 anomalies and NO2 columns during the lockdown of the COVID-19 pandemic from January to March 2020. Interestingly, the results demonstrate that the variations of XCO2 anomalies have a positive correlation with the decline of NO2 columns during this period. These correlations, moreover, are associated with the features of emitting sources. These results suggest that we can use simultaneously observed NO2, because of its high detectivity and co-emission with CO2, to assist the analysis and verification of CO2 emissions in future studies. |
|||||
BibTeX:
@article{sheng21a,
author = {Sheng, Mengya and Lei, Liping and Zeng, Zhao-Cheng and Rao, Weiqiang and Zhang, Shaoqing},
title = {Detecting the Responses of CO2 Column Abundances to Anthropogenic Emissions from Satellite Observations of GOSAT and OCO-2},
journal = {REMOTE SENSING},
year = {2021},
volume = {13},
number = {17},
doi = {https://doi.org/10.3390/rs13173524}
}
|
|||||
| Sheng, M., Lei, L., Zeng, Z.-C., Rao, W., Song, H. and Wu, C. | Global land 1 degrees mapping dataset of XCO2 from satellite observations of GOSAT and OCO-2 from 2009 to 2020 | BIG EARTH DATA | article | DOI | |
| Abstract: A global mapping data of atmospheric carbon dioxide (CO2) concentrations can help us to better understand the spatiotemporal variations of CO2 and the driving factors of the variations to support the actions for emissions reduction and control. Greenhouse gases satellites that measure atmospheric CO2, such as the Greenhouse Gases Observing Satellite (GOSAT) and Orbiting Carbon Observatory (OCO-2), have been providing global observations of the column averaged dry-air mole fractions of CO2 (XCO2) since 2009. However, these XCO2 retrievals are irregular in space and time with many gaps. In this paper, we mapped a global spatiotemporally continuous XCO2 dataset (Mapping-XCO2) using the XCO2 retrievals from GOSAT and OCO-2 during the period from April 2009 to December 2020 based on a geostatistical approach that fills those data gaps. The dataset covers a geographic range from 56 degrees S to 65 degrees N and 169 degrees W to 180 degrees E for a 1 degrees grid interval in space and 3-day time interval. The uncertainties of the mapped XCO2 values are generally less than 1.5 parts per million (ppm). The spatiotemporal characteristics of global XCO2 that are revealed by the Mapping-XCO2 are similar to the model data obtained from CarbonTracker. Compared to the ground observations, the overall standard bias is 1.13 ppm. The results indicate that this long-term Mapping-XCO2 dataset can be used to investigate the spatiotemporal variations of global atmospheric XCO2 and can support studies related to the carbon cycle and anthropogenic CO2 emissions. |
|||||
BibTeX:
@article{sheng21b,
author = {Sheng, Mengya and Lei, Liping and Zeng, Zhao-Cheng and Rao, Weiqiang and Song, Hao and Wu, Changjiang},
title = {Global land 1 degrees mapping dataset of XCO2 from satellite observations of GOSAT and OCO-2 from 2009 to 2020},
journal = {BIG EARTH DATA},
doi = {https://doi.org/10.1080/20964471.2022.2033149}
}
|
|||||
| Shichao, W., Xianhua, W., Hanhan, Y., Chao, L., Yuan, A. and Xiaodi, W. | Atmospheric CO2 Cooperative Inversion Algorithm Applied to GF-5 Satellite | 2021 | ACTA OPTICA SINICA Vol. 41(15) |
article | DOI |
| Abstract: This paper carried out CO2 inversion experiments based on the remote sensing data from the greenhouse gases monitoring instrument (GMI) on the GF-5 satellite in China, calculated the CO2 profile samples according to the differences in China's regional characteristics, and constructed the representative sample set suitable for China's regional characteristics. Then, it substituted the CO2 profile obtained by statistical inversion as the initial value into the physical inversion method to form a new algorithm for synergistic statistics and physical methods. By analyzing the inversion results of the new algorithm, we conclude that the collaborative inversion algorithm improves the accuracy by 47.7% on the basis of using the physical inversion algorithm alone, and the correlation between the inversion results of the new algorithm and the observation results provided by the international satellite of the same type, OCO-2, reaches 88.5%. |
|||||
BibTeX:
@article{shichao21a,
author = {Wu Shichao and Wang Xianhua and Ye Hanhan and Li Chao and An Yuan and Wang Xiaodi},
title = {Atmospheric CO2 Cooperative Inversion Algorithm Applied to GF-5 Satellite},
journal = {ACTA OPTICA SINICA},
year = {2021},
volume = {41},
number = {15},
doi = {https://doi.org/10.3788/AOS202141.1501002}
}
|
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| Shields-Menard, S.A., Amirsadeghi, M., French, W.T. and Boopathy, R. | A review on microbial lipids as a potential biofuel | {2018} | BIORESOURCE TECHNOLOGY Vol. {259}, pp. {451-460} |
article | DOI |
| Abstract: Energy security, environmental concerns, and unstable oil prices have been the driving trifecta of demand for alternative fuels in the United States. The United States' dependence on energy resources, often from unstable oil-producing countries has created political insecurities and concerns. As we try to gain energy security, unconventional oil becomes more common, flooding the market, and causing the major downshift of the usual unstable oil prices. Meanwhile, consumption of fossil fuels and the consequent CO2 emissions have driven disruptions in the Earth's atmosphere and are recognized to be responsible for global climate change. While the significance of each of these three factors may fluctuate with global politics or new technologies, transportation energy will remain the prominent focus of multi-disciplined research. Bioenergy future depends on the price of oil. Current energy policy of the United States heavily favors petroleum industry. In this review, the current trend in microbial lipids as a potential biofuel is discussed. |
|||||
BibTeX:
@article{shields-menard18a,
author = {Shields-Menard, Sara A. and Amirsadeghi, Marta and French, W. Todd and Boopathy, Raj},
title = {A review on microbial lipids as a potential biofuel},
journal = {BIORESOURCE TECHNOLOGY},
year = {2018},
volume = {259},
pages = {451-460},
doi = {https://doi.org/10.1016/j.biortech.2018.03.080}
}
|
|||||
| SHIGA, Y.P. | Characterizing Natural and Anthropogenic Carbon Flux Spatiotemporal Variability at Regional Scales Using a Dense Network of Atmospheric CO2 Observations over North America | 2018 | School: STANFORD UNIVERSITY | phdthesis | URL |
| Abstract: The anthropogenic and the natural biosphere components of the carbon cycle play critically important roles in determining the future status of earth's climate. While our knowledge of CO2 fluxes, at large (global) and small ( 1 km2) scales are fairly well known, much … | |||||
BibTeX:
@phdthesis{shiga18a,
author = {YOICHI PAOLO SHIGA},
title = {Characterizing Natural and Anthropogenic Carbon Flux Spatiotemporal Variability at Regional Scales Using a Dense Network of Atmospheric CO2 Observations over North America},
school = {STANFORD UNIVERSITY},
year = {2018},
url = {https://search.proquest.com/openview/9e50305cf61e1b775b06c4ef7b2d31cd/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
|||||
| Shin, D. | Lightweight Crowdsourcing: Monitoring Urban Travel Behavior Using Mobile-Based Sensing [BibTeX] |
2015 | School: Eidgenössische Technische Hochschule Zürich | phdthesis | URL |
BibTeX:
@phdthesis{shin15a,
author = {Shin, D.},
title = {Lightweight Crowdsourcing: Monitoring Urban Travel Behavior Using Mobile-Based Sensing},
school = {Eidgenössische Technische Hochschule Zürich},
year = {2015},
url = {https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/110726/2/eth-48181-01.pdf}
}
|
|||||
| Shirai, T., Ishizawa, M., Zhuravlev, R., Ganshin, A., Belikov, D., Saito, M., Oda, T., Valsala, V., Gomez-Pelaez, A.J., Langenfelds, R. and Maksyutov, S. | A decadal inversion of CO2 using the Global Eulerian-Lagrangian Coupled Atmospheric model (GELCA): sensitivity to the ground-based observation network | {2017} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {69} |
article | DOI |
| Abstract: We present an assimilation system for atmospheric carbon dioxide (CO2) using a Global Eulerian-Lagrangian Coupled Atmospheric model (GELCA), and demonstrate its capability to capture the observed atmospheric CO2 mixing ratios and to estimate CO2 fluxes. With the efficient data handling scheme in GELCA, our system assimilates non-smoothed CO2 data from observational data products such as the Observation Package (ObsPack) data products as constraints on surface fluxes. We conducted sensitivity tests to examine the impact of the site selections and the prior uncertainty settings of observation on the inversion results. For these sensitivity tests, we made five different site/data selections from the ObsPack product. In all cases, the time series of the global net CO2 flux to the atmosphere stayed close to values calculated from the growth rate of the observed global mean atmospheric CO2 mixing ratio. At regional scales, estimated seasonal CO2 fluxes were altered, depending on the CO2 data selected for assimilation. Uncertainty reductions were determined at the regional scale and compared among cases. As measures of the modeldata mismatch, we used the model-data bias, root-mean-square error, and the linear correlation. For most observation sites, the model-data mismatch was reasonably small. Regarding regional flux estimates, tropical Asia was one of the regions that showed a significant impact from the observation network settings. We found that the surface fluxes in tropical Asia were the most sensitive to the use of aircraft measurements over the Pacific, and the seasonal cycle agreed better with the results of bottom-up studies when the aircraft measurements were assimilated. These results confirm the importance of these aircraft observations, especially for constraining surface fluxes in the tropics. |
|||||
BibTeX:
@article{shirai17a,
author = {Shirai, T. and Ishizawa, M. and Zhuravlev, R. and Ganshin, A. and Belikov, D. and Saito, M. and Oda, T. and Valsala, V. and Gomez-Pelaez, A. J. and Langenfelds, R. and Maksyutov, S.},
title = {A decadal inversion of CO2 using the Global Eulerian-Lagrangian Coupled Atmospheric model (GELCA): sensitivity to the ground-based observation network},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2017},
volume = {69},
doi = {https://doi.org/10.1080/16000889.2017.1291158}
}
|
|||||
| Shusterman, A. | Urban greenhouse gas emissions as observed using a high-density sensor network [BibTeX] |
2018 | School: UC Berkeley | phdthesis | URL |
BibTeX:
@phdthesis{shusterman18a,
author = {A Shusterman},
title = {Urban greenhouse gas emissions as observed using a high-density sensor network},
school = {UC Berkeley},
year = {2018},
url = {https://escholarship.org/uc/item/2h57q4d1}
}
|
|||||
| Simmons, A. | Home Bulletin From Observations to Service Delivery: Challenges and Opportunities | 2011 | webpage | URL | |
| Abstract: How observations are processed is vital to the provision of monitoring and forecasting services for weather, air quality and climate. Assimilation of observational data into comprehensive forecast models is the established way of exploiting observations for … | |||||
BibTeX:
@webpage{simmons11o,
author = {Adrian Simmons},
title = {Home Bulletin From Observations to Service Delivery: Challenges and Opportunities},
year = {2011},
url = {https://public.wmo.int/en/bulletin/observations-service-delivery-challenges-and-opportunities}
}
|
|||||
| Simmons, A., Fellous, J.-L., Ramaswamy, V., Trenberth, K. and Res, S.T.C.S. | Observation and integrated Earth-system science: A roadmap for 2016-2025 | {2016} | ADVANCES IN SPACE RESEARCH Vol. {57}({10}), pp. 2037-2103 |
article | DOI |
| Abstract: This report is the response to a request by the Committee on Space Research of the International Council for Science to prepare a roadmap on observation and integrated Earth-system science for the coming ten years. Its focus is on the combined use of observations and modelling to address the functioning, predictability and projected evolution of interacting components of the Earth system on time scales out to a century or so. It discusses how observations support integrated Earth-system science and its applications, and identifies planned enhancements to the contributing observing systems and other requirements for observations and their processing. All types of observation are considered, but emphasis is placed on those made from space. The origins and development of the integrated view of the Earth system are outlined, noting the interactions between the main components that lead to requirements for integrated science and modelling, and for the observations that guide and support them. What constitutes an Earth-system model is discussed. Summaries are given of key cycles within the Earth system. The nature of Earth observation and the arrangements for international coordination essential for effective operation of global observing systems are introduced. Instances are given of present types of observation, what is already on the roadmap for 2016-2025 and some of the issues to be faced. Observations that are organised on a systematic basis and observations that are made for process understanding and model development, or other research or demonstration purposes, are covered. Specific accounts are given for many of the variables of the Earth system. The current status and prospects for Earth-system modelling are summarized. The evolution towards applying Earth-system models for environmental monitoring and prediction as well as for climate simulation and projection is outlined. General aspects of the improvement of models, whether through refining the representations of processes that are already incorporated or through adding new processes or components, are discussed. Some important elements of Earth-system models are considered more fully. Data assimilation is discussed not only because it uses observations and models to generate datasets for monitoring the Earth system and for initiating and evaluating predictions, in particular through reanalysis, but also because of the feedback it provides on the quality of both the observations and the models employed. Inverse methods for surface-flux or model-parameter estimation are also covered. Reviews are given of the way observations and the processed datasets based on them are used for evaluating models, and of the combined use of observations and models for monitoring and interpreting the behaviour of the Earth system and for predicting and projecting its future. A set of concluding discussions covers general developmental needs, requirements for continuity of space-based observing systems, further long-term requirements for observations and other data, technological advances and data challenges, and the importance of enhanced international co-operation. (C) 2016 COSPAR. Published by Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{simmons16a,
author = {Simmons, Adrian and Fellous, Jean-Louis and Ramaswamy, Venkatachalam and Trenberth, Kevin and Study Team Comm Space Res},
title = {Observation and integrated Earth-system science: A roadmap for 2016-2025},
journal = {ADVANCES IN SPACE RESEARCH},
year = {2016},
volume = {57},
number = {10},
pages = {2037--2103},
doi = {https://doi.org/10.1016/j.asr.2016.03.008}
}
|
|||||
| Smale, D., Sherlock, V., Griffith, D.T., Moss, R., Brailsford, G., Nichol, S. and Kotkamp, M. | A decade of CH4, CO and N2O in situ measurements at Lauder, New Zealand: assessing the long-term performance of a Fourier transform infrared trace gas and isotope analyser | {2019} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {12}({1}), pp. {637-673} |
article | DOI URL |
| Abstract: We present a 10-year (January 2007-December 2016) time series of continuous in situ measurements of methane (CH4), carbon monoxide (CO) and nitrous oxide (N2O) made by an in situ Fourier transform infrared trace gas and isotope analyser (FTIR) operated at Lauder, New Zealand (45.04 S, 169.68 E, 370ma. m.s.l.). Being the longest continuous deployed operational FTIR system of this type, we are in an ideal position to perform a practical evaluation of the multi-year performance of the analyser. The operational methodology, measurement precision, reproducibility, accuracy and instrument reliability are reported. We find the FTIR has a measurement repeatability of the order of 0.37 ppb (1 sigma standard deviation) for CH4, 0.31 ppb for CO and 0.12 ppb for N2O. Regular target cylinder measurements provide a reproducibility estimate of 1.19 ppb for CH4, 0.74 ppb for CO and 0.27 ppb for N2O. FTIR measurements are compared to co-located ambient air flask samples acquired at Lauder since May 2009, which allows a long-term assessment of the FTIR data set across annual and seasonal composition changes. Comparing FTIR and co-located flask measurements show that the bias (FTIR minus flask) for CH4 of -1.02 +/- 2.61 ppb and CO of -0.43 +/- 1.60 ppb are within the Global Atmospheric Watch (GAW)-recommended compatibility goals of 2 ppb. The N2O FTIR flask bias of -0.01 +/- 0.77 ppb is within the GAW-recommended compatibility goals of 0.1 ppb and should be viewed as a serendipitous result due to the large standard deviation along with known systematic differences in the measurement sets. Uncertainty budgets for each gas are also constructed based on instrument precision, reproducibility and accuracy. In the case of CH4, systematic uncertainty dominates, whilst for CO and N2O it is comparable to the random uncertainty component. The long-term instrument stability, precision estimates and flask comparison results indicate the FTIR CH4 and CO time series meet the GAW compatibility recommendations across multiple years of operation (and instrument changes) and are sufficient to capture annual trends and seasonal cycles observed at Lauder. The differences between FTIR and flask N2O measurements need to be reconciled. Trend analysis of the 10-year time series captures seasonal cycles and the secular upward trend of CH4 and N2O. The CH4 and CO time series have the required precision and accuracy at a high enough temporal resolution to be used in inversion models in a data-sparse region of the world. | |||||
BibTeX:
@article{smale19a,
author = {Smale, Dan and Sherlock, Vanessa and Griffith, DavidW. T. and Moss, Rowena and Brailsford, Gordon and Nichol, Sylvia and Kotkamp, Michael},
title = {A decade of CH4, CO and N2O in situ measurements at Lauder, New Zealand: assessing the long-term performance of a Fourier transform infrared trace gas and isotope analyser},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {12},
number = {1},
pages = {637--673},
note = {Query date: 2021-04-02 15:20:04},
url = {https://amt.copernicus.org/articles/12/637/2019/},
doi = {https://doi.org/10.5194/amt-12-637-2019}
}
|
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| Smallman, T.L., Williams, M. and Moncrieff, J.B. | Can seasonal and interannual variation in landscape CO2 fluxes be detected by atmospheric observations of CO2 concentrations made at a tall tower? | {2014} | BIOGEOSCIENCES Vol. {11}({3}), pp. 735-747 |
article | DOI |
| Abstract: The coupled numerical weather model WRF-SPA (Weather Research and Forecasting model and Soil-Plant-Atmosphere model) has been used to investigate a 3 yr time series of observed atmospheric CO2 concentrations from a tall tower in Scotland, UK. Ecosystem-specific tracers of net CO2 uptake and net CO2 release were used to investigate the contributions to the tower signal of key land covers within its footprint, and how contributions varied at seasonal and interannual timescales. In addition, WRF-SPA simulated atmospheric CO2 concentrations were compared with two coarse global inversion models, CarbonTrackerEurope and the National Oceanic and Atmospheric Administration's CarbonTracker (CTE-CT). WRF-SPA realistically modelled both seasonal (except post harvest) and daily cycles seen in observed atmospheric CO2 at the tall tower (R-2 = 0.67, rmse= 3.5 ppm, bias= 0.58 ppm). Atmospheric CO2 concentrations from the tall tower were well simulated by CTECT, but the inverse model showed a poorer representation of diurnal variation and simulated a larger bias from observations (up to 1.9 ppm) at seasonal timescales, compared to the forward modelling of WRF-SPA. However, we have highlighted a consistent post-harvest increase in the seasonal bias between WRF-SPA and observations. Ecosystem-specific tracers of CO2 exchange indicate that the increased bias is potentially due to the representation of agricultural processes within SPA and/or biases in land cover maps. The ecosystem-specific tracers also indicate that the majority of seasonal variation in CO2 uptake for Scotland's dominant ecosystems (forests, cropland and managed grassland) is detectable in observations within the footprint of the tall tower; however, the amount of variation explained varies between years. The between years variation in detectability of Scotland's ecosystems is potentially due to seasonal and interannual variation in the simulated prevailing wind direction. This result highlights the importance of accurately representing atmospheric transport used within atmospheric inversion models used to estimate terrestrial source/sink distribution and magnitude. |
|||||
BibTeX:
@article{smallman14a,
author = {Smallman, T. L. and Williams, M. and Moncrieff, J. B.},
title = {Can seasonal and interannual variation in landscape CO2 fluxes be detected by atmospheric observations of CO2 concentrations made at a tall tower?},
journal = {BIOGEOSCIENCES},
year = {2014},
volume = {11},
number = {3},
pages = {735--747},
doi = {https://doi.org/10.5194/bg-11-735-2014}
}
|
|||||
| So, S., Sani, A.A., Zhong, L., Tittel, F. and Wysocki, G. | Laser spectroscopic trace-gas sensor networks for atmospheric monitoring applications [BibTeX] |
2009 | ESSA Workshop | article | |
BibTeX:
@article{so09a,
author = {So, Stephen and Sani, Ardalan Amiri and Zhong, Lin and Tittel, Frank and Wysocki, Gerard},
title = {Laser spectroscopic trace-gas sensor networks for atmospheric monitoring applications},
journal = {ESSA Workshop},
year = {2009}
}
|
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| So, S., Jeng, E., Smith, C., Krueger, D. and Wysocki, G. | Next generation infrared sensor instrumentation: remote sensing and sensor networks using the openPHOTONS repository | 2010 | Infrared Remote Sensing and Instrumentation | article | URL |
| Abstract: We describe our novel instrumentation architectures for infrared laser spectrometers. Compact, power efficient, low noise modules allow for optimized implementation of cell phone sized sensors using VCSELs, diode, and quantum cascade laser sources. These … | |||||
BibTeX:
@article{so10a,
author = {Stephen So, Evan Jeng, Clinton Smith, David Krueger, Gerard Wysocki},
title = {Next generation infrared sensor instrumentation: remote sensing and sensor networks using the openPHOTONS repository},
journal = {Infrared Remote Sensing and Instrumentation},
year = {2010},
url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/7808/780818/Next-generation-infrared-sensor-instrumentation--remote-sensing-and-sensor/10.1117/12.861505.short}
}
|
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| Sofi, J.A., Lone, A.H., Ganie, M.A., Dar, N.A., Bhat, S.A., Mukhtar, M., Dar, M.A. and Ramzan, S. | Soil Microbiological Activity and Carbon Dynamics in the Current Climate Change Scenarios: A Review | {2016} | PEDOSPHERE Vol. {26}({5}), pp. 577-591 |
article | DOI |
| Abstract: Microbial activities are affected by a myriad of factors with end points involved in nutrient cycling and carbon sequestration issues. Because of their prominent role in the global carbon balance and their possible role in carbon sequestration, soil microbes are very important organisms in relation to global climate changes. This review focuses mainly on the responses of soil microbes to climate changes and subsequent effects on soil carbon dynamics. An overview table regarding extracellular enzyme activities (EAA) with all relevant literature data summarizes the effects of different ecosystems under various experimental treatments on EAA. Increasing temperature, altered soil moisture regimes, and elevated carbon dioxide significantly affect directly or indirectly soil microbial activities. High temperature regimes can increase the microbial activities which can provide positive feedback to climate change, whereas lower moisture condition in pedosystem can negate the increase, although the interactive effects still remain unanswered. Shifts in soil microbial community in response to climate change have been determined by gene probing, phospholipid fatty acid analysis (PLFA), terminal restriction length polymorphism (TRFLP), and denaturing gradient gel electrophoresis (DGGE), but in a recent investigations, omic technological interventions have enabled determination of the shift in soil microbe community at a taxa level, which can provide very important inputs for modeling C sequestration process. The intricacy and diversity of the soil microbial population and how it responds to climate change are big challenges, but new molecular and stable isotope probing tools are being developed for linking fluctuations in microbial diversity to ecosystem function. |
|||||
BibTeX:
@article{sofi16a,
author = {Sofi, Javid A. and Lone, Aabid H. and Ganie, Mumtaz A. and Dar, Naseer A. and Bhat, Sajad A. and Mukhtar, Malik and Dar, Mohd Ashraf and Ramzan, Shazia},
title = {Soil Microbiological Activity and Carbon Dynamics in the Current Climate Change Scenarios: A Review},
journal = {PEDOSPHERE},
year = {2016},
volume = {26},
number = {5},
pages = {577--591},
doi = {https://doi.org/10.1016/S1002-0160(15)60068-6}
}
|
|||||
| Steinkamp, K. | Inverse modeling of the sources and sinks of atmospheric CO₂ [BibTeX] |
2011 | School: ETH ZURICH | phdthesis | |
BibTeX:
@phdthesis{steinkamp11a,
author = {K Steinkamp},
title = {Inverse modeling of the sources and sinks of atmospheric CO₂},
school = {ETH ZURICH},
year = {2011}
}
|
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| Steinkamp, K. and Gruber, N. | A joint atmosphere-ocean inversion for the estimation of seasonal carbon sources and sinks | {2013} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {27}({3}), pp. 732-745 |
article | DOI |
| Abstract: We have estimated global surface fluxes of carbon dioxide for the period 1992-1996 using an inverse approach that sequentially considers four constraints: (1) atmospheric CO2, (2) ocean interior DIC (dissolved inorganic carbon) interpreted through an ocean interior inversion and surface ocean pCO(2) (partial pressure of CO2), (3) annual prior fluxes for selected land regions, and (4) atmospheric model selection based on vertical transport skill. Estimated fluxes are monthly resolved for each of the 22 Transcom regions over land and ocean. The ocean constraint is particularly valuable, as it does not only add prior information about air-sea fluxes to the inversion problem but also preserves the regional variance-covariance structure from the underlying ocean interior inversion. It allows to constrain annual oceanic uptake of 1.8 PgCyr(-1) to within 0.2 PgCyr(-1), which implies a net annual land uptake of 1.3 (0.3) PgCyr(-1). Furthermore, it leads to a pronounced asymmetry in the seasonal pattern of global land uptake, which was not seen in previous atmosphere-only inversions. Tropical land is consistently estimated to be a source of carbon, though the source magnitude is reduced as more constraints are applied. With all four constraints, the inversion suggests a net tropical source of 1.1 (0.9) PgCyr(-1), which is comparable to global estimates of deforestation rates in tropical forests and therefore implies an annually balanced tropical land biosphere flux. This balance is not found, however, at the regional level: For the Amazonian region and after accounting for deforestation, we find a biospheric source of 0.6 (0.5) PgCyr(-1). This is at the upper range of estimates from bottom-up methods, which tend to identify the region as a sink. |
|||||
BibTeX:
@article{steinkamp13a,
author = {Steinkamp, K. and Gruber, N.},
title = {A joint atmosphere-ocean inversion for the estimation of seasonal carbon sources and sinks},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2013},
volume = {27},
number = {3},
pages = {732--745},
doi = {https://doi.org/10.1002/gbc.20064}
}
|
|||||
| Steinkamp, K. and Gruber, N. | Decadal trends of ocean and land carbon fluxes from a regional joint ocean-atmosphere inversion | {2015} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {29}({12}), pp. 2108-2126 |
article | DOI |
| Abstract: From 1980 until 2010, the combined CO2 sink strengths of ocean and land increased by nearly 50% (-0.55 Pg C yr(-1) decade(-1)), but the spatial distribution of this trend is not well known. We address this by performing a joint cyclostationary ocean-atmosphere inversion for the three decades 1980-1989, 1990-1999, and 2000-2008, using only carbon data from the ocean and atmosphere as constraints, i.e., without applying any prior information about the land fluxes. We find that in the inversion, most of the 30 year sink trend stems from the ocean (-0.44 Pg C yr(-1) decade(-1)). The contribution of the terrestrial biosphere is commensurably smaller but has more decadal variability. First, the land sink strength intensified in the 1990s by 0.4 (+/- 0.3) Pg C yr(-1) compared to the 1980s but then weakened slightly by 0.2 (+/- 0.4) Pg C yr(-1) in the 2000s. The different land regions contributed very variedly to these global trends. While the northern extratropical land acted as an increasing carbon sink throughout the examined period primarily driven by boreal regions, the tropical land is estimated to have acted as an increasing source of CO2, with source magnitude and trend dominated by enhanced release in tropical America during the Amazon mean wet season. This pattern is largely unchanged if the oceanic inversion constraint, which is based on a stationary ocean circulation, is replaced by an estimate based on simulation results from an ocean biogeochemical general circulation model that includes year-to-year variability in the air-sea CO2 fluxes and also has a trend (-0.07 Pg C yr(-1) decade(-1)) that is at the very low end of current estimates. However, the land/ocean partitioning of the trend contribution is adjusted accordingly. Oceanic carbon data has a major impact on carbon exchange for all tropical regions and southern Africa but also for observationally better constrained regions in North America and temperate Asia. The European trend exhibits a strong sensitivity to the choice of the atmospheric CO2 network. |
|||||
BibTeX:
@article{steinkamp15a,
author = {Steinkamp, K. and Gruber, N.},
title = {Decadal trends of ocean and land carbon fluxes from a regional joint ocean-atmosphere inversion},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2015},
volume = {29},
number = {12},
pages = {2108--2126},
doi = {https://doi.org/10.1002/2014GB004907}
}
|
|||||
| Stephens, B.B., Miles, N.L., Richardson, S.J., Watt, A.S. and Davis, K.J. | Atmospheric CO2 monitoring with single-cell NDIR-based analyzers | {2011} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {4}({12}), pp. 2737-2748 |
article | DOI |
| Abstract: We describe CO2 concentration measurement systems based on relatively inexpensive single-cell non-dispersive infrared CO2 sensors. The systems utilize signal averaging to obtain precision (1-sigma in 100 s) of 0.1 parts per million dry air mole fraction (ppm), frequent calibrations and sample drying in order to achieve state-of-the-art compatibility, and can run autonomously for months at a time. Laboratory tests indicate compatibility among four to six systems to be +/- 0.1 ppm (1-sigma), and field measurements of known reference-gases yield median errors of 0.01 to 0.17 ppm with 1-sigma variance of +/- 0.1 to 0.2 ppm. From May to August 2007, a system co-located with a NOAA-ESRL dual-cell NDIR system at the WLEF tall tower in Wisconsin measured daytime-only daily averages of CO2 that differ by 0.26 +/- 0.15 ppm (median +/- 1 sigma), and from August 2005 to April 2011 a system co-located with weekly NOAA-ESRL network flask collection at Niwot Ridge, Colorado measured coincident CO2 concentrations that differed by -0.06 +/- 0.30 ppm (n = 585). Data from these systems are now supporting a wide range of analyses and this approach may be applicable in future studies where accuracy and initial cost of the sensors are priorities. |
|||||
BibTeX:
@article{stephens11a,
author = {Stephens, B. B. and Miles, N. L. and Richardson, S. J. and Watt, A. S. and Davis, K. J.},
title = {Atmospheric CO2 monitoring with single-cell NDIR-based analyzers},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2011},
volume = {4},
number = {12},
pages = {2737--2748},
doi = {https://doi.org/10.5194/amt-4-2737-2011}
}
|
|||||
| Stephens, B.B., Brailsford, G.W., Gomez, A.J., Riedel, K., Fletcher, S.E.M., Nichol, S. and Manning, M. | Analysis of a 39-year continuous atmospheric CO2 record from Baring Head, New Zealand | {2013} | BIOGEOSCIENCES Vol. {10}({4}), pp. 2683-2697 |
article | DOI |
| Abstract: We present an analysis of a 39-year record of continuous atmospheric CO2 observations made at Baring Head, New Zealand, filtered for steady background CO2 mole fractions during southerly wind conditions. We discuss relationships between variability in the filtered CO2 time series and regional to global carbon cycling. Baring Head is well situated to sample air that has been isolated from terrestrial influences over the Southern Ocean, and experiences extended episodes of strong southerly winds with low CO2 variability. The filtered Baring Head CO2 record reveals an average seasonal cycle with amplitude of 0.95 ppm that is 13% smaller and 3 weeks earlier in phase than that at the South Pole. Seasonal variations in a given year are sensitive to the timing and magnitude of the combined influences of Southern Ocean CO2 fluxes and terrestrial fluxes from both hemispheres. The amplitude of the seasonal cycle varies throughout the record, but we find no significant long-term seasonal changes with respect to the South Pole. Interannual variations in CO2 growth rate in the Baring Head record closely match the El Nino-Southern Oscillation, reflecting the global reach of CO2 mole fraction anomalies associated with this cycle. We use atmospheric transport model results to investigate contributions to seasonal and annual-mean components of the observed CO2 record. Long-term trends in mean gradients between Baring Head and other stations are predominately due to increases in Northern Hemisphere fossil-fuel burning and Southern Ocean CO2 uptake, for which there remains a wide range of future estimates. We find that the postulated recent reduction in the efficiency of Southern Ocean anthropogenic CO2 uptake, as a result of increased zonal winds, is too small to be detectable as significant differences in atmospheric CO2 between mid to high latitude Southern Hemisphere observing stations. |
|||||
BibTeX:
@article{stephens13a,
author = {Stephens, B. B. and Brailsford, G. W. and Gomez, A. J. and Riedel, K. and Fletcher, S. E. Mikaloff and Nichol, S. and Manning, M.},
title = {Analysis of a 39-year continuous atmospheric CO2 record from Baring Head, New Zealand},
journal = {BIOGEOSCIENCES},
year = {2013},
volume = {10},
number = {4},
pages = {2683--2697},
doi = {https://doi.org/10.5194/bg-10-2683-2013}
}
|
|||||
| Stinson, G., Kurz, W.A., Smyth, C.E., Neilson, E.T., Dymond, C.C., Metsaranta, J.M., Boisvenue, C., Rampley, G.J., Li, Q., White, T.M. and Blain, D. | An inventory-based analysis of Canada's managed forest carbon dynamics, 1990 to 2008 | {2011} | GLOBAL CHANGE BIOLOGY Vol. {17}({6}), pp. 2227-2244 |
article | DOI |
| Abstract: Canada's forests play an important role in the global carbon (C) cycle because of their large and dynamic C stocks. Detailed monitoring of C exchange between forests and the atmosphere and improved understanding of the processes that affect the net ecosystem exchange of C are needed to improve our understanding of the terrestrial C budget. We estimated the C budget of Canada's 2.3 x 106 km2 managed forests from 1990 to 2008 using an empirical modelling approach driven by detailed forestry datasets. We estimated that average net primary production (NPP) during this period was 809 +/- 5 Tg C yr-1 (352 g C m-2 yr-1) and net ecosystem production (NEP) was 71 +/- 9 Tg C yr-1 (31 g C m-2 yr-1). Harvesting transferred 45 +/- 4 Tg C yr-1 out of the ecosystem and 45 +/- 4 Tg C yr-1 within the ecosystem (from living biomass to dead organic matter pools). Fires released 23 +/- 16 Tg C yr-1 directly to the atmosphere, and fires, insects and other natural disturbances transferred 52 +/- 41 Tg C yr-1 from biomass to dead organic matter pools, from where C will gradually be released through decomposition. Net biome production (NBP) was only 2 +/- 20 Tg C yr-1 (1 g C m-2 yr-1); the low C sequestration ratio (NBP/NPP=0.3%) is attributed to the high average age of Canada's managed forests and the impact of natural disturbances. Although net losses of ecosystem C occurred during several years due to large fires and widespread bark beetle outbreak, Canada's managed forests were a sink for atmospheric CO(2) in all years, with an uptake of 50 +/- 18 Tg C yr-1 [net ecosystem exchange (NEE) of CO(2)=-22 g C m-2 yr-1]. |
|||||
BibTeX:
@article{stinson11a,
author = {Stinson, G. and Kurz, W. A. and Smyth, C. E. and Neilson, E. T. and Dymond, C. C. and Metsaranta, J. M. and Boisvenue, C. and Rampley, G. J. and Li, Q. and White, T. M. and Blain, D.},
title = {An inventory-based analysis of Canada's managed forest carbon dynamics, 1990 to 2008},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2011},
volume = {17},
number = {6},
pages = {2227--2244},
doi = {https://doi.org/10.1111/j.1365-2486.2010.02369.x}
}
|
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| Strandgren, J., Krutz, D., Wilzewski, J., Paproth, C., Sebastian, I., Gurney, K.R., Liang, J., Roiger, A. and Butz, A. | Towards spaceborne monitoring of localized CO2 emissions: an instrument concept and first performance assessment | {2020} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {13}({6}), pp. {2887-2904} |
article | DOI URL |
| Abstract: The UNFCCC (United Nations Framework Convention on Climate Change) requires the nations of the world to report their carbon dioxide (CO2) emissions. The independent verification of these reported emissions is a cornerstone for advancing towards the emission accounting and reduction measures agreed upon in the Paris Agreement. In this paper, we present the concept and first performance assessment of a compact spaceborne imaging spectrometer with a spatial resolution of 50 x 50m(2) that could contribute to the ``monitoring, verification and reporting'' (MVR) of CO2 emissions worldwide. CO2 emissions from medium-sized power plants (1-10 MtCO(2) yr(-1)), currently not targeted by other spaceborne missions, represent a significant part of the global CO2 emission budget. In this paper we show that the proposed instrument concept is able to resolve emission plumes from such localized sources as a first step towards corresponding CO2 flux estimates. Through radiative transfer simulations, including a realistic instrument noise model and a global trial ensemble covering various geophysical scenarios, it is shown that an instrument noise error of 1.1 ppm (1 sigma) can be achieved for the retrieval of the column-averaged dry-air mole fraction of CO2 (XCO2). Despite a limited amount of information from a single spectral window and a relatively coarse spectral resolution, scattering by atmospheric aerosol and cirrus can be partly accounted for in the XCO2 retrieval, with deviations of at most 4.0 ppm from the true abundance for two-thirds of the scenes in the global trial ensemble. We further simulate the ability of the proposed instrument concept to observe CO2 plumes from single power plants in an urban area using high-resolution CO2 emission and surface albedo data for the city of Indianapolis. Given the preliminary instrument design and the corresponding instrument noise error, emission plumes from point sources with an emission rate down to the order of 0.3 MtCO(2) yr(-1) can be resolved, i.e., well below the target source strength of 1 MtCO(2) yr(-1). This leaves a significant margin for additional error sources, like scattering particles and complex meteorology, and shows the potential for subsequent CO2 flux estimates with the proposed instrument concept. | |||||
BibTeX:
@article{strandgren20a,
author = {Strandgren, Johan and Krutz, David and Wilzewski, Jonas and Paproth, Carsten and Sebastian, Ilse and Gurney, Kevin R. and Liang, Jianming and Roiger, Anke and Butz, Andre},
title = {Towards spaceborne monitoring of localized CO2 emissions: an instrument concept and first performance assessment},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {13},
number = {6},
pages = {2887--2904},
note = {Query date: 2021-04-02 15:20:04},
url = {https://amt.copernicus.org/articles/13/2887/2020/},
doi = {https://doi.org/10.5194/amt-13-2887-2020}
}
|
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| Strong, K., Simpson, W., Bognar, K. and ... | Trace Gases in the Arctic Atmosphere | 2020 | Physics and Chemistry … | article | URL |
| Abstract: The Arctic atmosphere is coupled to lower latitudes, both as a receptor for global pollution and as a driver for the global climate system. Arctic atmospheric composition is variable and changing, making measurements of trace gas concentrations essential for understanding … | |||||
BibTeX:
@article{strong20a,
author = {K Strong and WR Simpson and K Bognar and ...},
title = {Trace Gases in the Arctic Atmosphere},
journal = {Physics and Chemistry …},
publisher = {Springer},
year = {2020},
note = {Query date: 2021-04-02 15:20:04},
url = {https://link.springer.com/chapter/10.1007/978-3-030-33566-3_3}
}
|
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| Strow, L.L. and Hannon, S.E. | A 4-year zonal climatology of lower tropospheric CO2 derived from ocean-only Atmospheric Infrared Sounder observations | {2008} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {113}({D18}) |
article | DOI |
| Abstract: A 4-year zonally averaged climatology of atmospheric CO2, ocean only, between +/- 60 degrees latitude has been derived from the Atmospheric Infrared Sounder (AIRS) radiances. Using only very clear fields of view, the CO2 profile in the computed radiances is scaled until agreement is found with observations. ECMWF forecast and analysis fields are used for the temperature profile in the computed radiances. The AIRS channels used to derive CO2 amounts are nominally sensitive to CO2 variability in the similar to 300 - 800 mbar region (2 - 9 km), significantly lower in the atmosphere than that in previous studies using AIRS. Validation using aircraft measurements of CO2 at 650 mbar indicates that the AIRS CO2 results presented here are accurate to the 0.5 - 1.0 ppm level. The AIRS-derived climatology clearly exhibits the CO2 rectifier effect, with mean CO2 values several parts per million lower than in those in the boundary layer. The AIRS CO2 seasonal cycle has a relatively constant amplitude of similar to 3 ppm from +10 degrees to +60 degrees latitude, which matches the boundary layer seasonal cycle amplitude near +10 degrees latitude but is about three times smaller than that in the boundary layer amplitude at +60 degrees latitude. Phase comparisons between the AIRS and boundary layer CO2 seasonal cycles show the boundary layer phase leading AIRS in the Northern Hemisphere until similar to+10 degrees latitude, where the phases cross and the AIRS higher-altitude CO2 begins to lead the boundary layer phase down to similar to-10 degrees latitude. These results may offer new insight into CO2 interhemispherical transport. Growth rates derived from the AIRS CO2 climatology are 2.21 +/- 0.24 ppm/year, in good agreement with in situ measurements. |
|||||
BibTeX:
@article{strow08a,
author = {Strow, L. Larrabee and Hannon, Scott E.},
title = {A 4-year zonal climatology of lower tropospheric CO2 derived from ocean-only Atmospheric Infrared Sounder observations},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2008},
volume = {113},
number = {D18},
doi = {https://doi.org/10.1029/2007JD009713}
}
|
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| Sun, M., Cho, C.-H., Kim, Y., Lee, J., Boo, K.-O. and Byun, Y.-H. | Response of the Terrestrial Carbon Exchange to the Climate Variability [BibTeX] |
2017 | Atmosphere Vol. 27(2), pp. 163-175 |
article | |
BibTeX:
@article{sun17a,
author = {Minah Sun and Chun-Ho Cho and Youngmi Kim and Johan Lee and Kyoung-On Boo and and Young-Hwa Byun},
title = {Response of the Terrestrial Carbon Exchange to the Climate Variability},
journal = {Atmosphere},
year = {2017},
volume = {27},
number = {2},
pages = {163--175}
}
|
|||||
| Sun, Z., Wang, X., Yamamoto, H., Tani, H., Zhong, G., Yin, S. and Guo, E. | Spatial pattern of GPP variations in terrestrial ecosystems and its drivers: Climatic factors, CO2 concentration and land-cover change, 1982-2015 | {2018} | ECOLOGICAL INFORMATICS Vol. {46}, pp. {156-165} |
article | DOI |
| Abstract: Quantitative estimation of spatial pattern of gross primary production (GPP) trends and its drivers plays a crucial role in global change research. This study applied C-Fix model to estimate the net effect of each factor on GPP trends of 1982-2015, used an unsupervised classifier to group similar GPP trend behaviors, and analyzed the responses of GPP to changes in climatic, atmospheric and environmental drivers. According to the features of monthly GPP trends and the patterns of growing season, we presented nine categories as aids in interpreting large-scale behavior. Land-cover change (LCC), rising CO2, temperature and water conditions changes have the positive overall effect on GPP over the entire world, contrary to radiation change effects. The global average contributions of LCC, CO2, temperature, radiation and water on GPP trend are 4.57%, 65.73%, 13.07%, -7.24 and 11.74%, respectively. LCC and climatic factors changes have had a greater impact on GPP in terms of a specific location or regional rather than globally, and the interactions between factors are positive on GPP. The effects of climatic factors trends on GPP in different locations can be opposite, in general: regionally, GPP changes at middle and high latitudes are likely dominated by rises in radiation and temperature; at lower latitudes, GPP changes are likely to be driven by shifts in water conditions; at high altitudes, GPP changes are probably caused by changes in temperature and water conditions. These results will increase the understanding of the variations of carbon flux under future CO2, LCC and climate conditions. |
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BibTeX:
@article{sun18a,
author = {Sun, Zhongyi and Wang, Xiufeng and Yamamoto, Haruhiko and Tani, Hiroshi and Zhong, Guosheng and Yin, Shuai and Guo, Enliang},
title = {Spatial pattern of GPP variations in terrestrial ecosystems and its drivers: Climatic factors, CO2 concentration and land-cover change, 1982-2015},
journal = {ECOLOGICAL INFORMATICS},
year = {2018},
volume = {46},
pages = {156-165},
doi = {https://doi.org/10.1016/j.ecoinf.2018.06.006}
}
|
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| Sun, Z., Wang, X., Zhang, X., Tani, H., Guo, E., Yin, S. and Zhang, T. | Evaluating and comparing remote sensing terrestrial GPP models for their response to climate variability and CO2 trends | {2019} | SCIENCE OF THE TOTAL ENVIRONMENT Vol. {668}, pp. {696-713} |
article | DOI URL |
| Abstract: Remote sensing (RS)-based models play an important role in estimating and monitoring terrestrial ecosystem gross primary productivity (GPP). Several RS-based GPP models have been developed using different criteria, yet the sensitivities to environmental factors vary among models; thus, a comparison of model sensitivity is necessary for analyzing and interpreting results and for choosing suitable models. In this study, we globally evaluated and compared the sensitivities of 14 RS-based models (2 process-, 4 vegetation-index-, 5 light-use-efficiency, and 3 machine-learning-based models) and benchmarked them against GPP responses to climatic factors measured at flux sites and to elevated CO2 concentrations measured at free-air CO2 enrichment experiment sites. The results demonstrated that the models with relatively high sensitivity to increasing atmospheric CO2 concentrations showed a higher increasing GPP trend. The fundamental difference in the CO2 effect in the models' algorithm either considers the effect of CO2 through changes in greenness indices (nine models) or introduces the influences on photosynthesis (three models). The overall effects of temperature and radiation, in terms of both magnitude and sign, vary among the models, while the models respond relatively consistently to variations in precipitation. Spatially, larger differences among model sensitivity to climatic factors occur in the tropics; at high latitudes, models have a consistent and obvious positive response to variations in temperature and radiation, and precipitation significantly enhances the GPP in mid-latitudes. Compared with the results calculated by flux-site measurements, the model performance differed substantially among different sites. However, the sensitivities of most models are basically within the confidence interval of the flux-site results. In general, the comparison revealed that models differed substantially in the effect of environmental regulations, particularly CO2 fertilization and water stress, on GPP, and none of the models performed consistently better across the different ecosystems and under the various external conditions. (c) 2019 Elsevier B.V. All rights reserved. | |||||
BibTeX:
@article{sun19a,
author = {Sun, Zhongyi and Wang, Xiufeng and Zhang, Xirui and Tani, Hiroshi and Guo, Enliang and Yin, Shuai and Zhang, Tianyou},
title = {Evaluating and comparing remote sensing terrestrial GPP models for their response to climate variability and CO2 trends},
journal = {SCIENCE OF THE TOTAL ENVIRONMENT},
publisher = {ELSEVIER},
year = {2019},
volume = {668},
pages = {696--713},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S004896971931006X},
doi = {https://doi.org/10.1016/j.scitotenv.2019.03.025}
}
|
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| Sun, W., Fang, Y., Luo, X., Shiga, Y.P., Zhang, Y., Andrews, A.E., Thoning, K.W., Fisher, J.B., Keenan, T.F. and Michalak, A.M. | Midwest US Croplands Determine Model Divergence in North American Carbon Fluxes | 2021 | AGU ADVANCES Vol. 2(2) |
article | DOI |
| Abstract: Large uncertainties in North American terrestrial carbon fluxes hinder regional climate projections. Terrestrial biosphere models (TBMs), the essential tools for understanding continental-scale carbon cycle, diverge on whether temperate forests or croplands dominate carbon uptake in North America. Evidence from novel photosynthetic proxies, such as those based on chlorophyll fluorescence, has cast doubt on the ``weak cropland, strong forest'' carbon uptake patterns simulated by most TBMs. However, no systematic evaluation of TBMs has yet been attempted to pin down space-time patterns that are most consistent with regional CO2 observational constraints. Here, we leverage atmospheric CO2 observations and satellite-observed photosynthetic proxies to understand emergent space-time patterns in North American carbon fluxes from a large suite of TBMs and data-driven models. To do so, we evaluate how well the atmospheric signals resulting from carbon flux estimates reproduce the space-time variability in atmospheric CO2, as is observed by a network of continuous-monitoring towers over North America. Models with gross or net carbon fluxes that are consistent with the observed CO2 variability share a salient feature of growing-season carbon uptake in Midwest US croplands. Conversely, the remaining models place most growing-season uptake in boreal or temperate forests. Differences in model explanatory power depend mainly on the simulated annual cycles of cropland uptake-especially, the timing of peak uptake-rather than the distribution of annual mean fluxes across biomes. Our results suggest that improved model representation of cropland phenology is crucial to robust, policy-relevant estimation of North American carbon exchange. |
|||||
BibTeX:
@article{sun21a,
author = {Sun, Wu and Fang, Yuanyuan and Luo, Xiangzhong and Shiga, Yoichi P. and Zhang, Yao and Andrews, Arlyn E. and Thoning, Kirk W. and Fisher, Joshua B. and Keenan, Trevor F. and Michalak, Anna M.},
title = {Midwest US Croplands Determine Model Divergence in North American Carbon Fluxes},
journal = {AGU ADVANCES},
year = {2021},
volume = {2},
number = {2},
doi = {https://doi.org/10.1029/2020AV000310}
}
|
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| Super, I. | Quantification and attribution of urban fossil fuel emissions through atmospheric measurements [BibTeX] |
2018 | School: Wageningen University | phdthesis | URL |
BibTeX:
@phdthesis{super18a,
author = {Ingrid Super},
title = {Quantification and attribution of urban fossil fuel emissions through atmospheric measurements},
school = {Wageningen University},
year = {2018},
url = {https://library.wur.nl/WebQuery/wurpubs/fulltext/457839}
}
|
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| Sweeney, C., Karion, A., Wolter, S., Newberger, T., Guenther, D., Higgs, J.A., Andrews, A.E., Lang, P.M., Neff, D., Dlugokencky, E., Miller, J.B., Montzka, S.A., Miller, B.R., Masarie, K.A., Biraud, S.C., Novelli, P.C., Crotwell, M., Crotwell, A.M., Thoning, K. and Tans, P.P. | Seasonal climatology of CO2 across North America from aircraft measurements in the NOAA/ESRL Global Greenhouse Gas Reference Network [BibTeX] |
{2015} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {120}({10}), pp. 5155-5190 |
article | DOI |
BibTeX:
@article{sweeney15a,
author = {Sweeney, Colm and Karion, Anna and Wolter, Sonja and Newberger, Timothy and Guenther, Doug and Higgs, Jack A. and Andrews, Arlyn Elyzabeth and Lang, Patricia M. and Neff, Don and Dlugokencky, Edward and Miller, John B. and Montzka, Stephen A. and Miller, Ben R. and Masarie, Ken Alan and Biraud, Sebastien Christophe and Novelli, Paul C. and Crotwell, Molly and Crotwell, Andrew M. and Thoning, Kirk and Tans, Pieter P.},
title = {Seasonal climatology of CO2 across North America from aircraft measurements in the NOAA/ESRL Global Greenhouse Gas Reference Network},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2015},
volume = {120},
number = {10},
pages = {5155--5190},
doi = {https://doi.org/10.1002/2014JD022591}
}
|
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| Sweeney, C., Chatterjee, A., Wolter, S., McKain, K., Bogue, R., Conley, S., Newberger, T., Hu, L., Ott, L., Poulter, B., Schiferl, L., Weir, B., Zhang, Z. and Miller, C.E. | Using atmospheric trace gas vertical profiles to evaluate model fluxes: a case study of Arctic-CAP observations and GEOS simulations for the ABoVE domain | 2022 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 22(9), pp. 6347-6364 |
article | DOI |
| Abstract: Accurate estimates of carbon-climate feedbacks require an independent means for evaluating surface flux models at regional scales. The altitude-integrated enhancement (AIE) derived from the Arctic Carbon Atmospheric Profiles (Arctic-CAP) project demonstrates the utility of this bulk quantity for surface flux model evaluation. This bulk quantity leverages background mole fraction values from the middle free troposphere, is agnostic to uncertainties in boundary layer height, and can be derived from model estimates of mole fractions and vertical gradients. To demonstrate the utility of the bulk quantity, six airborne profiling surveys of atmospheric carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) throughout Alaska and northwestern Canada between April and November 2017 were completed as part of NASA's Arctic-Boreal Vulnerability Experiment (ABoVE). The Arctic-CAP sampling strategy involved acquiring vertical profiles of CO2, CH4, and CO from the surface to 5 km altitude at 25 sites around the ABoVE domain on a 4- to 6-week time interval. All ArcticCAP measurements were compared to a global simulation using the Goddard Earth Observing System (GEOS) modeling system. Comparisons of the AIE bulk quantity from aircraft observations and GEOS simulations of atmospheric CO2, CH4, and CO highlight the fidelity of the modeled surface fluxes. The model-data comparison over the ABoVE domain reveals that while current state-of-the-art models and flux estimates are able to capture broad-scale spatial and temporal patterns in near-surface CO2 and CH4 concentrations, more work is needed to resolve fine-scale flux features that are captured in CO observations. |
|||||
BibTeX:
@article{sweeney22a,
author = {Sweeney, Colm and Chatterjee, Abhishek and Wolter, Sonja and McKain, Kathryn and Bogue, Robert and Conley, Stephen and Newberger, Tim and Hu, Lei and Ott, Lesley and Poulter, Benjamin and Schiferl, Luke and Weir, Brad and Zhang, Zhen and Miller, Charles E.},
title = {Using atmospheric trace gas vertical profiles to evaluate model fluxes: a case study of Arctic-CAP observations and GEOS simulations for the ABoVE domain},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2022},
volume = {22},
number = {9},
pages = {6347-6364},
doi = {https://doi.org/10.5194/acp-22-6347-2022}
}
|
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| Tadic, J.M. and Biraud, S.C. | An Approach to Estimate Atmospheric Greenhouse Gas Total Columns Mole Fraction from Partial Column Sampling | {2018} | ATMOSPHERE Vol. {9}({7}) |
article | DOI |
