Decoding spatiotemporal dynamics in atmospheric CO₂ in Chinese cities: Insights from satellite remote sensing and...

Understanding the primary factors influencing atmospheric carbon dioxide (CO₂) dynamics is essential for addressing global climate change. However, these factors' spatial and temporal impact is seldom considered in the extant literature. This study employs a geographically and temporally weighted regression (GTWR) to examine the magnitude and direction of the effects that human activities, ecological conditions, and meteorological parameters exert on atmospheric CO₂ variations. This examination encompasses 356 Chinese cities, utilizing satellite-derived column-averaged dry air mole fraction of carbon dioxide (XCO₂) data from 2010 to 2019. Our findings reveal that cities in eastern China predominantly exhibit higher atmospheric CO₂ concentrations, with most average values exceeding 399.34 ppm. Conversely, western regions generally maintain levels below 398.98 ppm. Trend analyses show a consistent increase over the decade, with a rate of 2.25-2.54 ppm/yr, coupled with pronounced seasonal variations. Anthropogenic emissions are found to amplify atmospheric CO₂ concentrations during springs (overall-averaged GTWR coefficient of 0.72 ppm), autumns (0.51 ppm), and winters (0.87 ppm), especially in western cities. Vegetative activities can effectively reduce atmospheric CO₂ during summers nationwide (temporally-averaged GTWR coefficients of -5.67 ~ -0.41 ppm) and autumn in southern cities (-1.32-0.00 ppm). From a meteorological perspective, increased summer relative humidity (overall-averaged coefficient of 2.41 ppm) and precipitation (1.57 ppm) can intensify atmospheric CO₂ in most Chinese Cities. At the same time, warmer winter temperatures (-0.63 ppm) can mitigate it. Wind speed generally reduces atmospheric CO₂ levels during spring (-1.02 ppm), autumn (-1.55 ppm), and winter (-1.76 ppm). Yet, it can heighten atmospheric CO₂ concentrations during summers, particularly in eastern cities (0.07 ppm). The relationships between atmospheric CO₂ concentrations and their influencing factors present significant spatial and seasonal variations. These findings offer comprehensive guidance for regions in developing targeted carbon emission control policies and enable a more practical approach to sustainable development.