Evaluation of the ACOS/GOSAT XCO2 Product Using TCCON Data

The JAXA/NIES/MOE Greenhouse Gases Observing Satellite "IBUKI" (GOSAT) was launched in 2009 carrying the TANSO-FTS (Fourier transform spectrometer). One goal of the TANSO-FTS instrument was to measure total columns of CO2 (XCO2). The Atmospheric CO2 Observations from Space (ACOS) group has produced an XCO2 product from GOSAT spectra. Exploiting the uniformity of XCO2 south of 25°S, offsets and biases in the ACOS data relative to Total Carbon Column Observing Network (TCCON) XCO2 are characterized. Correlation between free-tropospheric temperature and XCO2 is used to define coincidence between the spatially sparse TCCON sites and the GOSAT observations. We describe the current state of the ACOS data product compared with the TCCON results.