| Abstract: This study presents a new conceptual approach to estimate total column mole fractions of CO2 and CH4 using partial column data. It provides a link between airborne in situ and remote sensing observations of greenhouse gases. The method relies on in situ observations, external ancillary sources of information (e.g., atmospheric transport models), and a regression kriging framework. We evaluate our new approach using National Oceanic and Atmospheric Administration's (NOAA's) AirCore program-in situ vertical profiles of CO2 and CH4 collected from weather balloons. Our paper shows that under the specific conditions of this study and assumption of unbiasedness, airborne observations up to 6500-9500 m altitude are required to achieve comparable total column CO2 mole fraction uncertainty as the Total Carbon Column Observing Network (TCCON) network provides, given as a precision of the ratio between observed and true total column-integrated mole fraction, assuming 400 ppm XCO2 (2 sigma, e.g., 0.8 ppm). If properly calibrated, our approach could be applied to vertical profiles of CO2 collected from aircraft using a few flask samples, while retaining similar uncertainty level. Our total column CH4 estimates, by contrast, are less accurate than TCCON's. Aircrafts are not as spatially constrained as TCCON ground stations, so our approach adds value to aircraft-based vertical profiles for evaluating remote sensing platforms. |
|||||
BibTeX:
@article{tadic18a,
author = {Tadic, Jovan M. and Biraud, Sebastien C.},
title = {An Approach to Estimate Atmospheric Greenhouse Gas Total Columns Mole Fraction from Partial Column Sampling},
journal = {ATMOSPHERE},
year = {2018},
volume = {9},
number = {7},
doi = {https://doi.org/10.3390/atmos9070247}
}
|
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| 眞木貴 | データ同化と大気輸送モデル [BibTeX] |
2014 | 天気 | article | URL |
BibTeX:
@article{takashi14a,
author = {眞木貴},
title = {データ同化と大気輸送モデル},
journal = {天気},
year = {2014},
url = {http://www.metsoc.jp/tenki/pdf/2014/2014_11_0020.pdf}
}
|
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| Tang, X., Wang, Z., Xie, J., Liu, D., Desai, A.R., Jia, M., Dong, Z., Liu, X. and Liu, B. | Monitoring the seasonal and interannual variation of the carbon sequestration in a temperate deciduous forest with MODIS time series data | {2013} | FOREST ECOLOGY AND MANAGEMENT Vol. {306}, pp. 150-160 |
article | DOI |
| Abstract: Understanding the seasonal and interannual variation of the ecosystem carbon balance and the mechanisms that control it is crucial for assessing the vulnerability of the terrestrial carbon pools under future changing climate conditions. Expanding on the previous work, an improved predictive model was developed to estimate the carbon sequestration of a temperate deciduous forest exclusively from remotely sensed time series data, including MODIS land surface temperature (LST), Terra nighttime LST', enhanced vegetation index (EVI), land surface water index (LWSI), the fraction of absorbed photosynthetically active radiation (FPAR) and leaf area index (LAI). The objectives of this study are to relate remotely sensed proxies of environmental drivers to both seasonal and interannual carbon sequestration observed from seven years' net ecosystem carbon exchange (NEE) data, and to extrapolate long-term trends in forest carbon balance. Our results suggest that the improved model provided good estimates of NEE and well reflected the seasonal dynamics of the temperate deciduous forest, though with limited skill during the spring and autumn transitions. Correlation analysis showed that these MODIS products have different relationships to NEE at 8-day and interannual time scales. The mature forest ecosystem acted as a strong carbon sink during the entire decade; however, a trend of decreasing carbon sequestration in the forest was observed as time goes on. (C) 2013 Elsevier B.V. All rights reserved. |
|||||
BibTeX:
@article{tang13a,
author = {Tang, Xuguang and Wang, Zongming and Xie, Jing and Liu, Dianwei and Desai, Ankur R. and Jia, Mingming and Dong, Zhangyu and Liu, Xiuping and Liu, Bo},
title = {Monitoring the seasonal and interannual variation of the carbon sequestration in a temperate deciduous forest with MODIS time series data},
journal = {FOREST ECOLOGY AND MANAGEMENT},
year = {2013},
volume = {306},
pages = {150--160},
doi = {https://doi.org/10.1016/j.foreco.2013.06.032}
}
|
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| Tans, P. | REMINISCING ON THE USE AND ABUSE OF C-14 AND C-13 IN ATMOSPHERIC CO2 | 2022 | RADIOCARBON Vol. 64(4, SI), pp. 747-760 |
article | DOI |
| Abstract: We are observing a dramatic increase of CO2 in the atmosphere, unprecedented in the last several million years. Carbon isotopic ratios have been very useful in helping to untangle the respective roles of anthropogenic emissions and sources/sinks of CO2 in the oceans or terrestrial biosphere. However, this untangling has not been as simple as was often hoped. The isotope ratio signatures produced by emissions and removals that are present in atmospheric CO2 are always vigorously being erased by isotopic exchange with the oceans and terrestrial ecosystems, without there necessarily being any effect on total CO2. Especially in the last decades this pure isotopic exchange effect has led to gross errors that have clouded the public debate on climate change, obscuring mankind's role. This paper traces my own struggle with the scientific and public sides of this issue, which I ran into from the start of my career in Groningen and throughout my years at NOAA. It is still relevant today. |
|||||
BibTeX:
@article{tans22a,
author = {Tans, Pieter},
title = {REMINISCING ON THE USE AND ABUSE OF C-14 AND C-13 IN ATMOSPHERIC CO2},
journal = {RADIOCARBON},
year = {2022},
volume = {64},
number = {4, SI},
pages = {747-760},
doi = {https://doi.org/10.1017/RDC.2022.7}
}
|
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| Tao, Z., Kawa, S.R., Jacob, J.P., Liu, D.Y., Collatz, G.J., Wang, J.S., Ott, L.E. and Chin, M. | Application of NASA-Unified WRF model to carbon dioxide simulation-model development and evaluation | {2020} | ENVIRONMENTAL MODELLING & SOFTWARE Vol. {132} |
article | DOI URL |
| Abstract: The NASA-Unified Weather Research and Forecasting model has been coupled with the Carnegie-Ames-Stanford Approach biogeochemical model/Global Fire Emissions Database and the Parameterized Chemistry Transport Model (NU-WRF-CASA) to simulate CO2 transport and variability at fine spatial resolutions, which is anticipated to assist in better understanding the mechanisms and processes controlling carbon sources/sinks and in reducing uncertainty in carbon-climate interactions. NU-WRF-CASA is designed to operate in an internally consistent manner in which NASA's Goddard Earth Observing System Model, version 5, can be applied to drive the entire coupled modeling system. A 3-year simulation was carried out for North America to evaluate NU-WRF-CASA's performance under various regions and environmental conditions. Observational CO2 data from tower, flask, aircraft, and satellite measurements were used for model evaluations. The results showed that NU-WRF-CASA correctly distributed CO2 fluxes and reproduced spatial-temporal CO2 transport and variability reasonably well with overall bias within 1 ppmv. | |||||
BibTeX:
@article{tao20a,
author = {Tao, Zhining and Kawa, Stephan R. and Jacob, Jossy P. and Liu, David Y. and Collatz, George J. and Wang, James S. and Ott, Lesley E. and Chin, Mian},
title = {Application of NASA-Unified WRF model to carbon dioxide simulation-model development and evaluation},
journal = {ENVIRONMENTAL MODELLING & SOFTWARE},
publisher = {ELSEVIER SCI LTD},
year = {2020},
volume = {132},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S1364815219312101},
doi = {https://doi.org/10.1016/j.envsoft.2020.104785}
}
|
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| Taylor, T.E., O'Dell, C.W., Crisp, D., Kuze, A., Lindqvist, H., Wennberg, P.O., Chatterjee, A., Gunson, M., Eldering, A., Fisher, B., Kiel, M., Nelson, R.R., Merrelli, A., Osterman, G., Chevallier, F., Palmer I, P., Feng, L., Deutscher, N.M., Dubey, M.K., Feist, D.G., Garcia, O.E., Griffith, D.W.T., Hase, F., Iraci, L.T., Kivi, R., Liu, C., De Maziere, M., Morino, I., Notholt, J., Oh, Y.-S., Ohyama, H., Pollard, D.F., Rettinger, M., Schneider, M., Roehl, C.M., Sha, M.K., Shiomi, K., Strong, K., Sussmann, R., Te, Y., Velazco, V.A., Vrekoussis, M., Warneke, T. and Wunch, D. | An 11-year record of XCO2 estimates derived from GOSAT measurements using the NASA ACOS version 9 retrieval algorithm | 2022 | EARTH SYSTEM SCIENCE DATA Vol. 14(1), pp. 325-360 |
article | DOI |
| Abstract: The Thermal And Near infrared Sensor for carbon Observation - Fourier Transform Spectrometer (TANSO-FTS) on the Japanese Greenhouse gases Observing SATellite (GOSAT) has been returning data since April 2009. The version 9 (v9) Atmospheric Carbon Observations from Space (ACOS) Level 2 Full Physics (L2FP) retrieval algorithm (Kid et al., 2019) was used to derive estimates of carbon dioxide (CO2) dry air mole fraction (XCO2) from the TANSO-FTS measurements collected over its first 11 years of operation. The bias correction and quality filtering of the L2FP XCO2 product were evaluated using estimates derived from the Total Carbon Column Observing Network (TCCON) as well as values simulated from a suite of global atmospheric inversion systems (models) which do not assimilate satellite-derived CO2. In addition, the v9 ACOS GOSAT XCO2 results were compared with collocated XCO2 estimates derived from NASA's Orbiting Carbon Observatory-2 (OCO-2), using the version 10 (v10) ACOS L2FP algorithm. These tests indicate that the v9 ACOS GOSAT XCO2 product has improved throughput, scatter, and bias, when compared to the earlier v7.3 ACOS GOSAT product, which extended through mid 2016. Of the 37 million soundings collected by GOSAT through June 2020, approximately 20 % were selected for processing by the v9 L2FP algorithm after screening for clouds and other artifacts. After post-processing, 5.4 % of the soundings (2 x 10(6) out of 37 x 10(6)) were assigned a ``good'' XCO2 quality flag, as compared to 3.9 % in v7.3 (< 1 x 10(6) out of 24 x 10(6)). After quality filtering and bias correction, the differences in XCO2 between ACOS GOSAT v9 and both TCCON and models have a scatter (1 sigma) of approximately 1 ppm for ocean-glint observations and 1 to 1.5 ppm for land observations. Global mean biases against TCCON and models are less than approximately 0.2 ppm. Seasonal mean biases relative to the v10 OCO-2 XCO2 product are of the order of 0.1 ppm for observations over land. However, for ocean-glint observations, seasonal mean biases relative to OCO-2 range from 0.2 to 0.6 ppm, with substantial variation in time and latitude. The ACOS GOSAT v9 XCO2 data are available on the NASA Goddard Earth Science Data and Information Services Center (GES-DISC) in both the per-orbit full format (https://doi.org/10.5067/OSGTIL9OV0PN, OCO-2 Science Team et al., 2019b) and in the per-day lite format (https://doi.org/10.5067/VWSABTO7ZII4, OCO-2 Science Team et al., 2019a). In addition, a new set of monthly super-lite files, containing only the most essential variables for each satellite observation, has been generated to provide entry level users with a light-weight satellite product for initial exploration (CaltechDATA, https://doi.org/10.22002/D1.2178, Eldering, 2021). The v9 ACOS Data User's Guide (DUG) describes best-use practices for the GOSAT data (O'Dell et al., 2020). The GOSAT v9 data set should be especially useful for studies of carbon cycle phenomena that span a full decade or more and may serve as a useful complement to the shorter OCO-2 v10 data set, which begins in September 2014. |
|||||
BibTeX:
@article{taylor22a,
author = {Taylor, Thomas E. and O'Dell, Christopher W. and Crisp, David and Kuze, Akhiko and Lindqvist, Hannakaisa and Wennberg, Paul O. and Chatterjee, Abhishek and Gunson, Michael and Eldering, Annmarie and Fisher, Brendan and Kiel, Matthaus and Nelson, Robert R. and Merrelli, Aronne and Osterman, Greg and Chevallier, Frederic and Palmer, I, Paul and Feng, Liang and Deutscher, Nicholas M. and Dubey, Manvendra K. and Feist, Dietrich G. and Garcia, Omaira E. and Griffith, David W. T. and Hase, Frank and Iraci, Laura T. and Kivi, Rigel and Liu, Cheng and De Maziere, Martine and Morino, Isamu and Notholt, Justus and Oh, Young-Suk and Ohyama, Hirofumi and Pollard, David F. and Rettinger, Markus and Schneider, Matthias and Roehl, Coleen M. and Sha, Mahesh Kumar and Shiomi, Kei and Strong, Kimberly and Sussmann, Ralf and Te, Yao and Velazco, Voltaire A. and Vrekoussis, Mihalis and Warneke, Thorsten and Wunch, Debra},
title = {An 11-year record of XCO2 estimates derived from GOSAT measurements using the NASA ACOS version 9 retrieval algorithm},
journal = {EARTH SYSTEM SCIENCE DATA},
year = {2022},
volume = {14},
number = {1},
pages = {325-360},
doi = {https://doi.org/10.5194/essd-14-325-2022}
}
|
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| Temme, A.A., Liu, J.C., Cornwell, W.K., Cornelissen, J.H.C. and Aerts, R. | Winners always win: growth of a wide range of plant species from low to future high CO2 | {2015} | Ecology and Evolution Vol. {5}({21}), pp. 4949-4961 |
article | DOI |
| Abstract: Evolutionary adaptation to variation in resource supply has resulted in plant strategies that are based on trade-offs in functional traits. Here, we investigate, for the first time across multiple species, whether such trade-offs are also apparent in growth and morphology responses to past low, current ambient, and future high CO2 concentrations. We grew freshly germinated seedlings of up to 28 C-3 species (16 forbs, 6 woody, and 6 grasses) in climate chambers at 160ppm, 450ppm, and 750ppm CO2. We determined biomass, allocation, SLA (specific leaf area), LAR (leaf area ratio), and RGR (relative growth rate), thereby doubling the available data on these plant responses to low CO2. High CO2 increased RGR by 8%; low CO2 decreased RGR by 23%. Fast growers at ambient CO2 had the greatest reduction in RGR at low CO2 as they lost the benefits of a fast-growth morphology (decoupling of RGR and LAR [leaf area ratio]). Despite these shifts species ranking on biomass and RGR was unaffected by CO2, winners continued to win, regardless of CO2. Unlike for other plant resources we found no trade-offs in morphological and growth responses to CO2 variation, changes in morphological traits were unrelated to changes in growth at low or high CO2. Thus, changes in physiology may be more important than morphological changes in response to CO2 variation. |
|||||
BibTeX:
@article{temme15a,
author = {Temme, Andries A. and Liu, Jin Chun and Cornwell, William K. and Cornelissen, Johannes H. C. and Aerts, Rien},
title = {Winners always win: growth of a wide range of plant species from low to future high CO2},
journal = {Ecology and Evolution},
year = {2015},
volume = {5},
number = {21},
pages = {4949--4961},
doi = {https://doi.org/10.1002/ece3.1687}
}
|
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| Thilakan, V., Pillai, D., Gerbig, C., Galkowski, M., Ravi, A. and Anna Mathew, T. | Towards monitoring the CO2 source-sink distribution over India via inverse modelling: quantifying the fine-scale spatiotemporal variability in the atmospheric CO2 mole fraction | 2022 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 22(23), pp. 15287-15312 |
article | DOI |
| Abstract: Improving the estimates of CO2 sources and sinks over India through inverse methods calls for a comprehensive atmospheric monitoring system involving atmospheric transport models that make a realistic accounting of atmospheric CO2 variability along with a good coverage of ground-based monitoring stations. This study investigates the importance of representing fine-scale variability in atmospheric CO2 in models for the optimal use of observations through inverse modelling. The unresolved variability in atmospheric CO2 in coarse models is quantified by using WRF-Chem (Weather Research and Forecasting model coupled with Chemistry) simulations at a spatial resolution of 10 km x 10 km. We show that the representation errors due to unresolved variability in the coarse model with a horizontal resolution of 1 & LCIRC; (& SIM; 100 km) are considerable (median values of 1.5 and 0.4 ppm, parts per million, for the surface and column CO2, respectively) compared to the measurement errors. The monthly averaged surface representation error reaches up to & SIM; 5 ppm, which is even comparable to half of the magnitude of the seasonal variability or concentration enhancement due to hotspot emissions. Representation error shows a strong dependence on multiple factors such as time of the day, season, terrain heterogeneity, and changes in meteorology and surface fluxes. By employing a first-order inverse modelling scheme using pseudo-observations from nine tall-tower sites over India, we show that the net ecosystem exchange (NEE) flux uncertainty solely due to unresolved variability is in the range of 3.1 % to 10.3 % of the total NEE of the region. By estimating the representation error and its impact on flux estimations during different seasons, we emphasize the need to take account of fine-scale CO2 variability in models over the Indian subcontinent to better understand processes regulating CO2 sources and sinks. The efficacy of a simple parameterization scheme is further demonstrated to capture these unresolved variations in coarse models. |
|||||
BibTeX:
@article{thilakan22a,
author = {Thilakan, Vishnu and Pillai, Dhanyalekshmi and Gerbig, Christoph and Galkowski, Michal and Ravi, Aparnna and Anna Mathew, Thara},
title = {Towards monitoring the CO2 source-sink distribution over India via inverse modelling: quantifying the fine-scale spatiotemporal variability in the atmospheric CO2 mole fraction},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2022},
volume = {22},
number = {23},
pages = {15287-15312},
doi = {https://doi.org/10.5194/acp-22-15287-2022}
}
|
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| Tian, H., Melillo, J., Lu, C., Kicklighter, D., Liu, M., Ren, W., Xu, X., Chen, G., Zhang, C., Pan, S., Liu, J. and Running, S. | China's terrestrial carbon balance: Contributions from multiple global change factors | {2011} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {25} |
article | DOI |
| Abstract: The magnitude, spatial, and temporal patterns of the terrestrial carbon sink and the underlying mechanisms remain uncertain and need to be investigated. China is important in determining the global carbon balance in terms of both carbon emission and carbon uptake. Of particular importance to climate-change policy and carbon management is the ability to evaluate the relative contributions of multiple environmental factors to net carbon source and sink in China's terrestrial ecosystems. Here the effects of multiple environmental factors (climate, atmospheric CO2, ozone pollution, nitrogen deposition, nitrogen fertilizer application, and land cover/land use change) on net carbon balance in terrestrial ecosystems of China for the period 1961-2005 were modeled with newly developed, detailed historical information of these changes. For this period, results from two models indicated a mean land sink of 0.21 Pg C per year, with a multimodel range from 0.18 to 0.24 Pg C per year. The models' results are consistent with field observations and national inventory data and provide insights into the biogeochemical mechanisms responsible for the carbon sink in China's land ecosystems. In the simulations, nitrogen deposition and fertilizer applications together accounted for 61 percent of the net carbon storage in China's land ecosystems in recent decades, with atmospheric CO2 increases and land use also functioning to stimulate carbon storage. The size of the modeled carbon sink over the period 1961-2005 was reduced by both ozone pollution and climate change. The modeled carbon sink in response to per unit nitrogen deposition shows a leveling off or a decline in some areas in recent years, although the nitrogen input levels have continued to increase. |
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BibTeX:
@article{tian11a,
author = {Tian, Hanqin and Melillo, Jerry and Lu, Chaoqun and Kicklighter, David and Liu, Mingliang and Ren, Wei and Xu, Xiaofeng and Chen, Guangsheng and Zhang, Chi and Pan, Shufen and Liu, Jiyuan and Running, Steven},
title = {China's terrestrial carbon balance: Contributions from multiple global change factors},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2011},
volume = {25},
doi = {https://doi.org/10.1029/2010GB003838}
}
|
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| Tian, H., Chen, G., Zhang, C., Liu, M., Sun, G., Chappelka, A., Ren, W., Xu, X., Lu, C., Pan, S., Chen, H., Hui, D., McNulty, S., Lockaby, G. and Vance, E. | Century-Scale Responses of Ecosystem Carbon Storage and Flux to Multiple Environmental Changes in the Southern United States | {2012} | ECOSYSTEMS Vol. {15}({4}), pp. 674-694 |
article | DOI |
| Abstract: Terrestrial ecosystems in the southern United States (SUS) have experienced a complex set of changes in climate, atmospheric CO2 concentration, tropospheric ozone (O-3), nitrogen (N) deposition, and land-use and land-cover change (LULCC) during the past century. Although each of these factors has received attention for its alterations on ecosystem carbon (C) dynamics, their combined effects and relative contributions are still not well understood. By using the Dynamic Land Ecosystem Model (DLEM) in combination with spatially explicit, longterm historical data series on multiple environmental factors, we examined the century-scale responses of ecosystem C storage and flux to multiple environmental changes in the SUS. The results indicated that multiple environmental changes shifted SUS ecosystems from a C source of 1.20 +/- A 0.56 Pg (1 Pg = 10(15) g) during the period 1895 to 1950, to a C sink of 2.00 +/- A 0.94 Pg during the period 1951 to 2007. Over the entire period spanning 1895-2007, SUS ecosystems were a net C sink of 0.80 +/- A 0.38 Pg. The C sink was primarily due to an increase in the vegetation C pool, whereas the soil C pool decreased during the study period. The spatiotemporal changes of C storage were caused by changes in multiple environmental factors. Among the five factors examined (climate, LULCC, N deposition, atmospheric CO2, and tropospheric O-3), elevated atmospheric CO2 concentration was the largest contributor to C sequestration, followed by N deposition. LULCC, climate, and tropospheric O-3 concentration contributed to C losses during the study period. The SUS ecosystem C sink was largely the result of interactive effects among multiple environmental factors, particularly atmospheric N input and atmospheric CO2.. |
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BibTeX:
@article{tian12a,
author = {Tian, Hanqin and Chen, Guangsheng and Zhang, Chi and Liu, Mingliang and Sun, Ge and Chappelka, Arthur and Ren, Wei and Xu, Xiaofeng and Lu, Chaoqun and Pan, Shufen and Chen, Hua and Hui, Dafeng and McNulty, Steven and Lockaby, Graeme and Vance, Eric},
title = {Century-Scale Responses of Ecosystem Carbon Storage and Flux to Multiple Environmental Changes in the Southern United States},
journal = {ECOSYSTEMS},
year = {2012},
volume = {15},
number = {4},
pages = {674--694},
doi = {https://doi.org/10.1007/s10021-012-9539-x}
}
|
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| Tian, X., Xie, Z., Cai, Z., Liu, Y., Fu, Y. and Zhang, H. | The Chinese carbon cycle data-assimilation system (Tan-Tracker) | {2014} | CHINESE SCIENCE BULLETIN Vol. {59}({14}), pp. 1541-1546 |
article | DOI |
| Abstract: In this study, the Chinese carbon cyle data-assimilation system Tan-Tracker is developed based on the atmospheric chemical transport model (GEOS-Chem) platform. Tan-Tracker is a dual-pass data-assimilation system in which both CO2 concentrations and CO2 fluxes are simultaneously assimilated from atmospheric observations. It has several advantages, including its advanced data-assimilation method, its highly efficient computing performance, and its simultaneous assimilation of CO2 concentrations and CO2 fluxes. Preliminary observing system simulation experiments demonstrate its robust performance with high assimilation precision, making full use of observations. The Tan-Tracker system can only assimilate in situ observations for the moment. In the future, we hope to extend Tan-Tracker with functions for using satellite measurements, which will form the quasi-operational Chinese carbon cycle data-assimilation system. |
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BibTeX:
@article{tian14a,
author = {Tian, Xiangjun and Xie, Zhenghui and Cai, Zhaonan and Liu, Yi and Fu, Yu and Zhang, Huifang},
title = {The Chinese carbon cycle data-assimilation system (Tan-Tracker)},
journal = {CHINESE SCIENCE BULLETIN},
year = {2014},
volume = {59},
number = {14},
pages = {1541--1546},
doi = {https://doi.org/10.1007/s11434-014-0238-1}
}
|
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| Tian, X., Xie, Z., Liu, Y., Cai, Z., Fu, Y., Zhang, H. and Feng, L. | A joint data assimilation system (Tan-Tracker) to simultaneously estimate surface CO2 fluxes and 3-D atmospheric CO2 concentrations from observations | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({23}), pp. 13281-13293 |
article | DOI |
| Abstract: We have developed a novel framework (''TanTracker'') for assimilating observations of atmospheric CO2 concentrations, based on the POD-based (proper orthogonal decomposition) ensemble four-dimensional variational data assimilation method (PODEn4DVar). The high flexibility and the high computational efficiency of the PODEn4DVar approach allow us to include both the atmospheric CO2 concentrations and the surface CO2 fluxes as part of the large state vector to be simultaneously estimated from assimilation of atmospheric CO2 observations. Compared to most modern top-down flux inversion approaches, where only surface fluxes are considered as control variables, one major advantage of our joint data assimilation system is that, in principle, no assumption on perfect transport models is needed. In addition, the possibility for Tan-Tracker to use a complete dynamic model to consistently describe the time evolution of CO2 surface fluxes (CFs) and the atmospheric CO2 concentrations represents a better use of observation information for recycling the analyses at each assimilation step in order to improve the forecasts for the following assimilations. An experimental Tan-Tracker system has been built based on a complete augmented dynamical model, where (1) the surface atmosphere CO2 exchanges are prescribed by using a persistent forecasting model for the scaling factors of the first-guess net CO2 surface fluxes and (2) the atmospheric CO2 transport is simulated by using the GEOS-Chem three-dimensional global chemistry transport model. Observing system simulation experiments (OSSEs) for assimilating synthetic in situ observations of surface CO2 concentrations are carefully designed to evaluate the effectiveness of the Tan-Tracker system. In particular, detailed comparisons are made with its simplified version (referred to as TT-S) with only CFs taken as the prognostic variables. It is found that our Tan-Tracker system is capable of outperforming TT-S with higher assimilation precision for both CO2 concentrations and CO2 fluxes, mainly due to the simultaneous estimation of CO2 concentrations and CFs in our Tan-Tracker data assimilation system. A experiment for assimilating the real dry-air column CO2 retrievals (XCO2) from the Japanese Greenhouse Gases Observation Satellite (GOSAT) further demonstrates its potential wide applications. |
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BibTeX:
@article{tian14b,
author = {Tian, X. and Xie, Z. and Liu, Y. and Cai, Z. and Fu, Y. and Zhang, H. and Feng, L.},
title = {A joint data assimilation system (Tan-Tracker) to simultaneously estimate surface CO2 fluxes and 3-D atmospheric CO2 concentrations from observations},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {23},
pages = {13281--13293},
doi = {https://doi.org/10.5194/acp-14-13281-2014}
}
|
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| Tian, J., Zhang, Y. and Zhang, X. | Impacts of heterogeneous CO2 on water and carbon fluxes across the global land surface | 2021 | INTERNATIONAL JOURNAL OF DIGITAL EARTH Vol. 14(9), pp. 1175-1193 |
article | DOI |
| Abstract: Over the recent decades, the increase of atmospheric carbon dioxide (CO2) concentration has caused large effects on the earth system. However, few studies have paid attention to the effects of heterogeneity of CO2 on the biosphere and the hydrosphere. Using a coupled diagnostic biophysical model (PML-V2) and comparing three heterogeneous CO2 datasets (GOSAT, CMIP6 and CarbonTracker) against a baseline homogeneous data (ESRL), this study investigated the effects of heterogeneous CO2 on gross primary production (GPP), actual evapotranspiration (ET) and water use efficiency (WUE) across the global. The results show that among the three heterogeneity CO2, CarbonTracker produced the highest CO2 concentration and showed the largest difference in ET (-6% to 2%), GPP (-2% to 5%) and WUE (4% to 11%) compared to those from the baseline. The most effects of the CO2 heterogeneity occurred in summer. Russia was identified as a vulnerable region with prominent decrease in GPP and an increase in ET due to CO2 heterogeneity. An obvious increase in GPP and a decrease in ET appeared in the Amazon rainforest, the Congo rainforest, and eastern Asia. On global scale, the effects of the CO2 heterogeneity on ET/GPP/WUE were not significant. |
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BibTeX:
@article{tian21a,
author = {Tian, Jing and Zhang, Yongqiang and Zhang, Xuanze},
title = {Impacts of heterogeneous CO2 on water and carbon fluxes across the global land surface},
journal = {INTERNATIONAL JOURNAL OF DIGITAL EARTH},
year = {2021},
volume = {14},
number = {9},
pages = {1175-1193},
doi = {https://doi.org/10.1080/17538947.2021.1937352}
}
|
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| TianXing, W., JianCheng, S., YingYing, J. and YanHui, X. | Investigation of the consistency of atmospheric CO2 retrievals from different space-based sensors: Intercomparison and spatiotemporal analysis | {2013} | CHINESE SCIENCE BULLETIN Vol. {58}({33}), pp. {4161-4170} |
article | DOI |
| Abstract: In recent years, global warming caused by emission of CO2 has attracted considerable attention from the public. Although the measurements from AIRS, GOSAT, SCIAMACHY and IASI have been frequently used to derive atmospheric CO2 concentration, comprehensive quantification of the differences among these CO2 products is still not fully investigated yet. In this paper, a series of strategies have been proposed to allow the CO2 products from different instruments to be physically inter-comparable. Based on this, these CO2 products are inter-compared in terms of magnitude and their spatiotemporal distributions. The results reveal that the correlations among these CO2 products are relatively weak, and some discrepancies are detected in terms of the CO2 spatiotemporal characteristics, demonstrating more efforts should be made in the future to improve the retrievals of CO2. Their spatial coverage differences reflected in this study imply the great necessity to generate consistent products with improved spatial and temporal continuities by combining these CO2 measurements. |
|||||
BibTeX:
@article{tianxing13a,
author = {Wang TianXing and Shi JianCheng and Jing YingYing and Xie YanHui},
title = {Investigation of the consistency of atmospheric CO2 retrievals from different space-based sensors: Intercomparison and spatiotemporal analysis},
journal = {CHINESE SCIENCE BULLETIN},
year = {2013},
volume = {58},
number = {33},
pages = {4161-4170},
doi = {https://doi.org/10.1007/s11434-013-5996-7}
}
|
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| Tiwari, Y.K., Vellore, R.K., Kumar, K.R., van der Schoot, M. and Cho, C.-H. | Influence of monsoons on atmospheric CO2 spatial variability and ground-based monitoring over India | {2014} | SCIENCE OF THE TOTAL ENVIRONMENT Vol. {490}, pp. 570-578 |
article | DOI |
| Abstract: This study examines the role of Asian monsoons on transport and spatial variability of atmospheric CO2 over the Indian subcontinent, using transport modeling tools and available surface observations from two atmospheric CO2 monitoring sites Sinhagad (SNG) and Cape Rama (CRI) in the western part of peninsular India. The regional source contributions to these sites arise fromthe horizontal flowin conduitswithin the planetary boundary layer. Greater CO2 variability, greater than 15 ppm, is observed during winter, while it is reduced nearly by half during summer. The SNG air sampling site is more susceptible to narrowregional terrestrial fluxes transported fromthe Indo-Gangetic Plains in January, and to wider upwind marine source regions from the Arabian Sea in July. The Western Ghats mountains appear to play a role in the seasonal variability at SNG by trapping polluted air masses associated withweak monsoonalwinds. A Lagrangian back-trajectory analysis further suggests that the horizontal extent of regional sensitivity increases from north to south over the Indian subcontinent in January (Boreal winter). (C) 2014 Elsevier B.V. All rights reserved. |
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BibTeX:
@article{tiwari14a,
author = {Tiwari, Yogesh K. and Vellore, Ramesh K. and Kumar, K. Ravi and van der Schoot, Marcel and Cho, Chun-Ho},
title = {Influence of monsoons on atmospheric CO2 spatial variability and ground-based monitoring over India},
journal = {SCIENCE OF THE TOTAL ENVIRONMENT},
year = {2014},
volume = {490},
pages = {570--578},
doi = {https://doi.org/10.1016/j.scitotenv.2014.05.045}
}
|
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| Tolk, L.F., Meesters, A.G.C.A., Dolman, A.J. and Peters, W. | Modelling representation errors of atmospheric CO2 mixing ratios at a regional scale | {2008} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {8}({22}), pp. 6587-6596 |
article | DOI |
| Abstract: Inverse modelling of carbon sources and sinks requires an accurate quality estimate of the modelling framework to obtain a realistic estimate of the inferred fluxes and their uncertainties. So-called ``representation errors'' result from our inability to correctly represent point observations with simulated average values of model grid cells. They may add substantial uncertainty to the interpretation of atmospheric CO2 mixing ratio data. We simulated detailed variations in the CO2 mixing ratios with a high resolution (2 km) mesoscale model (RAMS) to estimate the representation errors introduced at larger model grid sizes of 10-100 km. We found that meteorology is the main driver of representation errors in our study causing spatial and temporal variations in the error estimate. Within the nocturnal boundary layer, the representation errors are relatively large and mainly caused by unresolved topography at lower model resolutions. During the day, convective structures, mesoscale circulations, and surface CO2 flux variability were found to be the main sources of representation errors. Interpreting observations near a mesoscale circulation as representative for air with the correct footprint relative to the front can reduce the representation error substantially. The remaining representation error is 0.5-1.5 ppm at 20-100 km resolution. |
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BibTeX:
@article{tolk08a,
author = {Tolk, L. F. and Meesters, A. G. C. A. and Dolman, A. J. and Peters, W.},
title = {Modelling representation errors of atmospheric CO2 mixing ratios at a regional scale},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2008},
volume = {8},
number = {22},
pages = {6587--6596},
doi = {https://doi.org/10.5194/acp-8-6587-2008}
}
|
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| Tolk, L.F., Peters, W., Meesters, A.G.C.A., Groenendijk, M., Vermeulen, A.T., Steeneveld, G.J. and Dolman, A.J. | Modelling regional scale surface fluxes, meteorology and CO2 mixing ratios for the Cabauw tower in the Netherlands | {2009} | BIOGEOSCIENCES Vol. {6}({10}), pp. 2265-2280 |
article | DOI |
| Abstract: We simulated meteorology and atmospheric CO2 transport over the Netherlands with the mesoscale model RAMS-Leaf3 coupled to the biospheric CO2 flux model 5PM. The results were compared with meteorological and CO2 observations, with emphasis on the tall tower of Cabauw. An analysis of the coupled exchange of energy, moisture and CO2 showed that the surface fluxes in the domain strongly influenced the atmospheric properties. The majority of the variability in the afternoon CO2 mixing ratio in the middle of the domain was determined by biospheric and fossil fuel CO2 fluxes in the limited area domain (640x640 km). Variation of the surface CO2 fluxes, reflecting the uncertainty of the parameters in the CO2 flux model 5PM, resulted in a range of simulated atmospheric CO2 mixing ratios of on average 11.7 ppm in the well-mixed boundary layer. Additionally, we found that observed surface energy fluxes and observed atmospheric temperature and moisture could not be reconciled with the simulations. Including this as an uncertainty in the simulation of surface energy fluxes changed simulated atmospheric vertical mixing and horizontal advection, leading to differences in simulated CO2 of on average 1.7 ppm. This is an important source of uncertainty and should be accounted for to avoid biased calculations of the CO2 mixing ratio, but it does not overwhelm the signal in the CO2 mixing ratio due to the uncertainty range of the surface CO2 fluxes. |
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BibTeX:
@article{tolk09a,
author = {Tolk, L. F. and Peters, W. and Meesters, A. G. C. A. and Groenendijk, M. and Vermeulen, A. T. and Steeneveld, G. J. and Dolman, A. J.},
title = {Modelling regional scale surface fluxes, meteorology and CO2 mixing ratios for the Cabauw tower in the Netherlands},
journal = {BIOGEOSCIENCES},
year = {2009},
volume = {6},
number = {10},
pages = {2265--2280},
doi = {https://doi.org/10.5194/bg-6-2265-2009}
}
|
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| Tolk, L.F., Dolman, A.J., Meesters, A.G.C.A. and Peters, W. | A comparison of different inverse carbon flux estimation approaches for application on a regional domain | {2011} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {11}({20}), pp. 10349-10365 |
article | DOI |
| Abstract: We have implemented six different inverse carbon flux estimation methods in a regional carbon dioxide (CO(2)) flux modeling system for the Netherlands. The system consists of the Regional Atmospheric Mesoscale Modeling System (RAMS) coupled to a simple carbon flux scheme which is run in a coupled fashion on relatively high resolution (10 km). Using an Ensemble Kalman filter approach we try to estimate spatiotemporal carbon exchange patterns from atmospheric CO(2) mole fractions over the Netherlands for a two week period in spring 2008. The focus of this work is the different strategies that can be employed to turn first-guess fluxes into optimal ones, which is known as a fundamental design choice that can affect the outcome of an inversion significantly. Different state-of-the-art approaches with respect to the estimation of net ecosystem exchange (NEE) are compared quantitatively: (1) where NEE is scaled by one linear multiplication factor per land-use type, (2) where the same is done for photosynthesis (GPP) and respiration (R) separately with varying assumptions for the correlation structure, (3) where we solve for those same multiplication factors but now for each grid box, and (4) where we optimize physical parameters of the underlying biosphere model for each land-use type. The pattern to be retrieved in this pseudo-data experiment is different in nearly all aspects from the first-guess fluxes, including the structure of the underlying flux model, reflecting the difference between the modeled fluxes and the fluxes in the real world. This makes our study a stringent test of the performance of these methods, which are currently widely used in carbon cycle inverse studies. Our results show that all methods struggle to retrieve the spatiotemporal NEE distribution, and none of them succeeds in finding accurate domain averaged NEE with correct spatial and temporal behavior. The main cause is the difference between the structures of the first-guess and true CO(2) flux models used. Most methods display overconfidence in their estimate as a result. A commonly used daytime-only sampling scheme in the transport model leads to compensating biases in separate GPP and R scaling factors that are readily visible in the nighttime mixing ratio predictions of these systems. Overall, we recommend that the estimate of NEE scaling factors should not be used in this regional setup, while estimating bias factors for GPP and R for every grid box works relatively well. The biosphere parameter inversion performs good compared to the other inversions at simultaneously producing space and time patterns of fluxes and CO(2) mixing ratios, but non-linearity may significantly reduce the information content in the inversion if true parameter values are far from the prior estimate. Our results suggest that a carefully designed biosphere model parameter inversion or a pixel inversion of the respiration and GPP multiplication factors are from the tested inversions the most promising tools to optimize spatiotemporal patterns of NEE. |
|||||
BibTeX:
@article{tolk11a,
author = {Tolk, L. F. and Dolman, A. J. and Meesters, A. G. C. A. and Peters, W.},
title = {A comparison of different inverse carbon flux estimation approaches for application on a regional domain},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
volume = {11},
number = {20},
pages = {10349--10365},
doi = {https://doi.org/10.5194/acp-11-10349-2011}
}
|
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| Torres, A.D., Keppel-Aleks, G., Doney, S.C., Fendrock, M., Luis, K., De Maziere, M., Hase, F., Petri, C., Pollard, D.F., Roehl, C.M., Sussmann, R., Velazco, V.A., Warneke, T. and Wunch, D. | A Geostatistical Framework for Quantifying the Imprint of Mesoscale Atmospheric Transport on Satellite Trace Gas Retrievals | {2019} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {124}({17-18}), pp. {9773-9795} |
article | DOI URL |
| Abstract: National Aeronautics and Space Administration's Orbiting Carbon Observatory-2 (OCO-2) satellite provides observations of total column-averaged CO2 mole fractions (X-CO2) at high spatial resolution that may enable novel constraints on surface-atmosphere carbon fluxes. Atmospheric inverse modeling provides an approach to optimize surface fluxes at regional scales, but the accuracy of the fluxes from inversion frameworks depends on key inputs, including spatially and temporally dense CO2 observations and reliable representations of atmospheric transport. Since X-CO2 observations are sensitive to both synoptic and mesoscale variations within the free troposphere, horizontal atmospheric transport imparts substantial variations in these data and must be either resolved explicitly by the atmospheric transport model or accounted for within the error covariance budget provided to inverse frameworks. Here, we used geostatistical techniques to quantify the imprint of atmospheric transport in along-track OCO-2 soundings. We compare high-pass-filtered (<250 km, spatial scales that primarily isolate mesoscale or finer-scale variations) along-track spatial variability in X-CO2 and X-H2O from OCO-2 tracks to temporal synoptic and mesoscale variability from ground-based X-CO2 and X-H2O observed by nearby Total Carbon Column Observing Network sites. Mesoscale atmospheric transport is found to be the primary driver of along-track, high-frequency variability for OCO-2 X-H2O. For X-CO2, both mesoscale transport variability and spatially coherent bias associated with other elements of the OCO-2 retrieval state vector are important drivers of the along-track variance budget. Plain Language Summary Numerous efforts have been made to quantify sources and sinks of atmospheric CO2 at regional spatial scales. A common approach to infer these sources and sinks requires accurate representation of variability of CO2 observations attributed to transport by weather systems. While numerical weather prediction models have a fairly reasonable representation of larger-scale weather systems, such as frontal systems, representation of smaller-scale features (<250 km), is less reliable. In this study, we find that the variability of total column-averaged CO2 observations attributed to these fine-scale weather systems accounts for up to half of the variability attributed to local sources and sinks. Here, we provide a framework for quantifying the drivers of spatial variability of atmospheric trace gases rather than simply relying on numerical weather prediction models. We use this framework to quantify potential sources of errors in measurements of total column-averaged CO2 and water vapor from National Aeronautics and Space Administration's Orbiting Carbon Observatory-2 satellite. | |||||
BibTeX:
@article{torres19a,
author = {Torres, Anthony D. and Keppel-Aleks, Gretchen and Doney, Scott C. and Fendrock, Michaela and Luis, Kelly and De Maziere, Martine and Hase, Frank and Petri, Christof and Pollard, David F. and Roehl, Coleen M. and Sussmann, Ralf and Velazco, Voltaire A. and Warneke, Thorsten and Wunch, Debra},
title = {A Geostatistical Framework for Quantifying the Imprint of Mesoscale Atmospheric Transport on Satellite Trace Gas Retrievals},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2019},
volume = {124},
number = {17-18},
pages = {9773--9795},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JD029933},
doi = {https://doi.org/10.1029/2018JD029933}
}
|
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| Tsuruta, A., Aalto, T., Backman, L., Peters, W., Krol, M., van der Laan-Luijkx, I.T., Hatakka, J., Heikkinen, P., Dlugokencky, E.J., Spahni, R. and Paramonova, N.N. | Evaluating atmospheric methane inversion model results for Pallas, northern Finland | {2015} | BOREAL ENVIRONMENT RESEARCH Vol. {20}({4}), pp. 506-525 |
article | |
| Abstract: A state-of-the-art inverse model, CarbonTracker Data Assimilation Shell (CTDAS), was used to optimize estimates of methane (CH4) surface fluxes using atmospheric observations of CH4 as a constraint. The model consists of the latest version of the TM5 atmospheric chemistry-transport model and an ensemble Kalman filter based data assimilation system. The model was constrained by atmospheric methane surface concentrations, obtained from the World Data Centre for Greenhouse Gases (WDCGG). Prior methane emissions were specified for five sources: biosphere, anthropogenic, fire, termites and ocean, of which biosphere and anthropogenic emissions were optimized. Atmospheric CH4 mole fractions for 2007 from northern Finland calculated from prior and optimized emissions were compared with observations. It was found that the root mean squared errors of the posterior estimates were more than halved. Furthermore, inclusion of NOAA observations of CH, from weekly discrete air samples collected at Pallas improved agreement between posterior CH4 mole fraction estimates and continuous observations, and resulted in reducing optimized biosphere emissions and their uncertainties in northern Finland. |
|||||
BibTeX:
@article{tsuruta15a,
author = {Tsuruta, Aki and Aalto, Tuula and Backman, Leif and Peters, Wouter and Krol, Maarten and van der Laan-Luijkx, Ingrid T. and Hatakka, Juha and Heikkinen, Pauli and Dlugokencky, Edward J. and Spahni, Renato and Paramonova, Nina N.},
title = {Evaluating atmospheric methane inversion model results for Pallas, northern Finland},
journal = {BOREAL ENVIRONMENT RESEARCH},
year = {2015},
volume = {20},
number = {4},
pages = {506--525},
note = {4th Pallas Symposium 2013, Muonio, FINLAND, SEP 25-27, 2013}
}
|
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| Tsuruta, A., Aalto, T., Backman, L., Hakkarainen, J., van der Laan-Luijkx, I.T., Krol, M.C., Spahni, R., Houweling, S., Laine, M., Dlugokencky, E., Gomez-Pelaez, A.J., van der Schoot, M., Langenfelds, R., Ellul, R., Arduini, J., Apadula, F., Gerbig, C., Feist, D.G., Kivi, R., Yoshida, Y. and Peters, W. | Global methane emission estimates for 2000-2012 from CarbonTracker Europe-CH4 v1.0 | {2017} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {10}({3}) |
article | DOI |
| Abstract: We present a global distribution of surface methane (CH4) emission estimates for 2000-2012 derived using the CarbonTracker Europe-CH4 (CTE-CH4) data assimilation system. In CTE-CH4, anthropogenic and biospheric CH4 emissions are simultaneously estimated based on constraints of global atmospheric in situ CH4 observations. The system was configured to either estimate only anthropogenic or biospheric sources per region, or to estimate both categories simultaneously. The latter increased the number of optimizable parameters from 62 to 78. In addition, the differences between two numerical schemes available to perform turbulent vertical mixing in the atmospheric transport model TM5 were examined. Together, the system configurations encompass important axes of uncertainty in inversions and allow us to examine the robustness of the flux estimates. The posterior emission estimates are further evaluated by comparing simulated atmospheric CH4 to surface in situ observations, vertical profiles of CH4 made by aircraft, remotely sensed dry-air total column-averaged mole fraction (XCH4) from the Total Carbon Column Observing Network (TCCON), and XCH4 from the Greenhouse gases Observing Satellite (GOSAT). The evaluation with non-assimilated observations shows that posterior XCH4 is better matched with the retrievals when the vertical mixing scheme with faster interhemispheric exchange is used. Estimated posterior mean total global emissions during 2000-2012 are 516 +/- 51 Tg CH4 yr(-1), with an increase of 18 Tg CH4 yr(-1) from 2000-2006 to 2007-2012. The increase is mainly driven by an increase in emissions from South American temperate, Asian temperate and Asian tropical TransCom regions. In addition, the increase is hardly sensitive to different model configurations (< 2 Tg CH4 yr(-1) difference), and much smaller than suggested by EDGAR v4.2 FT2010 inventory (33 Tg CH4 yr(-1)), which was used for prior anthropogenic emission estimates. The result is in good agreement with other published estimates from inverse modelling studies (16-20 Tg CH4 yr(-1)). However, this study could not conclusively separate a small trend in biospheric emissions (-5 to +6.9 Tg CH4 yr(-1)) from the much larger trend in anthropogenic emissions (15-27 Tg CH4 yr(-1)). Finally, we find that the global and North American CH4 balance could be closed over this time period without the previously suggested need to strongly increase anthropogenic CH4 emissions in the United States. With further developments, especially on the treatment of the atmospheric CH4 sink, we expect the data assimilation system presented here will be able to contribute to the ongoing interpretation of changes in this important greenhouse gas budget. |
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BibTeX:
@article{tsuruta17a,
author = {Tsuruta, Aki and Aalto, Tuula and Backman, Leif and Hakkarainen, Janne and van der Laan-Luijkx, Ingrid T. and Krol, Maarten C. and Spahni, Renato and Houweling, Sander and Laine, Marko and Dlugokencky, Ed and Gomez-Pelaez, Angel J. and van der Schoot, Marcel and Langenfelds, Ray and Ellul, Raymond and Arduini, Jgor and Apadula, Francesco and Gerbig, Christoph and Feist, Dietrich G. and Kivi, Rigel and Yoshida, Yukio and Peters, Wouter},
title = {Global methane emission estimates for 2000-2012 from CarbonTracker Europe-CH4 v1.0},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2017},
volume = {10},
number = {3},
doi = {https://doi.org/10.5194/gmd-10-1261-2017}
}
|
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| Tunnicliffe, R.L., Ganesan, A.L., Parker, R.J., Boesch, H., Gedney, N., Poulter, B., Zhang, Z., Lavric, J.V., Walter, D., Rigby, M., Henne, S., Young, D. and O'Doherty, S. | Quantifying sources of Brazil's CH4 emissions between 2010 and 2018 from satellite data | {2020} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {20}({21}), pp. {13041-13067} |
article | DOI URL |
| Abstract: Brazil's CH4 emissions over the period 2010-2018 were derived for the three main sectors of activity: anthropogenic, wetland and biomass burning. Our inverse modelling estimates were derived from GOSAT (Greenhouse gases Observing SATellite) satellite measurements of XCH4 combined with surface data from Ragged Point, Barbados, and the high-resolution regional atmospheric transport model NAME (Numerical Atmospheric-dispersion Modelling Environment). We find that Brazil's mean emissions over 2010-2018 are 33.6 +/- 3.6Tgyr(-1), which are comprised of 19.0 +/- 2.6Tgyr(-1) from anthropogenic (primarily related to agriculture and waste), 13.0 +/- 1.9Tgyr(-1) from wetlands and 1.7 +/- 0.3Tgyr(-1) from biomass burning sources. In addition, between the 2011-2013 and 2014-2018 periods, Brazil's mean emissions rose by 6.9 +/- 5.3Tgyr(-1) and this increase may have contributed to the accelerated global methane growth rate observed during the latter period. We find that wetland emissions from the western Amazon increased during the start of the 2015-2016 El Nino by 3.7 +/- 2.7Tgyr(-1) and this is likely driven by increased surface temperatures. We also find that our estimates of anthropogenic emissions are consistent with those reported by Brazil to the United Framework Convention on Climate Change. We show that satellite data are beneficial for constraining national-scale CH4 emissions, and, through a series of sensitivity studies and validation experiments using data not assimilated in the inversion, we demonstrate that (a) calibrated ground-based data are important to include alongside satellite data in a regional inversion and that (b) inversions must account for any offsets between the two data streams and their representations by models. | |||||
BibTeX:
@article{tunnicliffe20a,
author = {Tunnicliffe, Rachel L. and Ganesan, Anita L. and Parker, Robert J. and Boesch, Hartmut and Gedney, Nicola and Poulter, Benjamin and Zhang, Zhen and Lavric, Jost V. and Walter, David and Rigby, Matthew and Henne, Stephan and Young, Dickon and O'Doherty, Simon},
title = {Quantifying sources of Brazil's CH4 emissions between 2010 and 2018 from satellite data},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {20},
number = {21},
pages = {13041--13067},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/20/13041/2020/},
doi = {https://doi.org/10.5194/acp-20-13041-2020}
}
|
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| Turnbull, J.C., Tans, P.P., Lehman, S.J., Baker, D., Conway, T.J., Chung, Y.S., Gregg, J., Miller, J.B., Southon, J.R. and Zhou, L.-X. | Atmospheric observations of carbon monoxide and fossil fuel CO2 emissions from East Asia | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: Flask samples from two sites in East Asia, Tae-Ahn Peninsula, Korea (TAP), and Shangdianzi, China (SDZ), were measured for trace gases including CO2, CO and fossil fuel CO2(CO(2)ff, derived from Delta(CO2)-C-14 observations). The five-year TAP record shows high CO(2)ff when local air comes from the Korean Peninsula. Most samples, however, reflect air masses from Northeastern China with lower CO(2)ff. Our small set of SDZ samples from winter 2009/2010 have strongly elevated CO(2)ff. Biospheric CO2 contributes substantially to total CO2 variability at both sites, even in winter when non-fossil CO2 sources (including photosynthesis, respiration, biomass burning and biofuel use) contribute 20-30% of the total CO2 enhancement. Carbon monoxide (CO) correlates strongly with CO(2)ff. The SDZ and TAP far-field (China influenced) samples have CO: CO(2)ff ratios (R-CO:CO2ff) of 47 +/- 2 and 44 +/- 3 ppb/ppm respectively, consistent with recent bottom-up inventory estimates and other observational studies. Locally influenced TAP samples fall into two distinct data sets, ascribed to air sourced from South Korea and North Korea. The South Korea samples have low R-CO:CO2ff of 13 +/- 3 ppb/ppm, slightly higher than bottom-up inventories, but consistent with emission ratios for other developed nations. We compare our CO(2)ff observations with modeled CO(2)ff using the FLEXPART Lagrangian particle dispersion model convolved with a bottom-up CO(2)ff emission inventories. The modeled annual mean CO(2)ff mole fractions are consistent with our observations when the model inventory includes the reported 63% increase in Chinese emissions from 2004 to 2010, whereas a model version which holds Chinese emissions flat is unable to replicate the observations. |
|||||
BibTeX:
@article{turnbull11a,
author = {Turnbull, Jocelyn C. and Tans, Pieter P. and Lehman, Scott J. and Baker, David and Conway, Thomas J. and Chung, Y. S. and Gregg, Jay and Miller, John B. and Southon, John R. and Zhou, Ling-Xi},
title = {Atmospheric observations of carbon monoxide and fossil fuel CO2 emissions from East Asia},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2011JD016691}
}
|
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| Turner, D.P. | Global vegetation monitoring: toward a sustainable technobiosphere | {2011} | FRONTIERS IN ECOLOGY AND THE ENVIRONMENT Vol. {9}({2}), pp. 111-116 |
article | DOI |
| Abstract: The concept of sustainable resource management can be applied at multiple scales. Monitoring is an essential component of sustainable natural resource management schemes, and as we begin to confront the need to manage natural resources at the global scale, the importance of monitoring at the global scale is also growing. The combination of satellite remote sensing, in situ measurements, and simulation modeling has the potential to deliver an annual assessment of status and trends for several measures of terrestrial biosphere structure and function relevant to sustainability. However, there is, as yet, no internationally coordinated effort in place to perform that analysis. Synthesis activity of that kind would support the development of global environmental governance institutions, including both non-governmental organizations and international bodies. |
