Spatial and Temporal Distributions of Atmospheric CO2 in East China Based on Data from Three Satellites

Abstract

East China (23.6°–38.4°N, 113.6°–122.9°E) is the largest developed region in China. Based on CO2 products retrieved from the Greenhouse Gases Observing Satellite (GOSAT), the spatial and temporal distributions of CO2 mixing ratios in East China during 2014–17 are discussed, and the retrieved CO2 from AIRS (Atmospheric Infrared Sounder) and OCO-2 (Orbiting Carbon Observatory-2), as well as WLG (Waliguan) background station observations, are compared with those of GOSAT. The annual CO2 retrieved from GOSAT in East China ranged from 398.96 ± 0.24 ppm in 2014 to 407.39 ± 0.20 ppm in 2017, with a growth rate of 2.82 ± 0.15 ppm yr−1, which were higher than in other regions of China. The seasonal cycle presented a maximum in spring and a minimum in summer or autumn. Higher values were mainly concentrated in the coastal areas of Zhejiang Province, and lower values were concentrated in Jiangxi and the north of Fujian Province. CO2 observed in Fujian and parts of Jiangxi increased by less than 1.0 ppm during 2014–15, but enhanced significantly by more than 5.0 ppm during 2015–16, perhaps influenced by local emissions and global impacts. We calculated year-to-year CO2 enhancements in the Yangtze River Delta region during 2014–17 that were relatively low and stable, due to the region’s carbon emissions control and reduction policies. The annual and seasonal amplitudes of CO2 retrieved from AIRS were lower than those from GOSAT in East China, probably owing to the CO2 retrieved from AIRS better reflecting the characteristics of the mid-troposphere, while GOSAT is more representative of near-surface CO2. The spatial and temporal distribution characteristics of CO2 retrieved from OCO-2 were close to those from GOSAT in East China.