Left Panel: The pattern of CO2 exchange calculated in CarbonTracker for the time period indicated. Negative fluxes (blue regions) indicate places where uptake of CO2 occurs. Positive fluxes (red colors) indicate places where emission of CO2 occurs. The pattern of exchange follows swings in temperature and sunlight and changes with season. Units are gC/m2/yr. The figures include biological and fire fluxes, no fossil fuels.
Right Panel: The uncertainty on the estimated fluxes. All estimates started with 80% uncertainty on the land parameters, and 40% on the ocean parameters. Reduction of uncertainty occurs when observations inform us on the carbon cycle and limit the possible flux strength to less than we originally prescribed. Dark red areas show relatively large uncertainty, blue is relatively little. All uncertainties indicate a one-sigma standard deviation on the fluxes estimated assuming Gaussian errors. In the monthly and annual averages, we show the RMS uncertainty while temporal covariances are ignored. Units are gC/m2/yr. Uncertainties reported here are formal estimates from the inversion technique and do not include all sources of error. Flux uncertainties are among the most difficult quantities to compute, and care should be taken in their interpretation.
Results Summary: The table summarizes averages with uncertainty of the data displayed in the figure. The fossil and fire emissions are prescribed in CarbonTracker; the estimated mean includes ocean and terrestrial fluxes calculated by CarbonTracker. The total flux is the sum of the components in the table. Note that fossil fuel emissions can occur over regions characterized as ocean. This is partly due to real emissions from international shipping, and partly due to emissions occurring in coastal land regions that are assigned to the ocean in our coarse 1x1 degree division scheme. The same is true for fossil fuel emissions over non-optimized regions such as ice, polar deserts, and inland seas.