|||||
BibTeX:
@article{turner11a,
author = {Turner, David P.},
title = {Global vegetation monitoring: toward a sustainable technobiosphere},
journal = {FRONTIERS IN ECOLOGY AND THE ENVIRONMENT},
year = {2011},
volume = {9},
number = {2},
pages = {111--116},
doi = {https://doi.org/10.1890/090171}
}
|
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| Turner, D.P., Goeckede, M., Law, B.E., Ritts, W.D., Cohen, W.B., Yang, Z., Hudiburg, T., Kennedy, R. and Duane, M. | Multiple constraint analysis of regional land-surface carbon flux | {2011} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {63}({2}), pp. 207-221 |
article | DOI |
| Abstract: We applied and compared bottom-up (process model-based) and top-down (atmospheric inversion-based) scaling approaches to evaluate the spatial and temporal patterns of net ecosystem production (NEP) over a 2.5 x 105 km2 area (the state of Oregon) in the western United States. Both approaches indicated a carbon sink over this heterogeneous region in 2003 (a relatively warm, dry year in western Oregon) and 2007 (near normal), with carbon uptake primarily in forested and agricultural areas. The statewide mean NEP for 2007 using the bottom-up approach was 80 gC m-2 yr-1, which compares with 145 gC m-2 yr-1 for the top-down approach. Seasonality of daily NEP at the ecoregion scale showed similar patterns across the two approaches, but with less sensitivity to seasonal drought in the top-down model. In 2003, simulated annual NEP was lower than in 2007 for both scaling approaches, but the reduction was stronger with the bottom-up approach. Estimates of mean NEP on forested lands from a forest inventory approach, and from the CarbonTracker inversion scheme, bracketed that of our bottom-up approach (ratios to bottom-up estimates were 1.3 and 0.3, respectively). These results support the need for a multiple constraint approach to evaluation of regional trace gas budgets. |
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BibTeX:
@article{turner11b,
author = {Turner, D. P. and Goeckede, M. and Law, B. E. and Ritts, W. D. and Cohen, W. B. and Yang, Z. and Hudiburg, T. and Kennedy, R. and Duane, M.},
title = {Multiple constraint analysis of regional land-surface carbon flux},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2011},
volume = {63},
number = {2},
pages = {207--221},
doi = {https://doi.org/10.1111/j.1600-0889.2011.00525.x}
}
|
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| Turner, D.P., Jacobson, A.R., Ritts, W.D., Wang, W.L. and Nemani, R. | A large proportion of North American net ecosystem production is offset by emissions from harvested products, river/stream evasion, and biomass burning | {2013} | GLOBAL CHANGE BIOLOGY Vol. {19}({11}), pp. 3516-3528 |
article | DOI |
| Abstract: Diagnostic carbon cycle models produce estimates of net ecosystem production (NEP, the balance of net primary production and heterotrophic respiration) by integrating information from (i) satellite-based observations of land surface vegetation characteristics; (ii) distributed meteorological data; and (iii) eddy covariance flux tower observations of net ecosystem exchange (NEE) (used in model parameterization). However, a full bottom-up accounting of NEE (the vertical carbon flux) that is suitable for integration with atmosphere-based inversion modeling also includes emissions from decomposition/respiration of harvested forest and agricultural products, CO2 evasion from streams and rivers, and biomass burning. Here, we produce a daily time step NEE for North America for the year 2004 that includes NEP as well as the additional emissions. This NEE product was run in the forward mode through the CarbonTracker inversion setup to evaluate its consistency with CO2 concentration observations. The year 2004 was climatologically favorable for NEP over North America and the continental total was estimated at 1730 +/- 370TgCyr(-1) (a carbon sink). Harvested product emissions (316 +/- 80TgCyr(-1)), river/stream evasion (158 +/- 50TgCyr(-1)), and fire emissions (142 +/- 45TgCyr(-1)) counteracted a large proportion (35%) of the NEP sink. Geographic areas with strong carbon sinks included Midwest US croplands, and forested regions of the Northeast, Southeast, and Pacific Northwest. The forward mode run with CarbonTracker produced good agreement between observed and simulated wintertime CO2 concentrations aggregated over eight measurement sites around North America, but overestimates of summertime concentrations that suggested an underestimation of summertime carbon uptake. As terrestrial NEP is the dominant offset to fossil fuel emission over North America, a good understanding of its spatial and temporal variation - as well as the fate of the carbon it sequesters is needed for a comprehensive view of the carbon cycle. |
|||||
BibTeX:
@article{turner13a,
author = {Turner, David P. and Jacobson, Andrew R. and Ritts, William D. and Wang, Weile L. and Nemani, Ramakrishna},
title = {A large proportion of North American net ecosystem production is offset by emissions from harvested products, river/stream evasion, and biomass burning},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2013},
volume = {19},
number = {11},
pages = {3516--3528},
doi = {https://doi.org/10.1111/gcb.12313}
}
|
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| Turner, D.P., Ritts, W.D., Kennedy, R.E., Gray, A.N. and Yang, Z. | Effects of harvest, fire, and pest/pathogen disturbances on the West Cascades ecoregion carbon balance [BibTeX] |
2015 | Carbon balance and management Vol. 10(1), pp. 12 |
article | |
BibTeX:
@article{turner15a,
author = {Turner, David P and Ritts, William D and Kennedy, Robert E and Gray, Andrew N and Yang, Zhiqiang},
title = {Effects of harvest, fire, and pest/pathogen disturbances on the West Cascades ecoregion carbon balance},
journal = {Carbon balance and management},
year = {2015},
volume = {10},
number = {1},
pages = {12}
}
|
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| Turner, A.J., Jacob, D.J., Benmergui, J., Wofsy, S.C., Maasakkers, J.D., Butz, A., Hasekamp, O. and Biraud, S.C. | A large increase in US methane emissions over the past decade inferred from satellite data and surface observations | {2016} | GEOPHYSICAL RESEARCH LETTERS Vol. {43}({5}), pp. 2218-2224 |
article | DOI |
| Abstract: The global burden of atmospheric methane has been increasing over the past decade, but the causes are not well understood. National inventory estimates from the U.S. Environmental Protection Agency indicate no significant trend in U.S. anthropogenic methane emissions from 2002 to present. Here we use satellite retrievals and surface observations of atmospheric methane to suggest that U.S. methane emissions have increased by more than 30% over the 2002-2014 period. The trend is largest in the central part of the country, but we cannot readily attribute it to any specific source type. This large increase in U.S. methane emissions could account for 30-60% of the global growth of atmospheric methane seen in the past decade. |
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BibTeX:
@article{turner16a,
author = {Turner, A. J. and Jacob, D. J. and Benmergui, J. and Wofsy, S. C. and Maasakkers, J. D. and Butz, A. and Hasekamp, O. and Biraud, S. C.},
title = {A large increase in US methane emissions over the past decade inferred from satellite data and surface observations},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2016},
volume = {43},
number = {5},
pages = {2218--2224},
doi = {https://doi.org/10.1002/2016GL067987}
}
|
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| Turner, A.J., Shusterman, A.A., McDonald, B.C., Teige, V., Harley, R.A. and Cohen, R.C. | Network design for quantifying urban CO2 emissions: assessing trade-offs between precision and network density | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({21}), pp. 13465-13475 |
article | DOI |
| Abstract: The majority of anthropogenic CO2 emissions are attributable to urban areas. While the emissions from urban electricity generation often occur in locations remote from consumption, many of the other emissions occur within the city limits Evaluating the effectiveness of strategies for controlling these emissions depends on our ability to observe urban CO2 emissions and attribute them to specific activities. Cost-effective strategies for doing so have yet to be described. Here we characterize the ability of a prototype measurement network, modeled after the Berkeley Atmospheric CO2 Observation Network (BEACO(2)N) in California's Bay Area, in combination with an inverse model based on the coupled Weather Research and Forecasting/Stochastic Time Inverted Lagrangian Transport (WRF-STILT) to improve our understanding of urban emissions. The pseudo-measurement network includes 34 sites at roughly 2 km spacing covering an area of roughly 400 km(2). The model uses an hourly 1 x 1 km(2) emission inventory and 1 x 1 km(2) meteorological calculations. We perform an ensemble of Bayesian atmospheric inversions to sample the combined effects of uncertainties of the pseudo-measurements and the model. We vary the estimates of the combined uncertainty of the pseudo observations and model over a range of 20 to 0.005 ppm and vary the number of sites from 1 to 34. We use these inversions to develop statistical models that estimate the efficacy of the combined model observing system in reducing uncertainty in CO2 emissions. We examine uncertainty in estimated CO2 fluxes on the urban scale, as well as for sources embedded within the city such as a line source (e.g., a highway) or a point source (e.g., emissions from the stacks of small industrial facilities). Using our inversion framework, we find that a dense network with moderate precision is the preferred setup for estimating area, line, and point sources from a combined uncertainty and cost perspective. The dense network considered here (modeled after the BEACO(2)N network with an assumed mismatch error of 1 ppm at an hourly temporal resolution) could estimate weekly CO2 emissions from an urban region with less than 5 % error, given our characterization of the combined observation and model uncertainty. |
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BibTeX:
@article{turner16b,
author = {Turner, Alexander J. and Shusterman, Alexis A. and McDonald, Brian C. and Teige, Virginia and Harley, Robert A. and Cohen, Ronald C.},
title = {Network design for quantifying urban CO2 emissions: assessing trade-offs between precision and network density},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {21},
pages = {13465--13475},
doi = {https://doi.org/10.5194/acp-16-13465-2016}
}
|
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| Turner, A.J., Koehler, P., Magney, T.S., Frankenberg, C., Fung, I. and Cohen, R.C. | A double peak in the seasonality of California's photosynthesis as observed from space | {2020} | BIOGEOSCIENCES Vol. {17}({2}), pp. {405-422} |
article | DOI URL |
| Abstract: Solar-induced chlorophyll fluorescence (SIF) has been shown to be a powerful proxy for photosynthesis and gross primary productivity (GPP). The recently launched TROPOspheric Monitoring Instrument (TROPOMI) features the required spectral resolution and signal-to-noise ratio to retrieve SIF from space. Here, we present a downscaling method to obtain 500m spatial resolution SIF over California. We report daily values based on a 14 d window. TROPOMI SIF data show a strong correspondence with daily GPP estimates at AmeriFlux sites across multiple ecosystems in California. We find a linear relationship between SIF and GPP that is largely invariant across ecosystems with an intercept that is not significantly different from zero. Measurements of SIF from TROPOMI agree with MODerate Resolution Imaging Spectroradiometer (MODIS) vegetation indices the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and near-infrared reflectance of vegetation index (NIRv) - at annual timescales but indicate different temporal dynamics at monthly and daily timescales. TROPOMI SIF data show a double peak in the seasonality of photosynthesis, a feature that is not present in the MODIS vegetation indices. The different seasonality in the vegetation indices may be due to a clear-sky bias in the vegetation indices, whereas previous work has shown SIF to have a low sensitivity to clouds and to detect the downregulation of photosynthesis even when plants appear green. We further decompose the spatiotemporal patterns in the SIF data based on land cover. The double peak in the seasonality of California's photosynthesis is due to two processes that are out of phase: grasses, chaparral, and oak savanna ecosystems show an April maximum, while evergreen forests peak in June. An empirical orthogonal function (EOF) analysis corroborates the phase offset and spatial patterns driving the double peak. The EOF analysis further indicates that two spatiotemporal patterns explain 84% of the variability in the SIF data. Results shown here are promising for obtaining global GPP at sub-kilometer spatial scales and identifying the processes driving carbon uptake. | |||||
BibTeX:
@article{turner20a,
author = {Turner, Alexander J. and Koehler, Philipp and Magney, Troy S. and Frankenberg, Christian and Fung, Inez and Cohen, Ronald C.},
title = {A double peak in the seasonality of California's photosynthesis as observed from space},
journal = {BIOGEOSCIENCES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {17},
number = {2},
pages = {405--422},
note = {Query date: 2021-04-02 15:20:04},
url = {https://bg.copernicus.org/articles/17/405/2020/},
doi = {https://doi.org/10.5194/bg-17-405-2020}
}
|
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| Ueyama, M., Ichii, K., Iwata, H., Euskirchen, E.S., Zona, D., Rocha, A.V., Harazono, Y., Iwama, C., Nakai, T. and Oechel, W.C. | Upscaling terrestrial carbon dioxide fluxes in Alaska with satellite remote sensing and support vector regression | {2013} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {118}({3}), pp. 1266-1281 |
article | DOI |
| Abstract: Carbon dioxide (CO2) fluxes from a network of 21 eddy covariance towers were upscaled to estimate the Alaskan CO2 budget from 2000 to 2011 by combining satellite remote sensing data, disturbance information, and a support vector regression model. Data were compared with the CO2 budget from an inverse model (CarbonTracker). Observed gross primary productivity (GPP), ecosystem respiration (RE), and net ecosystem exchange (NEE) were each well reproduced by the model on the site scale; root-mean-square errors (RMSEs) for GPP, RE, and NEE were 0.52, 0.23, and 0.48g C m(-2) d(-1), respectively. Landcover classification was the most important input for predicting GPP, whereas visible reflectance index of green ratio was the most important input for predicting RE. During the period of 2000-2011, predicted GPP and RE were 36922 and 36212 Tg C yr(-1) (meaninterannual variability) for Alaska, respectively, indicating an approximately neutral CO2 budget for the decade. CarbonTracker also showed an approximately neutral CO2 budget during 2000-2011 (growing season RMSE=14g C m(-2) season(-1); annual RMSE=13g C m(-2) yr(-1)). Interannual CO2 flux variability was positively correlated with air temperature anomalies from June to August, with Alaska acting as a greater CO2 sink in warmer years. CO2 flux trends for the decade were clear in disturbed ecosystems; positive trends in GPP and CO2 sink were observed in areas where vegetation recovered for about 20 years after fire. |
|||||
BibTeX:
@article{ueyama13a,
author = {Ueyama, Masahito and Ichii, Kazuhito and Iwata, Hiroki and Euskirchen, Eugenie S. and Zona, Donatella and Rocha, Adrian V. and Harazono, Yoshinobu and Iwama, Chie and Nakai, Taro and Oechel, Walter C.},
title = {Upscaling terrestrial carbon dioxide fluxes in Alaska with satellite remote sensing and support vector regression},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2013},
volume = {118},
number = {3},
pages = {1266--1281},
doi = {https://doi.org/10.1002/jgrg.20095}
}
|
|||||
| Ueyama, M., Iwata, H., Harazono, Y., Euskirchen, E.S., Oechel, W.C. and Zona, D. | Growing season and spatial variations of carbon fluxes of Arctic and boreal ecosystems in Alaska (USA) | {2013} | ECOLOGICAL APPLICATIONS Vol. {23}({8}), pp. 1798-1816 |
article | DOI |
| Abstract: To better understand the spatial and temporal dynamics of CO2 exchange between Arctic ecosystems and the atmosphere, we synthesized CO2 flux data, measured in eight Arctic tundra and five boreal ecosystems across Alaska (USA) and identified growing season and spatial variations of the fluxes and environmental controlling factors. For the period examined, all of the boreal and seven of the eight Arctic tundra ecosystems acted as CO2 sinks during the growing season. Seasonal patterns of the CO2 fluxes were mostly determined by air temperature, except ecosystem respiration (RE) of tundra. For the tundra ecosystems, the spatial variation of gross primary productivity (GPP) and net CO2 sink strength were explained by growing season length, whereas RE increased with growing degree days. For boreal ecosystems, the spatial variation of net CO2 sink strength was mostly determined by recovery of GPP from fire disturbance. Satellite-derived leaf area index (LAI) was a better index to explain the spatial variations of GPP and NEE of the ecosystems in Alaska than were the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). Multiple regression models using growing degree days, growing season length, and satellite-derived LAI explained much of the spatial variation in GPP and net CO2 exchange among the tundra and boreal ecosystems. The high sensitivity of the sink strength to growing season length indicated that the tundra ecosystem could increase CO2 sink strength under expected future warming, whereas ecosystem compositions associated with fire disturbance could play a major role in carbon release from boreal ecosystems. |
|||||
BibTeX:
@article{ueyama13b,
author = {Ueyama, Masahito and Iwata, Hiroki and Harazono, Yoshinobu and Euskirchen, Eugenie S. and Oechel, Walter C. and Zona, Donatella},
title = {Growing season and spatial variations of carbon fluxes of Arctic and boreal ecosystems in Alaska (USA)},
journal = {ECOLOGICAL APPLICATIONS},
year = {2013},
volume = {23},
number = {8},
pages = {1798--1816},
doi = {https://doi.org/10.1890/11-0875.1}
}
|
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| Ueyama, M. and Ando, T. | Diurnal, weekly, seasonal, and spatial variabilities in carbon dioxide flux in different urban landscapes in Sakai, Japan | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({22}), pp. 14727-14740 |
article | DOI |
| Abstract: To evaluate CO2 emissions in urban areas and their temporal and spatial variability, continuous measurements of CO2 fluxes were conducted using the eddy covariance method at three locations in Sakai, Osaka, Japan. Based on the flux footprint at the measurement sites, CO2 fluxes from the three sites were partitioned into five datasets representing a dense urban center, a moderately urban area, a suburb, an urban park, and a rural area. A distinct biological uptake of CO2 was observed in the suburb, urban park, and rural areas in the daytime, whereas high emissions were observed in the dense and moderate urban areas in the daytime. Weekday CO2 emissions in the dense urban center and suburban area were approximately 50% greater than emissions during weekends and holidays, but the other landscapes did not exhibit a clear weekly cycle. Seasonal variations in the urban park, rural area, and suburban area were influenced by photosynthetic uptake, exhibiting the lowest daily emissions or even uptake during the summer months. In contrast, the dense and moderately urban areas emitted CO2 in all seasons. CO2 emissions in the urban areas were high in the winter and summer months, and they significantly increased with the increase in air temperature in the summer and the decrease in air temperature in the winter. Irrespective of the land cover type, all urban landscapes measured in this study acted as net annual CO2 sources, with emissions ranging from 0.5 to 4.9 kg Cm-2 yr(-1). The magnitude of the annual CO2 emissions was negatively correlated with the green fraction; areas with a smaller green fraction had higher annual CO2 emissions. Upscaled flux estimated based on the green fraction indicated that the emissions for the entire city were 3.3 kgCm(-2) yr(-1), which is equivalent to 0.5 Tg C yr(-1) or 1.8 MtCO(2) yr(-1), based on the area of the city (149.81 km(2)). A network of eddy covariance measurements is useful for characterizing the spatial and temporal variations in net CO2 fluxes from urban areas. Multiple methods would be required to evaluate the rationale behind the fluxes and overcome the limitations in the future. |
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BibTeX:
@article{ueyama16a,
author = {Ueyama, Masahito and Ando, Tomoya},
title = {Diurnal, weekly, seasonal, and spatial variabilities in carbon dioxide flux in different urban landscapes in Sakai, Japan},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {22},
pages = {14727--14740},
doi = {https://doi.org/10.5194/acp-16-14727-2016}
}
|
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| Ueyama, M., Ichii, K., Kobayashi, H., Kumagai, T., Beringer, J., Merbold, L., Euskirchen, E.S., Hirano, T., Marchesini, L.B., Baldocchi, D., Saitoh, T.M., Mizoguchi, Y., Ono, K., Kim, J., Varlagin, A., Kang, M., Shimizu, T., Kosugi, Y., Bret-Harte, M.S., Machimura, T., Matsuura, Y., Ohta, T., Takagi, K., Takanashi, S. and Yasuda, Y. | Inferring CO(2)fertilization effect based on global monitoring land-atmosphere exchange with a theoretical model | {2020} | ENVIRONMENTAL RESEARCH LETTERS Vol. {15}({8}) |
article | DOI URL |
| Abstract: Rising atmospheric CO(2)concentration ([CO2]) enhances photosynthesis and reduces transpiration at the leaf, ecosystem, and global scale via the CO(2)fertilization effect. The CO(2)fertilization effect is among the most important processes for predicting the terrestrial carbon budget and future climate, yet it has been elusive to quantify. For evaluating the CO(2)fertilization effect on land photosynthesis and transpiration, we developed a technique that isolated this effect from other confounding effects, such as changes in climate, using a noisy time series of observed land-atmosphere CO(2)and water vapor exchange. Here, we evaluate the magnitude of this effect from 2000 to 2014 globally based on constraint optimization of gross primary productivity (GPP) and evapotranspiration in a canopy photosynthesis model over 104 global eddy-covariance stations. We found a consistent increase of GPP (0.138 0.007% ppm(-1); percentile per rising ppm of [CO2]) and a concomitant decrease in transpiration (-0.073% 0.006% ppm(-1)) due to rising [CO2]. Enhanced GPP from CO(2)fertilization after the baseline year 2000 is, on average, 1.2% of global GPP, 12.4 g C m(-2)yr(-1)or 1.8 Pg C yr(-1)at the years from 2001 to 2014. Our result demonstrates that the current increase in [CO2] could potentially explain the recent land CO(2)sink at the global scale. | |||||
BibTeX:
@article{ueyama20a,
author = {Ueyama, Masahito and Ichii, Kazuhito and Kobayashi, Hideki and Kumagai, Tomo'omi and Beringer, Jason and Merbold, Lutz and Euskirchen, Eugenie S. and Hirano, Takashi and Marchesini, Luca Belelli and Baldocchi, Dennis and Saitoh, Taku M. and Mizoguchi, Yasuko and Ono, Keisuke and Kim, Joon and Varlagin, Andrej and Kang, Minseok and Shimizu, Takanori and Kosugi, Yoshiko and Bret-Harte, M. Syndonia and Machimura, Takashi and Matsuura, Yojiro and Ohta, Takeshi and Takagi, Kentaro and Takanashi, Satoru and Yasuda, Yukio},
title = {Inferring CO(2)fertilization effect based on global monitoring land-atmosphere exchange with a theoretical model},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
publisher = {IOP PUBLISHING LTD},
year = {2020},
volume = {15},
number = {8},
note = {Query date: 2021-04-02 15:20:04},
url = {https://iopscience.iop.org/article/10.1088/1748-9326/ab79e5/meta},
doi = {https://doi.org/10.1088/1748-9326/ab79e5}
}
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| Ueyama, M., Iwata, H., Kobayashi, H., Euskirchen, E., Merbold, L., Ohta, T., Machimura, T., Zona, D., Oechel, W.C. and Schuur, E.A.G. | Arctic Hydrology, Permafrost and Ecosystems: Greenhouse Gases and Energy Fluxes at Permafrost Zone | 2021 | Arctic Hydrology, Permafrost and Ecosystems | book | URL |
| Abstract: Energy, water, and greenhouse gas exchange in the permafrost zone play an important role in the regional and global climate system at multiple temporal and spatial scales. High-latitude warming in recent years has substantially altered ecosystem function, including … | |||||
BibTeX:
@book{ueyama21a,
author = {Masahito Ueyama and Hiroki Iwata and Hideki Kobayashi and Eugénie Euskirchen and Lutz Merbold and Takeshi Ohta and Takashi Machimura and Donatella Zona and Walter C. Oechel and Edward A. G. Schuur},
title = {Arctic Hydrology, Permafrost and Ecosystems: Greenhouse Gases and Energy Fluxes at Permafrost Zone},
journal = {Arctic Hydrology, Permafrost and Ecosystems},
publisher = {SPRINGER},
year = {2021},
url = {https://link.springer.com/chapter/10.1007/978-3-030-50930-9_18}
}
|
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| ul-Haq, Z., Tariq, S. and Ali, M. | Atmospheric variability of methane over Pakistan, Afghanistan and adjoining areas using retrievals from SCIAMACHY/ENVISAT | {2015} | JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS Vol. {135}, pp. 161-173 |
article | DOI |
| Abstract: In the present work we have studied spatial and temporal variability of methane total column (MTC) over Pakistan and neighboring regions of Afghanistan, India and Iran by using observations of SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) aboard EOS ENVISAT. Satellite measurements show large spatio-temporal variations in MTC over the study domain at different time scales. We find an average MTC of 1787 +/- 22 ppb (annual average +/- standard deviation) with 3.7% (slope 7.14 +/- 1.28, y-intercept 1751 +/- 7.19, r=0.91) increase during the period of January 2003 to April 2012. An enhanced MTC is observed mostly over the Indo-Gangetic Plain and areas with high anthropogenic activities. MTC exhibits a seasonal peak of 1804 + 28 ppb in summer followed by autumn (1800 + 25 ppb) and winter (1777 +/- 24 ppb). We have also discussed anthropogenic emission estimates in the study area obtained from EDGAR database. Substantial increments of 77% and 61% are observed in anthropogenic CH4 emissions for Pakistan and Afghanistan, respectively, during 1990-2008. Anthropogenic CH4 emissions from enteric fermentation and livestock sectors are found to be the highest. EDGAR data have also identified megacity Lahore, Sukkur, megacity Karachi, Dera Ghazi Khan, megacity Delhi and Ahmedabad as large point sources of CH4 emissions in the region. The emissions from Karachi show the highest increase of 107%, while Lahore is found with the highest annual average emissions of 8.8 x 10(-10) kg m(-2) s(-1). (C) 2015 Elsevier Ltd. All rights reserved. |
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BibTeX:
@article{ul-haq15a,
author = {ul-Haq, Zia and Tariq, Salman and Ali, Muhammad},
title = {Atmospheric variability of methane over Pakistan, Afghanistan and adjoining areas using retrievals from SCIAMACHY/ENVISAT},
journal = {JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS},
year = {2015},
volume = {135},
pages = {161--173},
doi = {https://doi.org/10.1016/j.jastp.2015.11.002}
}
|
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| Valsala, V., Tiwari, Y.K., Pillai, P., Roxy, M., Maksyutov, S. and Murtugudde, R. | Intraseasonal variability of terrestrial biospheric CO2 fluxes over India during summer monsoons | {2013} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {118}({2}), pp. 752-769 |
article | DOI |
| Abstract: The intraseasonal oscillations (ISOs) in terrestrial biospheric fluxes of carbondioxide (CO2) over the Indian subcontinent were investigated for the summer monsoon season from June to September. We utilized two optimized datasets of Net Ecosystem Exchange (NEE) fluxes of CO2 at a spatial resolution of 1 degrees x1 degrees grid and at daily time scale for the years 2000-2009. Seasonally, over the whole of Indian subcontinent, terrestrial biospheric CO2 fluxes were found to be a net source (sink) during June and July (August and September). Intraseasonal variability of CO2 fluxes for the two distinct time scales, 30-60days and 10-20days, was extracted with a spectral harmonic filter. The dominant ISO mode in the CO2 flux over India is at a period of 60days or longer during weak monsoons years but at 10-30days for strong monsoon years. The ISOs of CO2 flux show coherent structures along with corresponding rainfall ISOs at a 2-3day lag (CO2 lags rainfall) and nearly 3-4day lag with ISOs in surface air-temperature (CO2 lags air-temperature). The ranges of these lags are consistent in the two data products examined here. The apparent lags between CO2 flux and rainfall ISOs are found to be induced by the temperature effects on net primary production (NPP) and ecosystem respiration (RE). The terrestrial biospheric fluxes over the subcontinent are coherent with the northward propagating summer monsoon ISOs albeit as a combination of rainfall, available radiation, and air-temperature. The study offers a mechanistic understanding of variability of terrestrial biospheric sources and sinks of CO2 over the Indian subcontinent, in tandem with the intraseasonal variability of the summer monsoon rainfall. |
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BibTeX:
@article{valsala13a,
author = {Valsala, Vinu and Tiwari, Yogesh K. and Pillai, Prasanth and Roxy, Mathew and Maksyutov, Shamil and Murtugudde, Raghu},
title = {Intraseasonal variability of terrestrial biospheric CO2 fluxes over India during summer monsoons},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2013},
volume = {118},
number = {2},
pages = {752--769},
doi = {https://doi.org/10.1002/jgrg.20037}
}
|
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| van der Laan-Luijkx, I.T., van der Laan, S., Uglietti, C., Schibig, M.F., Neubert, R.E.M., Meijer, H.A.J., Brand, W.A., Jordan, A., Richter, J.M., Rothe, M. and Leuenberger, M.C. | Atmospheric CO2, delta(O-2/N-2) and delta(CO2)-C-13 measurements at Jungfraujoch, Switzerland: results from a flask sampling intercomparison program | {2013} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {6}({7}), pp. 1805-1815 |
article | DOI |
| Abstract: We present results from an intercomparison program of CO2, delta(O-2/N-2) and delta(CO2)-C-13 measurements from atmospheric flask samples. Flask samples are collected on a biweekly basis at the High Altitude Research Station Jungfraujoch in Switzerland for three European laboratories: the University of Bern, Switzerland, the University of Groningen, the Netherlands and the Max Planck Institute for Biogeochemistry in Jena, Germany. Almost 4 years of measurements of CO2, delta(O-2/N-2) and delta(CO2)-C-13 are compared in this paper to assess the measurement compatibility of the three laboratories. While the average difference for the CO2 measurements between the laboratories in Bern and Jena meets the required compatibility goal as defined by the World Meteorological Organization, the standard deviation of the average differences between all laboratories is not within the required goal. However, the obtained annual trend and seasonalities are the same within their estimated uncertainties. For delta(O-2/N-2) significant differences are observed between the three laboratories. The comparison for delta(CO2)-C-13 yields the least compatible results and the required goals are not met between the three laboratories. Our study shows the importance of regular intercomparison exercises to identify potential biases between laboratories and the need to improve the quality of atmospheric measurements. |
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BibTeX:
@article{vanderlaan-luijkx13a,
author = {van der Laan-Luijkx, I. T. and van der Laan, S. and Uglietti, C. and Schibig, M. F. and Neubert, R. E. M. and Meijer, H. A. J. and Brand, W. A. and Jordan, A. and Richter, J. M. and Rothe, M. and Leuenberger, M. C.},
title = {Atmospheric CO2, delta(O-2/N-2) and delta(CO2)-C-13 measurements at Jungfraujoch, Switzerland: results from a flask sampling intercomparison program},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2013},
volume = {6},
number = {7},
pages = {1805--1815},
doi = {https://doi.org/10.5194/amt-6-1805-2013}
}
|
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| van der Laan-Luijkx, I.T., van der Velde, I.R., Krol, M.C., Gatti, L.V., Domingues, L.G., Correia, C.S.C., Miller, J.B., Gloor, M., van Leeuwen, T.T., Kaiser, J.W., Wiedinmyer, C., Basu, S., Clerbaux, C. and Peters, W. | Response of the Amazon carbon balance to the 2010 drought derived with CarbonTracker South America | {2015} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {29}({7}), pp. 1092-1108 |
article | DOI |
| Abstract: Two major droughts in the past decade had large impacts on carbon exchange in the Amazon. Recent analysis of vertical profile measurements of atmospheric CO2 and CO by Gatti et al. (2014) suggests that the 2010 drought turned the normally close-to-neutral annual Amazon carbon balance into a substantial source of nearly 0.5 PgC/yr, revealing a strong drought response. In this study, we revisit this hypothesis and interpret not only the same CO2/CO vertical profile measurements but also additional constraints on carbon exchange such as satellite observations of CO, burned area, and fire hot spots. The results from our CarbonTracker South America data assimilation system suggest that carbon uptake by vegetation was indeed reduced in 2010 but that the magnitude of the decrease strongly depends on the estimated 2010 and 2011 biomass burning emissions. We have used fire products based on burned area (Global Fire Emissions Database version 4), satellite-observed CO columns (Infrared Atmospheric Sounding Interferometer), fire radiative power (Global Fire Assimilation System version 1), and fire hot spots (Fire Inventory from NCAR version 1), and found an increase in biomass burning emissions in 2010 compared to 2011 of 0.16 to 0.24 PgC/yr. We derived a decrease of biospheric uptake ranging from 0.08 to 0.26 PgC/yr, with the range determined from a set of alternative inversions using different biomass burning estimates. Our numerical analysis of the 2010 Amazon drought results in a total reduction of carbon uptake of 0.24 to 0.50 PgC/yr and turns the balance from carbon sink to source. Our findings support the suggestion that the hydrological cycle will be an important driver of future changes in Amazonian carbon exchange. |
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BibTeX:
@article{vanderlaan-luijkx15a,
author = {van der Laan-Luijkx, I. T. and van der Velde, I. R. and Krol, M. C. and Gatti, L. V. and Domingues, L. G. and Correia, C. S. C. and Miller, J. B. and Gloor, M. and van Leeuwen, T. T. and Kaiser, J. W. and Wiedinmyer, C. and Basu, S. and Clerbaux, C. and Peters, W.},
title = {Response of the Amazon carbon balance to the 2010 drought derived with CarbonTracker South America},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2015},
volume = {29},
number = {7},
pages = {1092--1108},
doi = {https://doi.org/10.1002/2014GB005082}
}
|
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| van der Laan-Luijkx, I.T., van der Velde, I.R., van der Veen, E., Tsuruta, A., Stanislawska, K., Babenhauserheide, A., Zhang, H.F., Liu, Y., He, W., Chen, H., Masarie, K.A., Krol, M.C. and Peters, W. | The CarbonTracker Data Assimilation Shell (CTDAS) v1.0: implementation and global carbon balance 2001-2015 | {2017} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {10}({7}), pp. 2785-2800 |
article | DOI |
| Abstract: Data assimilation systems are used increasingly to constrain the budgets of reactive and long-lived gases measured in the atmosphere. Each trace gas has its own lifetime, dominant sources and sinks, and observational network (from flask sampling and in situ measurements to space-based remote sensing) and therefore comes with its own optimal configuration of the data assimilation. The CarbonTracker Europe data assimilation system for CO2 estimates global carbon sources and sinks, and updates are released annually and used in carbon cycle studies. CarbonTracker Europe simulations are performed using the new modular implementation of the data assimilation system: the CarbonTracker Data Assimilation Shell (CTDAS). Here, we present and document this redesign of the data assimilation code that forms the heart of CarbonTracker, specifically meant to enable easy extension and modification of the data assimilation system. This paper also presents the setup of the latest version of CarbonTracker Europe (CTE2016), including the use of the gridded state vector, and shows the resulting carbon flux estimates. We present the distribution of the carbon sinks over the hemispheres and between the land biosphere and the oceans. We show that with equal fossil fuel emissions, 2015 has a higher atmospheric CO2 growth rate compared to 2014, due to reduced net land carbon uptake in later year. The European carbon sink is especially present in the forests, and the average net uptake over 2001-2015 was 0.17 +/- 0.11 PgCyr(-1) with reductions to zero during drought years. Finally, we also demonstrate the versatility of CTDAS by presenting an overview of the wide range of applications for which it has been used so far. |
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BibTeX:
@article{vanderlaan-luijkx17a,
author = {van der Laan-Luijkx, Ingrid T. and van der Velde, Ivar R. and van der Veen, Emma and Tsuruta, Aki and Stanislawska, Karolina and Babenhauserheide, Arne and Zhang, Hui Fang and Liu, Yu and He, Wei and Chen, Huilin and Masarie, Kenneth A. and Krol, Maarten C. and Peters, Wouter},
title = {The CarbonTracker Data Assimilation Shell (CTDAS) v1.0: implementation and global carbon balance 2001-2015},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2017},
volume = {10},
number = {7},
pages = {2785--2800},
doi = {https://doi.org/10.5194/gmd-10-2785-2017}
}
|
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| van der Velde, I.R., Miller, J.B., Schaefer, K., Masarie, K.A., Denning, S., White, J.W.C., Tans, P.P., Krol, M.C. and Peters, W. | Biosphere model simulations of interannual variability in terrestrial C-13/C-12 exchange | {2013} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {27}({3}), pp. 637-649 |
article | DOI |
| Abstract: Previous studies suggest that a large part of the variability in the atmospheric ratio of (CO2)-C-13/(12)CO(2)originates from carbon exchange with the terrestrial biosphere rather than with the oceans. Since this variability is used to quantitatively partition the total carbon sink, we here investigate the contribution of interannual variability (IAV) in biospheric exchange to the observed atmospheric C-13 variations. We use the Simple Biosphere - Carnegie-Ames-Stanford Approach biogeochemical model, including a detailed isotopic fractionation scheme, separate C-12 and C-13 biogeochemical pools, and satellite-observed fire disturbances. This model of (CO2)-C-12 and (CO2)-C-13 thus also produces return fluxes of (13)CO(2)from its differently aged pools, contributing to the so-called disequilibrium flux. Our simulated terrestrial C-13 budget closely resembles previously published model results for plant discrimination and disequilibrium fluxes and similarly suggests that variations in C-3 discrimination and year-to-year variations in C(3)and C-4 productivity are the main drivers of their IAV. But the year-to-year variability in the isotopic disequilibrium flux is much lower (1 sigma=1.5PgCyr(-1)) than required (12.5PgCyr(-1)) to match atmospheric observations, under the common assumption of low variability in net ocean CO2 fluxes. This contrasts with earlier published results. It is currently unclear how to increase IAV in these drivers suggesting that SiBCASA still misses processes that enhance variability in plant discrimination and relative C-3/C(4)productivity. Alternatively, C-13 budget terms other than terrestrial disequilibrium fluxes, including possibly the atmospheric growth rate, must have significantly different IAV in order to close the atmospheric C-13 budget on a year-to-year basis. |
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BibTeX:
@article{vandervelde13a,
author = {van der Velde, I. R. and Miller, J. B. and Schaefer, K. and Masarie, K. A. and Denning, S. and White, J. W. C. and Tans, P. P. and Krol, M. C. and Peters, W.},
title = {Biosphere model simulations of interannual variability in terrestrial C-13/C-12 exchange},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2013},
volume = {27},
number = {3},
pages = {637--649},
doi = {https://doi.org/10.1002/gbc.20048}
}
|
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| van der Velde, I. | Studying biosphere-atmosphere exchange of CO2 through Carbon-13 stable isotopes [BibTeX] |
2015 | School: Wageningen University | phdthesis | |
BibTeX:
@phdthesis{vandervelde15a,
author = {IR van der Velde},
title = {Studying biosphere-atmosphere exchange of CO2 through Carbon-13 stable isotopes},
school = {Wageningen University},
year = {2015}
}
|
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| van der Velde, I.R., Miller, J.B., van der Molen, M.K., Tans, P.P., Vaughn, B.H., White, J.W., Schaefer, K. and Peters, W. | A multi-species data assimilation system to retrieve information on land-atmosphere exchange processes [BibTeX] |
2017 | GEOSCIENTIFIC MODEL DEVELOPMENT | article | |
BibTeX:
@article{vandervelde17a,
author = {van der Velde, Ivar R and Miller, John B and van der Molen, Michiel K and Tans, Pieter P and Vaughn, Bruce H and White, James WC and Schaefer, Kevin and Peters, Wouter},
title = {A multi-species data assimilation system to retrieve information on land-atmosphere exchange processes},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2017}
}
|
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| van der Velde, I.R., Miller, J.B., van der Molen, M.K., Tans, P.P., Vaughn, B.H., White, J.W.C., Schaefer, K. and Peters, W. | The CarbonTracker Data Assimilation System for CO2 and δ13C (CTDAS-C13 v1. 0): retrieving information on land--atmosphere exchange processes [BibTeX] |
2018 | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. 11(1), pp. 283-304 |
article | URL |
BibTeX:
@article{vandervelde18a,
author = {van der Velde, I. R. and Miller, J. B. and van der Molen, M. K. and Tans, P. P. and Vaughn, B. H. and White, J. W. C. and Schaefer, K. and Peters, W.},
title = {The CarbonTracker Data Assimilation System for CO2 and δ13C (CTDAS-C13 v1. 0): retrieving information on land--atmosphere exchange processes},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2018},
volume = {11},
number = {1},
pages = {283-304},
url = {https://core.ac.uk/download/pdf/153217722.pdf}
}
|
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| van der Werf, G.R., Morton, D.C., DeFries, R.S., Giglio, L., Randerson, J.T., Collatz, G.J. and Kasibhatla, P.S. | Estimates of fire emissions from an active deforestation region in the southern Amazon based on satellite data and biogeochemical modelling | {2009} | BIOGEOSCIENCES Vol. {6}({2}), pp. 235-249 |
article | DOI |
| Abstract: Tropical deforestation contributes to the build-up of atmospheric carbon dioxide in the atmosphere. Within the deforestation process, fire is frequently used to eliminate biomass in preparation for agricultural use. Quantifying these deforestation-induced fire emissions represents a challenge, and current estimates are only available at coarse spatial resolution with large uncertainty. Here we developed a biogeochemical model using remote sensing observations of plant productivity, fire activity, and deforestation rates to estimate emissions for the Brazilian state of Mato Grosso during 2001-2005. Our model of DEforestation CArbon Fluxes (DECAF) runs at 250-m spatial resolution with a monthly time step to capture spatial and temporal heterogeneity in fire dynamics in our study area within the ``arc of deforestation'', the southern and eastern fringe of the Amazon tropical forest where agricultural expansion is most concentrated. Fire emissions estimates from our modelling framework were on average 90 Tg C year(-1), mostly stemming from fires associated with deforestation (74%) with smaller contributions from fires from conversions of Cerrado or pastures to cropland (19%) and pasture fires (7%). In terms of carbon dynamics, about 80% of the aboveground living biomass and litter was combusted when forests were converted to pasture, and 89% when converted to cropland because of the highly mechanized nature of the deforestation process in Mato Grosso. The trajectory of land use change from forest to other land uses often takes more than one year, and part of the biomass that was not burned in the dry season following deforestation burned in consecutive years. This led to a partial decoupling of annual deforestation rates and fire emissions, and lowered interannual variability in fire emissions. Interannual variability in the region was somewhat dampened as well because annual emissions from fires following deforestation and from maintenance fires did not covary, although the effect was small due to the minor contribution of maintenance fires. Our results demonstrate how the DECAF model can be used to model deforestation fire emissions at relatively high spatial and temporal resolutions. Detailed model output is suitable for policy applications concerned with annual emissions estimates distributed among post-clearing land uses and science applications in combination with atmospheric emissions modelling to provide constrained global deforestation fire emissions estimates. DECAF currently estimates emissions from fire; future efforts can incorporate other aspects of net carbon emissions from deforestation including soil respiration and regrowth. |
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BibTeX:
@article{vanderwerf09a,
author = {van der Werf, G. R. and Morton, D. C. and DeFries, R. S. and Giglio, L. and Randerson, J. T. and Collatz, G. J. and Kasibhatla, P. S.},
title = {Estimates of fire emissions from an active deforestation region in the southern Amazon based on satellite data and biogeochemical modelling},
journal = {BIOGEOSCIENCES},
year = {2009},
volume = {6},
number = {2},
pages = {235--249},
doi = {https://doi.org/10.5194/bg-6-235-2009}
}
|
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| van der Werf, G.R., Randerson, J.T., Giglio, L., van Leeuwen, T.T., Chen, Y., Rogers, B.M., Mu, M., van Marle, M.J.E., Morton, D.C., Collatz, G.J., Yokelson, R.J. and Kasibhatla, P.S. | Global fire emissions estimates during 1997-2016 | {2017} | EARTH SYSTEM SCIENCE DATA Vol. {9}({2}), pp. 697-720 |
article | DOI |
| Abstract: Climate, land use, and other anthropogenic and natural drivers have the potential to influence fire dynamics in many regions. To develop a mechanistic understanding of the changing role of these drivers and their impact on atmospheric composition, long-term fire records are needed that fuse information from different satellite and in situ data streams. Here we describe the fourth version of the Global Fire Emissions Database (GFED) and quantify global fire emissions patterns during 1997-2016. The modeling system, based on the Carnegie-Ames-Stanford Approach (CASA) biogeochemical model, has several modifications from the previous version and uses higher quality input datasets. Significant upgrades include (1) new burned area estimates with contributions from small fires, (2) a revised fuel consumption parameterization optimized using field observations, (3) modifications that improve the representation of fuel consumption in frequently burning landscapes, and (4) fire severity estimates that better represent continental differences in burning processes across boreal regions of North America and Eurasia. The new version has a higher spatial resolution (0.25 degrees) and uses a different set of emission factors that separately resolves trace gas and aerosol emissions from temperate and boreal forest ecosystems. Global mean carbon emissions using the burned area dataset with small fires (GFED4s) were 2.2 x 10(15) grams of carbon per year (Pg C yr(-1)) during 1997-2016, with a maximum in 1997 (3.0 Pg C yr(-1)) and minimum in 2013 (1.8 Pg C yr(-1)). These estimates were 11% higher than our previous estimates (GFED3) during 1997-2011, when the two datasets overlapped. This net increase was the result of a substantial increase in burned area (37 %), mostly due to the inclusion of small fires, and a modest decrease in mean fuel consumption (19 %) to better match estimates from field studies, primarily in savannas and grasslands. For trace gas and aerosol emissions, differences between GFED4s and GFED3 were often larger due to the use of revised emission factors. If small fire burned area was excluded (GFED4 without the ``s'' for small fires), average emissions were 1.5 Pg C yr(-1). The addition of small fires had the largest impact on emissions in temperate North America, Central America, Europe, and temperate Asia. This small fire layer carries substantial uncertainties; improving these estimates will require use of new burned area products derived from high-resolution satellite imagery. Our revised dataset provides an internally consistent set of burned area and emissions that may contribute to a better understanding of multi-decadal changes in fire dynamics and their impact on the Earth system. GFED data are available from http://www.globalfiredata.org. |
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BibTeX:
@article{vanderwerf17a,
author = {van der Werf, Guido R. and Randerson, James T. and Giglio, Louis and van Leeuwen, Thijs T. and Chen, Yang and Rogers, Brendan M. and Mu, Mingquan and van Marle, Margreet J. E. and Morton, Douglas C. and Collatz, G. James and Yokelson, Robert J. and Kasibhatla, Prasad S.},
title = {Global fire emissions estimates during 1997-2016},
journal = {EARTH SYSTEM SCIENCE DATA},
year = {2017},
volume = {9},
number = {2},
pages = {697--720},
doi = {https://doi.org/10.5194/essd-9-697-2017}
}
|
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| Vargas, R., Loescher, H.W., Arredondo, T., Huber-Sannwald, E., Lara-Lara, R. and Yepez, E.A. | Opportunities for advancing carbon cycle science in Mexico: toward a continental scale understanding | {2012} | ENVIRONMENTAL SCIENCE & POLICY Vol. {21}, pp. 84-93 |
article | DOI |
| Abstract: Solutions to current global environmental problems throughout fundamental ecological understandings are only reached through international programmatic and scientific collaborations. Both scientists and policymakers recognize the importance of the role of carbon cycle science (CCS) in North America, however regional ecological studies in North America often do not include the role of Mexico. Given the sharp ecological, climatic and socioeconomic differences among the three countries conforming North America it is fundamental to incorporate Mexico's unique contributions toward regional CCS. We provide a synthesis of opportunities and challenges for advancing land and ocean research in Mexico in order to move toward a complete North American continental scale CCS. First, we provide the socio-ecological context of Mexico relevant to CCS. Second, we compare the existing relationships among scientific/governmental entities and funding agencies that contribute to CCS in the United States and Mexico. Third, we discuss Mexico's state-of-the-art CCS, and synthesize its recent advances with emphasis on land- and ocean-atmosphere interactions. We highlight continental-scale opportunities toward a tri-national carbon research, infrastructure, and education network. (C) 2012 Elsevier Ltd. All rights reserved. |
|||||
BibTeX:
@article{vargas12a,
author = {Vargas, Rodrigo and Loescher, Henry W. and Arredondo, Tulio and Huber-Sannwald, Elisabeth and Lara-Lara, Ruben and Yepez, Enrico A.},
title = {Opportunities for advancing carbon cycle science in Mexico: toward a continental scale understanding},
journal = {ENVIRONMENTAL SCIENCE & POLICY},
year = {2012},
volume = {21},
pages = {84--93},
doi = {https://doi.org/10.1016/j.envsci.2012.04.003}
}
|
|||||
| van der Velde, I.R., van der Werf, G.R., Houweling, S., Eskes, H.J., Veefkind, J.P., Borsdorff, T. and Aben, I. | Biomass burning combustion efficiency observed from space using measurements of CO and NO2 by the TROPOspheric Monitoring Instrument (TROPOMI) | {2021} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {21}({2}), pp. {597-616} |
article | DOI URL |
| Abstract: The global fire emission inventories depend on ground and airborne measurements of species-specific emission factors (EFs), which translate dry matter losses due to fires to actual trace gas and aerosol emissions. The EFs of nitrogen oxides (NOx) and carbon monoxide (CO) can function as a proxy for combustion efficiency to distinguish flaming from smoldering combustion. The uncertainties in these EFs remain large as they are limited by the spatial and temporal representativeness of the measurements. The global coverage of satellite observations has the advantage of filling this gap, making these measurements highly complementary to ground-based or airborne data. We present a new analysis of biomass burning pollutants using space-borne data to investigate the spatiotemporal efficiency of fire combustion. Column measurements of nitrogen dioxide and carbon monoxide (XNO2 and XCO) from the TROPOspheric Monitoring Instrument (TROPOMI) are used to quantify the relative atmospheric enhancements of these species over different fireprone regions around the world. We find spatial and temporal patterns in the Delta XNO2 / Delta XCO ratio that point to distinct differences in biomass burning behavior. Such differences are induced by the burning phase of the fire (e.g., hightemperature flaming vs. low-temperature smoldering combustion) and burning practice (e.g., the combustion of logs, coarse woody debris and soil organic matter vs. the combustion of fine fuels such as savanna grasses). The sampling techniques and the signal-to-noise ratio of the retrieved Delta XNO2 / Delta XCO signals were quantified with WRF-Chem experiments and showed similar distinct differences in combustion types. The TROPOMI measurements show that the fraction of surface smoldering combustion is much larger for the boreal forest fires in the upper Northern Hemisphere and peatland fires in Indonesia. These types of fires cause a much larger increase (3 to 6 times) in Delta XCO relative to Delta XNO2 than elsewhere in the world. The high spatial and temporal resolution of TROPOMI also enables the detection of spatial gradients in combustion efficiency at smaller regional scales. For instance, in the Amazon, we found higher combustion efficiency (up to 3-fold) for savanna fires than for the nearby tropical deforestation fires. Out of two investigated fire emission products, the TROPOMI measurements support the broad spatial pattern of combustion efficiency rooted in GFED4s. Meanwhile, TROPOMI data also add new insights into regional variability in combustion characteristics that are not well represented in the different emission inventories, which can help the fire modeling community to improve their representation of the spatiotemporal variability in EFs. | |||||
BibTeX:
@article{velde21a,
author = {van der Velde, Ivar R. and van der Werf, Guido R. and Houweling, Sander and Eskes, Henk J. and Veefkind, J. Pepijn and Borsdorff, Tobias and Aben, Ilse},
title = {Biomass burning combustion efficiency observed from space using measurements of CO and NO2 by the TROPOspheric Monitoring Instrument (TROPOMI)},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2021},
volume = {21},
number = {2},
pages = {597--616},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/21/597/2021/acp-21-597-2021.html},
doi = {https://doi.org/10.5194/acp-21-597-2021}
}
|
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| Vellinga, O.S., Gioli, B., Elbers, J.A., Holtslag, A.A.M., Kabat, P. and Hutjes, R.W.A. | Regional carbon dioxide and energy fluxes from airborne observations using flight-path segmentation based on landscape characteristics | {2010} | BIOGEOSCIENCES Vol. {7}({4}), pp. 1307-1321 |
article | DOI |
| Abstract: This paper presents an analysis of regional fluxes obtained with a small aircraft over heterogeneous terrain in the south-west of France, during the large scale field experiment CERES'07. We use a method combining variable flight-path segmentation with basic airborne footprint analysis. The segmentation is based on topography, land use and soil type, using a.o. satellite imagery and digital maps. The segments are delineated using an average footprint length, based on all flights, and segment lengths, which are variable in space but not in time. The method results in segment averaged carbon and energy fluxes, which are shown to be representative of regional fluxes. Our analysis is focussed on carbon dioxide, heat and evaporative fluxes around solar noon. We will show that spatial and seasonal variations in the fluxes can be linked to the underlying landscape. In addition, a comparison between the airborne data and ground flux data is made to support our results. However, due to the incompleteness of ground data for some predominant vegetation types (even in such a data dense context), upscaling of ground data to regional fluxes was not possible. Without the comparison, we are still able to demonstrate that aircraft can provide direct and meaningful estimates of regional fluxes of energy and carbon dioxide. |
|||||
BibTeX:
@article{vellinga10a,
author = {Vellinga, O. S. and Gioli, B. and Elbers, J. A. and Holtslag, A. A. M. and Kabat, P. and Hutjes, R. W. A.},
