Quantifying Regional Sources and Sinks of CO2 Using Data From GOSAT and TES

Thursday, 18 December 2014
Feng Deng1, Dylan B. A. Jones1,2, Nicolas Bousserez3, Susan Sund Kulawik4, Daven K Henze3, Kevin W Bowman2,4 and Ray Nassar5, (1)University of Toronto, Physics, Toronto, ON, Canada, (2)University of California Los Angeles, Joint Institute for Regional Earth System Science and Engineering, Los Angeles, CA, United States, (3)University of Colorado at Boulder, Boulder, CO, United States, (4)Jet Propulsion Laboratory, Pasadena, CA, United States, (5)Environment Canada Toronto, Toronto, ON, Canada

Recent studies have shown that column-averaged volume mixing ratios of carbon dioxide (XCO2) from the Greenhouse Gases Observing Satellite (GOSAT) do provide constraints on CO2 flux estimates that are complementary to those obtained from in situ surface observations. However, reliably quantifying the CO2 fluxes on sub-continental scales is challenging. Using the GEOS-Chem four-dimensional variational (4D-Var) data assimilation system, we assess the potentially utility of combining GOSAT XCO2 data with CO2 profile retrievals from the Tropospheric Emission Spectrometer (TES), which provides estimates of free tropospheric CO2. In our previous inversion analyses of the TES data we identified regional biases in the data that resulted in unrealistic strong sinks of CO2, particularly for North and South America. Here we examine the use of different approaches of filtering the data, based in the retrieval parameters, to remove the biases, and we assess their impact on the inferred flux estimates. We also quantify the benefit of assimilating surface flask observations of CO2 together with the GOSAT and TES data.