Abstract
The atmospheric carbon dioxide (CO2) column concentrations observed by the Greenhouse Gases Observing Satellite (GOSAT) and ground stations at Mt Waliguan (36.29° N, 100.90° E) and Lulin (23.47° N, 120.87° E) in China are compared. The data covered time periods from June 2009 to November 2011 for GOSAT and from July 2009 to December 2010 for the ground stations. The GOSAT monthly mean data tend to be generally smaller than those of the ground measurements by 5–10 ppm. The spatial and temporal variations of the atmospheric XCO2 (dry air, column averaged, molar fraction of CO2) concentrations, especially in the regions of China, are analysed by using the GOSAT monthly mean data. The variations are more significant in the northern hemisphere than in the southern hemisphere and show relatively high values and obvious fluctuations in the 15° N–45° N latitudinal band. These are generally consistent with the measurements of the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) and Atmospheric Infrared Sounder (AIRS). The satellite data show significant seasonal variations, with maximum in April and May and minimum in September and October. This feature is in general agreement with that of the ground observations and previous reports. In the regions of China, the XCO2 ranged from 355 ppm to 385 ppm with a mean of 374 ppm, which is in agreement with the global concentration.
Acknowledgements
This work was supported by the Project of National Science and Technology, ‘Inversion algorithm of atmospheric CO2 data products based on the satellite observations of near-infrared hyperspectra’, (Grant No. E0310/1112/JC02). One of the co-authors (DYW) was supported by the ‘Overseas Expert’ Project of the Ministry of Education, China.