title = {Regional carbon dioxide and energy fluxes from airborne observations using flight-path segmentation based on landscape characteristics},
journal = {BIOGEOSCIENCES},
year = {2010},
volume = {7},
number = {4},
pages = {1307--1321},
doi = {https://doi.org/10.5194/bg-7-1307-2010}
}
|
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| Venkiteswaran, J.J., Schiff, S.L. and Wallin, M.B. | Large Carbon Dioxide Fluxes from Headwater Boreal and Sub-Boreal Streams | {2014} | PLOS ONE Vol. {9}({7}) |
article | DOI |
| Abstract: Half of the world's forest is in boreal and sub-boreal ecozones, containing large carbon stores and fluxes. Carbon lost from headwater streams in these forests is underestimated. We apply a simple stable carbon isotope idea for quantifying the CO2 loss from these small streams; it is based only on in-stream samples and integrates over a significant distance upstream. We demonstrate that conventional methods of determining CO2 loss from streams necessarily underestimate the CO2 loss with results from two catchments. Dissolved carbon export from headwater catchments is similar to CO2 loss from stream surfaces. Most of the CO2 originating in high CO2 groundwaters has been lost before typical in-stream sampling occurs. In the Harp Lake catchment in Canada, headwater streams account for 10% of catchment net CO2 uptake. In the Krycklan catchment in Sweden, this more than doubles the CO2 loss from the catchment. Thus, even when corrected for aquatic CO2 loss measured by conventional methods, boreal and sub-boreal forest carbon budgets currently overestimate carbon sequestration on the landscape. |
|||||
BibTeX:
@article{venkiteswaran14a,
author = {Venkiteswaran, Jason J. and Schiff, Sherry L. and Wallin, Marcus B.},
title = {Large Carbon Dioxide Fluxes from Headwater Boreal and Sub-Boreal Streams},
journal = {PLOS ONE},
year = {2014},
volume = {9},
number = {7},
doi = {https://doi.org/10.1371/journal.pone.0101756}
}
|
|||||
| Verdy, A. and Mazloff, M.R. | A data assimilating model for estimating Southern Ocean biogeochemistry | {2017} | JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS Vol. {122}({9}), pp. 6968-6988 |
article | DOI |
| Abstract: A Biogeochemical Southern Ocean State Estimate (B-SOSE) is introduced that includes carbon and oxygen fields as well as nutrient cycles. The state estimate is constrained with observations while maintaining closed budgets and obeying dynamical and thermodynamic balances. Observations from profiling floats, shipboard data, underway measurements, and satellites are used for assimilation. The years 2008-2012 are chosen due to the relative abundance of oxygen observations from Argo floats during this time. The skill of the state estimate at fitting the data is assessed. The agreement is best for fields that are constrained with the most observations, such as surface pCO(2) in Drake Passage (44% of the variance captured) and oxygen profiles (over 60% of the variance captured at 200 and 1000 m). The validity of adjoint method optimization for coupled physical-biogeochemical state estimation is demonstrated with a series of gradient check experiments. The method is shown to be mature and ready to synthesize in situ biogeochemical observations as they become more available. Documenting the B-SOSE configuration and diagnosing the strengths and weaknesses of the solution informs usage of this product as both a climate baseline and as a way to test hypotheses. Transport of Intermediate Waters across 32 degrees S supplies significant amounts of nitrate to the Atlantic Ocean (5.57 +/- 2.94 Tmol yr(-1)) and Indian Ocean (5.09 +/- 3.06 Tmol yr(-1)), but much less nitrate reaches the Pacific Ocean (1.78 +/- 1.91 Tmol yr(-1)). Estimates of air-sea carbon dioxide fluxes south of 50 degrees S suggest a mean uptake of 0.18 Pg C/yr for the time period analyzed. |
|||||
BibTeX:
@article{verdy17a,
author = {Verdy, A. and Mazloff, M. R.},
title = {A data assimilating model for estimating Southern Ocean biogeochemistry},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS},
year = {2017},
volume = {122},
number = {9},
pages = {6968--6988},
doi = {https://doi.org/10.1002/2016JC012650}
}
|
|||||
| Vetter, P., Schmid, W. and Schwarze, R. | Spatio-temporal statistical analysis of the carbon budget of the terrestrial ecosystem | {2016} | STATISTICAL METHODS AND APPLICATIONS Vol. {25}({1}), pp. 143-161 |
article | DOI |
| Abstract: The Net Ecosystem Exchange describes the net carbon dioxide flux between an ecosystem and the atmosphere and is a key quantity in climate change studies and in political negotiations. This paper provides a spatio-temporal statistical framework, which is able to infer the Net Ecosystem Exchange from remotely-sensed carbon dioxide ground concentrations together with data on the Normalized Difference Vegetation Index, the Gross Primary Production and the land cover classification. The model is based on spatial and temporal latent random effects, that act as space-time varying coefficients, which allows for a flexible modeling of the spatio-temporal auto- and cross-correlation structure. The intra- and inter-annual variations of the Net Ecosystem Exchange are evaluated and dynamic maps are provided on a nearly global grid and in intervals of 16 days. |
|||||
BibTeX:
@article{vetter16a,
author = {Vetter, Patrick and Schmid, Wolfgang and Schwarze, Reimund},
title = {Spatio-temporal statistical analysis of the carbon budget of the terrestrial ecosystem},
journal = {STATISTICAL METHODS AND APPLICATIONS},
year = {2016},
volume = {25},
number = {1},
pages = {143--161},
doi = {https://doi.org/10.1007/s10260-015-0342-7}
}
|
|||||
| Villalobos, Y., Rayner, P., Thomas, S. and Silver, J. | The potential of Orbiting Carbon Observatory-2 data to reduce the uncertainties in CO2 surface fluxes over Australia using a variational assimilation scheme | {2020} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {20}({14}), pp. {8473-8500} |
article | DOI URL |
| Abstract: This paper addresses the question of how much uncertainties in CO2 fluxes over Australia can be reduced by assimilation of total-column carbon dioxide retrievals from the Orbiting Carbon Observatory-2 (OCO-2) satellite instrument. We apply a four-dimensional variational data assimilation system, based around the Community Multiscale Air Quality (CMAQ) transport-dispersion model. We ran a series of observing system simulation experiments to estimate posterior error statistics of optimized monthly-mean CO2 fluxes in Australia. Our assimilations were run with a horizontal grid resolution of 81 km using OCO-2 data for 2015. Based on four representative months, we find that the integrated flux uncertainty for Australia is reduced from 0.52 to 0.13 Pg C yr(-1). Uncertainty reductions of up to 90 % were found at grid-point resolution over productive ecosystems. Our sensitivity experiments show that the choice of the correlation structure in the prior error covariance plays a large role in distributing information from the observations. We also found that biases in the observations would significantly impact the inverted fluxes and could contaminate the final results of the inversion. Biases in prior fluxes are generally removed by the inversion system. Biases in the boundary conditions have a significant impact on retrieved fluxes, but this can be mitigated by including boundary conditions in our retrieved parameters. In general, results from our idealized experiments suggest that flux inversions at this unusually fine scale will yield useful information on the carbon cycle at continental and finer scales. | |||||
BibTeX:
@article{villalobos20a,
author = {Villalobos, Yohanna and Rayner, Peter and Thomas, Steven and Silver, Jeremy},
title = {The potential of Orbiting Carbon Observatory-2 data to reduce the uncertainties in CO2 surface fluxes over Australia using a variational assimilation scheme},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {20},
number = {14},
pages = {8473--8500},
note = {Query date: 2021-04-02 15:20:04},
url = {https://acp.copernicus.org/articles/20/8473/2020/},
doi = {https://doi.org/10.5194/acp-20-8473-2020}
}
|
|||||
| Viskari, T., Hardiman, B., Desai, A.R. and Dietze, M.C. | Model-data assimilation of multiple phenological observations to constrain and predict leaf area index | {2015} | ECOLOGICAL APPLICATIONS Vol. {25}({2}), pp. 546-558 |
article | DOI |
| Abstract: Our limited ability to accurately simulate leaf phenology is a leading source of uncertainty in models of ecosystem carbon cycling. We evaluate if continuously updating canopy state variables with observations is beneficial for predicting phenological events. We employed ensemble adjustment Kalman filter (EAKF) to update predictions of leaf area index (LAI) and leaf extension using tower-based photosynthetically active radiation (PAR) and moderate resolution imaging spectrometer (MODIS) data for 2002-2005 at Willow Creek, Wisconsin, USA, a mature, even-aged, northern hardwood, deciduous forest. The ecosystem demography model version 2 (ED2) was used as the prediction model, forced by offline climate data. EAKF successfully incorporated information from both the observations and model predictions weighted by their respective uncertainties. The resulting estimate reproduced the observed leaf phenological cycle in the spring and the fall better than a parametric model prediction. These results indicate that during spring the observations contribute most in determining the correct bud-burst date, after which the model performs well, but accurately modeling fall leaf senesce requires continuous model updating from observations. While the predicted net ecosystem exchange (NEE) of CO2 precedes tower observations and unassimilated model predictions in the spring, overall the prediction follows observed NEE better than the model alone. Our results show state data assimilation successfully simulates the evolution of plant leaf phenology and improves model predictions of forest NEE. |
|||||
BibTeX:
@article{viskari15a,
author = {Viskari, Toni and Hardiman, Brady and Desai, Ankur R. and Dietze, Michael C.},
title = {Model-data assimilation of multiple phenological observations to constrain and predict leaf area index},
journal = {ECOLOGICAL APPLICATIONS},
year = {2015},
volume = {25},
number = {2},
pages = {546--558},
doi = {https://doi.org/10.1890/14-0497.1}
}
|
|||||
| Vleugel, R.V.D. | A Statistical Model of the Biospheric Carbon Cycle for Carbon Tracker | 2019 | School: Wageningen University | mastersthesis | URL |
| Abstract: The rate of anthropogenic carbon dioxide (CO2) emissions have reached an all-time high since pre-industrial times, due to population and economic growth (Pachauri et al., 2014). The natural carbon sinks are not able to keep up with these CO2 emissions causing a global … | |||||
BibTeX:
@mastersthesis{vleugel19a,
author = {Rolf Van Der Vleugel},
title = {A Statistical Model of the Biospheric Carbon Cycle for Carbon Tracker},
school = {Wageningen University},
year = {2019},
url = {https://edepot.wur.nl/471218}
}
|
|||||
| Vogel, F.R., Thiruchittampalam, B., Theloke, J., Kretschmer, R., Gerbig, C., Hammer, S. and Levin, I. | Can we evaluate a fine-grained emission model using high-resolution atmospheric transport modelling and regional fossil fuel CO2 observations? | {2013} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {65} |
article | DOI |
| Abstract: Quantifying carbon dioxide emissions from fossil fuel burning (FFCO2) is a crucial task to assess continental carbon fluxes and to track anthropogenic emissions changes in the future. In the present study, we investigate potentials and challenges when combining observational data with simulations using high-resolution atmospheric transport and emission modelling. These challenges concern, for example, erroneous vertical mixing or uncertainties in the disaggregation of national total emissions to higher spatial and temporal resolution. In our study, the hourly regional fossil fuel CO2 offset (Delta FFCO2) is simulated by transporting emissions from a 5 min x 5 min emission model (IER2005) that provides FFCO2 emissions from different emission categories. Our Lagrangian particle dispersion model (STILT) is driven by 25 km x 25 km meteorological data from the European Center for Medium-Range Weather Forecast (ECMWF). We evaluate this modelling framework (STILT/ECMWF + IER2005) for the year 2005 using hourly Delta FFCO2 estimates derived from C-14, CO and (222)Radon (Rn-222) observations at an urban site in south-western Germany (Heidelberg). Analysing the mean diurnal cycles of Delta FFCO2 for different seasons, we find that the large seasonal and diurnal variation of emission factors used in the bottom-up emission model (spanning one order of magnitude) are adequate. Furthermore, we show that the use of 222Rn as an independent tracer helps to overcome problems in timing as well as strength of the vertical mixing in the transport model. By applying this variability correction, the model-observation agreement is significantly improved for simulated Delta FFCO2. We found a significant overestimation of Delta FFCO2 concentrations during situations where the air masses predominantly originate from densely populated areas. This is most likely caused by the spatial disaggregation methodology for the residential emissions, which to some extent relies on a constant per capita-based distribution. In the case of domestic heating emissions, this does not appear to be sufficient. |
|||||
BibTeX:
@article{vogel13a,
author = {Vogel, Felix R. and Thiruchittampalam, Balendra and Theloke, Jochen and Kretschmer, Roberto and Gerbig, Christoph and Hammer, Samuel and Levin, Ingeborg},
title = {Can we evaluate a fine-grained emission model using high-resolution atmospheric transport modelling and regional fossil fuel CO2 observations?},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2013},
volume = {65},
doi = {https://doi.org/10.3402/tellusb.v65i0.18681}
}
|
|||||
| Wagle, P. and Kakani, V.G. | Environmental control of daytime net ecosystem exchange of carbon dioxide in switchgrass | {2014} | AGRICULTURE ECOSYSTEMS & ENVIRONMENT Vol. {186}, pp. 170-177 |
article | DOI |
| Abstract: Net ecosystem CO2 exchange (NEE) over a young switchgrass (Panicum virgatum) stand was measured with the eddy covariance technique across two growing seasons in the southern Great Plains of the United States at Chickasha, OK. The objectives of the study were to characterize the effects of environmental factors on daytime NEE and to explore the underlying mechanisms. Photosynthetic photon flux density (PPFD) was the most significant driver of NEE and explained over 90% of the NEE variation during optimum environmental conditions. The light-response curve showed hysteresis as carbon uptake by the ecosystem decreased up to 62% (monthly average) from morning to afternoon at similar light levels because of the stomatal closure control of photosynthesis at high vapor pressure deficit (VPD). This resultant large hysteresis led to the failure of the rectangular hyperbolic light-response function in explaining the NEE-PPFD relationship. The NEE exhibited an optimum temperature range of 28-34 degrees C and decreased markedly beyond 35 degrees C. Our results demonstrated that warm temperature and high VPD altered the NEE-PPFD relationship and thereby affected the ecosystem light-response parameters (respiration, quantum yield, and light saturated photosynthetic capacity). Thus, it is essential to incorporate the effects of temperature and VPD on ecosystem light-response into both empirical and mechanistic models. This study also suggests including the VPD effect in the NEE flux partitioning technique can account for the systematic presence of NEE hysteresis during non-optimal environmental conditions. The results of this study are useful for the modeling community to develop, improve, and validate the models for global change studies, and for the eddy covariance community to develop more robust gap filling methods. (c) 2014 Elsevier B.V. All rights reserved. |
|||||
BibTeX:
@article{wagle14a,
author = {Wagle, Pradeep and Kakani, Vijaya Gopal},
title = {Environmental control of daytime net ecosystem exchange of carbon dioxide in switchgrass},
journal = {AGRICULTURE ECOSYSTEMS & ENVIRONMENT},
year = {2014},
volume = {186},
pages = {170--177},
doi = {https://doi.org/10.1016/j.agee.2014.01.028}
}
|
|||||
| Wagle, P., Xiao, X., Torn, M.S., Cook, D.R., Matamala, R., Fischer, M.L., Jin, C., Dong, J. and Biradar, C. | Sensitivity of vegetation indices and gross primary production of tallgrass prairie to severe drought | {2014} | REMOTE SENSING OF ENVIRONMENT Vol. {152}, pp. 1-14 |
article | DOI |
| Abstract: Drought affects vegetation photosynthesis and growth. Many studies have used the normalized difference vegetation index (NDVI), which is calculated as the normalized ratio between near infrared and red spectral bands in satellite images, to evaluate the response of vegetation to drought. In this study, we examined the impacts of drought on three vegetation indices (NDVI, enhanced vegetation index, EVI, and land surface water index, LSWI) and CO2 flux from three tallgrass prairie eddy flux tower sites in the U.S. Gross primary production (GPP) was also modeled using a satellite-based Vegetation Photosynthesis Model (VPM), and the modeled GPP (GPP(VPM)) was compared with the GPP (GPP(EC)) derived from eddy covariance measurements. Precipitation at two sites in Oklahoma was 30% below the historical mean in both years of the study period (2005-2006), while the site in Illinois did not experience drought in the 2005-2007 study period. The EVI explained the seasonal dynamics of GPP better than did NDVI. The LSWI dropped below zero during severe droughts in the growing season, showing its potential to track drought. The result shows that GPP was more sensitive to drought than were vegetation indices, and EVI and LSWI were more sensitive than NDVI. We developed a modified function (Wsailar), calculated as a function of LSWI, to account for the effect of severe droughts on GPP in VPM. The GPP(VPM) from the modified VPM accounted for the rapid reduction in GPP during severe droughts and the seasonal dynamics of GPPvpm agreed reasonably well with GPP(EC). Our analysis shows that 8-day averaged values (temperature, vapor-pressure deficit) do not reflect the short-term extreme climate events well, suggesting that satellitebased models may need to be run at daily or hourly scales, especially under unfavorable climatic conditions. (C) 2014 Elsevier Inc. All rights reserved. |
|||||
BibTeX:
@article{wagle14b,
author = {Wagle, Pradeep and Xiao, Xiangming and Torn, Margaret S. and Cook, David R. and Matamala, Roser and Fischer, Marc L. and Jin, Cui and Dong, Jinwei and Biradar, Chandrashekhar},
title = {Sensitivity of vegetation indices and gross primary production of tallgrass prairie to severe drought},
journal = {REMOTE SENSING OF ENVIRONMENT},
year = {2014},
volume = {152},
pages = {1--14},
doi = {https://doi.org/10.1016/j.rse.2014.05.010}
}
|
|||||
| Wagle, P., Zhang, Y., Jin, C. and Xiao, X. | Comparison of solar-induced chlorophyll fluorescence, light-use efficiency, and process-based GPP models in maize | {2016} | ECOLOGICAL APPLICATIONS Vol. {26}({4}), pp. 1211-1222 |
article | DOI |
| Abstract: Accurately quantifying cropland gross primary production (GPP) is of great importance to monitor cropland status and carbon budgets. Satellite-based light-use efficiency (LUE) models and process-based terrestrial biosphere models (TBMs) have been widely used to quantify cropland GPP at different scales in past decades. However, model estimates of GPP are still subject to large uncertainties, especially for croplands. More recently, space-borne solar-induced chlorophyll fluorescence (SIF) has shown the ability to monitor photosynthesis from space, providing new insights into actual photosynthesis monitoring. In this study, we examined the potential of SIF data to describe maize phenology and evaluated three GPP modeling approaches (space-borne SIF retrievals, a LUE-based vegetation photosynthesis model [VPM], and a process-based soil canopy observation of photochemistry and energy flux [SCOPE] model constrained by SIF) at a maize (Zea mays L.) site in Mead, Nebraska, USA. The result shows that SIF captured the seasonal variations (particularly during the early and late growing season) of tower-derived GPP (GPP_EC) much better than did satellite-based vegetation indices (enhanced vegetation index [EVI] and land surface water index [LSWI]). Consequently, SIF was strongly correlated with GPP_EC than were EVI and LSWI. Evaluation of GPP estimates against GPP_EC during the growing season demonstrated that all three modeling approaches provided reasonable estimates of maize GPP, with Pearson's correlation coefficients (r) of 0.97, 0.94, and 0.93 for the SCOPE, VPM, and SIF models, respectively. The SCOPE model provided the best simulation of maize GPP when SIF observations were incorporated through optimizing the key parameter of maximum carboxylation capacity (V-cmax). Our results illustrate the potential of SIF data to offer an additional way to investigate the seasonality of photosynthetic activity, to constrain process-based models for improving GPP estimates, and to reasonably estimate GPP by integrating SIF and GPP_EC data without dependency on climate inputs and satellite-based vegetation indices. |
|||||
BibTeX:
@article{wagle16a,
author = {Wagle, Pradeep and Zhang, Yongguang and Jin, Cui and Xiao, Xiangming},
title = {Comparison of solar-induced chlorophyll fluorescence, light-use efficiency, and process-based GPP models in maize},
journal = {ECOLOGICAL APPLICATIONS},
year = {2016},
volume = {26},
number = {4},
pages = {1211--1222},
doi = {https://doi.org/10.1890/15-1434}
}
|
|||||
| Walley, S., Pal, S., Campbell, J.F., Dobler, J., Bell, E., Weir, B., Feng, S., Lauvaux, T., Baker, D., Blume, N., Erxleben, W., Fan, T.-F., Lin, B., McGregor, D., Obland, M.D., O'Dell, C. and Davis, K.J. | Airborne Lidar Measurements of XCO2 in Synoptically Active Environment and Associated Comparisons With Numerical Simulations | 2022 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 127(16) |
article | DOI |
| Abstract: Frontal boundaries have been shown to cause large changes in CO2 mole-fractions, but clouds and the complex vertical structure of fronts make these gradients difficult to observe. It remains unclear how the column average CO2 dry air mole-fraction (XCO2) changes spatially across fronts, and how well airborne lidar observations, data assimilation systems, and numerical models without assimilation capture XCO2 frontal contrasts (Delta XCO2, i.e., warm minus cold sector average of XCO2). We demonstrated the potential of airborne Multifunctional Fiber Laser Lidar (MFLL) measurements in heterogeneous weather conditions (i.e., frontal environment) to investigate the Delta XCO2 during four seasonal field campaigns of the Atmospheric Carbon and Transport-America (ACT-America) mission. Most frontal cases in summer (winter) reveal higher (lower) XCO2 in the warm (cold) sector than in the cold (warm) sector. During the transitional seasons (spring and fall), no clear signal in Delta XCO2 was observed. Intercomparison among the MFLL, assimilated fields from NASA's Global Modeling and Assimilation Office (GMAO), and simulations from the Weather Research and Forecasting--Chemistry (WRF-Chem) showed that (a) all products had a similar sign of Delta XCO2 though with different levels of agreement in Delta XCO2 magnitudes among seasons; (b) Delta XCO2 in summer decreases with altitude; and (c) significant challenges remain in observing and simulating XCO2 frontal contrasts. A linear regression analyses between Delta XCO2 for MFLL versus GMAO, and MFLL versus WRF-Chem for summer-2016 cases yielded a correlation coefficient of 0.95 and 0.88, respectively. The reported Delta XCO2 variability among four seasons provide guidance to the spatial structures of XCO2 transport errors in models and satellite measurements of XCO2 in synoptically-active weather systems. |
|||||
BibTeX:
@article{walley22a,
author = {Walley, Samantha and Pal, Sandip and Campbell, Joel F. and Dobler, Jeremy and Bell, Emily and Weir, Brad and Feng, Sha and Lauvaux, Thomas and Baker, David and Blume, Nathan and Erxleben, Wayne and Fan, Tai-Fang and Lin, Bing and McGregor, Doug and Obland, Michael D. and O'Dell, Chris and Davis, Kenneth J.},
title = {Airborne Lidar Measurements of XCO2 in Synoptically Active Environment and Associated Comparisons With Numerical Simulations},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2022},
volume = {127},
number = {16},
doi = {https://doi.org/10.1029/2021JD035664}
}
|
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| Wang, Y.-P., Trudinger, C.M. and Enting, I.G. | A review of applications of model-data fusion to studies of terrestrial carbon fluxes at different scales | {2009} | AGRICULTURAL AND FOREST METEOROLOGY Vol. {149}({11}), pp. 1829-1842 |
article | DOI |
| Abstract: Model-data fusion is defined as matching model prediction and observations by varying model parameters or states using statistical estimation. In this paper, we review the history of applications of various model-data fusion techniques in studies of terrestrial carbon fluxes in two approaches: top-down approaches that use measurements of global CO2 concentration and sometimes other atmospheric constituents to infer carbon fluxes from the land surface, and bottom-up approaches that estimate carbon fluxes using process-based models. We consider applications of model-data fusion in flux estimation, parameter estimation, model error analysis, experimental design and forecasting. Significant progress has been made by systematically studying the discrepancies between the predictions by different models and observations. As a result, some major controversies in global carbon cycle studies have been resolved, robust estimates of continental and global carbon fluxes over the last two decades have been obtained, and major deficiencies in the atmospheric models for tracer transport have been identified. In the bottom-up approaches, various optimization techniques have been used for a range of process-based models. Model-data fusion techniques have been successfully used to improve model predictions, and quantify the information content of carbon flux measurements and identify what other measurements are needed to further constrain model predictions. However, we found that very few studies in both top-down and bottom-up approaches have quantified the errors in the observations, model parameters and model structure systematically and consistently. We therefore suggest that future research will focus on developing an integrated Bayesian framework to study both model and measurement errors systematically. (C) 2009 Elsevier B.V. All rights reserved. |
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BibTeX:
@article{wang09a,
author = {Wang, Ying-Ping and Trudinger, Cathy M. and Enting, Ian G.},
title = {A review of applications of model-data fusion to studies of terrestrial carbon fluxes at different scales},
journal = {AGRICULTURAL AND FOREST METEOROLOGY},
year = {2009},
volume = {149},
number = {11},
pages = {1829--1842},
doi = {https://doi.org/10.1016/j.agrformet.2009.07.009}
}
|
|||||
| Wang, W., Dungan, J., Hashimoto, H., Michaelis, A.R., Milesi, C., Ichii, K. and Nemani, R.R. | Diagnosing and assessing uncertainties of terrestrial ecosystem models in a multimodel ensemble experiment: 1. Primary production | {2011} | GLOBAL CHANGE BIOLOGY Vol. {17}({3}), pp. 1350-1366 |
article | DOI |
| Abstract: We conducted an ensemble modeling exercise using the Terrestrial Observation and Prediction System (TOPS) to evaluate sources of uncertainty in carbon flux estimates resulting from structural differences among ecosystem models. The experiment ran public-domain versions of biome-bgc, lpj, casa, and tops-bgc over North America at 8 km resolution and for the period of 1982-2006. We developed the Hierarchical Framework for Diagnosing Ecosystem Models (HFDEM) to separate the simulated biogeochemistry into a cascade of three functional tiers and sequentially examine their characteristics in climate (temperature-precipitation) and other spaces. Analysis of the simulated annual gross primary production (GPP) in the climate domain indicates a general agreement among the models, all showing optimal GPP in regions where the relationship between annual average temperature (T, degrees C) and annual total precipitation (P, mm) is defined by P=50T+500. However, differences in simulated GPP are identified in magnitudes and distribution patterns. For forests, the GPP gradient along P=50T+500 ranges from similar to 50 g C yr-1 m-2 degrees C-1 (casa) to similar to 125 g C yr-1 m-2 degrees C-1 (biome-bgc) in cold/temperate regions; for nonforests, the diversity among GPP distributions is even larger. Positive linear relationships are found between annual GPP and annual mean leaf area index (LAI) in all models. For biome-bgc and lpj, such relationships lead to a positive feedback from LAI growth to GPP enhancement. Different approaches to constrain this feedback lead to different sensitivity of the models to disturbances such as fire, which contribute significantly to the diversity in GPP stated above. The ratios between independently simulated NPP and GPP are close to 50% on average; however, their distribution patterns vary significantly between models, reflecting the difficulties in estimating autotrophic respiration across various climate regimes. Although these results are drawn from our experiments with the tested model versions, the developed methodology has potential for other model exercises. |
|||||
BibTeX:
@article{wang11a,
author = {Wang, Weile and Dungan, Jennifer and Hashimoto, Hirofumi and Michaelis, Andrew R. and Milesi, Cristina and Ichii, Kazuhito and Nemani, Ramakrishna R.},
title = {Diagnosing and assessing uncertainties of terrestrial ecosystem models in a multimodel ensemble experiment: 1. Primary production},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2011},
volume = {17},
number = {3},
pages = {1350--1366},
doi = {https://doi.org/10.1111/j.1365-2486.2010.02309.x}
}
|
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| Wang, T., Shi, J. and Jing, Y. | EVALUATION AND INTERCOMPARISON OF THE ATMOSPHERIC CO2 RETRIEVALS FROM MEASUREMENTS OF AIRS, IASI, SCIAMACHY AND GOSAT | {2012} | 2012 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS), pp. 1325-1328 | inproceedings | DOI |
| Abstract: Quantifications of the differences among currently available CO2 products are very necessary for deeply understanding each product and their joint use. A spatio-temporal matching strategy has been proposed in this work to allow the CO2 products from AIRS, IASI, GOSAT and SCIAMACHY to be physically comparable by accounting for the a priori CO2 profiles employed in retrieval stage, averaging kernel functions and atmospheric pressure profiles etc. Based on this, these CO2 products are intercompared in terms of magnitudes of CO2 concentrations and their spatio-temporal distributions. The results show that relative large discrepancies are detected among these products, both in specific values of CO2 concentrations and the spatio-temporal distributions, implying more efforts should be made to fully understand the differences of such measurements and to better constrain the uncertainties in CO2 retrievals from space in the future. |
|||||
BibTeX:
@inproceedings{wang12a,
author = {Wang, Tianxing and Shi, Jiancheng and Jing, Yingying},
title = {EVALUATION AND INTERCOMPARISON OF THE ATMOSPHERIC CO2 RETRIEVALS FROM MEASUREMENTS OF AIRS, IASI, SCIAMACHY AND GOSAT},
booktitle = {2012 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS)},
year = {2012},
pages = {1325--1328},
note = {IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Munich, GERMANY, JUL 22-27, 2012},
doi = {https://doi.org/10.1109/IGARSS.2012.6351293}
}
|
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| Wang, T., Shi, J., Jing, Y. and Xie, Y. | Spatio-temporal characteristics of global atmospheric CO2 mole fractions (X-CO2) retrieved from remotely sensed data | {2012} | Vol. {8562}INFRARED, MILLIMETER-WAVE, AND TERAHERTZ TECHNOLOGIES II |
inproceedings | DOI |
| Abstract: To date, the measurements from AIRS, GOSAT, SCIAMACHY and IASI are widely used to derive atmospheric CO2 concentration globally. Quantification of the spatio-temporal differences between these CO2 products is crucial for deeply understanding each product and for exploring the potential for their joint use in the future. A series of processing has been proposed in this paper to unify these existing CO2 products, so that they can be theoretically comparable. Based on this, the spatio-temporal variations of these CO2 products have been conducted. The results reveal that AIRS show the largest spatial coverage of CO2 compared to other CO2 products. The valid X-CO2 data from SCIAMACHY are mainly restricted to land regions. Even if over the land, the X-CO2 distribution of ACOS is slightly wider than that of SCIAMACHY, especially over the region of Eurasia and North America. An obvious arch-shaped pattern along latitude for ACOS, Japan-GOSAT and SCIAMACHY is detected, while no distinct latitudinal variation can be observed for AIRS. For the seasonal variation, these datasets show a similar trend with the maximum CO2 loading occurring in spring. The discrepancy between these products implies that it is greatly necessary to better constrain the uncertainties in CO2 retrieval from space in the future. |
|||||
BibTeX:
@inproceedings{wang12b,
author = {Wang, Tianxing and Shi, Jiancheng and Jing, Yingying and Xie, Yanhui},
title = {Spatio-temporal characteristics of global atmospheric CO2 mole fractions (X-CO2) retrieved from remotely sensed data},
booktitle = {INFRARED, MILLIMETER-WAVE, AND TERAHERTZ TECHNOLOGIES II},
year = {2012},
volume = {8562},
note = {Conference on Infrared, Millimeter-Wave, and Terahertz Technologies II, Beijing, PEOPLES R CHINA, NOV 05-07, 2012},
doi = {https://doi.org/10.1117/12.2001088}
}
|
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| Wang, R., Tao, S., Ciais, P., Shen, H.Z., Huang, Y., Chen, H., Shen, G.F., Wang, B., Li, W., Zhang, Y.Y., Lu, Y., Zhu, D., Chen, Y.C., Liu, X.P., Wang, W.T., Wang, X.L., Liu, W.X., Li, B.G. and Piao, S.L. | High-resolution mapping of combustion processes and implications for CO2 emissions | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({10}), pp. 5189-5203 |
article | DOI |
| Abstract: High-resolution mapping of fuel combustion and CO2 emission provides valuable information for modeling pollutant transport, developing mitigation policy, and for inverse modeling of CO2 fluxes. Previous global emission maps included only few fuel types, and emissions were estimated on a grid by distributing national fuel data on an equal per capita basis, using population density maps. This process distorts the geographical distribution of emissions within countries. In this study, a sub-national disaggregation method (SDM) of fuel data is applied to establish a global 0.1 degrees x 0.1 degrees geo-referenced inventory of fuel combustion (PKU-FUEL) and corresponding CO2 emissions (PKU-CO2) based upon 64 fuel sub-types for the year 2007. Uncertainties of the emission maps are evaluated using a Monte Carlo method. It is estimated that CO2 emission from combustion sources including fossil fuel, biomass, and solid wastes in 2007 was 11.2 Pg C yr(-1) (9.1 Pg C yr(-1) and 13.3 Pg Cyr(-1) as 5th and 95th percentiles). Of this, emission from fossil fuel combustion is 7.83 Pg C yr(-1), which is very close to the estimate of the International Energy Agency (7.87 Pg Cyr(-1)). By replacing national data disaggregation with sub-national data in this study, the average 95th minus 5th percentile ranges of CO2 emission for all grid points can be reduced from 417 to 68.2 Mg km(-2) yr(-1). The spread is reduced because the uneven distribution of per capita fuel consumptions within countries is better taken into account by using sub-national fuel consumption data directly. Significant difference in per capita CO2 emissions between urban and rural areas was found in developing countries (2.08 vs. 0.598 Mg C/(cap. xyr)), but not in developed countries (3.55 vs. 3.41 Mg C/(cap. xyr)). This implies that rapid urbanization of developing countries is very likely to drive up their emissions in the future. |
|||||
BibTeX:
@article{wang13a,
author = {Wang, R. and Tao, S. and Ciais, P. and Shen, H. Z. and Huang, Y. and Chen, H. and Shen, G. F. and Wang, B. and Li, W. and Zhang, Y. Y. and Lu, Y. and Zhu, D. and Chen, Y. C. and Liu, X. P. and Wang, W. T. and Wang, X. L. and Liu, W. X. and Li, B. G. and Piao, S. L.},
title = {High-resolution mapping of combustion processes and implications for CO2 emissions},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {10},
pages = {5189--5203},
doi = {https://doi.org/10.5194/acp-13-5189-2013}
}
|
|||||
| Wang, T., Shi, J. and Jing, Y. | POTENTIAL ABILITY FOR JOINT-USE OF CO2 MEASUREMENTS RETRIEVED FROM DIFFERENT REMOTELY SENSED DATA | {2013} | 2013 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS), pp. 1778-1781 | inproceedings | DOI |
| Abstract: Remote sensing of atmospheric CO2 is essential to study global warming. To date, there are many instruments to detect CO2 from space, such as, AIRS, GOSAT, SCIAMACHY and IASI etc., while quantification of the differences among these CO2 products has not been fully investigated yet. In this study, the differences between CO2 products from AIRS, GOSAT, SCIAMAMCHY (totally four products) have been compared. The results showed that although these CO2 products are derived from different instruments, the complementarity in spatial coverage and relatively high correlation among them make it potentially possible to combine them, especially for GOSAT and SCIAMACHY. |
|||||
BibTeX:
@inproceedings{wang13b,
author = {Wang, Tianxing and Shi, Jiancheng and Jing, Yingying},
title = {POTENTIAL ABILITY FOR JOINT-USE OF CO2 MEASUREMENTS RETRIEVED FROM DIFFERENT REMOTELY SENSED DATA},
booktitle = {2013 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS)},
year = {2013},
pages = {1778--1781},
note = {IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Melbourne, AUSTRALIA, JUL 21-26, 2013},
doi = {https://doi.org/10.1109/IGARSS.2013.6723143}
}
|
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| Wang, T., Shi, J. and Jing, Y. | A METHOD FOR PHYSICALLY FUSING XCO2 MEASUREMENTS RETRIEVED FROM SCIAMACHY AND GOSAT | {2013} | 2013 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS), pp. 3351-3354 | inproceedings | DOI |
| Abstract: Space-based monitoring of atmospheric CO2 is very crucial for global carbon cycle studies and even global change. In this study, a method for physically fusing SCIAMACHY and GOSAT CO2 measurements has been proposed by fully considering the averaging kernel and spatio-temporal variations as well as the CO2 retrieval errors. The results revealed that the average global coverage of ACOS and BESD is around about 0.56% and 0.27% respectively at a daily scale. The monthly-mean coverage of such products accounts about 5.66% and 4.62% respectively. While spatial coverage of fused XCO2 can reach up to 0.76% and 8.51% on daily and monthly scale respectively. These findings in this paper proved the effectiveness of the proposed method. |
|||||
BibTeX:
@inproceedings{wang13c,
author = {Wang, Tianxing and Shi, Jiancheng and Jing, Yingying},
title = {A METHOD FOR PHYSICALLY FUSING XCO2 MEASUREMENTS RETRIEVED FROM SCIAMACHY AND GOSAT},
booktitle = {2013 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS)},
year = {2013},
pages = {3351--3354},
note = {IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Melbourne, AUSTRALIA, JUL 21-26, 2013},
doi = {https://doi.org/10.1109/IGARSS.2013.6723546}
}
|
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| Wang, T., Shi, J., Jing, Y. and Xie, Y. | Investigation of the consistency of atmospheric CO2 retrievals from different space-based sensors: Intercomparison and spatiotemporal analysis | {2013} | CHINESE SCIENCE BULLETIN Vol. {58}({33}), pp. 4161-4170 |
article | DOI |
| Abstract: In recent years, global warming caused by emission of CO2 has attracted considerable attention from the public. Although the measurements from AIRS, GOSAT, SCIAMACHY and IASI have been frequently used to derive atmospheric CO2 concentration, comprehensive quantification of the differences among these CO2 products is still not fully investigated yet. In this paper, a series of strategies have been proposed to allow the CO2 products from different instruments to be physically inter-comparable. Based on this, these CO2 products are inter-compared in terms of magnitude and their spatiotemporal distributions. The results reveal that the correlations among these CO2 products are relatively weak, and some discrepancies are detected in terms of the CO2 spatiotemporal characteristics, demonstrating more efforts should be made in the future to improve the retrievals of CO2. Their spatial coverage differences reflected in this study imply the great necessity to generate consistent products with improved spatial and temporal continuities by combining these CO2 measurements. |
|||||
BibTeX:
@article{wang13d,
author = {Wang, TianXing and Shi, JianCheng and Jing, YingYing and Xie, YanHui},
title = {Investigation of the consistency of atmospheric CO2 retrievals from different space-based sensors: Intercomparison and spatiotemporal analysis},
journal = {CHINESE SCIENCE BULLETIN},
year = {2013},
volume = {58},
number = {33},
pages = {4161--4170},
doi = {https://doi.org/10.1007/s11434-013-5996-7}
}
|
|||||
| Wang, T., Shi, J., Jing, Y., Zhao, T., Ji, D. and Xiong, C. | Combining XCO2 Measurements Derived from SCIAMACHY and GOSAT for Potentially Generating Global CO2 Maps with High Spatiotemporal Resolution | {2014} | PLOS ONE Vol. {9}({8}) |
article | DOI |
| Abstract: Global warming induced by atmospheric CO2 has attracted increasing attention of researchers all over the world. Although space-based technology provides the ability to map atmospheric CO2 globally, the number of valid CO2 measurements is generally limited for certain instruments owing to the presence of clouds, which in turn constrain the studies of global CO2 sources and sinks. Thus, it is a potentially promising work to combine the currently available CO2 measurements. In this study, a strategy for fusing SCIAMACHY and GOSAT CO2 measurements is proposed by fully considering the CO2 global bias, averaging kernel, and spatiotemporal variations as well as the CO2 retrieval errors. Based on this method, a global CO2 map with certain UTC time can also be generated by employing the pattern of the CO2 daily cycle reflected by Carbon Tracker (CT) data. The results reveal that relative to GOSAT, the global spatial coverage of the combined CO2 map increased by 41.3% and 47.7% on a daily and monthly scale, respectively, and even higher when compared with that relative to SCIAMACHY. The findings in this paper prove the effectiveness of the combination method in supporting the generation of global full-coverage XCO2 maps with higher temporal and spatial sampling by jointly using these two space-based XCO2 datasets. |
|||||
BibTeX:
@article{wang14a,
author = {Wang, Tianxing and Shi, Jiancheng and Jing, Yingying and Zhao, Tianjie and Ji, Dabin and Xiong, Chuan},
title = {Combining XCO2 Measurements Derived from SCIAMACHY and GOSAT for Potentially Generating Global CO2 Maps with High Spatiotemporal Resolution},
journal = {PLOS ONE},
year = {2014},
volume = {9},
number = {8},
doi = {https://doi.org/10.1371/journal.pone.0105050}
}
|
|||||
| Wang, J.S., Kawa, S.R., Eluszkiewicz, J., Baker, D.F., Mountain, M., Henderson, J., Nehrkorn, T. and Zaccheo, T.S. | A regional CO2 observing system simulation experiment for the ASCENDS satellite mission | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({23}), pp. 12897-12914 |
article | DOI |
| Abstract: Top down estimates of the spatiotemporal variations in emissions and uptake of CO2 will benefit from the increasing measurement density brought by recent and future additions to the suite of in situ and remote CO2 measurement platforms. In particular, the planned NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) satellite mission will provide greater coverage in cloudy regions, at high latitudes, and at night than passive satellite systems, as well as high precision and accuracy. In a novel approach to quantifying the ability of satellite column measurements to constrain CO2 fluxes, we use a portable library of footprints (surface influence functions) generated by the Stochastic Time-Inverted Lagrangian Transport (STILT) model in combination with the Weather Research and Forecasting (WRF) model in a regional Bayesian synthesis inversion. The regional Lagrangian particle dispersion model framework is well suited to make use of ASCENDS observations to constrain weekly fluxes in North America at a high resolution, in this case at 1 degrees latitude x 1 degrees longitude. We consider random measurement errors only, modeled as a function of the mission and instrument design specifications along with realistic atmospheric and surface conditions. We find that the ASCENDS observations could potentially reduce flux uncertainties substantially at biome and finer scales. At the grid scale and weekly resolution, the largest uncertainty reductions, on the order of 50 %, occur where and when there is good coverage by observations with low measurement errors and the a priori uncertainties are large. Uncertainty reductions are smaller for a 1.57 mu m candidate wavelength than for a 2.05 mu m wavelength, and are smaller for the higher of the two measurement error levels that we consider (1.0 ppm vs. 0.5 ppm clear-sky error at Railroad Valley, Nevada). Uncertainty reductions at the annual biome scale range from similar to 40% to similar to 75% across our four instrument design cases and from similar to 65% to similar to 85 % for the continent as a whole. Tests suggest that the quantitative results are moderately sensitive to assumptions regarding a priori uncertainties and boundary conditions. The a posteriori flux uncertainties we obtain, ranging from 0.01 to 0.06 Pg C yr(-1) across the biomes, would meet requirements for improved understanding of long-term carbon sinks suggested by a previous study. |
|||||
BibTeX:
@article{wang14b,
author = {Wang, J. S. and Kawa, S. R. and Eluszkiewicz, J. and Baker, D. F. and Mountain, M. and Henderson, J. and Nehrkorn, T. and Zaccheo, T. S.},
title = {A regional CO2 observing system simulation experiment for the ASCENDS satellite mission},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {23},
pages = {12897--12914},
doi = {https://doi.org/10.5194/acp-14-12897-2014}
}
|
|||||
| Wang, Y., Broquet, G., Ciais, P., Chevallier, F., Vogel, F., Kadygrov, N., Wu, L., Yin, Y., Wang, R. and Tao, S. | Estimation of observation errors for large-scale atmospheric inversion of CO2 emissions from fossil fuel combustion | {2017} | TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY Vol. {69} |
article | DOI |
| Abstract: National annual inventories of CO2 emitted during fossil fuel consumption (FFCO2) bear 5-10% uncertainties for developed countries, and are likely higher at intra annual scales or for developing countries. Given the current international efforts of mitigating actions, there is a need for independent verifications of these inventories. Atmospheric inversion assimilating atmospheric gradients of CO2 and radiocarbon measurements could provide an independent way of monitoring FFCO2 emissions. A strategy would be to deploy such measurements over continental scale networks and to conduct continental to global scale atmospheric inversions targeting the national and one-month scale budgets of the emissions. Uncertainties in the high-resolution distribution of the emissions could limit the skill for such a large-scale inversion framework. This study assesses the impact of such uncertainties on the potential for monitoring the emissions at large scale. In practice, it is more specifically dedicated to the derivation, typical quantification and analysis of critical sources of errors that affect the inversion of FFCO2 emissions when solving for them at a relatively coarse resolution with a coarse grid transport model. These errors include those due to the mismatch between the resolution of the transport model and the spatial variability of the actual fluxes and concentrations (i.e. the representation errors) and those due to the uncertainties in the spatial and temporal distribution of emissions at the transport model resolution when solving for the emissions at large scale (i.e. the aggregation errors). We show that the aggregation errors characterize the impact of the corresponding uncertainties on the potential for monitoring the emissions at large scale, even if solving for them at the transport model resolution. We propose a practical method to quantify these sources of errors, and compare them with the precision of FFCO2 measurements (i.e. the measurement errors) and the errors in the modelling of atmospheric transport (i.e. the transport errors). The results show that both the representation and measurement errors can be much larger than the aggregation errors. The magnitude of representation and aggregation errors is sensitive to sampling heights and temporal sampling integration time. The combination of these errors can reach up to about 50% of the typical signals, i.e. the atmospheric large-scale mean afternoon FFCO2 gradients between sites being assimilated by the inversion system. These errors have large temporal auto-correlation scales, but short spatial correlation scales. This indicates the need for accounting for these temporal auto-correlations in the atmospheric inversions and the need for dense networks to limit the impact of these errors on the inversion of FFCO2 emissions at large scale. More generally, comparisons of the representation and aggregation errors to the errors in simulated FFCO2 gradients due to uncertainties in current inventories suggest that the potential of inversions using global coarse-resolution models (with typical horizontal resolution of a couple of degrees) to retrieve FFCO2 emissions at sub-continental scale could be limited, and that meso-scale models with smaller representation errors would effectively increase the potential of inversions to constrain FFCO2 emission estimates. |
|||||
BibTeX:
@article{wang17a,
author = {Wang, Yilong and Broquet, Gregoire and Ciais, Philippe and Chevallier, Frederic and Vogel, Felix and Kadygrov, Nikolay and Wu, Lin and Yin, Yi and Wang, Rong and Tao, Shu},
title = {Estimation of observation errors for large-scale atmospheric inversion of CO2 emissions from fossil fuel combustion},
journal = {TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY},
year = {2017},
volume = {69},
doi = {https://doi.org/10.1080/16000889.2017.1325723}
}
|
|||||
| Wang, L., Lee, X., Wang, W., Wang, X., Wei, Z., Fu, C., Gao, Y., Lu, L., Song, W., Su, P. and Lin, G. | A Meta-Analysis of Open-Path Eddy Covariance Observations of Apparent CO2 Flux in Cold Conditions in FLUXNETR | {2017} | JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY Vol. {34}({11}), pp. 2475-2487 |
article | DOI |
| Abstract: Open-path eddy covariance systems are widely used for measuring the CO2 flux between land and atmosphere. A common problem is that they often yield negative fluxes or physiologically unreasonable CO2 uptake fluxes in the nongrowing season under cold conditions. In this study, a meta-analysis was performed on the eddy flux data from 64 FLUXNET sites and the relationship between the observed CO2 flux and the sensible heat flux was analyzed. In theory, these two fluxes should be independent of each other in cold conditions (air temperature lower than 0 degrees C) when photosynthesis is suppressed. However, the results show that a significant and negative linear relationship existed between these two fluxes at 37 of the sites. The mean linear slope value is -0.008 +/- 0.001 mu mol m(-2) s(-1) per W m(-2) among the 64 sites analyzed. The slope value was not significantly different among the three gas analyzer models (LI-7500, LI-7500A, IRGASON/EC150) used at these sites, indicating that self-heating may not be the only reason for the apparent wintertime net CO2 uptake. These results suggest a systematic bias toward larger carbon uptakes in the FLUXNET sites that deploy open-path eddy covariance systems. |
|||||
BibTeX:
@article{wang17b,
author = {Wang, Liming and Lee, Xuhui and Wang, Wei and Wang, Xufeng and Wei, Zhongwang and Fu, Congsheng and Gao, Yunqiu and Lu, Ling and Song, Weimin and Su, Peixi and Lin, Guanghui},
title = {A Meta-Analysis of Open-Path Eddy Covariance Observations of Apparent CO2 Flux in Cold Conditions in FLUXNETR},
journal = {JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY},
year = {2017},
volume = {34},
number = {11},
pages = {2475--2487},
doi = {https://doi.org/10.1175/JTECH-D-17-0085.1}
}
|
|||||
| Wang, J., Zeng, N., Wang, M., Jiang, F., Wang, H. and Jiang, Z. | Contrasting terrestrial carbon cycle responses to the 1997/98 and 2015/16 extreme El Nino events | {2018} | EARTH SYSTEM DYNAMICS Vol. {9}({1}), pp. {1-14} |
article | DOI |
| Abstract: Large interannual atmospheric CO2 variability is dominated by the response of the terrestrial biosphere to El Nino-Southern Oscillation (ENSO). However, the behavior of terrestrial ecosystems differs during different El Ninos in terms of patterns and biological processes. Here, we comprehensively compare two extreme El Ninos (2015/16 and 1997/98) in the context of a multi-event ``composite'' El Nino. We find large differences in the terrestrial carbon cycle responses, even though the two events were of similar magnitude. More specifically, we find that the global-scale land-atmosphere carbon flux (F-TA) anomaly during the 1997/98 El Nino was 1.64 Pg Cyr(-1), but half that quantity during the 2015/16 El Nino (at 0.73 Pg Cyr(-1)). Moreover, F-TA showed no obvious lagged response during the 2015/16 El Nino, in contrast to that during 1997/98. Separating the global flux by geographical regions, we find that the fluxes in the tropics and extratropical Northern Hemisphere were 1.70 and -0.05 PgCyr(-1) during 1997/98, respectively. During 2015/16, they were 1.12 and -0.52 PgCyr(-1), respectively. Analysis of the mechanism shows that, in the tropics, the widespread drier and warmer conditions caused a decrease in gross primary productivity (GPP; 0.73 PgCyr(-1)) and an increase in terrestrial ecosystem respiration (TER; 0.62 PgCyr(-1)) during the 1997/98 El Nino. In contrast, anomalously wet conditions occurred in the Sahel and East Africa during 2015/16, which caused an increase in GPP, compensating for its reduction in other tropical regions. As a result, the total 2015/16 tropical GPP and TER anomalies were -0.03 and 0.95 PgCyr(-1). GPP dominance during 1997/98 and TER dominance during 2015/16 accounted for the phase difference in their F-TA. In the extratropical Northern Hemisphere, the large difference occurred because temperatures over Eurasia were warmer during the 2015/16, as compared with the cooling seen during the 1997/98 and the composite El Nino. These warmer conditions enhanced GPP and TER over Eurasia during the 2015/16 El Nino, while these fluxes were suppressed during 1997/98. The total extratropical Northern Hemisphere GPP and TER anomalies were 0.63 and 0.55 PgCyr(-1) during1997/98, and 1.90 and 1.45 PgCyr(-1) during 2015/16, respectively. Additionally, wildfires played a less important role during the 2015/16 than during the 1997/98 El Nino. |
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BibTeX:
@article{wang18a,
author = {Wang, Jun and Zeng, Ning and Wang, Meirong and Jiang, Fei and Wang, Hengmao and Jiang, Ziqiang},
title = {Contrasting terrestrial carbon cycle responses to the 1997/98 and 2015/16 extreme El Nino events},
journal = {EARTH SYSTEM DYNAMICS},
year = {2018},
volume = {9},
number = {1},
pages = {1-14},
doi = {https://doi.org/10.5194/esd-9-1-2018}
}
|
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| Wang, J.S., Kawa, S.R., Collatz, G.J., Sasakawa, M., Gatti, L.V., Machida, T., Liu, Y. and Manyin, M.E. | A global synthesis inversion analysis of recent variability in CO2 fluxes using GOSAT and in situ observations | {2018} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {18}({15}), pp. {11097-11124} |
article | |
| Abstract: The precise contribution of the two major sinks for anthropogenic CO2 emissions, terrestrial vegetation and the ocean, and their location and year-to-year variability are not well understood. Top-down estimates of the spatiotemporal variations in emissions and uptake of CO2 are expected to benefit from the increasing measurement density brought by recent in situ and remote CO2 observations. We uniquely apply a batch Bayesian synthesis inversion at relatively high resolution to in situ surface observations and bias-corrected GOSAT satellite column CO2 retrievals to deduce the global distributions of natural CO2 fluxes during 2009-2010. The GOSAT inversion is generally better constrained than the in situ inversion, with smaller posterior regional flux uncertainties and correlations, because of greater spatial coverage, except over North America and northern and southern high-latitude oceans. Complementarity of the in situ and GOSAT data enhances uncertainty reductions in a joint inversion; however, remaining coverage gaps, including those associated with spatial and temporal sampling biases in the passive satellite measurements, still limit the ability to accurately resolve fluxes down to the sub-continental or subocean basin scale. The GOSAT inversion produces a shift in the global CO2 sink from the tropics to the north and south relative to the prior, and an increased source in the tropics of similar to 2 PgC yr(-1) relative to the in situ inversion, similar to what is seen in studies using other inversion approaches. This result may be driven by sampling and residual retrieval biases in the GOSAT data, as suggested by significant discrepancies between posterior CO2 distributions and surface in situ and HIPPO mission aircraft data. While the shift in the global sink appears to be a robust feature of the inversions, the partitioning of the sink between land and ocean in the inversions using either in situ or GOSAT data is found to be sensitive to prior uncertainties because of negative correlations in the flux errors. The GOSAT inversion indicates significantly less CO2 uptake in the summer of 2010 than in 2009 across northern regions, consistent with the impact of observed severe heat waves and drought. However, observations from an in situ network in Siberia imply that the GOSAT inversion exaggerates the 2010-2009 difference in uptake in that region, while the prior CASA-GFED model of net ecosystem production and fire emissions reasonably estimates that quantity. The prior, in situ posterior, and GOSAT posterior all indicate greater uptake over North America in spring to early summer of 2010 than in 2009, consistent with wetter conditions. The GOSAT inversion does not show the expected impact on fluxes of a 2010 drought in the Amazon; evaluation of posterior mole fractions against local aircraft profiles suggests that time-varying GOSAT coverage can bias the estimation of interannual flux variability in this region. |
