Influence of differences in current GOSAT X _CO2 retrievals on surface flux estimation

We investigated differences in the five currently-available datasets of column-integrated CO₂ concentrations (XCO₂) retrieved from spectral soundings collected by Greenhouse gases Observing SATellite (GOSAT) and assessed their impact on regional CO₂ flux estimates. We did so by estimating the fluxes from each of the five XCO₂ datasets combined with surface-based CO₂ data, using a single inversion system the five XCO₂ datasets are available in raw and bias-corrected versions, and we found that the bias corrections diminish the range of the five coincident values by ∼30% on average the departures of the five individual inversion results (annual-mean regional fluxes based on XCO₂-surface combined data) from the surface-data-only results were close to one another in some terrestrial regions where spatial coverage by each XCO₂ dataset was similar the mean of the five annual global land uptakes was 1.7-±-0.3 GtC yr^-1, and they were all smaller than the value estimated from the surface-based data alone. Key Points Differences in five recent satellite-based CO₂ datasets were investigated Influence of CO₂ data differences on surface CO₂ flux estimation was assessed Impact on flux estimates varies with number density of available data