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GMD Publications for 2017

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C
Cullis, Patrick, Chance Sterling, Emrys Hall, Allen Jordan, Bryan Johnson and Russell Schnell, (2017), Pop Goes the Balloon!: What Happens when a Weather Balloon Reaches 30,000 m asl?, Bulletin of the American Meteorological Society, 98, 2, 216-217, 10.1175/BAMS-D-16-0094.1

Abstract

Did you ever wonder what happens when a rubber weather balloon reaches maximum altitude and bursts? A weather balloon carrying a radiosonde or ozonesonde released at the Earth’s surface is generally about 1.5 m in diameter at launch. At 30,000 m asl it has expanded to about 10 m in diameter and bursts at temperatures often colder than –40°C, sometimes as cold as –75°C. With a volume 100 times greater than when the balloon was released at ground level, the deflation is not a gentle leak but an explosion!

The sequence of photos on the opposite page of an exploding rubber weather balloon were taken with a GoPro Hero4 Black camera with a resolution of 1,920 x 1,440 pixel frames operating at 48 frames per second. As such, the time between each frame is 0.02 seconds. The camera was suspended 10 m below the balloon, which burst at 29,690 m asl and –50°C. The camera was returned to Earth on a biodegradable plastic parachute used with sonde launches. A GPS on the radiosonde allowed for recovery of the sonde and camera launched from near Boulder, Colorado.

G
Godin-Beekmann, Sophie, Irina Petropavloskikh, Stefan Reis, Paul Newman, Wolfgang Steinbrecht, Markus Rex, Michelle L. Santee, Richard S. Eckman, Xiandong Zheng, Matthew B. Tully, David S. Stevenson, Paul Young, John Pyle, Mark Weber, Johanna Tamminen, Gina Mills, Alkis F. Bais, Clare Heaviside and Christos Zerefos, (2017), The Quadrennial Ozone Symposium 2016, Advances in Atmospheric Sciences, 34, 3, 283-288, 10.1007/s00376-016-6309-2

Abstract

The 2016 Quadrennial Ozone Symposium (QOS-2016) was held on 4–9 September 2016 in Edinburgh, UK. The Symposium was organized by the International Ozone Commission (IO3C), the NERC Centre for Ecology & Hydrology and the University of Edinburgh, and was co-sponsored by the International Union of Geodesy and Geophysics, the International Association of Meteorology and Atmospheric Sciences, and the World Meteorological Organization. More than 300 participants from 39 different countries attended the Symposium (Fig. 1). There were 6 keynote talks, 75 oral presentations and 270 poster presentations. QOS-2016 covered the breadth and depth of atmospheric ozone observations and research. Key topics included: stratospheric and tropospheric ozone observations and modelling; interactions between ozone, atmospheric chemistry and climate; ozone measurement techniques; and effects on human health, ecosystems, and agriculture. Engagement with stakeholders and policymakers was another key feature of QOS2016. The Symposium was opened by L. HEATHWAITE, Chief Scientific Advisor of Rural Affairs and Environment to the Scottish Government, and the Symposium’s final day included two talks on the “Future challenges for stratospheric and tropospheric ozone”, followed by a moderated panel discussion on policy issues related to atmospheric ozone.

J
Jeong, Seongeun, Xinguang Cui, Donald R. Blake, Ben Miller, Stephen A. Montzka, Arlyn Andrews, Abhinav Guha, Philip Martien, Ray P. Bambha, Brian LaFranchi, Hope A. Michelsen, Craig B. Clements, Pierre Glaize and Marc L. Fischer, (2017), Estimating methane emissions from biological and fossil-fuel sources in the San Francisco Bay Area, Geophysical Research Letters, , , 10.1002/2016GL071794

Abstract

We present the first sector-specific analysis of methane (CH4) emissions from the San Francisco Bay Area (SFBA) using CH4 and volatile organic compound (VOC) measurements from six sites during September – December 2015. We apply a hierarchical Bayesian inversion to separate the biological from fossil-fuel (natural gas and petroleum) sources using the measurements of CH4 and selected VOCs, a source-specific 1 km CH4 emission model, and an atmospheric transport model. We estimate that SFBA CH4 emissions are 166–289 Gg CH4/yr (at 95% confidence), 1.3–2.3 times higher than a recent inventory with much of the underestimation from landfill. Including the VOCs, 82 ± 27% of total posterior median CH4 emissions are biological and 17 ± 3% fossil fuel, where landfill and natural gas dominate the biological and fossil-fuel CH4 of prior emissions, respectively.

