Interannual and Seasonal Cycles of CO2 from GOSAT and AIRS

Abstract

In this paper, the spatiotemporal variations of carbon dioxide (CO2) are examined using the CO2 datasets retrieved from the Greenhouse Gases Observing Satellite (GOSAT) and Atmospheric Infrared Sounder (AIRS). These results demonstrate that the distribution of GOSAT CO2 is strongly influenced by CO2 emissions from human activities and natural processes, while the characteristics of AIRS CO2 are concerned with both surface sources and large-scale circulation systems. Meanwhile, the spatial difference (GOSAT minus AIRS) ranges from 2–10 ppm, with a maximum value near the Greenland region (>8 ppm). The major pattern of both GOSAT and AIRS CO2 variability exhibits a gradual increase globally. The dominant pattern of GOSAT is proportional to its average distribution, while the leading distributions of AIRS are relatively mixing homogeneity. Additionally, the seasonal amplitudes of GOSAT CO2 are larger in Northeast Asia and Northeast North American (>10 ppm). The largest fluctuation of AIRS CO2 occurs in the Arctic zone, which is dominated by the carbon cycle of the terrestrial biosphere. The seasonal fluctuation from the column-averaged CO2 is more significant than that in the mid-tropospheric CO2, possibly because of tropospheric adjustments of sensible and latent heat at the tropopause. These results regarding the spatial patterns of CO2 at the global scale will help us to better understand the vertical transport of CO2 and its impact on climate change.