XCO2 retrieval algorithm in short-wave infrared spectrum and validation with TCCON data

Based on the optimal estimation method, the global carbon dioxide hyperspectral remote sensing inversion system GF_VRTM is established for the greenhouse gas carbon dioxide remote sensing detection of GF-5 satellite. The period of April 2013 to April 2014 GOSAT-FTS observations over TCCON site Tsukba are simulated by GF_VRTM, and the retrieval results are compared with GOSAT-FTS products and TCCON XCO2. The mean residuals between the GOSAT-measured and GF_VRTM-simulated spectra are nearly zero for the O2-A band and WCO2 band over the spectral ranges. The average and standard deviation of ΔXCO2 between GF_VRTM retrievals and GOSAT-FTS L2 products are evaluated to be −1.63 and 1.78 ppm for the whole period, and the average and standard deviation of ΔXCO2 between GF_VRTM retrievals and TCCON data are evaluated to be −0.38 and 2.25 ppm for the whole period. The accuracy of the GF_VRTM retrieval is less than 1% based on the validation results with GOSAT-FTS L2 products and TCCON data.