L
Leonard, Mark, Irina Petropavlovskikh, Meiyun Lin, Audra McClure-Begley, Bryan J. Johnson, Samuel J. Oltmans and David Tarasick, (2017), An assessment of 10-year NOAA aircraft-based tropospheric ozone profiling in Colorado, Atmospheric Environment, 158, 116-127, 10.1016/j.atmosenv.2017.03.013

Abstract

The Global Greenhouse Gas Reference Network Aircraft Program at NOAA has sampled ozone and other atmospheric trace constituents in North America for over a decade (2005-present). The method to derive tropospheric ozone climatology from the light aircraft measurements equipped with the 2B Technology instruments is described in this paper. Since ozone instruments at most of aircraft locations are flown once a month, this raises the question of whether the sampling frequency allows for deriving a climatology that can adequately represent ozone seasonal and vertical variability over various locations. Here we interpret the representativeness of the tropospheric ozone climatology derived from these under-sampled observations using hindcast simulations conducted with the Geophysical Fluid Dynamics Laboratory chemistry-climate model (GFDL-AM3). We first focus on ozone measurements from monthly aircraft profiles over the Front Range of Colorado and weekly ozonesondes launched in Boulder, Colorado. The climatology is presented as monthly values separated in 5th, 25th, 50th, 75th, 95th percentiles, and averaged at three vertical layers: lower (1.6–3 km), middle (3–6 km), and upper (6–8 km) troposphere. The aircraft-based climatology is compared to the climatology derived from the nearest located ozonesondes launched from Boulder, Colorado, from GFDL-AM3 co-sampled in time with in-situ observations, and from GFDL-AM3 continuous 3-h samples. Based on these analyses, we recommend the sampling frequency to obtain adequate representation of ozone climatology in the free troposphere. The 3-h sampled AM3 model is used as a benchmark reference for the under-sampled time series. We find that the minimal number of soundings required per month for the all altitude bins (1.6–3, 3–6, and 6–8 km) to sufficiently match the 95% confidence level of the fully sampled monthly ozone means vary between 3 and 5 sounding per month, except in August with a minimum of 6 soundings per month. The middle altitude bin required the least number of samplings per month. We determine the reasonably good agreement between the ozonesondes and aircraft measurements near Boulder suggest that valuable climatologies could be developed from the aircraft sites where no ozonesondes exist even though the aircraft measurements are more limited in number than the ozonesondes. When averaged over a number of years the aircraft data provide valuable information. More frequent sampling could tell us more but the measurements given would indicate that they can provide interesting climatological results.

R
Ray, Eric A., Fred L. Moore, James W. Elkins, Karen Rosenlof, Johannes Laube, Thomas Röckmann, Daniel R. Marsh and Arlyn E. Andrews, (2017), Quantification of the SF6 Lifetime Based on Mesospheric Loss Measured in the Stratospheric Polar Vortex , Journal of Geophysical Research: Atmospheres, , , 10.1002/2016JD026198

Abstract

Sulfur hexafluoride (SF6) is a greenhouse gas with one of the highest radiative efficiencies in the atmosphere as well as an important indicator of transport time scales in the stratosphere. The current widely used estimate of the atmospheric lifetime of SF6 is 3200 years. In this study we use in situ measurements in the 2000 Arctic polar vortex that sampled air with up to 50% SF6 loss to calculate an SF6 lifetime. Comparison of these measurements with output from the Whole Atmosphere Community Climate Model (WACCM) show that WACCM transport into the vortex is accurate and that an important SF6 loss mechanism, believed to be electron attachment, is missing in the model. Based on the measurements and estimates of the size of the vortex, we calculate an SF6 lifetime of 850 years with an uncertainty range of 580-1400 years. The amount of SF6 loss is shown to be consistent with that of HFC-227ea, which has a lifetime of 670-780 years, adding independent support to our new SF6 lifetime estimate. Based on the revised lifetime the global warming potential of SF6 will decrease only slightly for short time horizons (<100 years), but will decrease substantially for time horizons longer than 2000 years. Also, the use of SF6 measurements as an indicator of transport time scales in the stratosphere clearly must account for potential influence from polar vortex air.

