Analysis of the carbon dioxide concentration in the lowest atmospheric layers and the factors affecting China based on satellite observations

Carbon dioxide (CO₂) is the most important anthropogenic greenhouse gas contributing to global climate change. SCIAMACHY on board ENVISAT (launched in 2002) is the first satellite instrument to monitor the changes in CO₂ concentration in the lowest atmospheric layers. The temporal and spatial distribution of CO₂ (2003–2009) concentration based on SCIAMACHY over China is presented and discussed. It shows an annual increase and a seasonal cycle. The CO₂ annual growth rate was about 1.8 ppm year⁻¹, with the highest value being in spring and the lowest in autumn. The CO₂ concentration variation is determined by many complex factors. In this article, we analyse the important factors affecting CO₂ variations, with special emphasis on terrestrial ecosystems and energy consumption. Terrestrial ecosystems are an important sink in the global carbon cycle. The relationship between CO₂ concentration and Moderate Resolution Imaging Spectroradiometer (MODIS) net primary production (NPP) in 2008 is analysed. CO₂ concentration is inversely proportional to NPP both in regions with high-density vegetation and in deserts. The Yunnan province has the highest NPP value and the lowest CO₂ concentration, whereas the Takla Makan Desert has the lowest NPP value and the highest CO₂ concentration. Energy consumption is the main emission source of atmospheric CO₂. CO₂ emissions from energy consumption show a steady increase in China since 1980. China's CO₂ concentration variation shows a high correlation with energy consumption (coefficient of determination (R ²) > 0.8). The regions with high energy consumption are major industrial regions such as Shandong, Guangdong, Jiangsu, Zhejiang, Hebei, and Henan.