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BibTeX:
@article{wang18b,
author = {Wang, James S. and Kawa, S. Randolph and Collatz, G. James and Sasakawa, Motoki and Gatti, Luciana V. and Machida, Toshinobu and Liu, Yuping and Manyin, Michael E.},
title = {A global synthesis inversion analysis of recent variability in CO2 fluxes using GOSAT and in situ observations},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2018},
volume = {18},
number = {15},
pages = {11097-11124}
}
|
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| Wang, S., Ju, W., Penuelas, J., Cescatti, A., Zhou, Y., Fu, Y., Huete, A., Liu, M. and Zhang, Y. | Urban-rural gradients reveal joint control of elevated CO2 and temperature on extended photosynthetic seasons | {2019} | NATURE ECOLOGY & EVOLUTION Vol. {3}({7}), pp. {1076-1085} |
article | DOI URL |
| Abstract: Photosynthetic phenology has large effects on the land-atmosphere carbon exchange. Due to limited experimental assessments, a comprehensive understanding of the variations of photosynthetic phenology under future climate and its associated controlling factors is still missing, despite its high sensitivities to climate. Here, we develop an approach that uses cities as natural laboratories, since plants in urban areas are often exposed to higher temperatures and carbon dioxide (CO2) concentrations, which reflect expected future environmental conditions. Using more than 880 urban-rural gradients across the Northern Hemisphere (>= 30 degrees N), combined with concurrent satellite retrievals of Sun-induced chlorophyll fluorescence (SIF) and atmospheric CO2, we investigated the combined impacts of elevated CO2 and temperature on photosynthetic phenology at the large scale. The results showed that, under urban conditions of elevated CO2 and temperature, vegetation photosynthetic activity began earlier (-5.6 +/- 0.7 d), peaked earlier (-4.9 +/- 0.9 d) and ended later (4.6 +/- 0.8 d) than in neighbouring rural areas, with a striking two- to fourfold higher climate sensitivity than greenness phenology. The earlier start and peak of season were sensitive to both the enhancements of CO2 and temperature, whereas the delayed end of season was mainly attributed to CO2 enrichments. We used these sensitivities to project phenology shifts under four Representative Concentration Pathway climate scenarios, predicting that vegetation will have prolonged photosynthetic seasons in the coming two decades. This observation-driven study indicates that realistic urban environments, together with SIF observations, provide a promising method for studying vegetation physiology under future climate change. | |||||
BibTeX:
@article{wang19a,
author = {Wang, Songhan and Ju, Weimin and Penuelas, Josep and Cescatti, Alessandro and Zhou, Yuyu and Fu, Yongshuo and Huete, Alfredo and Liu, Min and Zhang, Yongguang},
title = {Urban-rural gradients reveal joint control of elevated CO2 and temperature on extended photosynthetic seasons},
journal = {NATURE ECOLOGY & EVOLUTION},
publisher = {NATURE PUBLISHING GROUP},
year = {2019},
volume = {3},
number = {7},
pages = {1076--1085},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.nature.com/articles/s41559-019-0931-1},
doi = {https://doi.org/10.1038/s41559-019-0931-1}
}
|
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| Wang, H., Jiang, F., Wang, J., Ju, W. and Chen, J.M. | Terrestrial ecosystem carbon flux estimated using GOSAT and OCO-2 XCO2 retrievals | {2019} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {19}({18}), pp. {12067-12082} |
article | DOI |
| Abstract: In this study, both the Greenhouse Gases Observing Satellite (GOSAT) and the Orbiting Carbon Observatory 2 (OCO-2) XCO2 retrievals produced by the NASA Atmospheric CO2 Observations from Space (ACOS) project (version b7.3) are assimilated within the GEOS-Chem 4D-Var assimilation framework to constrain the terrestrial ecosystem carbon flux during 1 October 2014 to 31 December 2015. One inversion for the comparison, using in situ CO2 observations, and another inversion as a benchmark for the simulated atmospheric CO2 distributions of the real inversions, using global atmospheric CO2 trends and referred to as the poor-man inversion, are also conducted. The estimated global and regional carbon fluxes for 2015 are shown and discussed. CO2 observations from surface flask sites and XCO2 retrievals from Total Carbon Column Observing Network (TCCON) sites are used to evaluate the simulated concentrations with the posterior carbon fluxes. Globally, the terrestrial ecosystem carbon sink (excluding biomass burning emissions) estimated from GOSAT data is stronger than that inferred from OCO-2 data, weaker than the in situ inversion and matches the poor-man inversion the best. Regionally, in most regions, the land sinks inferred from GOSAT data are also stronger than those from OCO-2 data, and in North America, Asia and Europe, the carbon sinks inferred from GOSAT inversion are comparable to those from in situ inversion. For the latitudinal distribution of land sinks, the satellite-based inversions suggest a smaller boreal and tropical sink but larger temperate sinks in both the Northern and Southern Hemisphere than the in situ inversion. However, OCO-2 and GOSAT generally do not agree on which continent contains the smaller or larger sinks. Evaluations using flask and TCCON observations and the comparisons with in situ and poor-man inversions suggest that only GOSAT and the in situ inversions perform better than a poor-man solution. GOSAT data can effectively improve the carbon flux estimates in the Northern Hemisphere, while OCO-2 data, with the specific version used in this study, show only slight improvement. The differences of inferred land fluxes between GOSAT and OCO-2 inversions in different regions are mainly related to the spatial coverage, the data amount and the biases of these two satellite XCO2 retrievals. | |||||
BibTeX:
@article{wang19b,
author = {Wang, Hengmao and Jiang, Fei and Wang, Jun and Ju, Weimin and Chen, Jing M.},
title = {Terrestrial ecosystem carbon flux estimated using GOSAT and OCO-2 XCO2 retrievals},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {19},
number = {18},
pages = {12067--12082},
doi = {https://doi.org/10.5194/acp-19-12067-2019}
}
|
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| Wang, S., van der Ronald J., A, Stammes, P., Wang, W., Zhang, P., Lu, N. and Fang, L. | Carbon Dioxide Retrieval from TanSat Observations and Validation with TCCON Measurements | {2020} | REMOTE SENSING Vol. {12}({14}) |
article | DOI |
| Abstract: In this study we present the retrieval of the column-averaged dry air mole fraction of carbon dioxide (XCO2) from the TanSat observations using the ACOS (Atmospheric CO2 Observations from Space) algorithm. The XCO2 product has been validated with collocated ground-based measurements from the Total Carbon Column Observing Network (TCCON) for 2 years of TanSat data from 2017 to 2018. Based on the correlation of the XCO2 error over land with goodness of fit in three spectral bands at 0.76, 1.61 and 2.06 mu m, we applied an a posteriori bias correction to TanSat retrievals. For overpass averaged results, XCO2 retrievals show a standard deviation (SD) of similar to 2.45 ppm and a positive bias of similar to 0.27 ppm compared to collocated TCCON sites. The validation also shows a relatively higher positive bias and variance against TCCON over high-latitude regions. Three cases to evaluate TanSat target mode retrievals are investigated, including one field campaign at Dunhuang with measurements by a greenhouse gas analyzer deployed on an unmanned aerial vehicle and two cases with measurements by a ground-based Fourier-transform spectrometer in Beijing. The results show the retrievals of all footprints, except footprint-6, have relatively low bias (within similar to 2 ppm). In addition, the orbitalXCO(2)distributions over Australia and Northeast China between TanSat and the second Orbiting Carbon Observatory (OCO-2) on 20 April 2017 are compared. It shows that the meanXCO(2)from TanSat is slightly lower than that of OCO-2 with an average difference of similar to 0.85 ppm. A reasonable agreement in XCO2 distribution is found over Australia and Northeast China between TanSat and OCO-2. | |||||
BibTeX:
@article{wang20a,
author = {Wang, Shupeng and van der A, Ronald J. and Stammes, Piet and Wang, Weihe and Zhang, Peng and Lu, Naimeng and Fang, Li},
title = {Carbon Dioxide Retrieval from TanSat Observations and Validation with TCCON Measurements},
journal = {REMOTE SENSING},
publisher = {MDPI},
year = {2020},
volume = {12},
number = {14},
doi = {https://doi.org/10.3390/rs12142204}
}
|
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| Wang, J., Jiang, F., Wang, H., Qiu, B., Wu, M., He, W., Ju, W., Zhang, Y., Chen, J.M. and Zhou, Y. | Constraining global terrestrial gross primary productivity in a global carbon assimilation system with OCO-2 chlorophyll fluorescence data | 2021 | AGRICULTURAL AND FOREST METEOROLOGY Vol. 304 |
article | DOI |
| Abstract: The gross primary productivity (GPP) is the largest carbon flux in the terrestrial carbon cycle. Constraining GPP is critical for understanding the terrestrial carbon sources and sinks. In this study, we attempted to constrain the terrestrial GPP at regional to global scales through optimizing the key photosynthetic parameter (the carboxylation capacity at 25 degrees C, V-cmax(25)) using solar-induced chlorophyll fluorescence (SIF) observations from the Orbiting Carbon Observatory-2 (OCO-2). The optimization was made within the Global Carbon Assimilation System (GCAS), in which the Boreal Ecosystem Productivity Simulator (BEPS) model was used to simultaneously simulate the global GPP and SIF in the process-based manner. Optimized V-cmax(25) shows a distinguishable spatial pattern, with the largest values over the crop regions. After optimization, V-cmax(25) of crop is significantly increased. Importantly, the optimized V-cmax(25) of different plant functional types (PFTs) show unambiguous seasonal variations. With these optimized V-cmax(25), the simulated global GPP in 2015-2016 amounts to 119.1 PgC yr(-1), close to the median value (121.3 PgC yr(-1)) of the observation-based estimates. Global GPP decreases by 8.3% relative to the value simulated using prior V-cmax(25). In detail, GPP of crops increases by 16.4%, but it decreases over the other PFT regions, ranging from -4.4% over grasses to -34.0% over deciduous needleleaf forests. The spatiotemporal variations in the optimized PFT-dependent V-cmax(25) also reshape the seasonal cycle in GPP. We regard that it is an effective pathway to constrain GPP based on the satellite SIF and the process-based assimilation system, which can provide us an opportunity to better understand the terrestrial and global carbon cycle. |
|||||
BibTeX:
@article{wang21a,
author = {Wang, Jun and Jiang, Fei and Wang, Hengmao and Qiu, Bo and Wu, Mousong and He, Wei and Ju, Weimin and Zhang, Yongguang and Chen, Jing M. and Zhou, Yanlian},
title = {Constraining global terrestrial gross primary productivity in a global carbon assimilation system with OCO-2 chlorophyll fluorescence data},
journal = {AGRICULTURAL AND FOREST METEOROLOGY},
year = {2021},
volume = {304},
doi = {https://doi.org/10.1016/j.agrformet.2021.108424}
}
|
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| Wang, Q., Imasu, R., Arai, Y., Ito, S., Mizoguchi, Y., Kondo, H. and Xiao, J. | Sub-Daily Natural CO2 Flux Simulation Based on Satellite Data: Diurnal and Seasonal Pattern Comparisons to Anthropogenic CO2 Emissions in the Greater Tokyo Area | 2021 | REMOTE SENSING Vol. 13(11) |
article | DOI |
| Abstract: During the last decade, advances in the remote sensing of greenhouse gas (GHG) concentrations by the Greenhouse Gases Observing SATellite-1 (GOSAT-1), GOSAT-2, and Orbiting Carbon Observatory-2 (OCO-2) have produced finer-resolution atmospheric carbon dioxide (CO2) datasets. These data are applicable for a top-down approach towards the verification of anthropogenic CO2 emissions from megacities and updating of the inventory. However, great uncertainties regarding natural CO2 flux estimates remain when back-casting CO2 emissions from concentration data, making accurate disaggregation of urban CO2 sources difficult. For this study, we used Moderate Resolution Imaging Spectroradiometer (MODIS) land products, meso-scale meteorological data, SoilGrids250 m soil profile data, and sub-daily soil moisture datasets to calculate hourly photosynthetic CO2 uptake and biogenic CO2 emissions with 500 m resolution for the Kanto Plain, Japan, at the center of which is the Tokyo metropolis. Our hourly integrated modeling results obtained for the period 2010-2018 suggest that, collectively, the vegetated land within the Greater Tokyo Area served as a daytime carbon sink year-round, where the hourly integrated net atmospheric CO2 removal was up to 14.15 +/- 4.24% of hourly integrated anthropogenic emissions in winter and up to 55.42 +/- 10.39% in summer. At night, plants and soil in the Greater Tokyo Area were natural carbon sources, with hourly integrated biogenic CO2 emissions equivalent to 2.27 +/- 0.11%-4.97 +/- 1.17% of the anthropogenic emissions in winter and 13.71 +/- 2.44%-23.62 +/- 3.13% in summer. Between January and July, the hourly integrated biogenic CO2 emissions of the Greater Tokyo Area increased sixfold, whereas the amplitude of the midday hourly integrated photosynthetic CO2 uptake was enhanced by nearly five times and could offset up to 79.04 +/- 12.31% of the hourly integrated anthropogenic CO2 emissions in summer. The gridded hourly photosynthetic CO2 uptake and biogenic respiration estimates not only provide reference data for the estimation of total natural CO2 removal in our study area, but also supply prior input values for the disaggregation of anthropogenic CO2 emissions and biogenic CO2 fluxes when applying top-down approaches to update the megacity's CO2 emissions inventory. The latter contribution allows unprecedented amounts of GOSAT and ground measurement data regarding CO2 concentration to be analyzed in inverse modeling of anthropogenic CO2 emissions from Tokyo and the Kanto Plain. |
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BibTeX:
@article{wang21b,
author = {Wang, Qiao and Imasu, Ryoichi and Arai, Yutaka and Ito, Satoshi and Mizoguchi, Yasuko and Kondo, Hiroaki and Xiao, Jingfeng},
title = {Sub-Daily Natural CO2 Flux Simulation Based on Satellite Data: Diurnal and Seasonal Pattern Comparisons to Anthropogenic CO2 Emissions in the Greater Tokyo Area},
journal = {REMOTE SENSING},
year = {2021},
volume = {13},
number = {11},
doi = {https://doi.org/10.3390/rs13112037}
}
|
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| Wanninkhof, R., Pickers, P.A., Omar, A.M., Sutton, A., Murata, A., Olsen, A., Stephens, B.B., Tilbrook, B., Munro, D., Pierrot, D., Rehder, G., Magdalena Santana-Casiano, J., Mueller, J.D., Trinanes, J., Tedesco, K., O'Brien, K., Currie, K., Barberols, L., Telszewski, M., Hoppema, M., Ishii, M., Gonzalez-Davila, M., Bates, N.R., Metzl, N., Suntharalingam, P., Feely, R.A., Nakaoka, S.-i., Lauvset, S.K., Takahashi, T., Steinhoff, T. and Schuster, U. | A Surface Ocean CO2 Reference Network, SOCONET and Associated Marine Boundary Layer CO2 Measurements | {2019} | FRONTIERS IN MARINE SCIENCE Vol. {6} |
article | DOI |
| Abstract: The Surface Ocean CO2 NETwork (SOCONET) and atmospheric Marine Boundary Layer (MBL) CO2 measurements from ships and buoys focus on the operational aspects of measurements of CO2 in both the ocean surface and atmospheric MBLs. The goal is to provide accurate pCO(2) data to within 2 micro atmosphere (mu atm) for surface ocean and 0.2 parts per million (ppm) for MBL measurements following rigorous best practices, calibration and intercomparison procedures. Platforms and data will be tracked in near real-time and final quality-controlled data will be provided to the community within a year. The network, involving partners worldwide, will aid in production of important products such as maps of monthly resolved surface ocean CO2 and air-sea CO2 flux measurements. These products and other derivatives using surface ocean and MBL CO2 data, such as surface ocean pH maps and MBL CO2 maps, will be of high value for policy assessments and socio-economic decisions regarding the role of the ocean in sequestering anthropogenic CO2 and how this uptake is impacting ocean health by ocean acidification. SOCONET has an open ocean emphasis but will work with regional (coastal) networks. It will liaise with intergovernmental science organizations such as Global Atmosphere Watch (GAW), and the joint committee for and ocean and marine meteorology (JCOMM). Here we describe the details of this emerging network and its proposed operations and practices. | |||||
BibTeX:
@article{wanninkhof19a,
author = {Wanninkhof, Rik and Pickers, Penelope A. and Omar, Abdirahman M. and Sutton, Adrienne and Murata, Akihiko and Olsen, Are and Stephens, Britton B. and Tilbrook, Bronte and Munro, David and Pierrot, Denis and Rehder, Gregor and Magdalena Santana-Casiano, J. and Mueller, Jens D. and Trinanes, Joaquin and Tedesco, Kathy and O'Brien, Kevin and Currie, Kim and Barberols, Leticia and Telszewski, Maciej and Hoppema, Mario and Ishii, Masao and Gonzalez-Davila, Melchor and Bates, Nicholas R. and Metzl, Nicolas and Suntharalingam, Parvadha and Feely, Richard A. and Nakaoka, Shin-ichiro and Lauvset, Siv K. and Takahashi, Taro and Steinhoff, Tobias and Schuster, Ute},
title = {A Surface Ocean CO2 Reference Network, SOCONET and Associated Marine Boundary Layer CO2 Measurements},
journal = {FRONTIERS IN MARINE SCIENCE},
publisher = {FRONTIERS MEDIA SA},
year = {2019},
volume = {6},
doi = {https://doi.org/10.3389/fmars.2019.00400}
}
|
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| Ware, J., Kort, E.A., DeCola, P. and Duren, R. | Aerosol lidar observations of atmospheric mixing in Los Angeles: Climatology and implications for greenhouse gas observations | {2016} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {121}({16}), pp. 9862-9878 |
article | DOI |
| Abstract: Atmospheric observations of greenhouse gases provide essential information on sources and sinks of these key atmospheric constituents. To quantify fluxes from atmospheric observations, representation of transport-especially vertical mixing-is a necessity and often a source of error. We report on remotely sensed profiles of vertical aerosol distribution taken over a 2 year period in Pasadena, California. Using an automated analysis system, we estimate daytime mixing layer depth, achieving high confidence in the afternoon maximum on 51% of days with profiles from a Sigma Space Mini Micropulse LiDAR (MiniMPL) and on 36% of days with a Vaisala CL51 ceilometer. We note that considering ceilometer data on a logarithmic scale, a standard method, introduces, an offset in mixing height retrievals. The mean afternoon maximum mixing height is 770 m Above Ground Level in summer and 670 m in winter, with significant day-to-day variance (within season sigma = 220 m approximate to 30%). Taking advantage of the MiniMPL's portability, we demonstrate the feasibility of measuring the detailed horizontal structure of the mixing layer by automobile. We compare our observations to planetary boundary layer (PBL) heights from sonde launches, North American regional reanalysis (NARR), and a custom Weather Research and Forecasting (WRF) model developed for greenhouse gas (GHG) monitoring in Los Angeles. NARR and WRF PBL heights at Pasadena are both systematically higher than measured, NARR by 2.5 times; these biases will cause proportional errors in GHG flux estimates using modeled transport. We discuss how sustained lidar observations can be used to reduce flux inversion error by selecting suitable analysis periods, calibrating models, or characterizing bias for correction in post processing. |
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BibTeX:
@article{ware16a,
author = {Ware, John and Kort, Eric A. and DeCola, Phil and Duren, Riley},
title = {Aerosol lidar observations of atmospheric mixing in Los Angeles: Climatology and implications for greenhouse gas observations},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2016},
volume = {121},
number = {16},
pages = {9862--9878},
doi = {https://doi.org/10.1002/2016JD024953}
}
|
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| Ware, J.F. | Factors Impacting Observation-Based Estimates of Urban Greenhouse Gas Emissions | 2018 | School: The University of Michigan | phdthesis | URL |
| Abstract: Urban areas are responsible for a large and increasing fraction of anthropogenic greenhouse gas emissions. Accurate methods for quantifying and monitoring those emissions are needed to suggest and evaluate mitigation policies, as well as for … | |||||
BibTeX:
@phdthesis{ware18a,
author = {John Frederick Ware},
title = {Factors Impacting Observation-Based Estimates of Urban Greenhouse Gas Emissions},
school = {The University of Michigan},
year = {2018},
url = {https://deepblue.lib.umich.edu/handle/2027.42/145986}
}
|
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| Wassmann, A., Landgraf, J. and Aben, I. | Ozone profiles from clear sky thermal infrared measurements of the Infrared Atmospheric Sounding Interferometer: A retrieval approach accounting for thin cirrus | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: In this work we discuss the retrieval of ozone profiles from Infrared Atmospheric Sounding Interferometer (IASI) thermal infrared measurements in the presence of thin cirrus. An algorithm is presented which accounts for optically thin cirrus, described by an absorption layer at fixed altitude, where an effective cirrus optical depth is determined from IASI measurements at the 15 mu m CO2 absorption band. Subsequently, the cirrus characteristics are used for the ozone profile retrievals at the 9.6 mu m O-3 absorption band. To retrieve ozone we employ a Tikhonov regularization scheme in combination with the L curve approach. A sensitivity study shows that neglecting thin cirrus in the ozone profile retrieval leads to errors of >20% in the troposphere for an infrared optical depth of <0.1 (tau(550nm) < 0.05), while errors are around 5% when accounting for thin cirrus in the proposed manner. Uncertainties on cirrus height are mostly compensated by the retrieval of the effective cloud parameter. The findings are confirmed when we apply the retrieval scheme to IASI measurements which are filtered according to water clouds and optically thick cirrus. The ozone profiles are validated with 193 collocated ozonesonde profiles from nine stations and show good improvement at all altitudes. For the different stations the differences in the mean profiles between IASI ozone profiles and sonde profiles at 5 km altitude improve from (-10)%-(+80)% when cirrus is not accounted for in the retrieval to (-10)%-(+35)% when employing the new retrieval scheme. At the same time the root-mean-square differences between IASI ozone profiles and sonde profiles improve from 30%-100% to 20%-50%. |
|||||
BibTeX:
@article{wassmann11a,
author = {Wassmann, A. and Landgraf, J. and Aben, I.},
title = {Ozone profiles from clear sky thermal infrared measurements of the Infrared Atmospheric Sounding Interferometer: A retrieval approach accounting for thin cirrus},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2011JD016066}
}
|
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| Watson, A.J., Schuster, U., Bakker, D.C.E., Bates, N.R., Corbiere, A., Gonzalez-Davila, M., Friedrich, T., Hauck, J., Heinze, C., Johannessen, T., Koertzinger, A., Metzl, N., Olafsson, J., Olsen, A., Oschlies, A., Antonio Padin, X., Pfeil, B., Magdalena Santana-Casiano, J., Steinhoff, T., Telszewski, M., Rios, A.F., Wallace, D.W.R. and Wanninkhof, R. | Tracking the Variable North Atlantic Sink for Atmospheric CO2 | {2009} | SCIENCE Vol. {326}({5958}), pp. 1391-1393 |
article | DOI |
| Abstract: The oceans are a major sink for atmospheric carbon dioxide (CO2). Historically, observations have been too sparse to allow accurate tracking of changes in rates of CO2 uptake over ocean basins, so little is known about how these vary. Here, we show observations indicating substantial variability in the CO2 uptake by the North Atlantic on time scales of a few years. Further, we use measurements from a coordinated network of instrumented commercial ships to define the annual flux into the North Atlantic, for the year 2005, to a precision of about 10%. This approach offers the prospect of accurately monitoring the changing ocean CO2 sink for those ocean basins that are well covered by shipping routes. |
|||||
BibTeX:
@article{watson09a,
author = {Watson, Andrew J. and Schuster, Ute and Bakker, Dorothee C. E. and Bates, Nicholas R. and Corbiere, Antoine and Gonzalez-Davila, Melchor and Friedrich, Tobias and Hauck, Judith and Heinze, Christoph and Johannessen, Truls and Koertzinger, Arne and Metzl, Nicolas and Olafsson, Jon and Olsen, Are and Oschlies, Andreas and Antonio Padin, X. and Pfeil, Benjamin and Magdalena Santana-Casiano, J. and Steinhoff, Tobias and Telszewski, Maciej and Rios, Aida F. and Wallace, Douglas W. R. and Wanninkhof, Rik},
title = {Tracking the Variable North Atlantic Sink for Atmospheric CO2},
journal = {SCIENCE},
year = {2009},
volume = {326},
number = {5958},
pages = {1391--1393},
doi = {https://doi.org/10.1126/science.1177394}
}
|
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| Wei, J., Savtchenko, A., Vollmer, B., Hearty, T., Albayrak, A., Crisp, D. and Eldering, A. | Advances in CO2 Observations From AIRS and ACOS | {2014} | IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Vol. {11}({5}), pp. 891-895 |
article | DOI |
| Abstract: NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) archives and distributes pioneering collections of data on atmospheric greenhouse gases. In September of 2012, the Atmospheric Infrared Sounder (AIRS) marked a decade of tropospheric observations of carbon dioxide (CO2). Most recently, the Atmospheric CO2 Observations from Space (ACOS) project and GES DISC released CO2 retrievals derived from radiances observed by the Japanese Greenhouse gases Observing SATellite (GOSAT) satellite, launched in 2009. In this letter, we present the most recent estimates of decadal mid-tropospheric trends of CO2 from AIRS, as well as the most recent status of the total column-average distribution of CO2 from ACOS. We also demonstrate that significant discrepancies still exist in the global distribution of observed and modeled column amounts of CO2 using the CO2 retrievals from the ACOS project. |
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BibTeX:
@article{wei14a,
author = {Wei, J. and Savtchenko, A. and Vollmer, B. and Hearty, T. and Albayrak, A. and Crisp, D. and Eldering, A.},
title = {Advances in CO2 Observations From AIRS and ACOS},
journal = {IEEE GEOSCIENCE AND REMOTE SENSING LETTERS},
year = {2014},
volume = {11},
number = {5},
pages = {891--895},
doi = {https://doi.org/10.1109/LGRS.2013.2281147}
}
|
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| Wei, X., Wang, X., Wei, W. and Wan, W. | Use of Sun-Induced Chlorophyll Fluorescence Obtained by OCO-2 and GOME-2 for GPP Estimates of the Heihe River Basin, China [BibTeX] |
2018 | Remote Sensing Vol. 10(12) |
article | URL |
BibTeX:
@article{wei18a,
author = {Wei, Xiaoxu and Wang, Xufeng and Wei, Wei and Wan, Wei},
title = {Use of Sun-Induced Chlorophyll Fluorescence Obtained by OCO-2 and GOME-2 for GPP Estimates of the Heihe River Basin, China},
journal = {Remote Sensing},
year = {2018},
volume = {10},
number = {12},
url = {https://www.mdpi.com/2072-4292/10/12/2039}
}
|
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| Wei, X. | A Synthesis Program: Reducing Uncertainties of the Terrestrial Biosphere Carbon Cycle at Various Spatio Temporal Scales | 2020 | School: University of Maine | phdthesis | URL |
| Abstract: The terrestrial biosphere plays an important role in the global carbon cycle, and disturbance fire and climate extreme drought have strong direct and indirect impacts on the carbon fluxes. In addition, the lateral dissolved organic carbon (DOC) flux from soils to inland waters … | |||||
BibTeX:
@phdthesis{wei20a,
author = {Xinyuan Wei},
title = {A Synthesis Program: Reducing Uncertainties of the Terrestrial Biosphere Carbon Cycle at Various Spatio Temporal Scales},
school = {University of Maine},
year = {2020},
url = {https://digitalcommons.library.umaine.edu/etd/3173/}
}
|
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| Wei, Y., Shrestha, R., Pal, S., Gerken, T., Feng, S., McNelis, J., Singh, D., Thornton, M.M., Boyer, A.G., Shook, M.A., Chen, G., Baier, B.C., Barkley, Z.R., Barrick, J.D., Bennett, J.R., Browell, E.V., Campbell, J.F., Campbell, L.J., Choi, Y., Collins, J., Dobler, J., Eckl, M., Fiehn, A., Fried, A., Digangi, J.P., Barton-Grimley, R., Halliday, H., Klausner, T., Kooi, S., Kostinek, J., Lauvaux, T., Lin, B., McGill, M.J., Meadows, B., Miles, N.L., Nehrir, A.R., Nowak, J.B., Obland, M., O'Dell, C., Fao, R.M.P., Richardson, S.J., Richter, D., Roiger, A., Sweeney, C., Walega, J., Weibring, P., Williams, C.A., Yang, M.M., Zhou, Y. and Davis, K.J. | Atmospheric Carbon and Transport - America (ACT-America) Data Sets: Description, Management, and Delivery | 2021 | EARTH AND SPACE SCIENCE Vol. 8(7) |
article | DOI |
| Abstract: The ACT-America project is a NASA Earth Venture Suborbital-2 mission designed to study the transport and fluxes of greenhouse gases. The open and freely available ACT-America data sets provide airborne in situ measurements of atmospheric carbon dioxide, methane, trace gases, aerosols, clouds, and meteorological properties, airborne remote sensing measurements of aerosol backscatter, atmospheric boundary layer height and columnar content of atmospheric carbon dioxide, tower-based measurements, and modeled atmospheric mole fractions and regional carbon fluxes of greenhouse gases over the Central and Eastern United States. We conducted 121 research flights during five campaigns in four seasons during 2016-2019 over three regions of the US (Mid-Atlantic, Midwest and South) using two NASA research aircraft (B-200 and C-130). We performed three flight patterns (fair weather, frontal crossings, and OCO-2 underflights) and collected more than 1,140 h of airborne measurements via level-leg flights in the atmospheric boundary layer, lower, and upper free troposphere and vertical profiles spanning these altitudes. We also merged various airborne in situ measurements onto a common standard sampling interval, which brings coherence to the data, creates geolocated data products, and makes it much easier for the users to perform holistic analysis of the ACT-America data products. Here, we report on detailed information of data sets collected, the workflow for data sets including storage and processing of the quality controlled and quality assured harmonized observations, and their archival and formatting for users. Finally, we provide some important information on the dissemination of data products including metadata and highlights of applications of ACT-America data sets. |
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BibTeX:
@article{wei21a,
author = {Wei, Y. and Shrestha, R. and Pal, S. and Gerken, T. and Feng, S. and McNelis, J. and Singh, D. and Thornton, M. M. and Boyer, A. G. and Shook, M. A. and Chen, G. and Baier, B. C. and Barkley, Z. R. and Barrick, J. D. and Bennett, J. R. and Browell, E. V. and Campbell, J. F. and Campbell, L. J. and Choi, Y. and Collins, J. and Dobler, J. and Eckl, M. and Fiehn, A. and Fried, A. and Digangi, J. P. and Barton-Grimley, R. and Halliday, H. and Klausner, T. and Kooi, S. and Kostinek, J. and Lauvaux, T. and Lin, B. and McGill, M. J. and Meadows, B. and Miles, N. L. and Nehrir, A. R. and Nowak, J. B. and Obland, M. and O'Dell, C. and Fao, R. M. P. and Richardson, S. J. and Richter, D. and Roiger, A. and Sweeney, C. and Walega, J. and Weibring, P. and Williams, C. A. and Yang, M. M. and Zhou, Y. and Davis, K. J.},
title = {Atmospheric Carbon and Transport - America (ACT-America) Data Sets: Description, Management, and Delivery},
journal = {EARTH AND SPACE SCIENCE},
year = {2021},
volume = {8},
number = {7},
doi = {https://doi.org/10.1029/2020EA001634}
}
|
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| Weir, B., Ott, L.E., Collatz, G.J., Kawa, S.R., Poulter, B., Chatterjee, A., Oda, T. and Pawson, S. | Calibrating satellite-derived carbon fluxes for retrospective and near real-time assimilation systems | 2020 | ATMOSPHERIC CHEMISTRY AND PHYSICS | article | URL |
| Abstract: The ability to monitor and understand natural and anthropogenic variability in atmospheric carbon dioxide (CO 2) is a growing need of many stakeholders across the world. Systems that assimilate satellite observations, given their short latency and dense spatial coverage … | |||||
BibTeX:
@article{weir20a,
author = {Brad Weir and Lesley E. Ott and George J. Collatz and Stephan R. Kawa and Benjamin Poulter and Abhishek Chatterjee and Tomohiro Oda and Steven Pawson},
title = {Calibrating satellite-derived carbon fluxes for retrospective and near real-time assimilation systems},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2020},
url = {https://acp.copernicus.org/preprints/acp-2020-496/}
}
|
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| Weir, B., Ott, L.E., Collatz, G.J., Kawa, S.R., Poulter, B., Chatterjee, A., Oda, T. and Pawson, S. | Bias-correcting carbon fluxes derived from land-surface satellite data for retrospective and near-real-time assimilation systems | 2021 | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 21(12), pp. 9609-9628 |
article | DOI |
| Abstract: The ability to monitor and understand natural and anthropogenic variability in atmospheric carbon dioxide (CO2) is a growing need of many stakeholders across the world. Systems that assimilate satellite observations, given their short latency and dense spatial coverage, into high-resolution global models are valuable, if not essential, tools for addressing this need. A notable drawback of modern assimilation systems is the long latency of many vital input datasets; for example, inventories, in situ measurements, and reprocessed remote-sensing data can trail the current date by months to years. This paper describes techniques for biascorrecting surface fluxes derived from satellite observations of the Earth's surface to be consistent with constraints from inventories and in situ CO2 datasets. The techniques are applicable in both short-term forecasts and retrospective simulations, thus taking advantage of the coverage and short latency of satellite data while reproducing the major features of long-term inventory and in situ records. Our approach begins with a standard collection of diagnostic fluxes which incorporate a variety of remote-sensing driver data, viz. vegetation indices, fire radiative power, and nighttime lights. We then apply an empirical sink so that global budgets of the diagnostic fluxes match given atmospheric and oceanic growth rates for each year. This step removes coherent, systematic flux errors that produce biases in CO2 which mask the signals an assimilation system hopes to capture. Depending on the simulation mode, the empirical sink uses different choices of atmospheric growth rates: estimates based on observations in retrospective mode and projections based on seasonal forecasts of sea surface temperature in forecasting mode. The retrospective fluxes, when used in simulations with NASA's Goddard Earth Observing System (GEOS), reproduce marine boundary layer measurements with comparable skill to those using fluxes from a modern inversion system. The forecasted fluxes show promising accuracy in their application to the analysis of changes in the carbon cycle as they occur. |
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BibTeX:
@article{weir21a,
author = {Weir, Brad and Ott, Lesley E. and Collatz, George J. and Kawa, Stephan R. and Poulter, Benjamin and Chatterjee, Abhishek and Oda, Tomohiro and Pawson, Steven},
title = {Bias-correcting carbon fluxes derived from land-surface satellite data for retrospective and near-real-time assimilation systems},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2021},
volume = {21},
number = {12},
pages = {9609-9628},
doi = {https://doi.org/10.5194/acp-21-9609-2021}
}
|
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| Werth, D., Buckley, R., Zhang, G., Kurzeja, R., Leclerc, M., Duarte, H., Parker, M. and Watson, T. | Quantifying the local influence at a tall tower site in nocturnal conditions | {2017} | THEORETICAL AND APPLIED CLIMATOLOGY Vol. {127}({3-4}), pp. 627-642 |
article | DOI |
| Abstract: The influence of the local terrestrial environment on nocturnal atmospheric CO2 measurements at a 329-m television transmitter tower (and a component of a CO2 monitoring network) was estimated with a tracer release experiment and a subsequent simulation of the releases. This was done to characterize the vertical transport of emissions from the surface to the uppermost tower level and how it is affected by atmospheric stability. The tracer release experiment was conducted over two nights in May of 2009 near the Department of Energy's Savannah River Site (SRS) in South Carolina. Tracer was released on two contrasting nights-slightly stable and moderately stable-from several upwind surface locations. Measurements at the 329-m level on both nights indicate that tracer was able to mix vertically within a relatively short (similar to 24 km) distance, implying that nocturnal stable conditions do not necessarily prevent vertical dispersion in the boundary layer and that CO2 measurements at the tower are at least partly influenced by nearby emissions. A simulation of the tracer release is used to calculate the tower footprint on the two nights to estimate the degree to which the local domain affects the tower readings. The effect of the nocturnal boundary layer on the area sampled by the tower can be seen clearly, as the footprints were affected by changes in stability. The contribution of local sources to the measurements at the tower was minimal, however, suggesting that nocturnal concentrations at upper levels are contributed mostly by regional sources. |
|||||
BibTeX:
@article{werth17a,
author = {Werth, David and Buckley, Robert and Zhang, Gengsheng and Kurzeja, Robert and Leclerc, Monique and Duarte, Henrique and Parker, Matthew and Watson, Thomas},
title = {Quantifying the local influence at a tall tower site in nocturnal conditions},
journal = {THEORETICAL AND APPLIED CLIMATOLOGY},
year = {2017},
volume = {127},
number = {3-4},
pages = {627--642},
doi = {https://doi.org/10.1007/s00704-015-1648-y}
}
|
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| Wesloh, D., Lauvaux, T. and Davis, K.J. | Development of a Mesoscale Inversion System for Estimating Continental-Scale CO(2)Fluxes | {2020} | JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS Vol. {12}({9}) |
article | DOI |
| Abstract: Computational requirements often impose limitations on the spatial and temporal resolutions of atmospheric CO(2)inversions, increasing aggregation and representation errors. This study enables higher spatial and temporal resolution inversions with spatial and temporal error structures similar to those used in other published inversions by representing the prior flux error covariances as a Kronecker product of spatial and temporal covariances and by using spectral methods for the spatial correlations. Compared to existing inversion systems that are forced to degrade the resolution of the problem in order to bring the dimensionality down to computationally tractable levels, this inversion framework is able to take advantage of mesoscale transport simulations and more of the complexity of spatial and temporal covariances in the surface CO(2)fluxes. This approach was successfully implemented over one month with an identical-twin observing system simulation experiment (OSSE) using a set of assumptions about the prior flux uncertainties compatible both with continental-scale uncertainty estimates and with comparisons of vegetation models to flux towers. The demonstration illustrates the potential of the newly developed inversion system to use high-temporal-resolution information from the North American tower network, to extract high-resolution information about CO(2)fluxes that is inaccessible to coarser resolution inversion systems, and to simultaneously optimize an ensemble of prior estimates. This demonstration sets the stage for regional flux inversions that can take full advantage of the high-resolution data available in tower CO(2)records and mesoscale atmospheric transport reanalyses, include more realistic prior error structures, and explore specifying prior fluxes with ensembles. | |||||
BibTeX:
@article{wesloh20a,
author = {Wesloh, Daniel and Lauvaux, Thomas and Davis, Kenneth J.},
title = {Development of a Mesoscale Inversion System for Estimating Continental-Scale CO(2)Fluxes},
journal = {JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {12},
number = {9},
doi = {https://doi.org/10.1029/2019MS001818}
}
|
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| West, T.O., Bandaru, V., Brandt, C.C., Schuh, A.E. and Ogle, S.M. | Regional uptake and release of crop carbon in the United States | {2011} | BIOGEOSCIENCES Vol. {8}({8}), pp. 2037-2046 |
article | DOI |
| Abstract: Carbon fixed by agricultural crops in the US creates regional CO2 sinks where it is harvested and regional CO2 sources where it is released back to the atmosphere. The quantity and location of these fluxes differ depending on the annual supply and demand of crop commodities. Data on the harvest of crop biomass, storage, import and export, and on the use of biomass for food, feed, fiber, and fuel were compiled to estimate an annual crop carbon budget for 2000 to 2008. With respect to US Farm Resource Regions, net sources of CO2 associated with the consumption of crop commodities occurred in the Eastern Uplands, Southern Seaboard, and Fruitful Rim regions. Net sinks associated with the production of crop commodities occurred in the Heartland, Northern Great Plains, and Mississippi Portal regions. The national crop carbon budget was balanced to within 0.3 to 6.1% yr(-1) during the period of this analysis. |
|||||
BibTeX:
@article{west11a,
author = {West, T. O. and Bandaru, V. and Brandt, C. C. and Schuh, A. E. and Ogle, S. M.},
title = {Regional uptake and release of crop carbon in the United States},
journal = {BIOGEOSCIENCES},
year = {2011},
volume = {8},
number = {8},
pages = {2037--2046},
doi = {https://doi.org/10.5194/bg-8-2037-2011}
}
|
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| West, T.O., Brown, M.E., Duren, R.M., Ogle, S.M. and Moss, R.H. | Definition, capabilities and components of a terrestrial carbon monitoring system | {2013} | CARBON MANAGEMENT Vol. {4}({4}), pp. 413-422 |
article | DOI |
| Abstract: Research efforts for effectively and consistently monitoring terrestrial carbon are increasing in number. As such, there is a need to define carbon monitoring and how it relates to carbon cycle science and carbon management. There is also a need to identify capabilities of a carbon monitoring system and the system components needed to develop the capabilities. Capabilities that enable the effective application of a carbon monitoring system for monitoring and management purposes may include: reconciling carbon stocks and fluxes, developing consistency across spatial and temporal scales, tracking horizontal movement of carbon, attribution of emissions to originating sources, cross-sectoral accounting, uncertainty quantification, redundancy and policy relevance. Focused research is needed to integrate these capabilities for sustained estimates of carbon stocks and fluxes. Additionally, if monitoring is intended to inform management decisions, management priorities should be considered prior to development of a monitoring system. |
|||||
BibTeX:
@article{west13a,
author = {West, Tristram O. and Brown, Molly E. and Duren, Riley M. and Ogle, Stephen M. and Moss, Richard H.},
title = {Definition, capabilities and components of a terrestrial carbon monitoring system},
journal = {CARBON MANAGEMENT},
year = {2013},
volume = {4},
number = {4},
pages = {413--422},
doi = {https://doi.org/10.4155/CMT.13.36}
}
|
|||||
| Williams, I.N., Riley, W.J., Torn, M.S., Berry, J.A. and Biraud, S.C. | Using boundary layer equilibrium to reduce uncertainties in transport models and CO2 flux inversions | {2011} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {11}({18}), pp. 9631-9641 |
article | DOI |
| Abstract: This paper reexamines evidence for systematic errors in atmospheric transport models, in terms of the diagnostics used to infer vertical mixing rates from models and observations. Different diagnostics support different conclusions about transport model errors that could imply either stronger or weaker northern terrestrial carbon sinks. Conventional mixing diagnostics are compared to analyzed vertical mixing rates using data from the US Southern Great Plains Atmospheric Radiation Measurement Climate Research Facility, the CarbonTracker data assimilation system based on Transport Model version 5 (TM5), and atmospheric reanalyses. The results demonstrate that diagnostics based on boundary layer depth and vertical concentration gradients do not always indicate the vertical mixing strength. Vertical mixing rates are anti-correlated with boundary layer depth at some sites, diminishing in summer when the boundary layer is deepest. Boundary layer equilibrium concepts predict an inverse proportionality between CO2 vertical gradients and vertical mixing strength, such that previously reported discrepancies between observations and models most likely reflect overestimated as opposed to underestimated vertical mixing. However, errors in seasonal concentration gradients can also result from errors in modeled surface fluxes. This study proposes using the timescale for approach to boundary layer equilibrium to diagnose vertical mixing independently of seasonal surface fluxes, with applications to observations and model simulations of CO2 or other conserved boundary layer tracers with surface sources and sinks. Results indicate that frequently cited discrepancies between observations and inverse estimates do not provide sufficient proof of systematic errors in atmospheric transport models. Some previously hypothesized transport model biases, if found and corrected, could cause inverse estimates to further diverge from carbon inventory estimates of terrestrial sinks. |
|||||
BibTeX:
@article{williams11a,
author = {Williams, I. N. and Riley, W. J. and Torn, M. S. and Berry, J. A. and Biraud, S. C.},
title = {Using boundary layer equilibrium to reduce uncertainties in transport models and CO2 flux inversions},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
volume = {11},
number = {18},
pages = {9631--9641},
doi = {https://doi.org/10.5194/acp-11-9631-2011}
}
|
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| Williams, C.A., Collatz, G.J., Masek, J. and Goward, S.N. | Carbon consequences of forest disturbance and recovery across the conterminous United States | {2012} | GLOBAL BIOGEOCHEMICAL CYCLES Vol. {26} |
article | DOI |
| Abstract: Forests of North America are thought to constitute a significant long-term sink for atmospheric carbon. The United States Forest Service Forest Inventory and Analysis (FIA) program has developed a large database of stock changes derived from consecutive estimates of growing stock volume in the U.S. These data reveal a large and relatively stable increase in forest carbon stocks over the last two decades or more. The mechanisms underlying this national increase in forest stocks may include recovery of forests from past disturbances, net increases in forest area, and growth enhancement driven by climate or fertilization by CO2 and Nitrogen. Here we estimate the forest recovery component of the observed stock changes using FIA data on the age structure of U.S. forests and carbon stocks as a function of age. The latter are used to parameterize forest disturbance and recovery processes in a carbon cycle model. We then apply resulting disturbance/recovery dynamics to landscapes and regions based on the forest age distributions. The analysis centers on 28 representative climate settings spread about forested regions of the conterminous U.S. We estimate carbon fluxes for each region and propagate uncertainties in calibration data through to the predicted fluxes. The largest recovery-driven carbon sinks are found in the South Central, Pacific Northwest, and Pacific Southwest regions, with spatially averaged net ecosystem productivity (NEP) of about 100 g C m(-2) a(-1) driven by forest age structure. Carbon sinks from recovery in the Northeast and Northern Lakes States remain moderate to large owing to the legacy of historical clearing and relatively low modern disturbance rates from harvest and fire. At the continental scale, we find a conterminous U.S. forest NEP of only 0.16 Pg C a(-1) from age structure in 2005, or only 0.047 Pg C a(-1) of forest stock change after accounting for fire emissions and harvest transfers. Recent estimates of NEP derived from inventory stock change, harvest, and fire data show twice the NEP sink we derive from forest age distributions. We discuss possible reasons for the discrepancies including modeling errors and the possibility of climate and/or fertilization (CO2 or N) growth enhancements. |
|||||
BibTeX:
@article{williams12a,
author = {Williams, Christopher A. and Collatz, G. James and Masek, Jeffrey and Goward, Samuel N.},
title = {Carbon consequences of forest disturbance and recovery across the conterminous United States},
journal = {GLOBAL BIOGEOCHEMICAL CYCLES},
year = {2012},
volume = {26},
doi = {https://doi.org/10.1029/2010GB003947}
}
|
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| Williams, I.N., Riley, W.J., Torn, M.S., Biraud, S.C. and Fischer, M.L. | Biases in regional carbon budgets from covariation of surface fluxes and weather in transport model inversions | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({3}), pp. 1571-1585 |
article | DOI |
| Abstract: Recent advances in atmospheric transport model inversions could significantly reduce uncertainties in land carbon uptake through the assimilation of CO2 concentration measurements at weekly and shorter timescales. The potential of these measurements for reducing biases in estimated land carbon sinks depends on the strength of covariation between surface fluxes and atmospheric transport at these timescales and how well transport models represent this covariation. Daily to seasonal covariation of surface fluxes and atmospheric transport was estimated in observations at the US Southern Great Plains Atmospheric Radiation Measurement Climate Research Facility, and compared to an atmospheric transport model inversion (CarbonTracker). Covariation of transport and surface fluxes was stronger in CarbonTracker than in observations on synoptic (daily to weekly) timescales, with a wet year (2007) having significant covariation compared to a dry year (2006). Differences between observed and CarbonTracker synoptic covariation resulted in a 0.3 ppm CO2 enhancement in boundary layer concentrations during the growing season, and a corresponding enhancement in carbon uptake by 13% of the seasonal cycle amplitude in 2007, as estimated by an offline simplified transport model. This synoptic rectification of surface flux variability was of similar magnitude to the interannual variability in carbon sinks alone, and indicates that interannual variability in the inversions can be affected by biases in simulated synoptic rectifier effects. The most significant covariation of surface fluxes and transport had periodicities of 10 days and greater, suggesting that surface flux inversions would benefit from improved simulations of the effects of soil moisture on boundary layer heights and surface CO2 fluxes. Soil moisture remote sensing could be used along with CO2 concentration measurements to further constrain atmospheric transport model inversions. |
|||||
BibTeX:
@article{williams14a,
author = {Williams, I. N. and Riley, W. J. and Torn, M. S. and Biraud, S. C. and Fischer, M. L.},
title = {Biases in regional carbon budgets from covariation of surface fluxes and weather in transport model inversions},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {3},
pages = {1571--1585},
doi = {https://doi.org/10.5194/acp-14-1571-2014}
}
|
|||||
| Wolf, S., Keenan, T., Fisher, J., Baldocchi, D., Desai, A. and ... | Warm spring reduced carbon cycle impact of the 2012 US summer drought | 2017 | PNAS | article | URL |
| Abstract: The global terrestrial carbon sink offsets one-third of the world's fossil fuel emissions, but the strength of this sink is highly sensitive to large-scale extreme events. In 2012, the contiguous United States experienced exceptionally warm temperatures and the most severe drought … | |||||
BibTeX:
@article{wolf17a,
author = {Sebastian Wolf and TF Keenan and JB Fisher and DD Baldocchi and AR Desai and ...},
title = {Warm spring reduced carbon cycle impact of the 2012 US summer drought},
journal = {PNAS},
year = {2017},
url = {https://ir.library.oregonstate.edu/concern/articles/08612q353}
}
|
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| Worden, J.R., Turner, A.J., Bloom, A., Kulawik, S.S., Liu, J., Lee, M., Weidner, R., Bowman, K., Frankenberg, C., Parker, R. and Payne, V.H. | Quantifying lower tropospheric methane concentrations using GOSAT near-IR and TES thermal IR measurements | {2015} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {8}({8}), pp. 3433-3445 |
article | DOI |
| Abstract: Evaluating surface fluxes of CH4 using total column data requires models to accurately account for the transport and chemistry of methane in the free troposphere and stratosphere, thus reducing sensitivity to the underlying fluxes. Vertical profiles of methane have increased sensitivity to surface fluxes because lower tropospheric methane is more sensitive to surface fluxes than a total column, and quantifying free-tropospheric CH4 concentrations helps to evaluate the impact of transport and chemistry uncertainties on estimated surface fluxes. Here we demonstrate the potential for estimating lower tropospheric CH4 concentrations through the combination of free-tropospheric methane measurements from the Aura Tropospheric Emission Spectrometer (TES) and XCH4 (dry-mole air fraction of methane) from the Greenhouse gases Observing SATellite - Thermal And Near-infrared for carbon Observation (GOSAT TANSO, herein GOSAT for brevity). The calculated precision of these estimates ranges from 10 to 30 ppb for a monthly average on a 4 degrees x 5 degrees latitude/longitude grid making these data suitable for evaluating lower-tropospheric methane concentrations. Smoothing error is approximately 10 ppb or less. Comparisons between these data and the GEOS-Chem model demonstrate that these lower-tropospheric CH4 estimates can resolve enhanced concentrations over flux regions that are challenging to resolve with total column measurements. We also use the GEOS-Chem model and surface measurements in background regions across a range of latitudes to determine that these lower-tropospheric estimates are biased low by approximately 65 ppb, with an accuracy of approximately 6 ppb (after removal of the bias) and an actual precision of approximately 30 ppb. This 6 ppb accuracy is consistent with the accuracy of TES and GOSAT methane retrievals. |
|||||
BibTeX:
@article{worden15a,
author = {Worden, J. R. and Turner, A. J. and Bloom, A. and Kulawik, S. S. and Liu, J. and Lee, M. and Weidner, R. and Bowman, K. and Frankenberg, C. and Parker, R. and Payne, V. H.},
title = {Quantifying lower tropospheric methane concentrations using GOSAT near-IR and TES thermal IR measurements},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2015},
volume = {8},
number = {8},
pages = {3433--3445},
doi = {https://doi.org/10.5194/amt-8-3433-2015}
}
|
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| van der Woude, A. | Learning from machine learning | 2019 | School: Wageningen University | mastersthesis | URL |
| Abstract: Due to an imbalance in the sources and sinks of carbon, the CO2 mixing ratio in the atmosphere has increased from about 280 to over 400 ppm in the past 150 years (Etheridge et al., 1996; Dlugokencky and Tans, 2015). This increase in CO2, along with other gases … | |||||
BibTeX:
@mastersthesis{woude19a,
author = {Auke van der Woude},
title = {Learning from machine learning},
school = {Wageningen University},
year = {2019},
url = {https://edepot.wur.nl/473121}
}
|