S
Schmale, Julia, Silvia Henning, Bas Henzing, Helmi Keskinen, Karine Sellegri, Jurgita Ovadnevaite, Aikaterini Bougiatioti, Nikos Kalivitis, Iasonas Stavroulas, Anne Jefferson, Minsu Park, Patrick Schlag, Adam Kristensson, Yoko Iwamoto, Kirsty Pringle, Carly Reddington, Pasi Aalto, Mikko Äijälä, Urs Baltensperger, Jakub Bialek, Wolfram Birmili, Nicolas Bukowiecki, Mikael Ehn, Ann Mari Fjæraa, Markus Fiebig, Göran Frank, Roman Fröhlich, Arnoud Frumau, Masaki Furuya, Emanuel Hammer, Liine Heikkinen, Erik Herrmann, Rupert Holzinger, Hiroyuki Hyono, Maria Kanakidou, Astrid Kiendler-Scharr, Kento Kinouchi, Gerard Kos, Markku Kulmala, Nikolaos Mihalopoulos, Ghislain Motos, Athanasios Nenes, Colin O’Dowd, Mikhail Paramonov, Tuukka Petäjä, David Picard, Laurent Poulain, André Stephan Henry Prévôt, Jay Slowik, Andre Sonntag, Erik Swietlicki, Birgitta Svenningsson, Hiroshi Tsurumaru, Alfred Wiedensohler, Cerina Wittbom, John A. Ogren, Atsushi Matsuki, Seong Soo Yum, Cathrine Lund Myhre, Ken Carslaw, Frank Stratmann and Martin Gysel, (2017), Collocated observations of cloud condensation nuclei, particle size distributions, and chemical composition, Scientific Data, 4, 170003, 10.1038/sdata.2017.3

Abstract

Cloud condensation nuclei (CCN) number concentrations alongside with submicrometer particle number size distributions and particle chemical composition have been measured at atmospheric observatories of the Aerosols, Clouds, and Trace gases Research InfraStructure (ACTRIS) as well as other international sites over multiple years. Here, harmonized data records from 11 observatories are summarized, spanning 98,677 instrument hours for CCN data, 157,880 for particle number size distributions, and 70,817 for chemical composition data. The observatories represent nine different environments, e.g., Arctic, Atlantic, Pacific and Mediterranean maritime, boreal forest, or high alpine atmospheric conditions. This is a unique collection of aerosol particle properties most relevant for studying aerosol-cloud interactions which constitute the largest uncertainty in anthropogenic radiative forcing of the climate. The dataset is appropriate for comprehensive aerosol characterization (e.g., closure studies of CCN), model-measurement intercomparison and satellite retrieval method evaluation, among others. Data have been acquired and processed following international recommendations for quality assurance and have undergone multiple stages of quality assessment.

Schmeisser, Lauren, Elisabeth Andrews, John A. Ogren, Patrick Sheridan, Anne Jefferson, Sangeeta Sharma, Jeong Eun Kim, James P. Sherman, Mar Sorribas, Ivo Kalapov, Todor Arsov, Christo Angelov, Olga L. Mayol-Bracero, Casper Labuschagne, Sang-Woo Kim, András Hoffer, Neng-Heui Lin, Hao-Ping Chia, Michael Bergin, Junying Sun, Peng Liu and Hao Wu, (2017), Classifying aerosol type using in situ surface spectral aerosol optical properties, Atmospheric Chemistry and Physics Discussions, , 1-37, 10.5194/acp-2017-38

Abstract

Knowledge of aerosol size and composition is important for determining radiative forcing effects of aerosols, identifying aerosol sources, and improving aerosol satellite retrieval algorithms. The ability to extrapolate aerosol size and composition, or type, from intensive aerosol optical properties can help expand the current knowledge of spatio-temporal variability of aerosol type globally, particularly where chemical composition measurements do not exist concurrently with optical property measurements. This study uses medians of scattering Ångström exponent (SAE), absorption Ångström exponent (AAE) and single scattering albedo (SSA) from 24 stations within the NOAA federated aerosol network to infer aerosol type using previously published aerosol classification schemes.

Three methods are implemented to obtain a best estimate of dominant aerosol type at each station using aerosol optical properties. The first method plots station medians into an AAE vs. SAE plot space, so that a unique combination of intensive properties corresponds with an aerosol type. The second typing method expands on the first by introducing a multivariate cluster analysis, which aims to group stations with similar optical characteristics, and thus similar dominant aerosol type. The third and final classification method pairs 3-day backward air mass trajectories with median aerosol optical properties to explore the relationship between trajectory origin (proxy for likely aerosol type) and aerosol intensive parameters, while allowing for multiple dominant aerosol types at each station.

