Status of the Validation of the ACOS XCO2 Product

The Atmospheric CO2 Observations from Space (ACOS) team has been producing and distributing total column CO2 (XCO2) products using JAXA/NIES/MOE Greenhouse Gases Observing SATellite (GOSAT) spectra. In the past year, significant algorithmic updates have allowed for improvements in product quality. Currently the most complete data set, labeled version 2.9, has shown a global mean bias with respect to Total Carbon Column Observing Network (TCCON) XCO2 of less than 0.5 ppm (for data over land) and reduced scatter compared to previous versions. Additionally, a newer, provisional XCO2 product, labeled version 2.10, is available that has improved algorithmic performance but does not span the full GOSAT time period. We describe the status of preliminary validation work of these data sets with surface TCCON XCO2 and XCO2 from several global models.