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| Wu, L., Bocquet, M., Lauvaux, T., Chevallier, F., Rayner, P. and Davis, K. | Optimal representation of source-sink fluxes for mesoscale carbon dioxide inversion with synthetic data | {2011} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {116} |
article | DOI |
| Abstract: The inversion of CO2 surface fluxes from atmospheric concentration measurements involves discretizing the flux domain in time and space. The resolution choice is usually guided by technical considerations despite its impact on the solution to the inversion problem. In our previous studies, a Bayesian formalism has recently been introduced to describe the discretization of the parameter space over a large dictionary of adaptive multiscale grids. In this paper, we exploit this new framework to construct optimal space-time representations of carbon fluxes for mesoscale inversions. Inversions are performed using synthetic continuous hourly CO2 concentration data in the context of the Ring 2 experiment in support of the North American Carbon Program Mid Continent Intensive (MCI). Compared with the regular grid at finest scale, optimal representations can have similar inversion performance with far fewer grid cells. These optimal representations are obtained by maximizing the number of degrees of freedom for the signal (DFS) that measures the information gain from observations to resolve the unknown fluxes. Consequently information from observations can be better propagated within the domain through these optimal representations. For the Ring 2 network of eight towers, in most cases, the DFS value is relatively small compared to the number of observations d (DFS/d < 20%). In this multiscale setting, scale-dependent aggregation errors are identified and explicitly formulated for more reliable inversions. It is recommended that the aggregation errors should be taken into account, especially when the correlations in the errors of a priori fluxes are physically unrealistic. The optimal multiscale grids allow to adaptively mitigate the aggregation errors. |
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BibTeX:
@article{wu11a,
author = {Wu, Lin and Bocquet, Marc and Lauvaux, Thomas and Chevallier, Frederic and Rayner, Peter and Davis, Kenneth},
title = {Optimal representation of source-sink fluxes for mesoscale carbon dioxide inversion with synthetic data},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2011},
volume = {116},
doi = {https://doi.org/10.1029/2011JD016198}
}
|
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| Wu, X., Ju, W., Zhou, Y., He, M., Law, B.E., Black, T.A., Margolis, H.A., Cescatti, A., Gu, L., Montagnani, L., Noormets, A., Griffis, T.J., Pilegaard, K., Varlagin, A., Valentini, R., Blanken, P.D., Wang, S., Wang, H., Han, S., Yan, J., Li, Y., Zhou, B. and Liu, Y. | Performance of Linear and Nonlinear Two-Leaf Light Use Efficiency Models at Different Temporal Scales | {2015} | REMOTE SENSING Vol. {7}({3}), pp. 2238-2278 |
article | DOI |
| Abstract: The reliable simulation of gross primary productivity (GPP) at various spatial and temporal scales is of significance to quantifying the net exchange of carbon between terrestrial ecosystems and the atmosphere. This study aimed to verify the ability of a nonlinear two-leaf model (TL-LUEn), a linear two-leaf model (TL-LUE), and a big-leaf light use efficiency model (MOD17) to simulate GPP at half-hourly, daily and 8-day scales using GPP derived from 58 eddy-covariance flux sites in Asia, Europe and North America as benchmarks. Model evaluation showed that the overall performance of TL-LUEn was slightly but not significantly better than TL-LUE at half-hourly and daily scale, while the overall performance of both TL-LUEn and TL-LUE were significantly better (p < 0.0001) than MOD17 at the two temporal scales. The improvement of TL-LUEn over TL-LUE was relatively small in comparison with the improvement of TL-LUE over MOD17. However, the differences between TL-LUEn and MOD17, and TL-LUE and MOD17 became less distinct at the 8-day scale. As for different vegetation types, TL-LUEn and TL-LUE performed better than MOD17 for all vegetation types except crops at the half-hourly scale. At the daily and 8-day scales, both TL-LUEn and TL-LUE outperformed MOD17 for forests. However, TL-LUEn had a mixed performance for the three non-forest types while TL-LUE outperformed MOD17 slightly for all these non-forest types at daily and 8-day scales. The better performance of TL-LUEn and TL-LUE for forests was mainly achieved by the correction of the underestimation/overestimation of GPP simulated by MOD17 under low/high solar radiation and sky clearness conditions. TL-LUEn is more applicable at individual sites at the half-hourly scale while TL-LUE could be regionally used at half-hourly, daily and 8-day scales. MOD17 is also an applicable option regionally at the 8-day scale. |
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BibTeX:
@article{wu15a,
author = {Wu, Xiaocui and Ju, Weimin and Zhou, Yanlian and He, Mingzhu and Law, Beverly E. and Black, T. Andrew and Margolis, Hank A. and Cescatti, Alessandro and Gu, Lianhong and Montagnani, Leonardo and Noormets, Asko and Griffis, Timothy J. and Pilegaard, Kim and Varlagin, Andrej and Valentini, Riccardo and Blanken, Peter D. and Wang, Shaoqiang and Wang, Huimin and Han, Shijie and Yan, Junhua and Li, Yingnian and Zhou, Bingbing and Liu, Yibo},
title = {Performance of Linear and Nonlinear Two-Leaf Light Use Efficiency Models at Different Temporal Scales},
journal = {REMOTE SENSING},
year = {2015},
volume = {7},
number = {3},
pages = {2238--2278},
doi = {https://doi.org/10.3390/rs70302238}
}
|
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| Wu, L., Broquet, G., Ciais, P., Bellassen, V., Vogel, F., Chevallier, F., Xueref-Remy, I. and Wang, Y. | What would dense atmospheric observation networks bring to the quantification of city CO2 emissions? | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({12}), pp. 7743-7771 |
article | DOI |
| Abstract: Cities currently covering only a very small portion ( < aEuro-3aEuro-%) of the world's land surface directly release to the atmosphere about 44aEuro-% of global energy-related CO2, but they are associated with 71-76aEuro-% of CO2 emissions from global final energy use. Although many cities have set voluntary climate plans, their CO2 emissions are not evaluated by the monitoring, reporting, and verification (MRV) procedures that play a key role for market- or policy-based mitigation actions. Here we analyze the potential of a monitoring tool that could support the development of such procedures at the city scale. It is based on an atmospheric inversion method that exploits inventory data and continuous atmospheric CO2 concentration measurements from a network of stations within and around cities to estimate city CO2 emissions. This monitoring tool is configured for the quantification of the total and sectoral CO2 emissions in the Paris metropolitan area (similar to aEuro-12 million inhabitants and 11.4aEuro-TgC emitted in 2010) during the month of January 2011. Its performances are evaluated in terms of uncertainty reduction based on observing system simulation experiments (OSSEs). They are analyzed as a function of the number of sampling sites (measuring at 25aEuro-maEuro-a.g.l.) and as a function of the network design. The instruments presently used to measure CO2 concentrations at research stations are expensive (typically similar to aEuro-EURaEuro-50aEuro-k per sensor), which has limited the few current pilot city networks to around 10 sites. Larger theoretical networks are studied here to assess the potential benefit of hypothetical operational lower-cost sensors. The setup of our inversion system is based on a number of diagnostics and assumptions from previous city-scale inversion experiences with real data. We find that, given our assumptions underlying the configuration of the OSSEs, with 10 stations only the uncertainty for the total city CO2 emission during 1 month is significantly reduced by the inversion by similar to aEuro-42aEuro-%. It can be further reduced by extending the network, e.g., from 10 to 70 stations, which is promising for MRV applications in the Paris metropolitan area. With 70 stations, the uncertainties in the inverted emissions are reduced significantly over those obtained using 10 stations: by 32aEuro-% for commercial and residential buildings, by 33aEuro-% for road transport, by 18aEuro-% for the production of energy by power plants, and by 31aEuro-% for total emissions. These results indicate that such a high number of stations would be likely required for the monitoring of sectoral emissions in Paris using this observation-model framework. They demonstrate some high potential that atmospheric inversions can contribute to the monitoring and/or the verification of city CO2 emissions (baseline) and CO2 emission reductions (commitments) and the advantage that could be brought by the current developments of lower-cost medium precision (LCMP) sensors. |
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BibTeX:
@article{wu16a,
author = {Wu, Lin and Broquet, Gregoire and Ciais, Philippe and Bellassen, Valentin and Vogel, Felix and Chevallier, Frederic and Xueref-Remy, Irene and Wang, Yilong},
title = {What would dense atmospheric observation networks bring to the quantification of city CO2 emissions?},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {12},
pages = {7743--7771},
doi = {https://doi.org/10.5194/acp-16-7743-2016}
}
|
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| Wu, K., Lauvaux, T., Davis, K.J., Deng, A., Coto, I.L., Gurney, K.R. and Patarasuk, R. | Joint inverse estimation of fossil fuel and biogenic CO2 fluxes in an urban environment: An observing system simulation experiment to assess the impact of multiple uncertainties | {2018} | ELEMENTA-SCIENCE OF THE ANTHROPOCENE Vol. {6} |
article | DOI |
| Abstract: The Indianapolis Flux Experiment aims to utilize a variety of atmospheric measurements and a high-resolution inversion system to estimate the temporal and spatial variation of anthropogenic greenhouse gas emissions from an urban environment. We present a Bayesian inversion system solving for fossil fuel and biogenic CO2 fluxes over the city of Indianapolis, IN. Both components were described at 1 km resolution to represent point sources and fine-scale structures such as highways in the a priori fluxes. With a series of Observing System Simulation Experiments, we evaluate the sensitivity of inverse flux estimates to various measurement deployment strategies and errors. We also test the impacts of flux error structures, biogenic CO2 fluxes and atmospheric transport errors on estimating fossil fuel CO2 emissions and their uncertainties. The results indicate that high-accuracy and high-precision measurements produce significant improvement in fossil fuel CO2 flux estimates. Systematic measurement errors of 1 ppm produce significantly biased inverse solutions, degrading the accuracy of retrieved emissions by about 1 mu mol m(-2) s(-1) compared to the spatially averaged anthropogenic CO2 emissions of 5 mu mol m(-2) s(-1). The presence of biogenic CO2 fluxes (similar magnitude to the anthropogenic fluxes) limits our ability to correct for random and systematic emission errors. However, assimilating continuous fossil fuel CO2 measurements with 1 ppm random error in addition to total CO2 measurements can partially compensate for the interference from biogenic CO2 fluxes. Moreover, systematic and random flux errors can be further reduced by reducing model-data mismatch errors caused by atmospheric transport uncertainty. Finally, the precision of the inverse flux estimate is highly sensitive to the correlation length scale in the prior emission errors. This work suggests that improved fossil fuel CO2 measurement technology, and better understanding of both prior flux and atmospheric transport errors are essential to improve the accuracy and precision of high-resolution urban CO2 flux estimates. |
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BibTeX:
@article{wu18a,
author = {Wu, Kai and Lauvaux, Thomas and Davis, Kenneth J. and Deng, Aijun and Coto, Israel Lopez and Gurney, Kevin R. and Patarasuk, Risa},
title = {Joint inverse estimation of fossil fuel and biogenic CO2 fluxes in an urban environment: An observing system simulation experiment to assess the impact of multiple uncertainties},
journal = {ELEMENTA-SCIENCE OF THE ANTHROPOCENE},
year = {2018},
volume = {6},
doi = {https://doi.org/10.1525/elementa.138}
}
|
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| Wu, L., Hasekamp, O., Hu, H., Landgraf, J., Butz, A., aan de Brugh, J., Aben, I., Pollard, D.F., Griffith, D.W.T., Feist, D.G., Koshelev, D., Hase, F., Toon, G.C., Ohyama, H., Morino, I., Notholt, J., Shiomi, K., Iraci, L., Schneider, M., de Maziere, M., Sussmann, R., Kivi, R., Warneke, T., Goo, T.-Y. and Te, Y. | Carbon dioxide retrieval from OCO-2 satellite observations using the RemoTeC algorithm and validation with TCCON measurements | {2018} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {11}({5}), pp. {3111-3130} |
article | DOI |
| Abstract: In this study we present the retrieval of the column-averaged dry air mole fraction of carbon dioxide (X-CO2) from the Orbiting Carbon Observatory-2 (OCO-2) satellite observations using the RemoTeC algorithm, previously successfully applied to retrieval of greenhouse gas concentration from the Greenhouse Gases Observing Satellite (GOSAT). The X-CO2, product has been validated with collocated ground-based measurements from the Total Carbon Column Observing Network (TCCON) for almost 2 years of OCO-2 data from September 2014 to July 2016. We found that fitting an additive radiometric offset in all three spec tral bands of OCO-2 significantly improved the retrieval. Based on a small correlation of the X-CO2, error over land with goodness of fit, we applied an a posteriori bias correction to our OCO-2 retrievals. In overpass averaged results, X-CO2, retrievals have an SD of similar to 1.30 ppm and a station-tostation variability of similar to 0.40 ppm among collocated TCCON sites. The seasonal relative accuracy (SRA) has a value of 0.52 ppm. The validation shows relatively larger difference with TCCON over high-latitude areas and some specific regions like Japan. |
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BibTeX:
@article{wu18b,
author = {Wu, Lianghai and Hasekamp, Otto and Hu, Haili and Landgraf, Jochen and Butz, Andre and aan de Brugh, Joost and Aben, Ilse and Pollard, Dave F. and Griffith, David W. T. and Feist, Dietrich G. and Koshelev, Dmitry and Hase, Frank and Toon, Geoffrey C. and Ohyama, Hirofumi and Morino, Isamu and Notholt, Justus and Shiomi, Kei and Iraci, Laura and Schneider, Matthias and de Maziere, Martine and Sussmann, Ralf and Kivi, Rigel and Warneke, Thorsten and Goo, Tae-Young and Te, Yao},
title = {Carbon dioxide retrieval from OCO-2 satellite observations using the RemoTeC algorithm and validation with TCCON measurements},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
year = {2018},
volume = {11},
number = {5},
pages = {3111-3130},
doi = {https://doi.org/10.5194/amt-11-3111-2018}
}
|
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| Wu, X., Xiao, X., Zhang, Y., He, W., Wolf, S., Chen, J., He, M., Gough, C.M., Qin, Y., Zhou, Y., Doughty, R. and Blanken, P.D. | Spatiotemporal Consistency of Four Gross Primary Production Products and Solar-Induced Chlorophyll Fluorescence in Response to Climate Extremes Across CONUS in 2012 | {2018} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {123}({10}), pp. {3140-3161} |
article | DOI |
| Abstract: Large spatial-scale effects of climate extremes on gross primary production (GPP), the largest terrestrial carbon flux, are highly uncertain even as these extremes increase in frequency and extent. Here we report the impacts of spring warming and summer drought in 2012 on GPP across the contiguous United States (CONUS) using estimates from four GPP models: Vegetation Photosynthesis Model (VPM), MOD17A2H V006, Carnegie-Ames-Stanford Approach, and Simple Biosphere/Carnegie-Ames-Stanford Approach. VPM simulations are driven by Moderate Resolution Imaging Spectroradiometer, North American Regional Reanalysis climate data, and C-3 and C-4 cropland maps from the United States Department of Agriculture Cropland Data Layer data set. Across 25 eddy covariance flux tower sites, GPP estimates from VPM (GPP(VPM)) showed better accuracy in terms of cross-site variability and interannual variability (R-2=0.84 and 0.46, respectively) when compared to MOD17 GPP. We further assessed the spatial and temporal (seasonal) consistency between GPP products and the Global Ozone Monitoring Experiment-2 solar-induced chlorophyll fluorescence over CONUS during 2008-2014. The results suggested that GPP(VPM) agrees best with solar-induced chlorophyll fluorescence across space and time, capturing seasonal dynamics and interannual variations. Anomaly analyses showed that increased GPP during the spring compensated for the reduced GPP during the summer, resulting in near-neutral changes in annual GPP for the CONUS. This study demonstrates the importance of assessing the impacts of different types and timing of climate extremes on GPP and the need to improve light use efficiency models by incorporating C-3 and C-4 plant functional types. |
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BibTeX:
@article{wu18c,
author = {Wu, Xiaocui and Xiao, Xiangming and Zhang, Yao and He, Wei and Wolf, Sebastian and Chen, Jiquan and He, Mingzhu and Gough, Christopher M. and Qin, Yuanwei and Zhou, Yanlian and Doughty, Russell and Blanken, Peter D.},
title = {Spatiotemporal Consistency of Four Gross Primary Production Products and Solar-Induced Chlorophyll Fluorescence in Response to Climate Extremes Across CONUS in 2012},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2018},
volume = {123},
number = {10},
pages = {3140-3161},
doi = {https://doi.org/10.1029/2018JG004484}
}
|
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| Wu, D., Lin, J.C., Fasoli, B., Oda, T., Ye, X., Lauvaux, T., Yang, E.G. and Kort, E.A. | A Lagrangian approach towards extracting signals of urban CO2 emissions from satellite observations of atmospheric column CO2 (XCO2): X-Stochastic Time-Inverted Lagrangian Transport model (''X-STILT v1'') | {2018} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {11}({12}), pp. {4843-4871} |
article | |
| Abstract: Urban regions are responsible for emitting significant amounts of fossil fuel carbon dioxide (FFCO2), and emissions at the finer, city scales are more uncertain than those aggregated at the global scale. Carbon-observing satellites may provide independent top-down emission evaluations and compensate for the sparseness of surface CO2 observing networks in urban areas. Although some previous studies have attempted to derive urban CO2 signals from satellite column-averaged CO2 data (XCO2) using simple statistical measures, less work has been carried out to link upwind emission sources to downwind atmospheric columns using atmospheric models. In addition to Eulerian atmospheric models that have been customized for emission estimates over specific cities, the Lagrangian modeling approach - in particular, the Lagrangian particle dispersion model (LPDM) approach - has the potential to efficiently determine the sensitivity of downwind concentration changes to upwind sources. However, when applying LPDMs to interpret satellite XCO2, several issues have yet to be addressed, including quantifying uncertainties in urban XCO2 signals due to receptor configurations and errors in atmospheric transport and background XCO2. In this study, we present a modified version of the Stochastic Time-Inverted Lagrangian Transport (STILT) model, ``XSTILT'', for extracting urban XCO2 signals from NASA's Orbiting Carbon Observatory 2 (OCO-2) XCO2 data. X-STILT incorporates satellite profiles and provides comprehensive uncertainty estimates of urban XCO2 enhancements on a per sounding basis. Several methods to initialize receptor/particle setups and determine background XCO2 are presented and discussed via sensitivity analyses and comparisons. To illustrate X-STILT's utilities and applications, we examined five OCO-2 overpasses over Riyadh, Saudi Arabia, during a 2-year time period and performed a simple scaling factor-based inverse analysis. As a result, the model is able to reproduce most observed XCO2 enhancements. Error estimates show that the 68% confidence limit of XCO2 uncertainties due to transport (horizontal wind plus vertical mixing) and emission uncertainties contribute to similar to 33% and similar to 20% of the mean latitudinally integrated urban signals, respectively, over the five overpasses, using meteorological fields from the Global Data Assimilation System (GDAS). In addition, a sizeable mean difference of 0.55 ppm in background derived from a previous study employing simple statistics (regional daily median) leads to a similar to 39% higher mean observed urban signal and a larger posterior scaling factor. Based on our signal estimates and associated error impacts, we foresee X-STILT serving as a tool for interpreting column measurements, estimating urban enhancement signals, and carrying out inverse modeling to improve quantification of urban emissions. |
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BibTeX:
@article{wu18d,
author = {Wu, Dien and Lin, John C. and Fasoli, Benjamin and Oda, Tomohiro and Ye, Xinxin and Lauvaux, Thomas and Yang, Emily G. and Kort, Eric A.},
title = {A Lagrangian approach towards extracting signals of urban CO2 emissions from satellite observations of atmospheric column CO2 (XCO2): X-Stochastic Time-Inverted Lagrangian Transport model (''X-STILT v1'')},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2018},
volume = {11},
number = {12},
pages = {4843-4871}
}
|
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| Wu, L., Hasekamp, O., Hu, H., aan de Brugh, J., Landgraf, J., Butz, A. and Aben, I. | Full-physics carbon dioxide retrievals from the Orbiting Carbon Observatory-2 (OCO-2) satellite by only using the 2.06 mu m band | {2019} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {12}({11}), pp. {6049-6058} |
article | DOI |
| Abstract: Passive remote sensing of atmospheric carbon dioxide uses spectroscopic measurements of sunlight backscattered by the Earth's surface and atmosphere. The current state-of-the-art retrieval methods use three different spectral bands, the oxygen A band at 0.76 mu m and the weak and strong CO2 absorption bands at 1.61 and 2.06 mu m, respectively, to infer information on light scattering and the carbon dioxide column-averaged dry-air mole fraction XCO2. In this study, we propose a one-band XCO2 retrieval technique which uses only the 2.06 mu m band measurements from the Orbiting Carbon Observatory-2 (OCO-2) satellite. We examine the data quality by comparing the OCO-2 XCO2 with collocated ground-based measurements from the Total Carbon Column Observing Network (TCCON). Over land and ocean the OCO-2 one-band retrieval shows differences from TCCON observations with a standard deviation of similar to 1.30 ppm and a station-to-station variability of similar to 0.50 ppm. Moreover, we compare one-band and three-band retrievals over Europe, the Middle East, and Africa and see high correlation between the two retrievals with a SD of 0.93 ppm. Compared to the three-band retrievals, XCO2 retrievals using only the 2.06 mu m band have similar retrieval accuracy, precision, and data yield. | |||||
BibTeX:
@article{wu19a,
author = {Wu, Lianghai and Hasekamp, Otto and Hu, Haili and aan de Brugh, Joost and Landgraf, Jochen and Butz, Andre and Aben, Ilse},
title = {Full-physics carbon dioxide retrievals from the Orbiting Carbon Observatory-2 (OCO-2) satellite by only using the 2.06 mu m band},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2019},
volume = {12},
number = {11},
pages = {6049--6058},
doi = {https://doi.org/10.5194/amt-12-6049-2019}
}
|
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| Wu, L., Aan de Brugh, J., Meijer, Y., Sierk, B., Hasekamp, O., Butz, A. and Landgraf, J. | XCO2 observations using satellite measurements with moderate spectral resolution: investigation using GOSAT and OCO-2 measurements | {2020} | ATMOSPHERIC MEASUREMENT TECHNIQUES Vol. {13}({2}), pp. {713-729} |
article | DOI |
| Abstract: In light of the proposed space segment of Europe's future CO2 monitoring system, we investigate the spectral resolution of the CO2 spectrometer, which measures earthshine radiance in the three relevant spectral bands at 0.76, 1.61, and 2.06 mu m. The Orbiting Carbon Observatory-2 (OCO-2) mission covers these bands with fine spectral resolution but limited spatial coverage, which hampers the monitoring of localized anthropogenic CO2 emission. The future European CO2 monitoring constellation, currently undergoing feasibility studies at the European Space Agency (ESA), is targeting a moderate spectral resolution of 0.1, 0.3, and 0.3-0.55 nm in the three spectral bands with a high signal-to-noise ratio (SNR) as well as a spatial resolution of 4 km(2) and an across-track swath width > 250 km. This spectral and radiometric sizing is deemed to be favorable for large-swath imaging of point sources of CO2 emission. To assess this choice, we use real and synthetic OCO-2 satellite observations, which we spectrally degrade to the envisaged lower spectral resolution. We evaluate the corresponding CO2 retrieval accuracy by taking the Total Carbon Column Observing Network (TCCON) observations as reference. Here, a lower spectral resolution enhances the scatter error of the retrieved CO2 column mixing ratio (XCO2) but has little effect on the station-to-station variation in the biases. We show that the scatter error gradually increases with decreasing spectral resolution. Part of the scatter error increase can be attributed to the retrieval noise error which can be compensated for by a future instrument with improved SNR. Moreover, we consider the effect of the reduced spectral resolution on the capability to capture regional XCO2 variations and XCO2 plumes from selected OCO-2 orbits. The investigation using measurements from the Greenhouse gases Observing SATellite (GOSAT) and synthetic measurements confirms our finding and indicates that one major source of uncertainties regarding CO2 retrieval is the insufficient information on aerosol properties that can be inferred from the observations. We hence recommend the implementation of simultaneous, co-located measurements that have a larger information content on aerosols with an auxiliary instrument in the future European observing system. | |||||
BibTeX:
@article{wu20a,
author = {Wu, Lianghai and Aan de Brugh, Joost and Meijer, Yasjka and Sierk, Bernd and Hasekamp, Otto and Butz, Andre and Landgraf, Jochen},
title = {XCO2 observations using satellite measurements with moderate spectral resolution: investigation using GOSAT and OCO-2 measurements},
journal = {ATMOSPHERIC MEASUREMENT TECHNIQUES},
publisher = {COPERNICUS GESELLSCHAFT MBH},
year = {2020},
volume = {13},
number = {2},
pages = {713--729},
doi = {https://doi.org/10.5194/amt-13-713-2020}
}
|
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| Wu, J., Wu, H., Ding, Y., Qin, J., Li, H., Liu, S. and Zeng, D. | Interannual and seasonal variations in carbon exchanges over an alpine meadow in the northeastern edge of the Qinghai-Tibet Plateau, China | {2020} | PLOS ONE Vol. {15}({2}) |
article | DOI |
| Abstract: The alpine meadow is highly sensitive to global climate change due to its high elevation and cold environment. To understand the dynamics of ecosystem carbon cycling, CO2 fluxes were measured over the Suli alpine meadow, which is located at the upper reach of the Shule River basin at the northeastern edge of the Qinghai-Tibet Plateau (QTP), China. The measurements were taken from October 2008 to September 2012 using the eddy covariance technique. Obvious seasonal and inter-annual variations were observed in the CO2 flux. The annual net carbon exchange ranged from -195.28 g.CO2.m(-2) to -118.49 g.CO2.m(-2), indicating that the alpine meadow ecosystem in this area played a role as a carbon sink. The inter-annual variability in the net carbon exchange was significantly related to the length of the growing season for the alpine meadow. The results showed that the months of June, July and August were the strongest CO2 absorption periods, while April, May and October were the strongest CO2 release periods. The annual net exchanges of CO2 in the four years were -118.49 g.CO2.m(-2), -130.75 g.CO2.m(-2), -195.83 g.CO2.m(-2) and -160.65 g.CO2.m(-2), and the average value was -151.43 g.CO2.m(-2). On a seasonal scale, the monthly CO2 fluxes were largely controlled by temperature. At the annual scale, there was no dominant factor that influenced the interannual variations in the CO2 flux. | |||||
BibTeX:
@article{wu20b,
author = {Wu, Jinkui and Wu, Hao and Ding, Yongjian and Qin, Jia and Li, Hongyuan and Liu, Shiwei and Zeng, Di},
title = {Interannual and seasonal variations in carbon exchanges over an alpine meadow in the northeastern edge of the Qinghai-Tibet Plateau, China},
journal = {PLOS ONE},
publisher = {PUBLIC LIBRARY SCIENCE},
year = {2020},
volume = {15},
number = {2},
doi = {https://doi.org/10.1371/journal.pone.0228470}
}
|
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| Wuerth, S. | Development and applications of a carbon-weather data assimilation system | 2019 | School: University of California, Berkeley | phdthesis | URL |
| Abstract: This dissertation explores the utility of high-resolution satellite carbon dioxide (CO2) and water vapor measurements for advancing climate treaty verification, for improving numerical weather prediction (NWP), and for understanding natural carbon cycling in the terrestrial … | |||||
BibTeX:
@phdthesis{wuerth19a,
author = {Stephanie Wuerth},
title = {Development and applications of a carbon-weather data assimilation system},
school = {University of California, Berkeley},
year = {2019},
url = {https://escholarship.org/uc/item/8875f13t}
}
|
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| Wunch, D., Toon, G.C., Blavier, J.-F.L., Washenfelder, R.A., Notholt, J., Connor, B.J., Griffith, D.W.T., Sherlock, V. and Wennberg, P.O. | The Total Carbon Column Observing Network | {2011} | PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES Vol. {369}({1943}), pp. 2087-2112 |
article | DOI |
| Abstract: A global network of ground-based Fourier transform spectrometers has been founded to remotely measure column abundances of CO2, CO, CH4, N2O and other molecules that absorb in the near-infrared. These measurements are directly comparable with the near-infrared total column measurements from space-based instruments. With stringent requirements on the instrumentation, acquisition procedures, data processing and calibration, the Total Carbon Column Observing Network (TCCON) achieves an accuracy and precision in total column measurements that is unprecedented for remotesensing observations (better than 0.25% for CO2). This has enabled carbon-cycle science investigations using the TCCON dataset, and allows the TCCON to provide a link between satellite measurements and the extensive ground-based in situ network. |
|||||
BibTeX:
@article{wunch11a,
author = {Wunch, Debra and Toon, Geoffrey C. and Blavier, Jean-Francois L. and Washenfelder, Rebecca A. and Notholt, Justus and Connor, Brian J. and Griffith, David W. T. and Sherlock, Vanessa and Wennberg, Paul O.},
title = {The Total Carbon Column Observing Network},
journal = {PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES},
year = {2011},
volume = {369},
number = {1943},
pages = {2087--2112},
doi = {https://doi.org/10.1098/rsta.2010.0240}
}
|
|||||
| Wunch, D., Wennberg, P.O., Toon, G.C., Connor, B.J., Fisher, B., Osterman, G.B., Frankenberg, C., Mandrake, L., O'Dell, C., Ahonen, P., Biraud, S.C., Castano, R., Cressie, N., Crisp, D., Deutscher, N.M., Eldering, A., Fisher, M.L., Griffith, D.W.T., Gunson, M., Heikkinen, P., Keppel-Aleks, G., Kyro, E., Lindenmaier, R., Macatangay, R., Mendonca, J., Messerschmidt, J., Miller, C.E., Morino, I., Notholt, J., Oyafuso, F.A., Rettinger, M., Robinson, J., Roehl, C.M., Salawitch, R.J., Sherlock, V., Strong, K., Sussmann, R., Tanaka, T., Thompson, D.R., Uchino, O., Warneke, T. and Wofsy, S.C. | A method for evaluating bias in global measurements of CO2 total columns from space | {2011} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {11}({23}), pp. 12317-12337 |
article | DOI |
| Abstract: We describe a method of evaluating systematic errors in measurements of total column dry-air mole fractions of CO2 (X-CO2) from space, and we illustrate the method by applying it to the v2.8 Atmospheric CO2 Observations from Space retrievals of the Greenhouse Gases Observing Satellite (ACOS-GOSAT) measurements over land. The approach exploits the lack of large gradients in X-CO2 south of 25 degrees S to identify large-scale offsets and other biases in the ACOS-GOSAT data with several retrieval parameters and errors in instrument calibration. We demonstrate the effectiveness of the method by comparing the ACOS-GOSAT data in the Northern Hemisphere with ground truth provided by the Total Carbon Column Observing Network (TCCON). We use the observed correlation between free-tropospheric potential temperature and X-CO2 in the Northern Hemisphere to define a dynamically informed coincidence criterion between the ground-based TCCON measurements and the ACOS-GOSAT measurements. We illustrate that this approach provides larger sample sizes, hence giving a more robust comparison than one that simply uses time, latitude and longitude criteria. Our results show that the agreement with the TCCON data improves after accounting for the systematic errors, but that extrapolation to conditions found outside the region south of 25 degrees S may be problematic (e. g., high airmasses, large surface pressure biases, M-gain, measurements made over ocean). A preliminary evaluation of the improved v2.9 ACOS-GOSAT data is also discussed. |
|||||
BibTeX:
@article{wunch11b,
author = {Wunch, D. and Wennberg, P. O. and Toon, G. C. and Connor, B. J. and Fisher, B. and Osterman, G. B. and Frankenberg, C. and Mandrake, L. and O'Dell, C. and Ahonen, P. and Biraud, S. C. and Castano, R. and Cressie, N. and Crisp, D. and Deutscher, N. M. and Eldering, A. and Fisher, M. L. and Griffith, D. W. T. and Gunson, M. and Heikkinen, P. and Keppel-Aleks, G. and Kyro, E. and Lindenmaier, R. and Macatangay, R. and Mendonca, J. and Messerschmidt, J. and Miller, C. E. and Morino, I. and Notholt, J. and Oyafuso, F. A. and Rettinger, M. and Robinson, J. and Roehl, C. M. and Salawitch, R. J. and Sherlock, V. and Strong, K. and Sussmann, R. and Tanaka, T. and Thompson, D. R. and Uchino, O. and Warneke, T. and Wofsy, S. C.},
title = {A method for evaluating bias in global measurements of CO2 total columns from space},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
volume = {11},
number = {23},
pages = {12317--12337},
doi = {https://doi.org/10.5194/acp-11-12317-2011}
}
|
|||||
| Wunch, D., Wennberg, P.O., Messerschmidt, J., Parazoo, N.C., Toon, G.C., Deutscher, N.M., Keppel-Aleks, G., Roehl, C.M., Randerson, J.T., Warneke, T. and Notholt, J. | The covariation of Northern Hemisphere summertime CO2 with surface temperature in boreal regions | {2013} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {13}({18}), pp. 9447-9459 |
article | DOI |
| Abstract: We observe significant interannual variability in the strength of the seasonal cycle drawdown in northern midlatitudes from measurements of CO2 made by the Total Carbon Column Observing Network (TCCON) and the Greenhouse Gases Observing Satellite (GOSAT). This variability correlates with surface temperature in the boreal regions. Using TCCON measurements, we find that the slope of the relationship between the X-CO2 seasonal cycle minima and boreal surface temperature is 1.2 +/- 0.7 ppm K-1. Assimilations from CarbonTracker 2011 and CO2 simulations using the Simple Biosphere exchange Model (SiB) transported by GEOS-Chem underestimate this covariation. Both atmospheric transport and biospheric activity contribute to the observed covariation. |
|||||
BibTeX:
@article{wunch13a,
author = {Wunch, D. and Wennberg, P. O. and Messerschmidt, J. and Parazoo, N. C. and Toon, G. C. and Deutscher, N. M. and Keppel-Aleks, G. and Roehl, C. M. and Randerson, J. T. and Warneke, T. and Notholt, J.},
title = {The covariation of Northern Hemisphere summertime CO2 with surface temperature in boreal regions},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2013},
volume = {13},
number = {18},
pages = {9447--9459},
doi = {https://doi.org/10.5194/acp-13-9447-2013}
}
|
|||||
| Xiao, J., Zhuang, Q., Law, B.E., Baldocchi, D.D., Chen, J., Richardson, A.D., Melillo, J.M., Davis, K.J., Hollinger, D.Y., Wharton, S., Oren, R., Noormets, A., Fischer, M.L., Verma, S.B., Cook, D.R., Sun, G., McNulty, S., Wofsy, S.C., Bolstad, P.V., Burns, S.P., Curtis, P.S., Drake, B.G., Falk, M., Foster, D.R., Gu, L., Hadley, J.L., Katulk, G.G., Litvak, M., Ma, S., Martinz, T.A., Matamala, R., Meyers, T.P., Monson, R.K., Munger, J.W., Oechel, W.C., Paw, U.K.T., Schmid, H.P., Scott, R.L., Starr, G., Suyker, A.E. and Torn, M.S. | Assessing net ecosystem carbon exchange of U.S. terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations | {2011} | AGRICULTURAL AND FOREST METEOROLOGY Vol. {151}({1}), pp. 60-69 |
article | DOI |
| Abstract: More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr(-1) with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and temporal (8-day) resolutions derived from NEE measurements from eddy covariance flux towers and wall-to-wall satellite observations from Moderate Resolution Imaging Spectroradiometer (MODIS). We find that the U.S. terrestrial ecosystems could offset a maximum of 40% of the fossil-fuel carbon emissions Our results show that the U.S. terrestrial carbon sink varied between 0.51 and 0.70 pg C yr(-1) over the period 2001-2006. The dominant sources of interannual variation of the carbon sink Included extreme climate events and disturbances. Droughts in 2002 and 2006 reduced the U.S. carbon sink by similar to 20% relative to a normal year. Disturbances including wildfires and hurricanes reduced carbon uptake or resulted in carbon release at regional scales. Our results provide an alternative, independent, and novel constraint to the U.S. terrestrial carbon sink. (C) 2010 Elsevier B.V. All rights reserved |
|||||
BibTeX:
@article{xiao11a,
author = {Xiao, Jingfeng and Zhuang, Qianlai and Law, Beverly E. and Baldocchi, Dennis D. and Chen, Jiquan and Richardson, Andrew D. and Melillo, Jerry M. and Davis, Kenneth J. and Hollinger, David Y. and Wharton, Sonia and Oren, Ram and Noormets, Asko and Fischer, Marc L. and Verma, Shashi B. and Cook, David R. and Sun, Ge and McNulty, Steve and Wofsy, Steven C. and Bolstad, Paul V. and Burns, Sean P. and Curtis, Peter S. and Drake, Bert G. and Falk, Matthias and Foster, David R. and Gu, Lianhong and Hadley, Julian L. and Katulk, Gabriel G. and Litvak, Marcy and Ma, Siyan and Martinz, Timothy A. and Matamala, Roser and Meyers, Tilden P. and Monson, Russell K. and Munger, J. William and Oechel, Walter C. and Paw, U. Kyaw Tha and Schmid, Hans Peter and Scott, Russell L. and Starr, Gregory and Suyker, Andrew E. and Torn, Margaret S.},
title = {Assessing net ecosystem carbon exchange of U.S. terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations},
journal = {AGRICULTURAL AND FOREST METEOROLOGY},
year = {2011},
volume = {151},
number = {1},
pages = {60--69},
doi = {https://doi.org/10.1016/j.agrformet.2010.09.002}
}
|
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| Xie, Y., Li, Z., Zhang, X., Xu, H., Li, D. and Li, K. | A new ground-based differential absorption sunphotometer for measuring atmospheric columnar CO2 and preliminary applications | {2015} | Vol. {9678}AOPC 2015: TELESCOPE AND SPACE OPTICAL INSTRUMENTATION |
inproceedings | DOI |
| Abstract: Carbon dioxide is commonly considered as the most important greenhouse gas. Ground-based remote sensing technology of acquiring CO2 columnar concentration is needed to provide validation for spaceborne CO2 products. A new groundbased sunphotometer prototype for remotely measuring atmospheric CO2 is introduced in this paper, which is designed to be robust, portable, automatic and suitable for field observation. A simple quantity, Differential Absorption Index (DAI) related to CO2 optical depth, is proposed to derive the columnar CO2 information based on the differential absorption principle around 1.57 micron. Another sun/sky radiometer CE318, is used to provide correction parameters of aerosol extinction and water vapor absorption. A cloud screening method based on the measurement stability is developed. A systematic error assessment of the prototype and DAI is also performed. We collect two-year DAI observation from 2010 to 2012 in Beijing, analyze the DAI seasonal variation and find that the daily average DAI decreases in growing season and reaches to a minimum on August, while increases after that until January of the next year, when DAI reaches its highest peak, showing generally the seasonal cycle of CO2. We also investigate the seasonal differences of DAI variation and attribute the tendencies of high in the morning and evening while low in the noon to photosynthesis efficiency variation of vegetation and anthropogenic emissions. Preliminary comparison between DAI and model simulated XCO2 (Carbon Tracker 2011) is conducted, showing that DAI roughly reveals some temporal characteristics of CO2 when using the average of multiple measurements. |
|||||
BibTeX:
@inproceedings{xie15a,
author = {Xie, Yisong and Li, Zhengqiang and Zhang, Xingying and Xu, Hua and Li, Donghui and Li, Kaitao},
title = {A new ground-based differential absorption sunphotometer for measuring atmospheric columnar CO2 and preliminary applications},
booktitle = {AOPC 2015: TELESCOPE AND SPACE OPTICAL INSTRUMENTATION},
year = {2015},
volume = {9678},
note = {Conference on Applied Optics and Photonics (AOPC) - Telescope and Space Optical Instrumentation, Beijing, PEOPLES R CHINA, MAY 05-07, 2015},
doi = {https://doi.org/10.1117/12.2199379}
}
|
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| Xie, X., Huang, X., Wang, T., Li, M., Li, S. and Chen, P. | Simulation of Non-Homogeneous CO2 and Its Impact on Regional Temperature in East Asia | {2018} | JOURNAL OF METEOROLOGICAL RESEARCH Vol. {32}({3}), pp. {456-468} |
article | DOI |
| Abstract: Carbon dioxide (CO2) is an important greenhouse gas that influences regional climate through disturbing the earth's energy balance. The CO2 concentrations are usually prescribed homogenously in most climate models and the spatiotemporal variations of CO2 are neglected. To address this issue, a regional climate model (RegCM4) is modified to investigate the non-homogeneous distribution of CO2 and its effects on regional longwave radiation flux and temperature in East Asia. One-year simulation is performed with prescribed surface CO2 fluxes that include fossil fuel emission, biomass burning, air-sea exchange, and terrestrial biosphere flux. Two numerical experiments (one using constant prescribed CO2 concentrations in the radiation scheme and the other using the simulated CO2 concentrations that are spatially non-homogeneous) are conducted to assess the impact of non-homogeneous CO2 on the regional longwave radiation flux and temperature. Comparison of CO2 concentrations from the model with the observations from the GLOBALVIEW-CO2 network suggests that the model can well capture the spatiotemporal patterns of CO2 concentrations. Generally, high CO2 mixing ratios appear in the heavily industrialized eastern China in cold seasons, which probably relates to intensive human activities. The accommodation of non-homogeneous CO2 concentrations in the radiative transfer scheme leads to an annual mean change of-0.12 W m(-2) in total sky surface upward longwave flux in East Asia. The experiment with non-homogeneous CO2 tends to yield a warmer lower troposphere. Surface temperature exhibits a maximum difference in summertime, ranging from-4.18 K to 3.88 K, when compared to its homogeneous counterpart. Our results indicate that the spatial and temporal distributions of CO2 have a considerable impact on regional longwave radiation flux and temperature, and should be taken into account in future climate modeling. |
|||||
BibTeX:
@article{xie18a,
author = {Xie, Xiaodong and Huang, Xiaoxian and Wang, Tijian and Li, Mengmeng and Li, Shu and Chen, Pulong},
title = {Simulation of Non-Homogeneous CO2 and Its Impact on Regional Temperature in East Asia},
journal = {JOURNAL OF METEOROLOGICAL RESEARCH},
year = {2018},
volume = {32},
number = {3},
pages = {456-468},
doi = {https://doi.org/10.1007/s13351-018-7159-x}
}
|
|||||
| Xie, X., Wang, T., Yue, X., Li, S., Zhuang, B., Wang, M. and Yang, X. | Numerical modeling of ozone damage to plants and its effects on atmospheric CO2 in China | {2019} | ATMOSPHERIC ENVIRONMENT Vol. {217} |
article | DOI |
| Abstract: Tropospheric ozone (O-3) is known to damage plant cells and suppress leaf photosynthesis, which can further reduce terrestrial carbon uptake and leave more carbon dioxide (CO2) in the atmosphere. While recent studies have assessed the effects of O-3 on terrestrial carbon fluxes, the potential impacts on atmospheric CO2 concentrations have not been quantified. Here, we use a regional climate model (RegCM-CHEM4) coupled with the Yale Interactive terrestrial Biosphere model YD3s to estimate the effects of O-3 exposure on atmospheric CO2 over China. Compared to simulations without O-3 effects, sensitivity experiments with O-3 damage show a significant reduction (12.1 +/- 4.4%) in the gross primary productivity (GPP), up to 35% in summer. Meanwhile, terrestrial carbon sink is suppressed by 112.2 +/- 22.5 Tg C for 2013 at the national level. Strong inhibitions of O-3 on carbon fluxes are found in North, Northeast and South Central China, where O-3 levels are high. Consequently, we find a significant increase in atmospheric CO2 concentrations due to O-3 -induced terrestrial carbon sink reduction. The increases of CO2 are more evident in the growing season. The maximum CO2 enhancement reaches as high as 6 ppm in Yunnan and Guizhou provinces. Our assessments indicate that tropospheric O-3 has a detrimental impact on plant carbon uptake and leads to more CO2 accumulating in the atmosphere. Such impacts of O-3 should be taken into account in global carbon cycle and future climate change. | |||||
BibTeX:
@article{xie19a,
author = {Xie, Xiaodong and Wang, Tijian and Yue, Xu and Li, Shu and Zhuang, Bingliang and Wang, Minghuai and Yang, Xiuqun},
title = {Numerical modeling of ozone damage to plants and its effects on atmospheric CO2 in China},
journal = {ATMOSPHERIC ENVIRONMENT},
publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
year = {2019},
volume = {217},
doi = {https://doi.org/10.1016/j.atmosenv.2019.116970}
}
|
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| Xie, X., Wang, T., Yue, X., Li, S., Zhuang, B. and Wang, M. | Effects of atmospheric aerosols on terrestrial carbon fluxes and CO2 concentrations in China | {2020} | ATMOSPHERIC RESEARCH Vol. {237} |
article | DOI |
| Abstract: Atmospheric aerosols have contributed to the terrestrial carbon cycle through diffuse radiation fertilization effect and hydrometeorological feedbacks. Subsequently, perturbations in terrestrial carbon sink alter atmospheric carbon dioxide (CO2) concentrations and influence future climate change. Here, we use a regional climate model, RegCM4, coupled with the Yale Interactive terrestrial Biosphere model (YIBs) to assess the effects of the current aerosol loading on terrestrial carbon fluxes and atmospheric CO2 concentrations during 2006-2015 over China. We found that aerosols enhance gross primary production (GPP) by 0.36 Pg C yr(-1) (5%), which primarily stems from Southwest and Southeast China. Meanwhile, the aerosol-induced diffuse fraction (DF) increase, surface cooling and vapor pressure deficit (VPD) decrease together lead to a - 0.06 Pg C yr(-1) (21%) reduction in the net ecosystem exchange (NEE). Among them, aerosol-induced DF increment is found to be the dominant contributor, which covers similar to 59-62% of China's land area. The effects of aerosols on GPP and NEE are more evident in the growing season, with maximum effects occurring in July and August, respectively. Moreover, the terrestrial carbon sink enhancement due to aerosols further results in a significant decline in CO2 concentrations, with a large reduction (> 2 ppm) found in southern and eastern parts of China during the summer. Our results highlight the importance of understanding the interactions among aerosol pollution, climate change, and the global carbon cycle. | |||||
BibTeX:
@article{xie20a,
author = {Xie, Xiaodong and Wang, Tijian and Yue, Xu and Li, Shu and Zhuang, Bingliang and Wang, Minghuai},
title = {Effects of atmospheric aerosols on terrestrial carbon fluxes and CO2 concentrations in China},
journal = {ATMOSPHERIC RESEARCH},
publisher = {ELSEVIER SCIENCE INC},
year = {2020},
volume = {237},
doi = {https://doi.org/10.1016/j.atmosres.2020.104859}
}
|
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| Xing-Xia, K., Mei-Gen, Z. and Zhen, P. | Numerical Simulation of CO2 Concentrations in East Asia with RAMS-CMAQ | {2013} | ATMOSPHERIC AND OCEANIC SCIENCE LETTERS Vol. {6}({4}), pp. {179-184} |
article | DOI |
| Abstract: The regional air quality modeling system RAMS-CMAQ (Regional Atmospheric Modeling System and Models-3 Community Multi-scale Air Quality) was developed by incorporating a vegetation photosynthesis and respiration module (VPRM) and used to simulate temporal-spatial variations in atmospheric CO2 concentrations in East Asia, with prescribed surface CO2 fluxes (i.e., fossil fuel emission, biomass burning, sea-air CO2 exchange, and terrestrial biosphere CO2 flux). Comparison of modeled CO2 mixing ratios with eight ground-based in-situ measurements demonstrated that the model was able to capture most observed CO2 temporal-spatial features. Simulated CO2 concentrations were generally in good agreement with observed concentrations. Results indicated that the accumulated impacts of anthropogenic emissions contributed more to increased CO2 concentrations in urban regions relative to remote locations. Moreover, RAMS-CMAQ analysis demonstrates that surface CO2 concentrations in East Asia are strongly influenced by terrestrial ecosystems. |
|||||
BibTeX:
@article{xing-xia13a,
author = {Kou Xing-Xia and Zhang Mei-Gen and Peng Zhen},
title = {Numerical Simulation of CO2 Concentrations in East Asia with RAMS-CMAQ},
journal = {ATMOSPHERIC AND OCEANIC SCIENCE LETTERS},
year = {2013},
volume = {6},
number = {4},
pages = {179-184},
doi = {https://doi.org/10.3878/j.issn.1674-2834.13.0022}
}
|
|||||
| Xingxia, K., Meigen, Z., Zhen, P. and Yinghong, W. | Assessment of the biospheric contribution to surface atmospheric CO2 concentrations over East Asia with a regional chemical transport model | {2015} | ADVANCES IN ATMOSPHERIC SCIENCES Vol. {32}({3}), pp. {287-300} |
article | DOI URL |
| Abstract: A regional chemical transport model, RAMS-CMAQ, was employed to assess the impacts of biosphere-atmosphere C-2 exchange on seasonal variations in atmospheric C-2 concentrations over East Asia. Simulated C-2 concentrations were compared with observations at 12 surface stations and the comparison showed they were generally in good agreement. Both observations and simulations suggested that surface C-2 over East Asia features a summertime trough due to biospheric absorption, while in some urban areas surface C-2 has a distinct summer peak, which could be attributed to the strong impact from anthropogenic emissions. Analysis of the model results indicated that biospheric fluxes and fossil-fuel emissions are comparably important in shaping spatial distributions of C-2 near the surface over East Asia. Biospheric flux plays an important role in the prevailing spatial pattern of C-2 enhancement and reduction on the synoptic scale due to the strong seasonality of biospheric C-2 flux. The elevation of C-2 levels by the biosphere during winter was found to be larger than 5 ppm in North China and Southeast China, and during summertime a significant depletion (a (c) 3/4 7 ppm) occurred in most areas, except for the Indo-China Peninsula where positive bioflux values were found. | |||||
BibTeX:
@article{xingxia15a,
author = {Kou Xingxia and Zhang Meigen and Peng Zhen and Wang Yinghong},
title = {Assessment of the biospheric contribution to surface atmospheric CO2 concentrations over East Asia with a regional chemical transport model},
journal = {ADVANCES IN ATMOSPHERIC SCIENCES},
publisher = {SCIENCE PRESS},
year = {2015},
volume = {32},
number = {3},
pages = {287--300},
note = {Query date: 2021-04-02 15:20:04},
url = {https://link.springer.com/article/10.1007/s00376-014-4059-6},
doi = {https://doi.org/10.1007/s00376-014-4059-6}
}
|
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| Xu, X., Riley, W.J., Koven, C.D., Billesbach, D.P., Chang, R.Y.W., Commane, R., Euskirchen, E.S., Hartery, S., Harazono, Y., Iwata, H., McDonald, K.C., Miller, C.E., Oechel, W.C., Poulter, B., Raz-Yaseef, N., Sweeney, C., Torn, M., Wofsy, S.C., Zhang, Z. and Zona, D. | A multi-scale comparison of modeled and observed seasonal methane emissions in northern wetlands [BibTeX] |
{2016} | BIOGEOSCIENCES Vol. {13}({17}), pp. 5043-5056 |
article | DOI |
BibTeX:
@article{xu16a,
author = {Xu, Xiyan and Riley, William J. and Koven, Charles D. and Billesbach, Dave P. and Chang, Rachel Y. -W. and Commane, Roisin and Euskirchen, Eugenie S. and Hartery, Sean and Harazono, Yoshinobu and Iwata, Hiroki and McDonald, Kyle C. and Miller, Charles E. and Oechel, Walter C. and Poulter, Benjamin and Raz-Yaseef, Naama and Sweeney, Colm and Torn, Margaret and Wofsy, Steven C. and Zhang, Zhen and Zona, Donatella},
title = {A multi-scale comparison of modeled and observed seasonal methane emissions in northern wetlands},
journal = {BIOGEOSCIENCES},
year = {2016},
volume = {13},
number = {17},
pages = {5043--5056},
doi = {https://doi.org/10.5194/bg-13-5043-2016}
}
|
|||||
| Xu, J., Li, X., Xiao, W., Ciren, W., Wen, X., Liu, S., Du, X. and Cao, C. | C^13-based Sources Partitioning of Atmopheric CO2 During Youth Olympic Games, Nanjing [BibTeX] |
2016 | Environmental Science Vol. 37(12) |
article | |
BibTeX:
@article{xu16b,
author = {Xu, Jiaping and Li, Xuhui and Xiao, Wei and Ciren, Wangmu and Wen, Xuefa and Liu, Shoudong and Du, Xueting and Cao, Chang},
title = {C^13-based Sources Partitioning of Atmopheric CO2 During Youth Olympic Games, Nanjing},
journal = {Environmental Science},
year = {2016},
volume = {37},
number = {12}
}
|
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| Xu, J., Lee, X., Xiao, W., Cao, C., Liu, S., Wen, X., Xu, J., Zhang, Z. and Zhao, J. | Interpreting the C-13 / C-12 ratio of carbon dioxide in an urban airshed in the Yangtze River Delta, China | {2017} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {17}({5}), pp. 3385-3399 |
article | DOI |
| Abstract: Observations of atmospheric CO2 mole fraction and the C-13 / C-12 ratio (expressed as delta C-13) in urban airsheds provide constraints on the roles of anthropogenic and natural sources and sinks in local and regional carbon cycles. In this study, we report observations of these quantities in Nanjing at hourly intervals from March 2013 to August 2015, using a laser-based optical instrument. Nanjing is the second largest city located in the highly industrialized Yangtze River Delta (YRD), eastern China. The mean CO2 mole fraction and delta C-13 were (439.7 +/- 7.5) mu mol mol 1 and (8.48 +/- 0.56)% over this observational period. The peak monthly mean delta C-13 (-7.44 %, July 2013) was 0.74% higher than that observed at Mount Waliguan, a WMO (World Meteorological Organization) baseline site on the Tibetan Plateau and upwind of the YRD region. The highly C-13-enriched signal was partly attributed to the influence of cement production in the region. By applying the Miller-Tans method to nighttime and daytime observations to represent signals from the city of Nanjing and the YRD, respectively, we showed that the C-13 / C-12 ratio of CO2 sources in the Nanjing municipality was (0.21 +/- 0.53)% lower than that in the YRD. Flux partitioning calculations revealed that natural ecosystems in the YRD were a negligibly small source of atmospheric CO2. |
|||||
BibTeX:
@article{xu17a,
author = {Xu, Jiaping and Lee, Xuhui and Xiao, Wei and Cao, Chang and Liu, Shoudong and Wen, Xuefa and Xu, Jingzheng and Zhang, Zhen and Zhao, Jiayu},
title = {Interpreting the C-13 / C-12 ratio of carbon dioxide in an urban airshed in the Yangtze River Delta, China},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2017},
volume = {17},
number = {5},
pages = {3385--3399},
doi = {https://doi.org/10.5194/acp-17-3385-2017}
}
|
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| Xu, Y.-Y., Cai, W.-J., Wanninkhof, R., Salisbury, J., Reimer, J. and Chen, B. | Long-Term Changes of Carbonate Chemistry Variables Along the North American East Coast | {2020} | JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS Vol. {125}({7}) |
article | DOI URL |