The three aerosol classification methods have some common, and thus robust, results. In general, estimating dominant aerosol type using optical properties is best suited for site locations with a stable and homogenous aerosol population, particularly continental polluted (carbonaceous aerosol), marine polluted (carbonaceous aerosol mixed with sea salt), and continental dust/biomass sites (dust and carbonaceous aerosol); however, current classification schemes perform poorly when predicting dominant aerosol type at remote marine and Arctic sites, and at stations with more complex locations and topography where variable aerosol populations are not well represented by median optical properties. Although the aerosol classification methods presented here provide new ways to reduce ambiguity in typing schemes, there is more work needed to find aerosol typing methods that are useful for a larger range of geographic locations and aerosol populations.

Sorribas, M., J.A. Adame, E. Andrews and M. Yela, (2017), An anomalous African dust event and its impact on aerosol radiative forcing on the Southwest Atlantic coast of Europe in February 2016, Science of the Total Environment, 583, 269-279, 10.1016/j.scitotenv.2017.01.064

Abstract

A desert dust (DD) event that had its origin in North Africa occurred on the 20th–23rd of February 2016. The dust transport phenomenon was exceptional because of its unusual intensity during the coldest season. A historical dataset (2006–2015) of February meteorological scenarios using ECMWF fields, meteorological parameters, aerosol optical properties, surface O3 and AOD retrieved from MODIS at the El Arenosillo observatory (southwestern Spain) were analysed and compared with the levels during the DD event to highlight its exceptionality. Associated with a low-pressure system in western North Africa, flows transported air from the Sahel to Algeria and consequently increased temperatures from the surface to 700 hPa by up to 7–9 °C relative to the last decade. These conditions favoured the formation of a Saharan air layer. Dust was transported to the north and reached the Western Mediterranean Basin and the Iberian Peninsula. The arrival of the DD event at El Arenosillo did not affect the surface weather conditions or ozone but did impact the aerosol radiative forcing at the top of atmosphere (RFTOA). Aerosol radiative properties did not change relative to historical; however, the particle size and the amount of the aerosol were significantly higher. The DD event caused an increase (in absolute terms) of the mean aerosol RFTOA to a value of − 8.1 W m− 2 (long-term climatological value ~ − 1.5 W m− 2). The aerosol RFTOA was not very large relative other DD episodes; however, our analysis of the historical data concluded that the importance of this DD event lay in the month of occurrence. European phenological datasets related to extreme atmospheric events predominantly reflect changes that are probably associated with climate change. This work is an example of this phenomenon, showing an event that occurred in a hotspot, the Saharan desert, and its impact two thousand km away.

Stauffer, Ryan M., Anne M. Thompson, Samuel J. Oltmans and Bryan J. Johnson, (2017), Tropospheric ozonesonde profiles at long-term U.S. monitoring sites: 2. Links between Trinidad Head, CA, profile clusters and inland surface ozone measurements, Journal of Geophysical Research: Atmospheres, 122, 2, 1261-1280, 10.1002/2016JD025254

Abstract

Much attention has been focused on the transport of ozone (O3) to the western U.S., particularly given the latest revision of the National Ambient Air Quality Standard to 70 parts per billion by volume (ppbv) of O3. This makes quantifying the contributions of stratosphere-to-troposphere exchange, local pollution, and pollution transport to this region essential. To evaluate free-tropospheric and surface O3 in the western U.S., we use self-organizing maps to cluster 18 years of ozonesonde profiles from Trinidad Head, CA. Three of nine O3 mixing ratio profile clusters exhibit thin laminae of high O3 above Trinidad Head. The high O3 layers are located between 1 and 6 km above mean sea level and reside above an inversion associated with a northern location of the Pacific subtropical high. Ancillary data (reanalyses, trajectories, and remotely sensed carbon monoxide) help identify the high O3 sources in one cluster, but distinguishing mixed influences on the elevated O3 in other clusters is difficult. Correlations between the elevated tropospheric O3 and surface O3 at high-altitude monitors at Lassen Volcanic and Yosemite National Parks, and Truckee, CA, are marked and long lasting. The temporal correlations likely result from a combination of transport of baseline O3 and covarying meteorological parameters. Days corresponding to the high O3 clusters exhibit hourly surface O3 anomalies of +5–10 ppbv compared to a climatology; the positive anomalies can last up to 3 days after the ozonesonde profile. The profile and surface O3 links demonstrate the importance of regular ozonesonde profiling at Trinidad Head.

