The latest version can be found at https://www.gml.noaa.gov/ccgg/OCO2_v10mip/.

In the OCO-2 model intercomparison leading to this Level 4 product release, bottom-up estimates of fossil fuel were applied directly without optimization. Inverse modelers were asked to estimate optimal fluxes from the ocean and land biosphere. This optimization for each model generally starts with a first guess of the flux component and its uncertainty. The distribution of prior estimates is shown in panel 1a. The first-guess fluxes are subsequently evaluated against atmospheric CO2 observations and/or retrievals. These fluxes are then modified to be consistent with those observational constraints. The optimized results (panels 1b through 1e) have different mean fluxes and uncertainty ranges, indicating the influence of information brought by the observations. The bars extend to the across-model mean flux and the error bar represents one standard deviation of the model suite. The one standard-deviation level of uncertainty for the land flux is shown with a thin green vertical line, and the uncertainty for oceanic exchange is shown with a thin blue vertical line. The net flux as the sum of these three components uncertainty is shown in black. The uncertainty on the net flux (black vertical line) is the sum in quadrature of land biosphere and oceanic flux uncertainties.

In the OCO-2 model intercomparison leading to this Level 4 product release, bottom-up estimates of fossil fuel were applied directly without optimization. Inverse modelers were asked to estimate optimal fluxes from the ocean and land biosphere. This optimization for each model generally starts with a first guess of the flux component and its uncertainty. The distribution of prior estimates is shown in panel 1a. The first-guess fluxes are subsequently evaluated against atmospheric CO2 observations and/or retrievals. These fluxes are then modified to be consistent with those observational constraints. The optimized results (panels 3b through 3e) have different mean fluxes and uncertainty ranges, indicating the influence of information brought by the observations. The bars extend to the across-model mean flux and the error bar represents one standard deviation of the model suite. The one standard-deviation level of uncertainty for the land flux is shown with a thin green vertical line, and the uncertainty for oceanic exchange is shown with a thin blue vertical line. The net flux as the sum of these three components uncertainty is shown in black. The uncertainty on the net flux (black vertical line) is the sum in quadrature of land biosphere and oceanic flux uncertainties.