Variation patterns and driving factors of regional atmospheric CO₂ anomalies in China

Atmospheric CO₂ anomaly (△XCO₂) is essential in evaluating regional carbon balance. However, it is difficult to understand △XCO₂ variation characteristics due to regional differences. This paper explored the inter-annual and inter-monthly variation patterns of △XCO₂ in different regions of China based on satellite observations. The relation model between regional △XCO₂ and anthropogenic emissions, gross primary productivity (GPP), wind speed, upwind region's emission, and upwind region's CO₂ concentration was established. Results show that the annual average △XCO₂ in the northwest and southeast regions is stable at around 0 and 1-2 ppm, respectively. Some municipalities directly under the central government and the southern coastal areas showed relatively intense inter-annual fluctuations. Four inter-monthly △XCO₂ variation patterns were observed: the northern region has a stable change, the northeast region has the lowest in summer, the southwest region has the highest in summer, and the central region has no obvious change rule. Furthermore, △XCO₂ in most areas can be explained by the emission-absorption-transportation model. Significant positive △XCO₂ in the southern coastal region in summer may be related to the stable GPP seasonal variation and increased power generation. In the southwestern plateau region, it may be related to the low wind speed and increased soil emission with rising temperature. The stability of the plateau carbon sink and inter-regional cooperation cannot be ignored for improving regional atmospheric environments.