T
Telg, Hagen, Daniel M. Murphy, Timothy S. Bates, James E. Johnson, Patricia K. Quinn, Fabio Giardi and Ru-Shan Gao, (2017), A practical set of miniaturized instruments for vertical profiling of aerosol physical properties, Aerosol Science and Technology, , 1-9, 10.1080/02786826.2017.1296103

Abstract

n situ atmospheric aerosol measurements have been performed from a Manta unmanned aircraft system (UAS) using recently developed miniaturized aerosol instruments. Flights were conducted up to an altitude of 3000 m (AMSL) during spring 2015 in Ny-Ålesund, Svalbard, Norway. We use these flights to demonstrate a practical set of miniaturized instruments that can be deployed onboard small UASs and can provide valuable information on ambient aerosol. Measured properties include size-resolved particle number concentrations, aerosol absorption coefficient, relative humidity, and direct sun intensity. From these parameters, it is possible to derive a comprehensive set of aerosol optical properties: aerosol optical depth, single scattering albedo, and asymmetry parameter. The combination of instruments also allows us to determine the aerosol hygroscopicity.

W
Werner, Bodo, Jochen Stutz, Max Spolaor, Lisa Scalone, Rasmus Raecke, James Festa, Santo Fedele Colosimo, Ross Cheung, Catalina Tsai, Ryan Hossaini, Martyn P. Chipperfield, Giorgio S. Taverna, Wuhu Feng, James W. Elkins, David W. Fahey, Ru-Shan Gao, Eric J. Hintsa, Troy D. Thornberry, Fred L. Moore, Maria A. Navarro, Elliot Atlas, Bruce C. Daube, Jasna Pittman, Steve Wofsy and Klaus Pfeilsticker, (2017), Probing the subtropical lowermost stratosphere and the tropical upper troposphere and tropopause layer for inorganic bromine, Atmospheric Chemistry and Physics, 17, 2, 1161-1186, 10.5194/acp-17-1161-2017

Abstract

We report measurements of CH4 (measured in situ by the Harvard University Picarro Cavity Ringdown Spectrometer (HUPCRS) and NOAA Unmanned Aircraft System Chromatograph for Atmospheric Trace Species (UCATS) instruments), O3 (measured in situ by the NOAA dual-beam ultraviolet (UV) photometer), NO2, BrO (remotely detected by spectroscopic UV–visible (UV–vis) limb observations; see the companion paper of Stutz et al., 2016), and of some key brominated source gases in whole-air samples of the Global Hawk Whole Air Sampler (GWAS) instrument within the subtropical lowermost stratosphere (LS) and the tropical upper troposphere (UT) and tropopause layer (TTL). The measurements were performed within the framework of the NASA-ATTREX (National Aeronautics and Space Administration – Airborne Tropical Tropopause Experiment) project from aboard the Global Hawk (GH) during six deployments over the eastern Pacific in early 2013. These measurements are compared with TOMCAT/SLIMCAT (Toulouse Off-line Model of Chemistry And Transport/Single Layer Isentropic Model of Chemistry And Transport) 3-D model simulations, aiming at improvements of our understanding of the bromine budget and photochemistry in the LS, UT, and TTL.

Changes in local O3 (and NO2 and BrO) due to transport processes are separated from photochemical processes in intercomparisons of measured and modeled CH4 and O3. After excellent agreement is achieved among measured and simulated CH4 and O3, measured and modeled [NO2] are found to closely agree with  ≤  15 ppt in the TTL (which is the detection limit) and within a typical range of 70 to 170 ppt in the subtropical LS during the daytime. Measured [BrO] ranges between 3 and 9 ppt in the subtropical LS. In the TTL, [BrO] reaches 0.5 ± 0.5 ppt at the bottom (150 hPa∕355 K∕14 km) and up to about 5 ppt at the top (70 hPa∕425 K∕18.5 km; see Fueglistaler et al., 2009 for the definition of the TTL used), in overall good agreement with the model simulations. Depending on the photochemical regime, the TOMCAT∕SLIMCAT simulations tend to slightly underpredict measured BrO for large BrO concentrations, i.e., in the upper TTL and LS. The measured BrO and modeled BrO ∕ Bryinorg ratio is further used to calculate inorganic bromine, Bryinorg. For the TTL (i.e., when [CH4]  ≥  1790 ppb), [Bryinorg] is found to increase from a mean of 2.63 ± 1.04 ppt for potential temperatures (θ) in the range of 350–360 K to 5.11 ± 1.57 ppt for θ  = 390 − 400 K, whereas in the subtropical LS (i.e., when [CH4]  ≤  1790 ppb), it reaches 7.66 ± 2.95 ppt for θ in the range of 390–400 K. Finally, for the eastern Pacific (170–90° W), the TOMCAT/SLIMCAT simulations indicate a net loss of ozone of −0.3 ppbv day−1 at the base of the TTL (θ  =  355 K) and a net production of +1.8 ppbv day−1 in the upper part (θ  =  383 K).