| Abstract: Decadal variability of carbonate chemistry variables has been studied for the open ocean using observations and models, but less is known about the variations in the coastal ocean due to observational gaps and the more complex environments. In this work, we use a Bayesian-neural-network approach to reconstruct surface carbonate chemistry variables for the Mid-Atlantic Bight (MAB) and the South Atlantic Bight (SAB) along the North American East Coast from 1982 to 2015. The reconstructed monthly time series data suggest that the rate offCO(2)increase in the MAB (18 +/- 1 mu atm per decade) is faster than those in the SAB (14 +/- 1 mu atm per decade) and the open ocean (14 +/- 1 mu atm per decade). Correspondingly, pH decreases faster in the MAB. The observed stagnation in the aragonite saturation state, omega(arag)decrease during 2005-2015 in the MAB, is attributed to the intrusion of water from southern and offshore regions with high omega(arag), which offsets the decrease expected from anthropogenic CO(2)uptake. Furthermore, seasonal asymmetry in the evolution of long-term change leads to the faster change in the amplitudes of the seasonal cycle in carbonate chemistry variables in coastal waters than those in the open ocean. In particular, the increase in the seasonal-cycle amplitude of dissolved inorganic carbon in the MAB is 2.9 times larger than that of the open ocean. This leads to the faster increase in the season-cycle amplitude of omega(arag)and earlier occurrence of undersaturation in coastal waters as acidification continues. | |||||
BibTeX:
@article{xu20a,
author = {Xu, Yuan-Yuan and Cai, Wei-Jun and Wanninkhof, Rik and Salisbury, Joseph and Reimer, Janet and Chen, Baoshan},
title = {Long-Term Changes of Carbonate Chemistry Variables Along the North American East Coast},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {125},
number = {7},
note = {Query date: 2021-04-02 15:20:04},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JC015982},
doi = {https://doi.org/10.1029/2019JC015982}
}
|
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| Xu, B., Wang, T., Ma, D., Song, R., Zhang, M., Gao, L., Li, S., Zhuang, B., Li, M. and Xie, M. | Impacts of regional emission reduction and global climate change on air quality and temperature to attain carbon neutrality in China | 2022 | ATMOSPHERIC RESEARCH Vol. 279 |
article | DOI |
| Abstract: Future air quality and temperature are major concerns worldwide, especially in East Asia, leading to carbon neutrality targets. China is committed to achieving carbon neutrality by 2060. This study evaluated regional emission reduction targets and global climate change impacts in China. We investigated changes to air quality and temperature in China using the coupled regional climate-ecology model RegCM-Chem-YIBs. The Ambitious-Pollution-Neutral-Goals scenario from the Dynamic Projection model for Emissions in China (DPEC) database was chosen as the future emission reduction pathway in China. Representative concentration pathway (RCP) climate scenarios were used to represent one possibility for future global climate change. The results showed that annual average PM2.5 and O-3 concentrations in China could meet World Health Organization (WHO) guidelines if the carbon neutral reduction pathway is followed. Emission reduction is far more effective than climate change in improving air quality. PM2.5 and O-3 concentrations in 2060 will decline to 2.6 and 63.0 mu g m(-3), respectively, under stringent emission reduction policies. Both carbon reduction and photosynthesis of vegetation promoted by global warming will reduce CO2 concentrations by at least 8 ppm in 2060. Global climate change will heat up the entire country by at least 1 K. Regional emission reduction will diminish the cooling effect of particulate matter, resulting in slight warming, which would slow progress in global warming control. This study shows that regional emission reduction is the main factor affecting future air quality, whereas global climate change is the primary driver of future increases in air temperature. The emission reduction policy, which is designed to achieve carbon neutrality in China, is sufficient to mitigate air pollution, and generate additional health benefits; however, it will contribute to higher air temperature in some areas. Therefore, mitigating rising temperatures requires global efforts and a more rational pathway to reduce emissions. |
|||||
BibTeX:
@article{xu22a,
author = {Xu, Beiyao and Wang, Tijian and Ma, Danyang and Song, Rong and Zhang, Ming and Gao, Libo and Li, Shu and Zhuang, Bingliang and Li, Mengmeng and Xie, Min},
title = {Impacts of regional emission reduction and global climate change on air quality and temperature to attain carbon neutrality in China},
journal = {ATMOSPHERIC RESEARCH},
year = {2022},
volume = {279},
doi = {https://doi.org/10.1016/j.atmosres.2022.106384}
}
|
|||||
| Yang, J. | Global fire activities and their impacts on the terrestrial carbon budget in context of multiple environmental changes [BibTeX] |
2015 | School: Auburn University | phdthesis | |
BibTeX:
@phdthesis{yang15a,
author = {Jia Yang},
title = {Global fire activities and their impacts on the terrestrial carbon budget in context of multiple environmental changes},
school = {Auburn University},
year = {2015}
}
|
|||||
| Yang, D., Zhang, H., Liu, Y., Chen, B., Cai, Z. and Lu, D. | Monitoring carbon dioxide from space: Retrieval algorithm and flux inversion based on GOSAT data and using CarbonTracker-China | {2017} | ADVANCES IN ATMOSPHERIC SCIENCES Vol. {34}({8, SI}), pp. 965-976 |
article | DOI |
| Abstract: Monitoring atmospheric carbon dioxide (CO2) from space-borne state-of-the-art hyperspectral instruments can provide a high precision global dataset to improve carbon flux estimation and reduce the uncertainty of climate projection. Here, we introduce a carbon flux inversion system for estimating carbon flux with satellite measurements under the support of ``The Strategic Priority Research Program of the Chinese Academy of Sciences-Climate Change: Carbon Budget and Relevant Issues''. The carbon flux inversion system is composed of two separate parts: the Institute of Atmospheric Physics Carbon Dioxide Retrieval Algorithm for Satellite Remote Sensing (IAPCAS), and CarbonTracker-China (CT-China), developed at the Chinese Academy of Sciences. The Greenhouse gases Observing SATellite (GOSAT) measurements are used in the carbon flux inversion experiment. To improve the quality of the IAPCAS-GOSAT retrieval, we have developed a post-screening and bias correction method, resulting in 25%-30% of the data remaining after quality control. Based on these data, the seasonal variation of XCO2 (column-averaged CO2 dry-air mole fraction) is studied, and a strong relation with vegetation cover and population is identified. Then, the IAPCAS-GOSAT XCO2 product is used in carbon flux estimation by CT-China. The net ecosystem CO2 exchange is -0.34 Pg C yr(-1) (+/- 0.08 Pg C yr(-1)), with a large error reduction of 84%, which is a significant improvement on the error reduction when compared with in situ-only inversion. |
|||||
BibTeX:
@article{yang17a,
author = {Yang, Dongxu and Zhang, Huifang and Liu, Yi and Chen, Baozhang and Cai, Zhaonan and Lu, Daren},
title = {Monitoring carbon dioxide from space: Retrieval algorithm and flux inversion based on GOSAT data and using CarbonTracker-China},
journal = {ADVANCES IN ATMOSPHERIC SCIENCES},
year = {2017},
volume = {34},
number = {8, SI},
pages = {965--976},
doi = {https://doi.org/10.1007/s00376-017-6221-4}
}
|
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| Yang, D., Liu, Y., Feng, L., Wang, J., Yao, L., Cai, Z., Zhu, S., Lu, N. and Lyu, D. | The First Global Carbon Dioxide Flux Map Derived from TanSat Measurements | 2021 | ADVANCES IN ATMOSPHERIC SCIENCES Vol. 38(9), pp. 1433-1443 |
article | DOI |
| Abstract: Space-borne measurements of atmospheric greenhouse gas concentrations provide global observation constraints for top-down estimates of surface carbon flux. Here, the first estimates of the global distribution of carbon surface fluxes inferred from dry-air CO2 column (XCO2) measurements by the Chinese Global Carbon Dioxide Monitoring Scientific Experimental Satellite (TanSat) are presented. An ensemble transform Kalman filter (ETKF) data assimilation system coupled with the GEOS-Chem global chemistry transport model is used to optimally fit model simulations with the TanSat XCO2 observations, which were retrieved using the Institute of Atmospheric Physics Carbon dioxide retrieval Algorithm for Satellite remote sensing (IAPCAS). High posterior error reduction (30%-50%) compared with a priori fluxes indicates that assimilating satellite XCO2 measurements provides highly effective constraints on global carbon flux estimation. Their impacts are also highlighted by significant spatiotemporal shifts in flux patterns over regions critical to the global carbon budget, such as tropical South America and China. An integrated global land carbon net flux of 6.71 +/- 0.76 Gt C yr(-1) over 12 months (May 2017-April 2018) is estimated from the TanSat XCO2 data, which is generally consistent with other inversions based on satellite data, such as the JAXA GOSAT and NASA OCO-2 XCO2 retrievals. However, discrepancies were found in some regional flux estimates, particularly over the Southern Hemisphere, where there may still be uncorrected bias between satellite measurements due to the lack of independent reference observations. The results of this study provide the groundwork for further studies using current or future TanSat XCO2 data together with other surface-based and space-borne measurements to quantify biosphere-atmosphere carbon exchange. |
|||||
BibTeX:
@article{yang21a,
author = {Yang, Dongxu and Liu, Yi and Feng, Liang and Wang, Jing and Yao, Lu and Cai, Zhaonan and Zhu, Sihong and Lu, Naimeng and Lyu, Daren},
title = {The First Global Carbon Dioxide Flux Map Derived from TanSat Measurements},
journal = {ADVANCES IN ATMOSPHERIC SCIENCES},
year = {2021},
volume = {38},
number = {9},
pages = {1433-1443},
doi = {https://doi.org/10.1007/s00376-021-1179-7}
}
|
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| YanLi, C., XingQin, A., FangHua, Y., LingXi, Z., LiXin, L., ShuangXi, F. and Lin, X. | Simulation of CO2 variations at Chinese background atmospheric monitoring stations between 2000 and 2009: Applying a CarbonTracker model | {2013} | CHINESE SCIENCE BULLETIN Vol. {58}({32}), pp. 3986-3993 |
article | DOI |
| Abstract: We carried out a downscaling treatment over China using the CarbonTracker numerical model, which was applied using double grid nesting technology (3A degrees x 2A degrees over the whole globe, 1A degrees x 1A degrees over China), simulating and analyzing atmospheric CO2 concentrations over 10 recent years (2000-2009). The simulation results agreed very well with observed data from four background atmospheric monitoring stations in China (The periods for which the simulation results and observed values be compared were January 2000 to December 2009 for the WLG station and June 2006 to December 2009 for the SDZ, LFS, and LAN stations), giving correlation coefficients of > 0.7. The high-resolution simulation data correlated slightly better than the low resolution simulation data with the observed data for three of the regions' atmospheric background stations. Further analysis of the annual, seasonal CO2 concentration variations at the background stations showed that the CO2 concentration increased each year over the study period, with an average annual increase of more than 5%, and annual increases of more than 7% at the Shangdianzi and Lin'an stations. Seasonal CO2 variations were greater at the Longfengshan station than at the Shangdianzi or Lin'an stations. However, the CO2 concentrations were higher at the Shangdianzi and Lin'an stations because they are greatly affected by human activities in the Jingjinji and Changjiang Delta economic zones. Spatial distribution in CO2 concentrations and fluxes were higher in eastern than in western China. |
|||||
BibTeX:
@article{yanli13a,
author = {Cheng YanLi and An XingQin and Yun FangHua and Zhou LingXi and Liu LiXin and Fang ShuangXi and Xu Lin},
title = {Simulation of CO2 variations at Chinese background atmospheric monitoring stations between 2000 and 2009: Applying a CarbonTracker model},
journal = {CHINESE SCIENCE BULLETIN},
year = {2013},
volume = {58},
number = {32},
pages = {3986--3993},
doi = {https://doi.org/10.1007/s11434-013-5895-y}
}
|
|||||
| Yelland, M.J., Holliday, N.P., Skjelvan, I., Osterbus, S. and Conway, T.J. | Continuous observations from the weather ship Polarfront at Station M [BibTeX] |
2009 | Proceedings of OceanObs Vol. 9 |
article | |
BibTeX:
@article{yelland09a,
author = {Yelland, Margaret J and Holliday, N Penny and Skjelvan, Ingunn and Osterbus, S and Conway, Thomas J},
title = {Continuous observations from the weather ship Polarfront at Station M},
journal = {Proceedings of OceanObs},
year = {2009},
volume = {9}
}
|
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| Yi, C., Rustic, G., Xu, X., Wang, J., Dookie, A., Wei, S., Hendrey, G., Ricciuto, D., Meyers, T., Nagy, Z. and Pinter, K. | Climate extremes and grassland potential productivity | {2012} | ENVIRONMENTAL RESEARCH LETTERS Vol. {7}({3}) |
article | DOI |
| Abstract: The considerable interannual variability (IAV) (similar to 5 PgC yr(-1)) observed in atmospheric CO2 is dominated by variability in terrestrial productivity. Among terrestrial ecosystems, grassland productivity IAV is greatest. Relationships between grassland productivity IAV and climate drivers are poorly explained by traditional multiple-regression approaches. We propose a novel method, the perfect-deficit approach, to identify climate drivers of grassland IAV from observational data. The maximum daily value of each ecological or meteorological variable for each day of the year, over the period of record, defines the `perfect' annual curve. Deficits of these variables can be identified by comparing daily observational data for a given year against the perfect curve. Links between large deficits of ecosystem activity and extreme climate events are readily identified. We applied this approach to five grassland sites with 26 site-years of observational data. Large deficits of canopy photosynthetic capacity and evapotranspiration derived from eddy-covariance measurements, and leaf area index derived from satellite data occur together and are driven by a local-dryness index during the growing season. This new method shows great promise in using observational evidence to demonstrate how extreme climate events alter yearly dynamics of ecosystem potential productivity and exchanges with atmosphere, and shine a new light on climate-carbon feedback mechanisms. |
|||||
BibTeX:
@article{yi12a,
author = {Yi, Chuixiang and Rustic, Gerald and Xu, Xiyan and Wang, Jingxin and Dookie, Anand and Wei, Suhua and Hendrey, George and Ricciuto, Daniel and Meyers, Tilden and Nagy, Zoltan and Pinter, Krisztina},
title = {Climate extremes and grassland potential productivity},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
year = {2012},
volume = {7},
number = {3},
doi = {https://doi.org/10.1088/1748-9326/7/3/035703}
}
|
|||||
| Yi, Y., Kimball, J.S. and Reichle, R.H. | Spring hydrology determines summer net carbon uptake in northern ecosystems | {2014} | ENVIRONMENTAL RESEARCH LETTERS Vol. {9}({6}) |
article | DOI |
| Abstract: Increased photosynthetic activity and enhanced seasonal CO2 exchange of northern ecosystems have been observed from a variety of sources including satellite vegetation indices (such as the normalized difference vegetation index; NDVI) and atmospheric CO2 measurements. Most of these changes have been attributed to strong warming trends in the northern high latitudes (>= 50 degrees N). Here we analyze the interannual variation of summer net carbon uptake derived from atmospheric CO2 measurements and satellite NDVI in relation to surface meteorology from regional observational records. We find that increases in spring precipitation and snow pack promote summer net carbon uptake of northern ecosystems independent of air temperature effects. However, satellite NDVI measurements still show an overall benefit of summer photosynthetic activity from regional warming and limited impact of spring precipitation. This discrepancy is attributed to a similar response of photosynthesis and respiration to warming and thus reduced sensitivity of net ecosystem carbon uptake to temperature. Further analysis of boreal tower eddy covariance CO2 flux measurements indicates that summer net carbon uptake is positively correlated with early growing-season surface soil moisture, which is also strongly affected by spring precipitation and snow pack based on analysis of satellite soil moisture retrievals. This is attributed to strong regulation of spring hydrology on soil respiration in relatively wet boreal and arctic ecosystems. These results document the important role of spring hydrology in determining summer net carbon uptake and contrast with prevailing assumptions of dominant cold temperature limitations to high-latitude ecosystems. Our results indicate potentially stronger coupling of boreal/arctic water and carbon cycles with continued regional warming trends. |
|||||
BibTeX:
@article{yi14a,
author = {Yi, Yonghong and Kimball, John S. and Reichle, Rolf H.},
title = {Spring hydrology determines summer net carbon uptake in northern ecosystems},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
year = {2014},
volume = {9},
number = {6},
doi = {https://doi.org/10.1088/1748-9326/9/6/064003}
}
|
|||||
| Yin, Y., Ciais, P., Chevallier, F., Li, W., Bastos, A., Piao, S., Wang, T. and Liu, H. | Changes in the Response of the Northern Hemisphere Carbon Uptake to Temperature Over the Last Three Decades | {2018} | GEOPHYSICAL RESEARCH LETTERS Vol. {45}({9}), pp. {4371-4380} |
article | DOI |
| Abstract: The CO2 seasonal cycle amplitude (SCA) in the Northern Hemisphere has increased since the 1960sa feature attributed mainly to enhanced vegetation activity along climate warming and CO2 increase. We identified a temporal change in the sign of the correlation between SCA and air temperature (T) from positive to negative around the year 2000 at most Northern Hemisphere ground stations, consistent with signals from satellite column CO2 measurements since the mid-2000s. Further, we explored potential causes of this change using net biome productivity estimates from three atmospheric inversions for the period 1980-2015. The change in the SCA-T relationship is primarily attributable to changes in the net biome productivity-T relationship: positive correlations weakened in the spring in the high latitudes, confirming a limit to the ``warmer spring-bigger carbon sink'' mechanism; negative correlations diminished in the autumn/winter in the mid-to-high latitudes, challenging the ``warmer winter-larger carbon release'' assumption and highlighting the complexity of carbon processes outside the peak growing season. Plain Language Summary The seasonal cycle amplitude (SCA) of atmospheric CO(2)an integrated signal of the terrestrial ecosystem metabolismhas increased since the 1960s in the Northern Hemisphere, a feature attributed mainly to enhanced vegetation activity along climate warming and CO2 increase. Earlier studies suggest a strong positive year-to-year correlation between SCA and air temperature (T). Here we identified a temporal change in the sign of the SCA-T correlation from positive to negative around the year 2000 at most Northern Hemisphere ground stations, consistent with signals from satellite column CO2 observations. We further explored potential causes of this change using land carbon flux (termed as net biome productivity) estimates from three atmospheric inversions for the period 1980-2015. The change in the SCA-T relationship is primarily attributable to changes in the net biome productivity-T relationship: positive correlations weakened in the spring in the high latitudes, confirming a limit to the ``warmer spring-bigger carbon sink'' mechanism; negative correlations diminished in the autumn/winter in the mid-to-high latitudes, challenging the ``warmer winter-larger carbon release'' assumption. This finding highlights a dynamic temperature sensitivity of the terrestrial ecosystem to climate warming and cautions the use of current carbon-climate response to constrain future projections. |
|||||
BibTeX:
@article{yin18a,
author = {Yin, Yi and Ciais, Philippe and Chevallier, Frederic and Li, Wei and Bastos, Ana and Piao, Shilong and Wang, Tao and Liu, Hongyan},
title = {Changes in the Response of the Northern Hemisphere Carbon Uptake to Temperature Over the Last Three Decades},
journal = {GEOPHYSICAL RESEARCH LETTERS},
year = {2018},
volume = {45},
number = {9},
pages = {4371-4380},
doi = {https://doi.org/10.1029/2018GL077316}
}
|
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| Yin, Y., Bowman, K., Bloom, A.A. and Worden, J. | Detection of fossil fuel emission trends in the presence of natural carbon cycle variability | {2019} | ENVIRONMENTAL RESEARCH LETTERS Vol. {14}({8}) |
article | DOI |
| Abstract: Atmospheric CO2 observations have the potential to monitor regional fossil fuel emission (FFCO2) changes to support carbon mitigation efforts such as the Paris Accord, but they must contend with the confounding impacts of the natural carbon cycle. Here, we quantify trend detection time and magnitude in gridded total CO2 fluxes-the sum of FFCO2 and natural carbon fluxes-under an idealized assumption that monthly total CO2 fluxes can be perfectly resolved at a 2 degrees x 2 degrees resolution. Using Coupled Model Intercomparison Project 5 (CMIP5) `business-as-usual' emission scenarios to represent FFCO2 and simulated net biome exchange (NBE) to represent natural carbon fluxes, we find that trend detection time for the total CO2 fluxes at such a resolution has a median of 10 years across the globe, with significant spatial variability depending on FFCO2 magnitude and NBE variability. Differences between trends in the total CO2 fluxes and the underlying FFCO2 component highlight the role of natural carbon cycle variability in modulating regional detection of FFCO2 emission trends using CO2 observations alone, particularly in the tropics and subtropics where mega-cities with large populations are developing rapidly. Using CO2 estimates alone at such a spatiotemporal resolution can only quantify fossil fuel trends in a few places-mostly limited to arid regions. For instance, in the Middle East, FFCO2 can explain more than 75% of the total CO2 trends in similar to 70% of the grids, but only similar to 20% of grids in China can meet such criteria. Only a third of the 25 megacities we analyze here show total CO2 trends that are primarily explained (>75%) by FFCO2. Our analysis provides a theoretical baseline at a global scale for the design of regional FFCO2 monitoring networks and underscores the importance of estimating biospheric interannual variability to improve the accuracy of FFCO2 trend monitoring. We envision that this can be achieved with a fully integrated carbon cycle assimilation system with explicit constraints on FFCO2 and NBE, respectively. | |||||
BibTeX:
@article{yin19a,
author = {Yin, Yi and Bowman, Kevin and Bloom, A. Anthony and Worden, John},
title = {Detection of fossil fuel emission trends in the presence of natural carbon cycle variability},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
publisher = {IOP PUBLISHING LTD},
year = {2019},
volume = {14},
number = {8},
doi = {https://doi.org/10.1088/1748-9326/ab2dd7}
}
|
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| Yu, F., Hong, L., Xiang-Jun, T., Hao, G., Zhao-Nan, C. and Rui, H. | Sensitivity of the simulated CO2 concentration to inter-annual variations of its sources and sinks over East Asia | {2019} | ADVANCES IN CLIMATE CHANGE RESEARCH Vol. {10}({4}), pp. {250-263} |
article | DOI URL |
| Abstract: The study on how the variations in CO2 sources and sinks can affect the CO2 concentration over East Asia would be useful to provide information for policymaker concerning carbon emission reduction. In this study, a nested-grid version of global chemical transport model (GEOS-Chem) is employed to assess the impacts of variations in meteorological parameters, terrestrial fluxes, fossil fuel emissions, and biomass burning on inter-annual variations of CO2 concentrations over East Asia in 2004-2012. Simulated CO2 concentrations are compared with observations at 14 surface stations from the World Data Centre for Greenhouse Gases (WDCGG) and satellite-derived CO2 column density (X-CO2) from the Gases Observing SATellite (GOSAT). The comparison shows that the simulated CO2 column density is generally higher than that of GOSAT by 1.33 x 10(-6) (annual mean point by point biases averaged over East Asia). The model reasonably captures the temporal variations of CO2 concentrations observed at the ground-based stations, but it is likely to underestimate the peaks-to-troughs amplitude of the seasonal cycle by 50% or more. The simulated surface CO2 concentration in East Asia exhibits the largest inter-annual variation in December-January February (DJF). The regional mean absolute deviation (MAD) values over East Asia are within (4.4-5.0) x 10(-6) for all seasons. Model sensitivity simulations indicate that the inter-annual variations of surface CO2 concentrations are mainly driven by variations of meteorological parameters, and partly modulated by the inter-annual variations of terrestrial fluxes and fossil fuel emissions in local regions. The variations of the terrestrial fluxes and fossil fuel emissions may account for similar to 28% of the inter-annual variation of surface CO2 concentration in southern China. The inter-annual variations of the peaks-to-troughs amplitude are dependent on variations of meteorological parameters, terrestrial fluxes and fossil fuel emissions in local regions. The influence of biomass burning emissions is relatively weak. | |||||
BibTeX:
@article{yu19a,
author = {Fu Yu and Liao Hong and Tian Xiang-Jun and Gao Hao and Cai Zhao-Nan and Han Rui},
title = {Sensitivity of the simulated CO2 concentration to inter-annual variations of its sources and sinks over East Asia},
journal = {ADVANCES IN CLIMATE CHANGE RESEARCH},
publisher = {SCIENCE PRESS},
year = {2019},
volume = {10},
number = {4},
pages = {250--263},
note = {Query date: 2021-04-02 15:20:04},
url = {https://www.sciencedirect.com/science/article/pii/S1674927820300034},
doi = {https://doi.org/10.1016/j.accre.2020.03.001}
}
|
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| Yu, Z., Griffis, T. and Baker, J. | Warming temperatures lead to reduced summer carbon sequestration in the US Corn Belt | 2021 | NATURE COMMUNICATIONS Vol. 2(53) |
article | URL |
| Abstract: The response of highly productive croplands at northern mid-latitudes to climate change is a primary source of uncertainty in the global carbon cycle, and a concern for future food production. We present a decadal time series (2007 to 2019) of hourly CO 2 concentration … | |||||
BibTeX:
@article{yu21a,
author = {Z Yu and TJ Griffis and JM Baker},
title = {Warming temperatures lead to reduced summer carbon sequestration in the US Corn Belt},
journal = {NATURE COMMUNICATIONS},
year = {2021},
volume = {2},
number = {53},
url = {https://www.nature.com/articles/s43247-021-00123-9}
}
|
|||||
| Yu, Z., Ciais, P., Piao, S., Houghton, R.A., Lu, C., Tian, H., Agathokleous, E., Kattel, G.R., Sitch, S., Goll, D., Yue, X., Walker, A., Friedlingstein, P., Jain, A.K., Liu, S. and Zhou, G. | Forest expansion dominates China's land carbon sink since 1980 | 2022 | NATURE COMMUNICATIONS Vol. 13(1) |
article | DOI |
| Abstract: Carbon budget accounting relies heavily on Food and Agriculture Organization land-use data reported by governments. Here we develop a new land-use and cover-change database for China, finding that differing historical survey methods biased China's reported data causing large errors in Food and Agriculture Organization databases. Land ecosystem model simulations driven with the new data reveal a strong carbon sink of 8.9 +/- 0.8 Pg carbon from 1980 to 2019 in China, which was not captured in Food and Agriculture Organization data-based estimations due to biased land-use and cover-change signals. The land-use and cover-change in China, characterized by a rapid forest expansion from 1980 to 2019, contributed to nearly 44% of the national terrestrial carbon sink. In contrast, climate changes (22.3%), increasing nitrogen deposition (12.9%), and rising carbon dioxide (8.1%) are less important contributors. This indicates that previous studies have greatly underestimated the impact of land-use and cover-change on the terrestrial carbon balance of China. This study underlines the importance of reliable land-use and cover-change databases in global carbon budget accounting. The impact of land-use and cover-change (LUCC) on ecosystem carbon stock in China is poorly known due to large biases in existing databases. Here the authors develop a new LUCC database with corrected false signals and reveal that forest expansion is the dominant driver of China's recent carbon sink. |
|||||
BibTeX:
@article{yu22a,
author = {Yu, Zhen and Ciais, Philippe and Piao, Shilong and Houghton, Richard A. and Lu, Chaoqun and Tian, Hanqin and Agathokleous, Evgenios and Kattel, Giri Raj and Sitch, Stephen and Goll, Daniel and Yue, Xu and Walker, Anthony and Friedlingstein, Pierre and Jain, Atul K. and Liu, Shirong and Zhou, Guoyi},
title = {Forest expansion dominates China's land carbon sink since 1980},
journal = {NATURE COMMUNICATIONS},
year = {2022},
volume = {13},
number = {1},
doi = {https://doi.org/10.1038/s41467-022-32961-2}
}
|
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| Yuan, Y., Sussmann, R., Rettinger, M., Ries, L., Petermeier, H. and Menzel, A. | Comparison of Continuous In-Situ CO2 Measurements with Co-Located Column-Averaged XCO2 TCCON/Satellite Observations and CarbonTracker Model Over the Zugspitze Region | {2019} | REMOTE SENSING Vol. {11}({24}) |
article | DOI |
| Abstract: Atmospheric CO2 measurements are important in understanding the global carbon cycle and in studying local sources and sinks. Ground and satellite-based measurements provide information on different temporal and spatial scales. However, the compatibility of such measurements at single sites is still underexplored, and the applicability of consistent data processing routines remains a challenge. In this study, we present an inter-comparison among representative surface and column-averaged CO2 records derived from continuous in-situ measurements, ground-based Fourier transform infrared measurements, satellite measurements, and modeled results over the Mount Zugspitze region of Germany. The mean annual growth rates agree well with around 2.2 ppm yr(-1) over a 17-year period (2002-2018), while the mean seasonal amplitudes show distinct differences (surface: 11.7 ppm/column-averaged: 6.6 ppm) due to differing air masses. We were able to demonstrate that, by using consistent data processing routines with proper data retrieval and gap interpolation algorithms, the trend and seasonality can be well extracted from all measurement data sets. | |||||
BibTeX:
@article{yuan19a,
author = {Yuan, Ye and Sussmann, Ralf and Rettinger, Markus and Ries, Ludwig and Petermeier, Hannes and Menzel, Annette},
title = {Comparison of Continuous In-Situ CO2 Measurements with Co-Located Column-Averaged XCO2 TCCON/Satellite Observations and CarbonTracker Model Over the Zugspitze Region},
journal = {REMOTE SENSING},
publisher = {MDPI},
year = {2019},
volume = {11},
number = {24},
doi = {https://doi.org/10.3390/rs11242981}
}
|
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| Yue, T., Liu, Y., Zhao, M., Du, Z. and Zhao, N. | A fundamental theorem of Earth's surface modelling | {2016} | ENVIRONMENTAL EARTH SCIENCES Vol. {75}({9}) |
article | DOI |
| Abstract: Ground observation is able to obtain highly accurate data with high temporal resolution at observation points, but these observation points are too sparse to satisfy some application requirements. Satellite remote sensing and system models can frequently supply spatially continuous information about the Earth's surface, which is impossible from ground-based investigations, but remote sensing description and system model simulation are not able to directly obtain process parameters. The most effective method for Earth surface modelling entails the integration of satellite observations or system models with ground observations. However, the full integration was ignored in most of the methods. For finding a solution for this problem, we suggest an alternative method, high accuracy surface modeling (HASM), which takes global approximate information (e.g., remote sensing images or model simulation results) as its driving field and local accurate information (e.g., ground observation data and/or sampling data) as its optimum control constraints. HASM completes its operation when its output satisfies the iteration stopping criterion which is determined by application requirement for accuracy. A Fundamental Theorem of Earth Surface Modelling (FTESM) is abstracted on the basis of applying HASM to simulating surfaces of elevation, soil properties, changes of ecosystem services, and driving forces of the changes on multi-scales for about 20 years. FTESM is described as ``an Earth's surface system or a component surface of the Earth's surface environment can be simulated with HASM when its spatial resolution is fine enough, which is uniquely defined by both extrinsic and intrinsic invariants of the surface''. From FTESM, seven corollaries have been deduced, corresponding to interpolation, upsaling, downscaling, data fusion and data assimilation respectively. |
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BibTeX:
@article{yue16a,
author = {Yue, TianXiang and Liu, Yu and Zhao, MingWei and Du, ZhengPing and Zhao, Na},
title = {A fundamental theorem of Earth's surface modelling},
journal = {ENVIRONMENTAL EARTH SCIENCES},
year = {2016},
volume = {75},
number = {9},
doi = {https://doi.org/10.1007/s12665-016-5310-5}
}
|
|||||
| Jeongmin Yun Sujong Jeong, C.-H.H.H.P.J.L.H.L.S.S.P.F.S.L.D.L.V.H.A.J.S.Z.E.K.H.T.N.V.A.W.N.Z. | Enhanced regional terrestrial carbon uptake over Korea revealed by atmospheric CO2 measurements from 1999 to 2017 | 2020 | GLOBAL CHANGE BIOLOGY Vol. 26(6) |
article | URL |
| Abstract: Understanding changes in terrestrial carbon balance is important to improve our knowledge of the regional carbon cycle and climate change. However, evaluating regional changes in the terrestrial carbon balance is challenging due to the lack of surface flux measurements … | |||||
BibTeX:
@article{yun20a,
author = {Jeongmin Yun, Sujong Jeong, Chang-Hoi Ho, Hoonyoung Park, Junjie Liu, Haeyoung Lee, Stephen Sitch, Pierre Friedlingstein, Sebastian Lienert, Danica Lombardozzi, Vanessa Haverd, Atual Jain, Sönke Zaehle, Etsushi Kato, Hanqin Tian, Nicolas Vuichard, Andy Wiltshire, Ning Zeng},
title = {Enhanced regional terrestrial carbon uptake over Korea revealed by atmospheric CO2 measurements from 1999 to 2017},
journal = {GLOBAL CHANGE BIOLOGY},
year = {2020},
volume = {26},
number = {6},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.15061}
}
|
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| Yun, J. and Jeong, S. | Contributions of economic growth, terrestrial sinks, and atmospheric transport to the increasing atmospheric CO2 concentrations over the Korean Peninsula | 2021 | CARBON BALANCE AND MANAGEMENT Vol. 16(1) |
article | DOI |
| Abstract: Background Understanding a carbon budget from a national perspective is essential for establishing effective plans to reduce atmospheric CO2 growth. The national characteristics of carbon budgets are reflected in atmospheric CO2 variations; however, separating regional influences on atmospheric signals is challenging owing to atmospheric CO2 transport. Therefore, in this study, we examined the characteristics of atmospheric CO2 variations over South and North Korea during 2000-2016 and unveiled the causes of their regional differences in the increasing rate of atmospheric CO2 concentrations by utilizing atmospheric transport modeling. Results The atmospheric CO2 concentration in South Korea is rising by 2.32 ppm year(- 1), which is more than the globally-averaged increase rate of 2.05 ppm year(- 1). Atmospheric transport modeling indicates that the increase in domestic fossil energy supply to support manufacturing export-led economic growth leads to an increase of 0.12 ppm year(- 1) in atmospheric CO2 in South Korea. Although enhancements of terrestrial carbon uptake estimated from both inverse modeling and process-based models have decreased atmospheric CO2 by up to 0.02 ppm year(- 1), this decrease is insufficient to offset anthropogenic CO2 increases. Meanwhile, atmospheric CO2 in North Korea is also increasing by 2.23 ppm year(- 1), despite a decrease in national CO2 emissions close to carbon neutrality. The great increases estimated in both South Korea and North Korea are associated with changes in atmospheric transport, including increasing emitted and transported CO2 from China, which have increased the national atmospheric CO2 concentrations by 2.23 ppm year(- 1) and 2.27 ppm year(- 1), respectively. Conclusions This study discovered that economic activity is the determinant of regional differences in increasing atmospheric CO2 in the Korea Peninsula. However, from a global perspective, changes in transported CO2 are a major driver of rising atmospheric CO2 over this region, yielding an increase rate higher than the global mean value. Our findings suggest that accurately separating the contributions of atmospheric transport and regional sources to the increasing atmospheric CO2 concentrations is important for developing effective strategies to achieve carbon neutrality at the national level. |
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BibTeX:
@article{yun21a,
author = {Yun, Jeongmin and Jeong, Sujong},
title = {Contributions of economic growth, terrestrial sinks, and atmospheric transport to the increasing atmospheric CO2 concentrations over the Korean Peninsula},
journal = {CARBON BALANCE AND MANAGEMENT},
year = {2021},
volume = {16},
number = {1},
doi = {https://doi.org/10.1186/s13021-021-00186-3}
}
|
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| Zeng, N., Zhao, F., Collatz, G.J., Kalnay, E., Salawitch, R.J., West, T.O. and Guanter, L. | Agricultural Green Revolution as a driver of increasing atmospheric CO2 seasonal amplitude | {2014} | NATURE Vol. {515}({7527}), pp. {394+} |
article | DOI |
| Abstract: The atmospheric carbon dioxide (CO2) record displays a prominent seasonal cycle that arises mainly from changes in vegetation growth and the corresponding CO2 uptake during the boreal spring and summer growing seasons and CO2 release during the autumn and winter seasons(1). The CO2 seasonal amplitude has increased over the past five decades, suggesting an increase in Northern Hemisphere biospheric activity(2,5,6). It has been proposed that vegetation growth may have been stimulated by higher concentrations of CO2 as well as by warming in recent decades, but such mechanisms have been unable to explain the full range and magnitude of the observed increase in CO2 seasonal amplitude(2,6-13). Here we suggest that the intensification of agriculture (the Green Revolution, in which much greater crop yield per unit area was achieved by hybridization, irrigation and fertilization) during the past five decades is a driver of changes in the seasonal characteristics of the global carbon cycle. Our analysis of CO2 data and atmospheric inversions shows a robust 15 per cent long-term increase in CO2 seasonal amplitude from 1961 to 2010, punctuated by large decadal and interannual variations. Using a terrestrial carbon cycle model that takes into account high-yield cultivars, fertilizer use and irrigation, we find that the long-term increase in CO2 seasonal amplitude arises from two major regions: the midlatitude cropland between 25 degrees N and 60 degrees N and the high-latitude natural vegetation between 50 degrees N and 70 degrees N. The long-term trend of seasonal amplitude increase is 0.311 +/- 0.027 per cent per year, of which sensitivity experiments attribute 45,29 and 26 per cent to land-use change, climate variability and change, and increased productivity due to CO2 fertilization, respectively. Vegetation growth was earlier by one to two weeks, as measured by the mid-point of vegetation carbon uptake, and took up 0.5 petagrams more carbon in July, the height of the growing season, during 2001-2010 than in 1961-1970, suggesting that human land use and management contribute to seasonal changes in the CO2 exchange between the biosphere and the atmosphere. |
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BibTeX:
@article{zeng14a,
author = {Zeng, Ning and Zhao, Fang and Collatz, George J. and Kalnay, Eugenia and Salawitch, Ross J. and West, Tristram O. and Guanter, Luis},
title = {Agricultural Green Revolution as a driver of increasing atmospheric CO2 seasonal amplitude},
journal = {NATURE},
year = {2014},
volume = {515},
number = {7527},
pages = {394+},
doi = {https://doi.org/10.1038/nature13893}
}
|
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| Zeng, Z.-C., Lei, L., Strong, K., Jones, D.B.A., Guo, L., Liu, M., Deng, F., Deutscher, N.M., Dubey, M.K., Griffith, D.W.T., Hase, F., Henderson, B., Kivi, R., Lindenmaier, R., Morino, I., Notholt, J., Ohyama, H., Petri, C., Sussmann, R., Velazco, V.A., Wennberg, P.O. and Lin, H. | Global land mapping of satellite-observed CO2 total columns using spatio-temporal geostatistics | {2017} | INTERNATIONAL JOURNAL OF DIGITAL EARTH Vol. {10}({4, SI}), pp. 426-456 |
article | DOI |
| Abstract: This study presents an approach for generating a global land mapping dataset of the satellite measurements of CO2 total column (XCO2) using spatio-temporal geostatistics, which makes full use of the joint spatial and temporal dependencies between observations. The mapping approach considers the latitude-zonal seasonal cycles and spatiotemporal correlation structure of XCO2, and obtains global land maps of XCO2, with a spatial grid resolution of 1 degrees latitude by 1 degrees longitude and temporal resolution of 3 days. We evaluate the accuracy and uncertainty of the mapping dataset in the following three ways: (1) in crossvalidation, the mapping approach results in a high correlation coefficient of 0.94 between the predictions and observations, (2) in comparison with ground truth provided by the Total Carbon Column Observing Network (TCCON), the predicted XCO2 time series and those from TCCON sites are in good agreement, with an overall bias of 0.01 ppm and a standard deviation of the difference of 1.22 ppm and (3) in comparison with model simulations, the spatio-temporal variability of XCO2 between the mapping dataset and simulations from the CT2013 and GEOS-Chem are generally consistent. The generated mapping XCO2 data in this study provides a new global geospatial dataset in global understanding of greenhouse gases dynamics and global warming. |
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BibTeX:
@article{zeng17a,
author = {Zeng, Zhao-Cheng and Lei, Liping and Strong, Kimberly and Jones, Dylan B. A. and Guo, Lijie and Liu, Min and Deng, Feng and Deutscher, Nicholas M. and Dubey, Manvendra K. and Griffith, David W. T. and Hase, Frank and Henderson, Bradley and Kivi, Rigel and Lindenmaier, Rodica and Morino, Isamu and Notholt, Justus and Ohyama, Hirofumi and Petri, Christof and Sussmann, Ralf and Velazco, Voltaire A. and Wennberg, Paul O. and Lin, Hui},
title = {Global land mapping of satellite-observed CO2 total columns using spatio-temporal geostatistics},
journal = {INTERNATIONAL JOURNAL OF DIGITAL EARTH},
year = {2017},
volume = {10},
number = {4, SI},
pages = {426--456},
doi = {https://doi.org/10.1080/17538947.2016.1156777}
}
|
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| Zeng, Z.-C., Natraj, V., Xu, F., Chen, S., Gong, F.-Y., Pongetti, T.J., Sung, K., Toon, G., Sander, S.P. and Yung, Y.L. | GFIT3: A full physics retrieval algorithm for remote sensing of greenhouse gases in the presence of aerosols | 2021 | Atmospheric Measurement Techniques | article | URL |
| Abstract: Remote sensing of greenhouse gases (GHGs) in cities, where high GHG emissions are typically associated with heavy aerosol loading, is challenging due to retrieval uncertainties caused by imperfect characterization of scattering by aerosols. We investigate this problem … | |||||
BibTeX:
@article{zeng21a,
author = {Zhao-Cheng Zeng and Vijay Natraj and Feng Xu and Sihe Chen and Fang-Ying Gong and Thomas J. Pongetti and Keeyoon Sung and Geoffrey Toon and Stanley P. Sander and Yuk L. Yung},
title = {GFIT3: A full physics retrieval algorithm for remote sensing of greenhouse gases in the presence of aerosols},
journal = {Atmospheric Measurement Techniques},
year = {2021},
url = {https://amt.copernicus.org/preprints/amt-2021-84/}
}
|
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| Zeng, Z.-C., Byrne, B., Gong, F.-Y., He, Z. and Lei, L. | Correlation between paddy rice growth and satellite-observed methane column abundance does not imply causation [BibTeX] |
{2021} | NATURE COMMUNICATIONS Vol. {12}({1}) |
article | DOI |
BibTeX:
@article{zeng21b,
author = {Zeng, Zhao-Cheng and Byrne, Brendan and Gong, Fang-Ying and He, Zhonghua and Lei, Liping},
title = {Correlation between paddy rice growth and satellite-observed methane column abundance does not imply causation},
journal = {NATURE COMMUNICATIONS},
publisher = {NATURE RESEARCH},
year = {2021},
volume = {12},
number = {1},
doi = {https://doi.org/10.1038/s41467-021-21434-7}
}
|
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| Zhang, X., Zhao, Y. and Ashton, M.S. | Methods of measuring carbon in forests [BibTeX] |
2009 | Forests and carbon: a synthesis of science, management, and policy for carbon sequestration in forests, pp. 183-221 | article | |
BibTeX:
@article{zhang09a,
author = {Zhang, Xin and Zhao, Yong and Ashton, Mark S},
title = {Methods of measuring carbon in forests},
journal = {Forests and carbon: a synthesis of science, management, and policy for carbon sequestration in forests},
year = {2009},
pages = {183--221}
}
|
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| Zhang, F., Chen, J.M., Pan, Y., Birdsey, R.A., Shen, S., Ju, W. and He, L. | Attributing carbon changes in conterminous U.S. forests to disturbance and non-disturbance factors from 1901 to 2010 | {2012} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {117} |
article | DOI |
| Abstract: Recent climate variability (increasing temperature, droughts) and atmospheric composition changes (nitrogen deposition, rising CO2 concentration) along with harvesting, wildfires, and insect infestations have had significant effects on U. S. forest carbon (C) uptake. In this study, we attribute C changes in the conterminous U. S. forests to disturbance and non-disturbance factors with the help of forest inventory data, a continental stand age map, and an updated Integrated Terrestrial Ecosystem Carbon Cycle model (InTEC). We grouped factors into disturbances (harvesting, fire, insect infestation) and non-disturbances (CO2 concentration, N deposition, and climate variability) and estimated their subsequent impacts on forest regrowth patterns. Results showed that on average, the C sink in the conterminous U. S. forests from 1950 to 2010 was 206 Tg C yr(-1) with 87% (180 Tg C yr(-1)) of the sink in living biomass. Compared with the simulation of all factors combined, the estimated C sink would be reduced by 95 Tg C yr(-1) if disturbance factors were omitted, and reduced by 50 Tg C yr(-1) if non-disturbance factors were omitted. Our study also showed diverse regional patterns of C sinks related to the importance of driving factors. During 1980-2010, disturbance effects dominated the C changes in the South and Rocky Mountain regions, were almost equal to non-disturbance effects in the North region, and had minor effects compared with non-disturbance effects in the West Coast region. |
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BibTeX:
@article{zhang12a,
author = {Zhang, Fangmin and Chen, Jing M. and Pan, Yude and Birdsey, Richard A. and Shen, Shuanghe and Ju, Weimin and He, Liming},
title = {Attributing carbon changes in conterminous U.S. forests to disturbance and non-disturbance factors from 1901 to 2010},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2012},
volume = {117},
doi = {https://doi.org/10.1029/2011JG001930}
}
|
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| Zhang, Z., Jiang, H., Liu, J.X., Zhou, G.M., Liu, S.R. and Zhang, X.Y. | Assessment on water use efficiency under climate change and heterogeneous carbon dioxide in China terrestrial ecosystems | {2012} | Vol. {13}18TH BIENNIAL ISEM CONFERENCE ON ECOLOGICAL MODELLING FOR GLOBAL CHANGE AND COUPLED HUMAN AND NATURAL SYSTEM, pp. 2031-2044 |
inproceedings | DOI |
| Abstract: Assessing the effects of climate change on water use efficiency (WUE) is critical for policymaking and adaptation. The influences of heterogeneous distribution of atmospheric carbon dioxide (CO2) concentration on WUE have not considered in China. In this study, we used a spatial-temporal distribution of CO2 constructed from remote sensing data and ground-based observations, to quantify the heterogeneity of CO2 concentrations. Based on the initial conditions, the spatial patterns of WUE in history and future were estimated using the Integrated Biosphere Simulator (IBIS). Results showed that the geographical distributions of the averaged WUE have significant difference under the heterogeneous surface CO2 fertilization condition during 1951-2006. Partial correlation analysis indicated that the cold temperate zones are strong associated with the spatial heterogeneity of CO2, suggesting the special relationship of carbon-water cycle coupling with the interannual variations of CO2. WUE showed high negative correlations with temperature in subtropical zones and positive correlations in Tibet Plateau. The correlation between WUE and precipitation exhibits high positive in wet temperate zones, where the cropland is mainly located. Our estimates of WUE and its covariation with major climate variables can improve understanding of carbon-water cycle coupling under climate change. (C) 2011 Published by Elsevier B. V. Selection and/or peer-review under responsibility of School of Environment, Beijing Normal University. |
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BibTeX:
@inproceedings{zhang12b,
author = {Zhang, Z. and Jiang, H. and Liu, J. X. and Zhou, G. M. and Liu, S. R. and Zhang, X. Y.},
title = {Assessment on water use efficiency under climate change and heterogeneous carbon dioxide in China terrestrial ecosystems},
booktitle = {18TH BIENNIAL ISEM CONFERENCE ON ECOLOGICAL MODELLING FOR GLOBAL CHANGE AND COUPLED HUMAN AND NATURAL SYSTEM},
year = {2012},
volume = {13},
pages = {2031--2044},
note = {18th Biennial ISEM Conference on Ecological Modelling for Global Change and Coupled Human and Natural Systems, Beijing Normal Univ, Beijing, PEOPLES R CHINA, SEP 20-23, 2011},
doi = {https://doi.org/10.1016/j.proenv.2012.01.194}
}
|
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| Zhang, X., Zhao, Y., Ashton, M.S. and Lee, X. | Measuring carbon in forests [BibTeX] |
2012 | book | ||
BibTeX:
@book{zhang12c,
author = {Zhang, Xin and Zhao, Yong and Ashton, Mark S and Lee, Xuhui},
title = {Measuring carbon in forests},
publisher = {Springer},
year = {2012}
}
|
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| Zhang, Z., Jiang, H., Liu, J., Ju, W. and Zhang, X. | Effect of heterogeneous atmospheric CO2 on simulated global carbon budget | {2013} | GLOBAL AND PLANETARY CHANGE Vol. {101}, pp. 33-51 |
article | DOI |
| Abstract: The effects of rising atmospheric carbon dioxide (CO2) on terrestrial carbon (C) sequestration have been a key focus in global change studies. As anthropological CO2 emissions substantially increase, the spatial variability of atmospheric CO2 should be considered to reduce the potential bias on C source and sink estimations. In this study, the global spatial-temporal patterns of near surface CO2 concentrations for the period 2003-2009 were established using the SCIAMACHY satellite observations and the GLOBALVIEW-CO2 field observations. With this CO2 data and the Integrated Biosphere Simulator (IBIS), our estimation of the global mean annual NPP and NEP was 0.5% and 7% respectively which differs from the traditional C sequestration assessments. The Amazon, Southeast Asia, and Tropical Africa showed higher C sequestration than the traditional assessment, and the rest of the areas around the world showed slightly lower C sequestration than the traditional assessment. We find that the variability of NEP is less intense under heterogeneous CO2 pattern on a global scale. Further studies of the cause of CO2 variation and the interactions between natural and anthropogenic processes of C sequestration are needed. (C) 2012 Elsevier B.V. All rights reserved. |
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BibTeX:
@article{zhang13a,
author = {Zhang, Zhen and Jiang, Hong and Liu, Jinxun and Ju, Weimin and Zhang, Xiuying},
title = {Effect of heterogeneous atmospheric CO2 on simulated global carbon budget},
journal = {GLOBAL AND PLANETARY CHANGE},
year = {2013},
volume = {101},
pages = {33--51},
doi = {https://doi.org/10.1016/j.gloplacha.2012.12.002}
}
|
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| Zhang, Z., Jiang, H., Liu, J., Han, J., Zhu, Q. and Zhang, X. | Implications of Future Water Use Efficiency for Ecohydrological Responses to Climate Change and Spatial Heterogeneity of Atmospheric CO2 in China | {2013} | TERRESTRIAL ATMOSPHERIC AND OCEANIC SCIENCES Vol. {24}({3}), pp. 451-465 |
article | DOI |
| Abstract: As the atmospheric carbon dioxide (CO2) increases substantially, the spatial distribution of atmospheric CO2 should be considered when estimating the effects of CO2 on the carbon and water cycle coupling of terrestrial ecosystems. To evaluate this effect on future ecohydrological processes, the spatial-temporal patterns of CO2 were established over 1951 - 2099 according to the IPCC emission scenarios SRES A2 and SRES B1. Thereafter, water use efficiency (WUE) was used (i.e., Net Primary Production/Evaportranspiration) as an indicator to quantify the effects of climate change and uneven CO2 fertilization in China. We carried out several simulated experiments to estimate WUE under different future scenarios using a land process model (Integrated Biosphere Simulator, IBIS). Results indicated that the geographical distributions of averaged WUE have considerable differences under a heterogeneous atmospheric CO2 condition. Under the SRES A2 scenario, WUE decreased slightly with a 5% value in most areas of the southeastern and northwestern China during the 2050s, while decreasing by approximately 15% in southeastern China during the 2090s. During the period of the 2050s under SRES B1 scenario, the change rate of WUE was similar with that under SRES A2 scenario, but the WUE has a more moderate decreasing trend than that under the SRES A2 scenario. In all, the ecosystems in median and low latitude areas had a weakened effect on resisting extreme climate event such as drought. Conversely, the vegetation in a boreal forest had an enhanced buffering capability to tolerate drought events. |
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BibTeX:
@article{zhang13b,
author = {Zhang, Zhen and Jiang, Hong and Liu, Jinxun and Han, Juejing and Zhu, Qiuan and Zhang, Xiuying},
title = {Implications of Future Water Use Efficiency for Ecohydrological Responses to Climate Change and Spatial Heterogeneity of Atmospheric CO2 in China},
journal = {TERRESTRIAL ATMOSPHERIC AND OCEANIC SCIENCES},
year = {2013},
volume = {24},
number = {3},
pages = {451--465},
doi = {https://doi.org/10.3319/TAO.2012.12.03.01(Hy)}
}
|
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| Zhang, Z., Jiang, H., Liu, J., Zhang, X., Huang, C., Lu, X., Jin, J. and Zhou, G. | An analysis of the global spatial variability of column-averaged CO2 from SCIAMACHY and its implications for CO2 sources and sinks | {2014} | INTERNATIONAL JOURNAL OF REMOTE SENSING Vol. {35}({6}), pp. 2047-2066 |
article | DOI |
| Abstract: Satellite observations of carbon dioxide (CO2) are important because of their potential for improving the scientific understanding of global carbon cycle processes and budgets. We present an analysis of the column-averaged dry air mole fractions of CO2 (denoted XCO2) of the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) retrievals, which were derived from a satellite instrument with relatively long-term records (2003-2009) and with measurements sensitive to the near surface. The spatial-temporal distributions of remotely sensed XCO2 have significant spatial heterogeneity with about 6-8% variations (367-397 ppm) during 2003-2009, challenging the traditional view that the spatial heterogeneity of atmospheric CO2 is not significant enough (<4%) to have any large effect on terrestrial ecosystem carbon cycles. By comparison with surface measurements from the NOAA Earth System Research Laboratory (ESRL) GLOBALVIEW network, significant statistical relationships between XCO2 and surface CO2 were found for major ecosystems, with the exception of tropical forest. In addition, when compared with a simulated terrestrial carbon uptake from the Integrated Biosphere Simulator (IBIS) and the Emissions Database for Global Atmospheric Research (EDGAR) carbon emission inventory, the latitudinal gradient of XCO2 seasonal amplitude was influenced by the combined effect of terrestrial carbon uptake, carbon emission, and atmospheric transport, suggesting no direct implications for terrestrial carbon sinks. From the investigation of the growth rate of XCO2 we found that the increase of CO2 concentration was dominated by temperature in the northern hemisphere (20-90 degrees N) and by precipitation in the southern hemisphere (20-90 degrees S), with the major contribution to global average occurring in the northern hemisphere. These findings indicated that the satellite measurements of atmospheric CO2 improve not only the estimations of atmospheric inversion, but also the understanding of the terrestrial ecosystem carbon dynamics and its feedback to atmospheric CO2. |
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BibTeX:
@article{zhang14a,
author = {Zhang, Zhen and Jiang, Hong and Liu, Jinxun and Zhang, Xiuying and Huang, Chunlin and Lu, Xuehe and Jin, Jiaxin and Zhou, Guomo},
title = {An analysis of the global spatial variability of column-averaged CO2 from SCIAMACHY and its implications for CO2 sources and sinks},
