Temporal and spatial distribution of tropospheric CO_2 over China based on satellite observations during 2003-2010

摘要

Mid-troposphere CO_2 data retrieved by the AIRS (Atmospheric Infrared Sounder) were validated with five ground-based stations and aircraft measurements in the Northern Hemisphere. AIRS CO_2 products show good agreement with ground and aircraft observations. The data had a monthly average accuracy better than 3 ppmv. In this study, the spatial and temporal distribution of mid-troposphere CO_2 from January 2003 to December 2010 was analyzed based on this satellite product. The average concentration of atmospheric CO_2 was higher in the Northern Hemisphere than in the Southern Hemisphere. The yearly average results show a gradual increase from 2003 to 2010. In China, the annual growth rate was about 2 ppmv/a, similar to the United States, Europe, Australia and India, but was slightly lower than Canada and Russia. Mid-troposphere CO_2 concentrations were higher over northern China than over southern areas, due to differences in natural conditions and industrial layout. There were four centers of high CO_2 concentration between 35 and 45°N over China, with low concentrations over Yunnan Province. There was a significant seasonal CO_2 variation with peak concentration in spring and the lowest concentration in autumn.