Spatiotemporal evaluation of atmospheric CO₂ fluctuations in Shaanxi Province (2013-2022) utilizing multi-source...

Despite the rapid and well-documented surge in global atmospheric CO₂ levels, predominantly driven by fossil fuel combustion and industrialization, the characterization of CO₂ variations at regional scales remains notably sparse. This study integrates satellite remote sensing (RS) and ground-based measurements to examine the spatiotemporal distributions and drivers of CO₂ in China's Shaanxi Province from 2013 to 2022. Although Shaanxi has experienced rapid development, its CO₂ trends have remained unclear. By integrating CO₂ observations from satellite sources, specifically the Orbiting Carbon Observatory-2 (OCO-2) and Fourier Transform Spectrometer (FTS), with data from the World Data Centre for Greenhouse Gases (WDCGG) Hong Kong ground station, we have synthesized a uniquely comprehensive dataset that enables enhanced resolution in exploring intra-annual, interannual, and spatial CO₂ variations across the province. The results reveal pronounced seasonal CO₂ cycles and a consistent upward trend over the past decade. The monthly concentrations exhibited a sinusoidal pattern, oscillating between a minimum of 399.68 ± 6.58 ppm in August and peaking at 407.48 ± 6.58 ppm in April. High CO₂ regions within Shaanxi are predominantly found in its southern subtropical and temperate areas, reaching 418.4 ppm in 2022. From 2013 to 2022, the annual average CO₂ increased by 4.12% from 396 to 412.34 ppm, with a higher growth rate in southern compared to northern Shaanxi. This study elucidates the distinct spatiotemporal variations in CO₂ levels across Shaanxi Province, revealing prominent seasonal cycles and a discernible upward trend over the past decade. The results offer new insights into CO₂ characteristics and dynamics in this rapidly developing region of China, and further investigation into the factors underlying the observed variations is warranted.