journal = {INTERNATIONAL JOURNAL OF REMOTE SENSING},
year = {2014},
volume = {35},
number = {6},
pages = {2047--2066},
doi = {https://doi.org/10.1080/01431161.2014.885151}
}
|
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| Zhang, H.F., Chen, B.Z., van der Laan-Luijkx, I.T., Chen, J., Xu, G., Yan, J.W., Zhou, L.X., Fukuyama, Y., Tans, P.P. and Peters, W. | Net terrestrial CO2 exchange over China during 2001-2010 estimated with an ensemble data assimilation system for atmospheric CO2 | {2014} | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. {119}({6}), pp. 3500-3515 |
article | DOI |
| Abstract: In this paper we present an estimate of net ecosystem CO2 exchange over China for the years 2001-2010 using the CarbonTracker Data Assimilation System for CO2 (CTDAS). Additional Chinese and Asian CO2 observations are used in CTDAS to improve our estimate. We found that the combined terrestrial ecosystems in China absorbed about -0.33 Pg C yr(-1) during 2001-2010. The uncertainty on Chinese terrestrial carbon exchange estimates as derived from a set of sensitivity experiments suggests a range of -0.29 to -0.64 Pg C yr(-1). This total Chinese terrestrial CO2 sink is attributed to the three major biomes (forests, croplands, and grass/shrublands) with estimated CO2 fluxes of -0.12 Pg C yr(-1) (range from -0.09 to -0.19 Pg C yr(-1)), -0.12 Pg C yr(-1) (range from -0.09 to -0.26 Pg C yr(-1)), and -0.09 Pg C yr(-1) (range from -0.09 to -0.17 Pg C yr(-1)), respectively. The peak-to-peak amplitude of interannual variability of the Chinese terrestrial ecosystem carbon flux is 0.21 Pg C yr(-1) (similar to 64% of mean annual average), with the smallest CO2 sink (-0.19 Pg C yr(-1)) in 2003 and the largest CO2 sink (-0.40 Pg C yr(-1)) in 2007. We stress that our estimate of terrestrial ecosystem CO2 uptake based on inverse modeling strongly depends on a limited number of atmospheric CO2 observations used. More observations in China specifically and in Asia in general are needed to improve the accuracy of terrestrial carbon budgeting for this region. |
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BibTeX:
@article{zhang14b,
author = {Zhang, H. F. and Chen, B. Z. and van der Laan-Luijkx, I. T. and Chen, J. and Xu, G. and Yan, J. W. and Zhou, L. X. and Fukuyama, Y. and Tans, P. P. and Peters, W.},
title = {Net terrestrial CO2 exchange over China during 2001-2010 estimated with an ensemble data assimilation system for atmospheric CO2},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2014},
volume = {119},
number = {6},
pages = {3500--3515},
doi = {https://doi.org/10.1002/2013JD021297}
}
|
|||||
| Zhang, H.F., Chen, B.Z., van der Laan-Luijkx, I.T., Machida, T., Matsueda, H., Sawa, Y., Fukuyama, Y., Langenfelds, R., van der Schoot, M., Xu, G., Yan, J.W., Cheng, M.L., Zhou, L.X., Tans, P.P. and Peters, W. | Estimating Asian terrestrial carbon fluxes from CONTRAIL aircraft and surface CO2 observations for the period 2006-2010 | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({11}), pp. 5807-5824 |
article | DOI |
| Abstract: Current estimates of the terrestrial carbon fluxes in Asia show large uncertainties particularly in the boreal and mid-latitudes and in China. In this paper, we present an updated carbon flux estimate for Asia ('Asia' refers to lands as far west as the Urals and is divided into boreal Eurasia, temperate Eurasia and tropical Asia based on TransCom regions) by introducing aircraft CO2 measurements from the CONTRAIL (Comprehensive Observation Network for Trace gases by Airline) program into an inversion modeling system based on the CarbonTracker framework. We estimated the averaged annual total Asian terrestrial land CO2 sink was about -1.56 Pg C yr(-1) over the period 2006-2010, which offsets about one-third of the fossil fuel emission from Asia (+4.15 Pg C yr(-1)). The uncertainty of the terrestrial uptake estimate was derived from a set of sensitivity tests and ranged from -1.07 to -1.80 Pg C yr(-1), comparable to the formal Gaussian error of +/- 1.18 Pg C yr(-1) (1-sigma). The largest sink was found in forests, predominantly in coniferous forests (-0.64 +/- 0.70 Pg C yr(-1)) and mixed forests (-0.14 +/- 0.27 Pg C yr(-1)); and the second and third large carbon sinks were found in grass/shrub lands and croplands, accounting for -0.44 +/- 0.48 Pg C yr(-1) and -0.20 +/- 0.48 Pg C yr(-1), respectively. The carbon fluxes per ecosystem type have large a priori Gaussian uncertainties, and the reduction of uncertainty based on assimilation of sparse observations over Asia is modest (8.7-25.5%) for most individual ecosystems. The ecosystem flux adjustments follow the detailed a priori spatial patterns by design, which further increases the reliance on the a priori biosphere exchange model. The peak-to-peak amplitude of inter-annual variability (IAV) was 0.57 Pg C yr(-1) ranging from -1.71 Pg C yr(-1) to -2.28 Pg C yr(-1). The IAV analysis reveals that the Asian CO2 sink was sensitive to climate variations, with the lowest uptake in 2010 concurrent with a summer flood and autumn drought and the largest CO2 sink in 2009 owing to favorable temperature and plentiful precipitation conditions. We also found the inclusion of the CONTRAIL data in the inversion modeling system reduced the uncertainty by 11% over the whole Asian region, with a large reduction in the southeast of boreal Eurasia, southeast of temperate Eurasia and most tropical Asian areas. |
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BibTeX:
@article{zhang14c,
author = {Zhang, H. F. and Chen, B. Z. and van der Laan-Luijkx, I. T. and Machida, T. and Matsueda, H. and Sawa, Y. and Fukuyama, Y. and Langenfelds, R. and van der Schoot, M. and Xu, G. and Yan, J. W. and Cheng, M. L. and Zhou, L. X. and Tans, P. P. and Peters, W.},
title = {Estimating Asian terrestrial carbon fluxes from CONTRAIL aircraft and surface CO2 observations for the period 2006-2010},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {11},
pages = {5807--5824},
doi = {https://doi.org/10.5194/acp-14-5807-2014}
}
|
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| Zhang, X., Lee, X., Griffis, T.J., Baker, J.M. and Xiao, W. | Estimating regional greenhouse gas fluxes: an uncertainty analysis of planetary boundary layer techniques and bottom-up inventories | {2014} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {14}({19}), pp. 10705-10719 |
article | DOI |
| Abstract: Quantification of regional greenhouse gas (GHG) fluxes is essential for establishing mitigation strategies and evaluating their effectiveness. Here, we used multiple top-down approaches and multiple trace gas observations at a tall tower to estimate regional-scale GHG fluxes and evaluate the GHG fluxes derived from bottom-up approaches. We first applied the eddy covariance, equilibrium, inverse modeling (CarbonTracker), and flux aggregation methods using 3 years of carbon dioxide (CO2) measurements on a 244m tall tower in the upper Midwest, USA. We then applied the equilibrium method for estimating CH4 and N2O fluxes with 1-month high-frequency CH4 and N2O gradient measurements on the tall tower and 1-year concentration measurements on a nearby tall tower, and evaluated the uncertainties of this application. The results indicate that (1) the flux aggregation, eddy covariance, the equilibrium method, and the CarbonTracker product all gave similar seasonal patterns of the regional CO2 flux (10(5)-10(6) km(2)), but that the equilibrium method underestimated the July CO2 flux by 52-69 %. (2) The annual budget varied among these methods from -54 to -131 g C-CO2 m(-2) yr(-1), indicating a large uncertainty in the annual CO2 flux estimation. (3) The regional CH4 and N2O emissions according to a top-down method were at least 6 and 2 times higher than the emissions from a bottom-up inventory (Emission Database for Global Atmospheric Research), respectively. (4) The global warming potentials of the CH4 and N2O emissions were equal in magnitude to the cooling benefit of the regional CO2 uptake. The regional GHG budget, including both biological and anthropogenic origins, is estimated at 7 +/- 160 gCO(2) equivalent m(-2) yr(-1). |
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BibTeX:
@article{zhang14d,
author = {Zhang, X. and Lee, X. and Griffis, T. J. and Baker, J. M. and Xiao, W.},
title = {Estimating regional greenhouse gas fluxes: an uncertainty analysis of planetary boundary layer techniques and bottom-up inventories},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
volume = {14},
number = {19},
pages = {10705--10719},
doi = {https://doi.org/10.5194/acp-14-10705-2014}
}
|
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| Zhang, X., Gurney, K.R., Rayner, P., Liu, Y. and Asefi-Najafabady, S. | Sensitivity of simulated CO2 concentration to regridding of global fossil fuel CO2 emissions | {2014} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {7}({6}), pp. 2867-2874 |
article | DOI |
| Abstract: Errors in the specification or utilization of fossil fuel CO2 emissions within carbon budget or atmospheric CO2 inverse studies can alias the estimation of biospheric and oceanic carbon exchange. A key component in the simulation of CO2 concentrations arising from fossil fuel emissions is the spatial distribution of the emission near coastlines. Regridding of fossil fuel CO2 emissions (FFCO2) from fine to coarse grids to enable atmospheric transport simulations can give rise to mismatches between the emissions and simulated atmospheric dynamics which differ over land or water. For example, emissions originally emanating from the land are emitted from a grid cell for which the vertical mixing reflects the roughness and/or surface energy exchange of an ocean surface. We test this potential ``dynamical inconsistency'' by examining simulated global atmospheric CO2 concentration driven by two different approaches to regridding fossil fuel CO2 emissions. The two approaches are as follows: (1) a commonly used method that allocates emissions to grid cells with no attempt to ensure dynamical consistency with atmospheric transport and (2) an improved method that reallocates emissions to grid cells to ensure dynamically consistent results. Results show large spatial and temporal differences in the simulated CO2 concentration when comparing these two approaches. The emissions difference ranges from -30.3 TgC grid cell(-1) yr(-1) (3.39 kgCm(-2) yr(-1)) to +30.0 TgC grid cell(-1) yr(-1) (+2.6 kgCm(-2) yr(-1)) along coastal margins. Maximum simulated annual mean CO2 concentration differences at the surface exceed +/- 6 ppm at various locations and times. Examination of the current CO2 monitoring locations during the local afternoon, consistent with inversion modeling system sampling and measurement protocols, finds maximum hourly differences at 38 stations exceed +/- 0.10 ppm with individual station differences exceeding 32 ppm. The differences implied by not accounting for this dynamical consistency problem are largest at monitoring sites proximal to large coastal urban areas and point sources. These results suggest that studies comparing simulated to observed atmospheric CO2 concentration, such as atmospheric CO2 inversions, must take measures to correct for this potential problem and ensure flux and dynamical consistency. |
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BibTeX:
@article{zhang14e,
author = {Zhang, X. and Gurney, K. R. and Rayner, P. and Liu, Y. and Asefi-Najafabady, S.},
title = {Sensitivity of simulated CO2 concentration to regridding of global fossil fuel CO2 emissions},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2014},
volume = {7},
number = {6},
pages = {2867--2874},
doi = {https://doi.org/10.5194/gmd-7-2867-2014}
}
|
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| Zhang, S., Yi, X., Zheng, X., Chen, Z., Dan, B. and Zhang, X. | Global carbon assimilation system using a local ensemble Kalman filter with multiple ecosystem models | {2014} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {119}({11}), pp. 2171-2187 |
article | DOI |
| Abstract: In this paper, a global carbon assimilation system (GCAS) is developed for optimizing the global land surface carbon flux at 1 degrees resolution using multiple ecosystem models. In GCAS, three ecosystem models, Boreal Ecosystem Productivity Simulator, Carnegie-Ames-Stanford Approach, and Community Atmosphere Biosphere Land Exchange, produce the prior fluxes, and an atmospheric transport model, Model for OZone And Related chemical Tracers, is used to calculate atmospheric CO2 concentrations resulting from these prior fluxes. A local ensemble Kalman filter is developed to assimilate atmospheric CO2 data observed at 92 stations to optimize the carbon flux for six land regions, and the Bayesian model averaging method is implemented in GCAS to calculate the weighted average of the optimized fluxes based on individual ecosystem models. The weights for the models are found according to the closeness of their forecasted CO2 concentration to observation. Results of this study show that the model weights vary in time and space, allowing for an optimum utilization of different strengths of different ecosystem models. It is also demonstrated that spatial localization is an effective technique to avoid spurious optimization results for regions that are not well constrained by the atmospheric data. Based on the multimodel optimized flux from GCAS, we found that the average global terrestrial carbon sink over the 2002-2008 period is 2.971.1 PgC yr(-1), and the sinks are 0.880.52, 0.270.33, 0.670.39, 0.90 +/- 0.68, 0.21 +/- 0.31, and 0.04 +/- 0.08 PgC yr(-1) for the North America, South America, Africa, Eurasia, Tropical Asia, and Australia, respectively. This multimodel GCAS can be used to improve global carbon cycle estimation. |
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BibTeX:
@article{zhang14f,
author = {Zhang, Shupeng and Yi, Xue and Zheng, Xiaogu and Chen, Zhuoqi and Dan, Bo and Zhang, Xuanze},
title = {Global carbon assimilation system using a local ensemble Kalman filter with multiple ecosystem models},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
year = {2014},
volume = {119},
number = {11},
pages = {2171--2187},
doi = {https://doi.org/10.1002/2014JG002792}
}
|
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| Zhang, H., Chen, B., Xu, G., Yan, J., Che, M., Chen, J., Fang, S., Lin, X. and Sun, S. | Comparing simulated atmospheric carbon dioxide concentration with GOSAT retrievals | {2015} | SCIENCE BULLETIN Vol. {60}({3}), pp. 380-386 |
article | DOI |
| Abstract: Satellite observations of atmospheric carbon dioxide (CO2) provide a useful way to improve the understanding of global carbon cycling. In this paper, we present a comparison between simulated CO2 concentrations from an inversion model of the CarbonTracker Data Assimilation System (CTDAS) and satellite-based CO2 measurements of column-averaged dry air mole fraction (denoted XCO2) derived from version 3.3 Atmospheric CO2 Observations from Space retrievals of the Greenhouse Gases Observing SATellite (ACOS-GOSAT) L2 data products. We examine the differences of CTDAS and GOSAT to provide important guidance for the further investigation of CTDAS in order to quantify the corresponding flux estimates with satellite-based CO2 observations. We find that the mean point-by-point difference (CTDAS-GOSAT) between CTDAS and GOSAT XCO2 is -0.11 +/- A 1.81 ppm, with a high agreement (correlation r = 0.77, P < 0.05) over the studied period. The latitudinal zonal variations of CTDAS and GOSAT are in general agreement with clear seasonal fluctuations. The major exception occurs in the zonal band of 0A degrees aEuro''15A degrees N where the difference is approximately 4 ppm, indicating that large uncertainty may exist in the assimilated CO2 for the low-latitude region of the Northern Hemisphere (NH). Additionally, we find that the hemispherical/continental differences between CTDAS and GOSAT are typically less than 1 ppm, but obvious discrepancies occur in different hemispheres/continents, with high consistency (point-by-point correlation r = 0.79, P < 0.05) in the NH and a weak correlation (point-by-point correlation r = 0.65, P < 0.05) in the Southern Hemisphere. Overall, the difference of CTDAS and GOSAT is small, and the comparison of CTDAS and GOSAT will further instruct the inverse modeling of CO2 fluxes using GOSAT. |
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BibTeX:
@article{zhang15a,
author = {Zhang, Huifang and Chen, Baozhang and Xu, Guang and Yan, Jianwu and Che, Mingliang and Chen, Jing and Fang, Shifeng and Lin, Xiaofeng and Sun, Shaobo},
title = {Comparing simulated atmospheric carbon dioxide concentration with GOSAT retrievals},
journal = {SCIENCE BULLETIN},
year = {2015},
volume = {60},
number = {3},
pages = {380--386},
doi = {https://doi.org/10.1007/s11434-014-0676-9}
}
|
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| Zhang, S., Zheng, X., Chen, J.M., Chen, Z., Dan, B., Yi, X., Wang, L. and Wu, G. | A global carbon assimilation system using a modified ensemble Kalman filter | {2015} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {8}({3}), pp. 805-816 |
article | DOI |
| Abstract: A Global Carbon Assimilation System based on the ensemble Kalman filter (GCAS-EK) is developed for assimilating atmospheric CO2 data into an ecosystem model to simultaneously estimate the surface carbon fluxes and atmospheric CO2 distribution. This assimilation approach is similar to CarbonTracker, but with several new developments, including inclusion of atmospheric CO2 concentration in state vectors, using the ensemble Kalman filter (EnKF) with 1-week assimilation windows, using analysis states to iteratively estimate ensemble forecast errors, and a maximum likelihood estimation of the inflation factors of the forecast and observation errors. The proposed assimilation approach is used to estimate the terrestrial ecosystem carbon fluxes and atmospheric CO2 distributions from 2002 to 2008. The results show that this assimilation approach can effectively reduce the biases and uncertainties of the carbon fluxes simulated by the ecosystem model. |
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BibTeX:
@article{zhang15b,
author = {Zhang, S. and Zheng, X. and Chen, J. M. and Chen, Z. and Dan, B. and Yi, X. and Wang, L. and Wu, G.},
title = {A global carbon assimilation system using a modified ensemble Kalman filter},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2015},
volume = {8},
number = {3},
pages = {805--816},
doi = {https://doi.org/10.5194/gmd-8-805-2015}
}
|
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| Zhang, X., Gurney, K.R., Rayner, P., Baker, D. and Liu, Y.-p. | Sensitivity of simulated CO2 concentration to sub-annual variations in fossil fuel CO2 emissions | {2016} | ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. {16}({4}), pp. 1907-1918 |
article | DOI |
| Abstract: Recent advances in fossil fuel CO2 (FFCO2) emission inventories enable sensitivity tests of simulated atmospheric CO2 concentrations to sub-annual variations in FFCO2 emissions and what this implies for the interpretation of observed CO2. Six experiments are conducted to investigate the potential impact of three cycles of FFCO2 emission variability (diurnal, weekly and monthly) using a global tracer transport model. Results show an annual FFCO2 rectification varying from -1.35 to +0.13 ppm from the combination of all three cycles. This rectification is driven by a large negative diurnal FFCO2 rectification due to the covariation of diurnal FFCO2 emissions and diurnal vertical mixing, as well as a smaller positive seasonal FFCO2 rectification driven by the covariation of monthly FFCO2 emissions and monthly atmospheric transport. The diurnal FFCO2 emissions are responsible for a diurnal FFCO2 concentration amplitude of up to 9.12 ppm at the grid cell scale. Similarly, the monthly FFCO2 emissions are responsible for a simulated seasonal Cv amplitude of up to 6.11 ppm at the grid cell scale. The impact of the diurnal FFCO2 emissions, when only sampled in the local afternoon, is also important, causing an increase of +1.13 ppmv at the grid cell scale. The simulated CO2 concentration impacts from the diurnally and seasonally varying FFCO2 emissions are centered over large source regions in the Northern Hemisphere, extending to downwind regions. This study demonstrates the influence of sub-annual variations in FFCO2 emissions on simulated CO2 concentration and suggests that inversion studies must take account of these variations in the affected regions. |
|||||
BibTeX:
@article{zhang16a,
author = {Zhang, Xia and Gurney, Kevin R. and Rayner, Peter and Baker, David and Liu, Yu-ping},
title = {Sensitivity of simulated CO2 concentration to sub-annual variations in fossil fuel CO2 emissions},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2016},
volume = {16},
number = {4},
pages = {1907--1918},
doi = {https://doi.org/10.5194/acp-16-1907-2016}
}
|
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| Zhang, Q., Li, M., Wei, C., Mizzi, A.P., Huang, Y. and Gu, Q. | Assimilation of OCO-2 retrievals with WRF-Chem/DART: A case study for the Midwestern United States | {2021} | ATMOSPHERIC ENVIRONMENT Vol. {246} |
article | DOI |
| Abstract: The Data Assimilation Research Testbed (DART) has been extended to be able to assimilate the column-average dry-air mole fraction of CO2 (XCO2) retrievals from the Orbiting Carbon Observatory 2 (OCO-2) satellite. Atmospheric CO2 concentrations over the Midwestern United States were estimated by the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), with and without assimilating OCO-2 retrievals by the extended-DART. To focus on evaluating the effect of the assimilation, the study period was deliberately set to January 2016, the coldest month in the dormant season, to minimize the influence of biogenic CO2 flux. Independent ground-based and flight observations, as well as the CarbonTracker 2017 products (CT2017), were used to evaluate the results of two distinct approaches. Comparing to the estimated CO2 concentration distribution without assimilating the OCO-2 retrievals, the overall root mean square error (RMSE) and mean bias error (MBE) between the results with the assimilation and the observations were averagely reduced by 20.65% and 78.49%, the overall difference in the RMSE and MBE with respect to CT2017 were averagely reduced by 48.29% and 28.61%, respectively. Experiments showed that the assimilation of OCO-2 retrievals by the extended-DART could make the estimated CO2 concentration distribution significantly more consistent with the observations and the CarbonTracker products. | |||||
BibTeX:
@article{zhang21a,
author = {Zhang, Qinwei and Li, Mingqi and Wei, Chong and Mizzi, Arthur P. and Huang, Yongjian and Gu, Qianrong},
title = {Assimilation of OCO-2 retrievals with WRF-Chem/DART: A case study for the Midwestern United States},
journal = {ATMOSPHERIC ENVIRONMENT},
publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
year = {2021},
volume = {246},
doi = {https://doi.org/10.1016/j.atmosenv.2020.118106}
}
|
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| Zhang, S., Bai, Y., He, X., Huang, H., Zhu, Q. and Gong, F. | Comparisons of OCO-2 satellite derived XCO2 with in situ and modeled data over global ocean | 2021 | ACTA OCEANOLOGICA SINICA Vol. 40(4), pp. 136-142 |
article | DOI |
| Abstract: Atmospheric CO2 is one of key parameters to estimate air-sea CO2 flux. The Orbiting Carbon Observatory-2 (OCO-2) satellite has observed the column-averaged dry-air mole fractions of global atmospheric carbon dioxide (XCO2) since 2014. In this study, the OCO-2 XCO2 products were compared between in-situ data from the Total Carbon Column Network (TCCON) and Global Monitoring Division (GMD), and modeling data from CarbonTracker2019 over global ocean and land. Results showed that the OCO-2 XCO2 data are consistent with the TCCON and GMD in situ XCO2 data, with mean absolute biases of 0.25x10(-6) and 0.67x10(-6), respectively. Moreover, the OCO-2 XCO2 data are also consistent with the CarbonTracker2019 modeling XCO2 data, with mean absolute biases of 0.78x10(-6) over ocean and 1.02x10(-6) over land. The results indicated the high accuracy of the OCO-2 XCO2 product over global ocean which could be applied to estimate the air-sea CO2 flux. |
|||||
BibTeX:
@article{zhang21b,
author = {Zhang, Siqi and Bai, Yan and He, Xianqiang and Huang, Haiqing and Zhu, Qiangkun and Gong, Fang},
title = {Comparisons of OCO-2 satellite derived XCO2 with in situ and modeled data over global ocean},
journal = {ACTA OCEANOLOGICA SINICA},
year = {2021},
volume = {40},
number = {4},
pages = {136-142},
doi = {https://doi.org/10.1007/s13131-021-1844-9}
}
|
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| Zhang, Q., Li, M., Wang, M., Mizzi, A.P., Huang, Y., Wei, C., Jin, J. and Gu, Q. | CO2 Flux over the Contiguous United States in 2016 Inverted by WRF-Chem/DART from OCO-2 XCO2 Retrievals | 2021 | REMOTE SENSING Vol. 13(15) |
article | DOI |
| Abstract: High spatial resolution carbon dioxide (CO2) flux inversion systems are needed to support the global stocktake required by the Paris Agreement and to complement the bottom-up emission inventories. Based on the work of Zhang, a regional CO2 flux inversion system capable of assimilating the column-averaged dry air mole fractions of CO2 (XCO2) retrieved from Orbiting Carbon Observatory-2 (OCO-2) observations had been developed. To evaluate the system, under the constraints of the initial state and boundary conditions extracted from the CarbonTracker 2017 product (CT2017), the annual CO2 flux over the contiguous United States in 2016 was inverted (1.08 Pg C yr(-1)) and compared with the corresponding posterior CO2 fluxes extracted from OCO-2 model intercomparison project (OCO-2 MIP) (mean: 0.76 Pg C yr(-1), standard deviation: 0.29 Pg C yr(-1), 9 models in total) and CT2017 (1.19 Pg C yr(-1)). The uncertainty of the inverted CO2 flux was reduced by 14.71% compared to the prior flux. The annual mean XCO2 estimated by the inversion system was 403.67 ppm, which was 0.11 ppm smaller than the result (403.78 ppm) simulated by a parallel experiment without assimilating the OCO-2 retrievals and closer to the result of CT2017 (403.29 ppm). Independent CO2 flux and concentration measurements from towers, aircraft, and Total Carbon Column Observing Network (TCCON) were used to evaluate the results. Mean bias error (MBE) between the inverted CO2 flux and flux measurements was 0.73 g C m(-2) d(-1), was reduced by 22.34% and 28.43% compared to those of the prior flux and CT2017, respectively. MBEs between the CO2 concentrations estimated by the inversion system and concentration measurements from TCCON, towers, and aircraft were reduced by 52.78%, 96.45%, and 75%, respectively, compared to those of the parallel experiment. The experiment proved that CO2 emission hotspots indicated by the inverted annual CO2 flux with a relatively high spatial resolution of 50 km consisted well with the locations of most major metropolitan/urban areas in the contiguous United States, which demonstrated the potential of combing satellite observations with high spatial resolution CO2 flux inversion system in supporting the global stocktake. |
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BibTeX:
@article{zhang21c,
author = {Zhang, Qinwei and Li, Mingqi and Wang, Maohua and Mizzi, Arthur Paul and Huang, Yongjian and Wei, Chong and Jin, Jiuping and Gu, Qianrong},
title = {CO2 Flux over the Contiguous United States in 2016 Inverted by WRF-Chem/DART from OCO-2 XCO2 Retrievals},
journal = {REMOTE SENSING},
year = {2021},
volume = {13},
number = {15},
doi = {https://doi.org/10.3390/rs13152996}
}
|
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| Zhang, L., Davis, K.J., Schuh, A.E., Jacobson, A.R., Pal, S., Cui, Y.Y., Baker, D., Crowell, S., Chevallier, F., Remaud, M., Liu, J., Weir, B., Philip, S., Johnson, M.S., Deng, F. and Basu, S. | Multi-Season Evaluation of CO2 Weather in OCO-2 MIP Models | 2022 | JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES Vol. 127(2) |
article | DOI |
| Abstract: The ability of current global models to simulate the transport of CO2 by mid-latitude, synopticscale weather systems (i.e., CO2 weather) is important for inverse estimates of regional and global carbon budgets but remains unclear without comparisons to targeted measurements. Here, we evaluate ten models that participated in the Orbiting Carbon Observatory-2 model intercomparison project (OCO-2 MIP version 9) with intensive aircraft measurements collected from the Atmospheric Carbon Transport (ACT)-America mission. We quantify model-data differences in the spatial variability of CO2 mole fractions, mean winds, and boundary layer depths in 27 mid-latitude cyclones spanning four seasons over the central and eastern United States. We find that the OCO-2 MIP models are able to simulate observed CO2 frontal differences with varying degrees of success in summer and spring, and most underestimate frontal differences in winter and autumn. The models may underestimate the observed boundary layer-to-free troposphere CO2 differences in spring and autumn due to model errors in boundary layer height. Attribution of the causes of model biases in other seasons remains elusive. Transport errors, prior fluxes, and/or inversion algorithms appear to be the primary cause of these biases since model performance is not highly sensitive to the CO2 data used in the inversion. The metrics presented here provide new benchmarks regarding the ability of atmospheric inversion systems to reproduce the CO2 structure of mid-latitude weather systems. Controlled experiments are needed to link these metrics more directly to the accuracy of regional or global flux estimates. Plain Language Summary Global flux estimate systems use CO(2 )observations, atmospheric transport models, CO2 flux models (emissions and absorption), and mathematical optimization methods to estimate biosphere-atmosphere CO2 exchange. Accurate representation of atmospheric transport is important for a reliable optimization of fluxes in these systems. We use intensive aircraft measurements of wind speed, boundary layer height, and horizontal and vertical differences of CO(2 )concentrations within 27 mid-latitude cyclones collected by the Atmospheric Carbon Transport (ACT)-America mission to evaluate the performance of ten global flux estimate systems from the Orbiting Carbon Observatory-2 model intercomparison project (OCO-2 MIP). We find the models can simulate observed horizontal CO2 differences between the warm and cold parts of cyclones with different degrees of success in summer and spring, but often underestimate the observed cross-frontal and vertical differences in CO2 in winter and autumn. The models may underestimate the CO2 differences between the boundary layer and the free troposphere due to model errors in boundary layer height and surface fluxes. These weather-oriented CO2 metrics provide benchmarks for testing simulations of the CO2 structure within cyclones. Future efforts are needed to link these metrics more directly to the accuracy of CO2 flux estimates. |
|||||
BibTeX:
@article{zhang22a,
author = {Zhang, Li and Davis, Kenneth J. and Schuh, Andrew E. and Jacobson, Andrew R. and Pal, Sandip and Cui, Yu Yan and Baker, David and Crowell, Sean and Chevallier, Frederic and Remaud, Marine and Liu, Junjie and Weir, Brad and Philip, Sajeev and Johnson, Matthew S. and Deng, Feng and Basu, Sourish},
title = {Multi-Season Evaluation of CO2 Weather in OCO-2 MIP Models},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
year = {2022},
volume = {127},
number = {2},
doi = {https://doi.org/10.1029/2021JD035457}
}
|
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| Zhao, F., Zeng, N., Asrar, G., Friedlingstein, P., Ito, A., Jain, A., Kalnay, E., Kato, E., Koven, C.D., Poulter, B., Rafique, R., Sitch, S., Shu, S., Stocker, B., Viovy, N., Wiltshire, A. and Zaehle, S. | Role of CO2, climate and land use in regulating the seasonal amplitude increase of carbon fluxes in terrestrial ecosystems: a multimodel analysis | {2016} | BIOGEOSCIENCES Vol. {13}({17}), pp. 5121-5137 |
article | DOI |
| Abstract: We examined the net terrestrial carbon flux to the atmosphere (F-TA/simulated by nine models from the TRENDY dynamic global vegetation model project for its seasonal cycle and amplitude trend during 1961-2012. While some models exhibit similar phase and amplitude compared to atmospheric inversions, with spring drawdown and autumn rebound, others tend to rebound early in summer. The model ensemble mean underestimates the magnitude of the seasonal cycle by 40% compared to atmospheric inversions. Global F-TA amplitude increase (19 +/- 8 %) and its decadal variability from the model ensemble are generally consistent with constraints from surface atmosphere observations. However, models disagree on attribution of this long-term amplitude increase, with factorial experiments attributing 83 +/- 56 %, 3 +/- 74 and 20 +/- 30% to rising CO2, climate change and land use/cover change, respectively. Seven out of the nine models suggest that CO2 fertilization is the strongest control - with the notable exception of VEGAS, which attributes approximately equally to the three factors. Generally, all models display an enhanced seasonality over the boreal region in response to high-latitude warming, but a negative climate contribution from part of the Northern Hemisphere temperate region, and the net result is a divergence over climate change effect. Six of the nine models show that land use/cover change amplifies the seasonal cycle of global F-TA: some are due to forest regrowth, while others are caused by crop expansion or agricultural intensification, as revealed by their divergent spatial patterns. We also discovered a moderate cross-model correlation between F-TA amplitude increase and increase in land carbon sink (R-2 = 0.61). Our results suggest that models can show similar results in some benchmarks with different underlying mechanisms; therefore, the spatial traits of CO2 fertilization, climate change and land use/cover changes are crucial in determining the right mechanisms in seasonal carbon cycle change as well as mean sink change. |
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BibTeX:
@article{zhao16a,
author = {Zhao, Fang and Zeng, Ning and Asrar, Ghassem and Friedlingstein, Pierre and Ito, Akihiko and Jain, Atul and Kalnay, Eugenia and Kato, Etsushi and Koven, Charles D. and Poulter, Ben and Rafique, Rashid and Sitch, Stephen and Shu, Shijie and Stocker, Beni and Viovy, Nicolas and Wiltshire, Andy and Zaehle, Sonke},
title = {Role of CO2, climate and land use in regulating the seasonal amplitude increase of carbon fluxes in terrestrial ecosystems: a multimodel analysis},
journal = {BIOGEOSCIENCES},
year = {2016},
volume = {13},
number = {17},
pages = {5121--5137},
doi = {https://doi.org/10.5194/bg-13-5121-2016}
}
|
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| Zheng, H., Li, Y., Chen, J., Wang, T., Huang, Q. and Sheng, Y. | Applying a dual optimization method to quantify carbon fluxes: recent progress in carbon flux inversion | {2014} | CHINESE SCIENCE BULLETIN Vol. {59}({2}), pp. 222-226 |
article | DOI |
| Abstract: The widely performed Bayesian synthesis inversion method (BSIM) utilizes prior carbon flux and atmospheric carbon dioxide observations to optimize the unknown flux. The prior flux is usually computed from ecological models with large biases. The BSIM is useful in solving the problem of insufficient data, but it will increase the inaccuracies in the estimates caused by the biased prior flux. In this study, we propose a dual optimization method (DOM) to introduce a set of scaling factors as new state variables to correct for the prior flux according to information on plant functional types. The DOM estimates the scaling factors and carbon flux simultaneously by minimizing the cost function. The statistical properties of the DOM, which compare favorably with the BSIM, are provided in this article. We tested the DOM through simulation experiments which represent a true ecosystem. The results, according to the root mean squared error, show that the DOM has a higher accuracy than the BSIM in flux estimates. |
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BibTeX:
@article{zheng14a,
author = {Zheng, Heng and Li, Yong and Chen, Jingming and Wang, Ting and Huang, Qing and Sheng, Yao},
title = {Applying a dual optimization method to quantify carbon fluxes: recent progress in carbon flux inversion},
journal = {CHINESE SCIENCE BULLETIN},
year = {2014},
volume = {59},
number = {2},
pages = {222--226},
doi = {https://doi.org/10.1007/s11434-013-0016-5}
}
|
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| Zheng, H., Li, Y., Chen, J.M., Wang, T., Huang, Q., Huang, W.X., Wang, L.H., Li, S.M., Yuan, W.P., Zheng, X., Zhang, S.P., Chen, Z.Q. and Jiang, F. | A global carbon assimilation system based on a dual optimization method | {2015} | BIOGEOSCIENCES Vol. {12}({4}), pp. 1131-1150 |
article | DOI |
| Abstract: Ecological models are effective tools for simulating the distribution of global carbon sources and sinks. However, these models often suffer from substantial biases due to inaccurate simulations of complex ecological processes. We introduce a set of scaling factors (parameters) to an ecological model on the basis of plant functional type (PFT) and latitudes. A global carbon assimilation system (GCAS-DOM) is developed by employing a dual optimization method (DOM) to invert the time-dependent ecological model parameter state and the net carbon flux state simultaneously. We use GCAS-DOM to estimate the global distribution of the CO2 flux on 1 degrees x 1 degrees grid cells for the period from 2001 to 2007. Results show that land and ocean absorb -3.63 +/- 0.50 and 1.82 +/- 0.16 Pg C yr(-1), respectively. North America, Europe and China contribute -0.98 +/- 0.15, -0.42 +/- 0.08 and 0.20 +/- 0.29 Pg C yr(-1), respectively. The uncertainties in the flux after optimization by GCAS-DOM have been remarkably reduced by more than 60 %. Through parameter optimization, GCAS-DOM can provide improved estimates of the carbon flux for each PFT. Coniferous forest (-0.97 +/- 0.27 Pg C yr(-1)) is the largest contributor to the global carbon sink. Fluxes of once-dominant deciduous forest generated by the Boreal Ecosystems Productivity Simulator (BEPS) are reduced to -0.78 +/- 0.23 Pg C yr(-1), the third largest carbon sink. |
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BibTeX:
@article{zheng15a,
author = {Zheng, H. and Li, Y. and Chen, J. M. and Wang, T. and Huang, Q. and Huang, W. X. and Wang, L. H. and Li, S. M. and Yuan, W. P. and Zheng, X. and Zhang, S. P. and Chen, Z. Q. and Jiang, F.},
title = {A global carbon assimilation system based on a dual optimization method},
journal = {BIOGEOSCIENCES},
year = {2015},
volume = {12},
number = {4},
pages = {1131--1150},
doi = {https://doi.org/10.5194/bg-12-1131-2015}
}
|
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| Zheng, T., French, N. and Baxter, M. | Development of the WRF-CO2 4DVar assimilation system [BibTeX] |
2016 | GEOSCIENTIFIC MODEL DEVELOPMENT | article | |
BibTeX:
@article{zheng16a,
author = {Zheng, Tao and French, Nancy and Baxter, Martin},
title = {Development of the WRF-CO2 4DVar assimilation system},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2016}
}
|
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| Zheng, T., Nassar, R. and Baxter, M. | Estimating power plant CO2 emission using OCO-2 XCO2 and high resolution WRF-Chem simulations | {2019} | ENVIRONMENTAL RESEARCH LETTERS Vol. {14}({8}) |
article | DOI |
| Abstract: Anthropogenic CO2 emission from fossil fuel combustion has major impacts on the global climate. The Orbiting Carbon Observatory 2 (OCO-2) observations have previously been used to estimate individual power plant emissions with a Gaussian plume model assuming constant wind fields. The present work assesses the feasibility of estimating power plant CO2 emission using high resolution chemistry transport model simulations with OCO-2 observation data. In the new framework, 1.33 km Weather Research and Forecasting-Chem (WRF)-Chem simulation results are used to calculate the Jacobian matrix, which is then used with the OCO-2 XCO2 data to obtain power plant daily mean emission rates, through a maximum likelihood estimation. We applied the framework to the seven OCO-2 observations of near mid-to-large coal burning power plants identified in Nassar et al (2017 Geophys. Res. Lett. 44, 10045-53). Our estimation results closely match the reported emission rates at the Westar power plant (Kansas, USA), with a reported value of 26.67 ktCO(2)/day, and our estimated value at 25.82-26.47 ktCO(2)/day using OCO-2 v8 data, and 22.09-22.80 ktCO(2)/day using v9 data. At Ghent, KY, USA, our estimations using three versions (v7, v8, and v9) range from 9.84-20.40 ktCO(2)/day, which are substantially lower than the reported value (29.17 ktCO(2)/day). We attribute this difference to diminished WRF-Chem wind field simulation accuracy. The results from the seven cases indicate that accurate estimation requires accurate meteorological simulations and high quality XCO2 data. In addition, the strength and orientation (relative to the OCO-2 ground track) of the XCO2 enhancement are important for accurate and reliable estimation. Compared with the Gaussian plume model based approach, the high resolution WRF-Chem simulation based approach provides a framework for addressing varying wind fields, and possible expansion to city level emission estimation. | |||||
BibTeX:
@article{zheng19a,
author = {Zheng, Tao and Nassar, Ray and Baxter, Martin},
title = {Estimating power plant CO2 emission using OCO-2 XCO2 and high resolution WRF-Chem simulations},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
publisher = {IOP PUBLISHING LTD},
year = {2019},
volume = {14},
number = {8},
doi = {https://doi.org/10.1088/1748-9326/ab25ae}
}
|
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| Zhou, Y., Williams, C.A., Lauvaux, T., Davis, K.J., Feng, S., Baker, I., Denning, S. and Wei, Y. | A Multiyear Gridded Data Ensemble of Surface Biogenic Carbon Fluxes for North America: Evaluation and Analysis of Results | {2020} | JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES Vol. {125}({2}) |
article | DOI |
| Abstract: Accurate and fine-scale estimates of biogenic carbon fluxes are critical for measuring and monitoring the biosphere's responses and feedback to the climate system. Currently available data products from flux towers and model-intercomparison projects struggle to adequately represent spatiotemporal dynamics of surface biogenic carbon fluxes, and to quantify their uncertainties, which also are crucial to atmospheric inversion systems. To address these gaps, we introduce a new perturbed-parameter model ensemble with the CASA model to estimate surface biogenic carbon fluxes at monthly and 3-hourly scales for North America at similar to 500-m and 5-km resolutions. We first use the Extended Fourier Amplitude Sensitivity Testing to choose the three most sensitive parameters to be perturbed, maximum light use efficiency (E-max), optimal temperature of photosynthesis (T-opt), and temperature response of respiration (Q(10)). The initial range for each parameter is broadly sampled for the L1 ensemble, but then we pruned E-max with site-level primary productivity to derive an L2 ensemble with narrower uncertainty ranges. Ensembles are strongly correlated with site-level results at both monthly and 3-hourly scales, and the spread across L1/L2 ensemble members encompasses the range of AmeriFlux observations. Monthly variability in the L2 ensemble mean is 85% of the observed variability. The L2 ensemble outperforms diverse data products with the highest Taylor skill scores at diurnal to annual scales. The ensemble's seasonality agrees well with other models for most biome types and in high and middle latitudes, but inconsistencies are found in subtropical and tropical ecoregions and for annual totals over North America. | |||||
BibTeX:
@article{zhou20a,
author = {Zhou, Yu and Williams, Christopher A. and Lauvaux, Thomas and Davis, Kenneth J. and Feng, Sha and Baker, Ian and Denning, Scott and Wei, Yaxing},
title = {A Multiyear Gridded Data Ensemble of Surface Biogenic Carbon Fluxes for North America: Evaluation and Analysis of Results},
journal = {JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES},
publisher = {AMER GEOPHYSICAL UNION},
year = {2020},
volume = {125},
number = {2},
doi = {https://doi.org/10.1029/2019JG005314}
}
|
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| Zhu, C. and Yoshikawa-Inoue, H. | Temporal variations in atmospheric CO_2 on Rishiri Island in 2006--2013: responses of the interannual variation in amplitude to climate and the terrestrial sink in East Asia [BibTeX] |
2014 | Earth System Dynamics Discussions Vol. 5, pp. 809-848 |
article | |
BibTeX:
@article{zhu14a,
author = {Zhu, C. and Yoshikawa-Inoue, H.},
title = {Temporal variations in atmospheric CO_2 on Rishiri Island in 2006--2013: responses of the interannual variation in amplitude to climate and the terrestrial sink in East Asia},
journal = {Earth System Dynamics Discussions},
year = {2014},
volume = {5},
pages = {809-848}
}
|
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| Zhu, Q. | Improving the quantification of terrestrial ecosystem carbon budget with models of biogeochemistry and atmospheric transport and chemistry using in situ and satellite … | 2014 | School: Purdue University | phdthesis | URL |
| Abstract: To better understand the role of terrestrial ecosystems in the global carbon cycle and their feedbacks to the global climate system, the predictability of ecosystem models that are used for quantifying net carbon exchanges between the terrestrial biosphere and the atmosphere … | |||||
BibTeX:
@phdthesis{zhu14b,
author = {Qing Zhu},
title = {Improving the quantification of terrestrial ecosystem carbon budget with models of biogeochemistry and atmospheric transport and chemistry using in situ and satellite …},
school = {Purdue University},
year = {2014},
url = {https://search.proquest.com/openview/588e8297bebcaeb6e74d70e81f172192/1?pq-origsite=gscholar&cbl=18750&diss=y}
}
|
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| Zhu, Q., Zhuang, Q., Henze, D., Bowman, K., Chen, M., Liu, Y., He, Y., Matsueda, H., Machida, T., Sawa, Y. and Oechel, W. | Constraining terrestrial ecosystem CO2 fluxes by integrating models of biogeochemistry and atmospheric transport and data of surface carbon fluxes and atmospheric CO2 concentrations | 2014 | ATMOSPHERIC CHEMISTRY AND PHYSICS | article | URL |
| Abstract: Regional net carbon fluxes of terrestrial ecosystems could be estimated with either biogeochemistry models by assimilating surface carbon flux measurements or atmospheric CO 2 inversions by assimilating observations of atmospheric CO 2 concentrations. Here we … | |||||
BibTeX:
@article{zhu14c,
author = {Q. Zhu and Q. Zhuang and D. Henze and K. Bowman and M. Chen and Y. Liu and Y. He and H. Matsueda and T. Machida and Y. Sawa and W. Oechel},
title = {Constraining terrestrial ecosystem CO2 fluxes by integrating models of biogeochemistry and atmospheric transport and data of surface carbon fluxes and atmospheric CO2 concentrations},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2014},
url = {https://acp.copernicus.org/preprints/acp-2014-498/}
}
|
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| Zhu, B., Bai, Y., He, X., Chen, X., Li, T. and Gong, F. | Long-Term Changes in the Land-Ocean Ecological Environment in Small Island Countries in the South Pacific: A Fiji Vision | 2021 | REMOTE SENSING Vol. 13(18) |
article | DOI |
| Abstract: Small island countries in the South Pacific are ecologically fragile areas, vulnerable to climate change, and the long-term ecological changes in the sea and land have an important impact on their sustainable development. This study takes Fiji, a typical small island country in the South Pacific, as an example, to analyze the change and connection of marine and terrestrial ecosystem environments based on 30 years of multi-source, satellite, remote-sensing data. From 1991 to 2019, according to the change in forest area in Fiji, three stages were delineated: first was a period of stability, then a decrease, and then a recovery in recent years. From 1991 to 2002, Fiji's vegetation accounted for 73% of the total area; sea environment surrounding the islands, such as sea level height and sea surface temperature, were relatively low, with high water transparency. From 2002 to 2014, with the development of forestry and tourism, vegetation decreased by 6.89% and bare land increased, which changes the runoff erosion in the drainage basin; correspondingly, the chlorophyll a concentration in three major estuaries was found to be slightly increased with low water transparency. Meanwhile, coupled with the rising sea temperature, the area of Fiji's coral reefs shrank significantly, with 51.13% of the total loss of coral reefs occurring in the Vanua Levu, where bare land and runoff were more distributed in its drainage basin. From 2014 to 2019, Fiji's vegetation and coral reef areas recovered from the former stage; affected by short-term climate oscillations such as El Nino-Southern Oscillation (ENSO), the sea surface temperature showed a significant abnormal drop and the water transparency decreased. In the past 30 years (1993-2018), the sea level rise rate around Fiji reached 4 mm/year, and the temperature increased by 0.3 degrees C, which threatens the coastal ecosystem environment, including coral reefs and mangrove; inappropriate land-use change would worsen the situation in these ecologically fragile areas. |
|||||
BibTeX:
@article{zhu21a,
author = {Zhu, Bozhong and Bai, Yan and He, Xianqiang and Chen, Xiaoyan and Li, Teng and Gong, Fang},
title = {Long-Term Changes in the Land-Ocean Ecological Environment in Small Island Countries in the South Pacific: A Fiji Vision},
journal = {REMOTE SENSING},
year = {2021},
volume = {13},
number = {18},
doi = {https://doi.org/10.3390/rs13183740}
}
|
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| Zhuravlev, R., Khattatov, B., Kiryushov, B. and Maksyutov, S. | A novel approach to estimation of time-variable surface sources and sinks of carbon dioxide using empirical orthogonal functions and the Kalman filter | 2011 | ATMOSPHERIC CHEMISTRY AND PHYSICS | article | URL |
| Abstract: In this work we propose an approach to solving a source estimation problem based on representation of carbon dioxide surface emissions as a linear combination of a finite number of pre-computed empirical orthogonal functions (EOFs). We used National Institute … | |||||
BibTeX:
@article{zhuravlev11a,
author = {R. Zhuravlev and B. Khattatov and B. Kiryushov and S. Maksyutov},
title = {A novel approach to estimation of time-variable surface sources and sinks of carbon dioxide using empirical orthogonal functions and the Kalman filter},
journal = {ATMOSPHERIC CHEMISTRY AND PHYSICS},
year = {2011},
url = {https://acp.copernicus.org/articles/11/10305/2011/}
}
|
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| Zobitz, J.M. | Quantifying the Atmospheric Impact and Carbon Footprint of an Urban Biomass Incinerator [BibTeX] |
2009 | SCIENCE EDUCATION & CIVIC ENGAGEMENT | article | |
BibTeX:
@article{zobitz09b,
author = {John M. Zobitz},
title = {Quantifying the Atmospheric Impact and Carbon Footprint of an Urban Biomass Incinerator},
journal = {SCIENCE EDUCATION & CIVIC ENGAGEMENT},
year = {2009}
}
|
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| Zscheischler, J., Mahecha, M.D., von Buttlar, J., Harmeling, S., Jung, M., Rammig, A., Randerson, J.T., Schoelkopf, B., Seneviratne, S.I., Tomelleri, E., Zaehle, S. and Reichstein, M. | A few extreme events dominate global interannual variability in gross primary production | {2014} | ENVIRONMENTAL RESEARCH LETTERS Vol. {9}({3}) |
article | DOI |
| Abstract: Understanding the impacts of climate extremes on the carbon cycle is important for quantifying the carbon-cycle climate feedback and highly relevant to climate change assessments. Climate extremes and fires can have severe regional effects, but a spatially explicit global impact assessment is still lacking. Here, we directly quantify spatiotemporal contiguous extreme anomalies in four global data sets of gross primary production (GPP) over the last 30 years. We find that positive and negative GPP extremes occurring on 7% of the spatiotemporal domain explain 78% of the global interannual variation in GPP and a significant fraction of variation in the net carbon flux. The largest thousand negative GPP extremes during 1982-2011 (4.3% of the data) account for a decrease in photosynthetic carbon uptake of about 3.5 Pg C yr(-1), with most events being attributable to water scarcity. The results imply that it is essential to understand the nature and causes of extremes to understand current and future GPP variability. |
|||||
BibTeX:
@article{zscheischler14a,
author = {Zscheischler, Jakob and Mahecha, Miguel D. and von Buttlar, Jannis and Harmeling, Stefan and Jung, Martin and Rammig, Anja and Randerson, James T. and Schoelkopf, Bernhard and Seneviratne, Sonia I. and Tomelleri, Enrico and Zaehle, Soenke and Reichstein, Markus},
title = {A few extreme events dominate global interannual variability in gross primary production},
journal = {ENVIRONMENTAL RESEARCH LETTERS},
year = {2014},
volume = {9},
number = {3},
doi = {https://doi.org/10.1088/1748-9326/9/3/035001}
}
|
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| Zscheischler, J. | A global analysis of extreme events and consequences for the terrestrial carbon cycle [BibTeX] |
2014 | School: Humboldt University of Berlin | phdthesis | |
BibTeX:
@phdthesis{zscheischler14b,
author = {Jakob Zscheischler},
title = {A global analysis of extreme events and consequences for the terrestrial carbon cycle},
school = {Humboldt University of Berlin},
year = {2014}
}
|
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| Zwaaftink, C.D.G., Henne, S., Thompson, R.L., Dlugokencky, E.J., Machida, T., Paris, J.-D., Sasakawa, M., Segers, A., Sweeney, C. and Stohl, A. | Three-dimensional methane distribution simulated with FLEXPART 8-CTM-1.1 constrained with observation data | {2018} | GEOSCIENTIFIC MODEL DEVELOPMENT Vol. {11}({11}), pp. {4469-4487} |
article | DOI |
| Abstract: A Lagrangian particle dispersion model, the FLEXible PARTicle dispersion chemical transport model (FLEXPART CTM), is used to simulate global three-dimensional fields of trace gas abundance. These fields are constrained with surface observation data through nudging, a data assimilation method, which relaxes model fields to observed values. Such fields are of interest to a variety of applications, such as inverse modelling, satellite retrievals, radiative forcing models and estimating global growth rates of greenhouse gases. Here, we apply this method to methane using 6 million model particles filling the global model domain. For each particle, methane mass tendencies due to emissions (based on several inventories) and loss by reaction with OH, Cl and O(D-1), as well as observation data nudging were calculated. Model particles were transported by mean, turbulent and convective transport driven by 1 degrees x 1 degrees ERA-Interim meteorology. Nudging is applied at 79 surface stations, which are mostly included in the World Data Centre for Greenhouse Gases (WDCGG) database or the Japan-Russia Siberian Tall Tower Inland Observation Network (JR-STATION) in Siberia. For simulations of 1 year (2013), we perform a sensitivity analysis to show how nudging settings affect modelled concentration fields. These are evaluated with a set of independent surface observations and with vertical profiles in North America from the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL), and in Siberia from the Airborne Extensive Regional Observations in SIBeria (YAK-AEROSIB) and the National Institute for Environmental Studies (NIES). FLEXPART CTM results are also compared to simulations from the global Eulerian chemistry Transport Model version 5 (TM5) based on optimized fluxes. Results show that nudging strongly improves modelled methane near the surface, not only at the nudging locations but also at independent stations. Mean bias at all surface locations could be reduced from over 20 to less than 5 ppb through nudging. Near the surface, FLEXPART CTM, including nudging, appears better able to capture methane molar mixing ratios than TM5 with optimized fluxes, based on a larger bias of over 13 ppb in TM5 simulations. The vertical profiles indicate that nudging affects model methane at high altitudes, yet leads to little improvement in the model results there. Averaged from 19 aircraft profile locations in North America and Siberia, root mean square error (RMSE) changes only from 16.3 to 15.7 ppb through nudging, while the mean absolute bias increases from 5.3 to 8.2 ppb. The performance for vertical profiles is thereby similar to TM5 simulations based on TM5 optimized fluxes where we found a bias of 5 ppb and RMSE of 15.9 ppb. With this rather simple model setup, we thus provide three-dimensional methane fields suitable for use as boundary conditions in regional inverse modelling as a priori information for satellite retrievals and for more accurate estimation of mean mixing ratios and growth rates. The method is also applicable to other long-lived trace gases. |
|||||
BibTeX:
@article{zwaaftink18a,
author = {Zwaaftink, Christine D. Groot and Henne, Stephan and Thompson, Rona L. and Dlugokencky, Edward J. and Machida, Toshinobu and Paris, Jean-Daniel and Sasakawa, Motoki and Segers, Arjo and Sweeney, Colm and Stohl, Andreas},
title = {Three-dimensional methane distribution simulated with FLEXPART 8-CTM-1.1 constrained with observation data},
journal = {GEOSCIENTIFIC MODEL DEVELOPMENT},
year = {2018},
volume = {11},
number = {11},
pages = {4469-4487},
doi = {https://doi.org/10.5194/gmd-11-4469-2018}
}
|
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