The applicability of column-averaged CO2dry-air mixing ratio（ XCO2） data derived from Greenhouse Gases Observing Satellite（ GOSAT） observations should be comprehensibly analyzed. Such assessment is important to reveal spatiotemporal variations in atmospheric CO2 concentration at the global and regional scales

as the XCO2 retrieval bias of GOSAT has decreased to 1—2 ppm. We analyzed and evaluated the spatial and temporal variations in XCO2 at a global and regional scale using GOSAT data from 2010 to 2012. Furthermore

we preliminarily analyzed the response of GOSAT data to anthropogenic emissions. Two data sets of XCO2 from the OCO team of NASA（ ACOS） and the Japan National Institute of Environmental Studies（ NIES） GOSAT team

respectively

were used with different retrieval algorithms for GOSAT observations. ACOS-XCO2 is generally approximately 2 ppm higher than NIES-XCO2

whereas similar variability at space and time is shown in the two data sets. The annual increment of global averaged atmospheric XCO2 concentration is 1. 8 ppm from 2010 to 2011 and 2. 0 ppm from 2011 to 2012; the seasonal variation is4—6 ppm in the Northern Hemisphere and approximately 2 ppm in the Southern Hemisphere; this finding is generally consistent with the statistical results of CO2 variability from ground-based measurements. In addition

GOSAT observations respond weakly to the anthropogenic emissions on the basis of correlation analysis between yearly averaged GOSAT XCO2 and cumulative yearly anthropogenic emissions obtained from the Emissions Database for Global Atmospheric Research data. Our results demonstrate that GOSAT observations can detect the spatial and seasonal variability in CO2 at a global and regional scale. These observations can be applied in monitoring the cumulative effects of anthropogenic emissions at the regional scale

although GOSAT encounters difficulty in detecting the variation magnitude of CO2 induced by the point source emission because of the unrefined spatial resolution of GOSAT footprints.