Comparison of CO2 fluxes estimated using atmospheric and oceanic inversions, and role of fluxes and their interannual variability in simulating atmospheric CO2 concentrations

摘要

We use a time-dependent inverse (TDI) model to estimate regionalsources and sinks of atmospheric CO from 64 and then 22 regionsbased on atmospheric CO observations at 87 stations.The air-sea fluxes from the 64-region atmospheric-CO inversionare compared with fluxes from an analogous ocean inversionthat uses ocean interior observations of dissolved inorganic carbon (DIC) andother tracers and an ocean general circulation model (OGCM). We find that,unlike previous atmospheric inversions, our flux estimates in the southernhemisphere are generally in good agreement with the results from the oceaninversion, which gives us added confidence in our flux estimates.In addition, a forward tracer transport model (TTM) is used to simulate the observedCO concentrations using (1) estimates of fossil fuel emissions anda priori estimates of the terrestrial and oceanic fluxes of CO, and(2) two sets of TDI model corrected fluxes. The TTM simulations of TDImodel corrected fluxes show improvements in fitting the observed interannualvariability in growth rates and seasonal cycles in atmospheric CO.Our analysis suggests that the use of interannually varying (IAV)meteorology and a larger observational network have helped to capture theregional representation and interannual variabilities in COfluxes realistically.