Global atmospheric CO2 inversions in RECCAP2 and GCP

The annual updates of the Global Carbon Project’s Carbon Budget present the community effort on estimating global carbon emissions and carbon sinks and their long-term trends. The budget analysis includes a set of global atmospheric CO2 inversions that are used to estimate latitudinal sinks of CO2, split into land and ocean sinks. In the GCB2023 there were 14 inversions included of which 6 used satellite XCO2 data, and 8 used in-situ observations. Global CO2 inversions are also used in the Regional Carbon Cycle and Processes study (RECCAP2) project to estimate carbon sink on regional level. The aims of RECCAP2 are to develop robust observation-based estimates of regional greenhouse gas emissions and sinks by oceans and terrestrial ecosystems. Results for this new set of global GCP and RECCAP2 CO2 inversions will be shown and discussed at the conference, as a follow up of the work in the first RECCAP project by Peylin et al. (2013). The analysis will include the regional distribution of the carbon sinks for land and ocean, its spatial and interannual variability and a comparison to independent CO2 mole fraction observations from the global observational network. We will also focus on the comparison between bottom-up and top-down estimates, discussing the adjustments made to facilitate the comparisons. Special emphasis will be on the differences between flux estimates from the satellite and surface inversions. References: Peylin, R.M. Law, K.R. Gurney, F. Chevallier, A.R. Jacobson, T. Maki, Y. Niwa, P.K. Patra, W. Peters, P.J. Rayner, C. Rödenbeck, I.T. van der Laan-Luijkx, X. Zhang, Global atmospheric carbon budget: Results from an ensemble of atmospheric CO2 inversions, Biogeosciences. 10 (2013) 6699–6720. https://doi.org/10.5194/bg-10-6699-2013.