Evaluating satellite observed CO2 column by a 3-D atmospheric transport model

Abstract

Satellite remote sensing is the latest method of measuring atmospheric CO2, which covers a wide range and makes periodic observation. But due to lack of ground-based observation sites, global satellite observed CO 2 column is not evaluated efficiently. This paper assess the applicability of using GEOS-Chem model to forward simulate atmospheric CO 2 for verifying Greenhouse Gas Observation SATellite (GOSAT) observed CO2 column. It is shown that GEOS-Chem performs well in modelling atmospheric CO2 and there are generally no significant differences between ground-based observation and model results. According to the comparsion, the spatial and temporal distribution of XCO2 agrees well between GOSAT and GEOS-Chem. GOSAT XCO2 is turned out to be 2.6 ppm lower than the model results. The mean difference observed between GOSAT and GEOS-Chem varies from -1.8 to -3.1 ppm seasonally, with the standard deviation ranging from 1.4 to 2.1 ppm. And in general, the difference is larger in summer than that in winter, in land area than in sea area. It might have been caused by the different land-sea distribution and eco-system's changing with seasons.