资源环境科技发展态势分析平台

Long-term (from 2005 to 2016) trends in wet SO42- deposition across China are assessed using Ozone Monitoring Instrument (OMI) SO2 columns within the planetary boundary layer. The models for estimating monthly SO42- deposition from precipitation in eight ecological regions are constructed based on SO2 columns and ground-based measurements. An accuracy assessment shows that the models achieve highly precise predictive values for monthly deposition (R=0.93, with a relative/absolute error of -0.1/0.3kgSha(-1)month(-1)). In terms of spatial distribution, SO42- deposition shows substantial variations across China, ranging from 0.9 to 63.9kgSha(-1)year(-1), with an average of 10.4kgSha(-1)year(-1). Additionally, wet SO42- deposition shows significant seasonal variations, increasing from January to July and then decreasing thereafter. Regarding long-term trends, the wet SO42- deposition in northern, central, and southern China decreased at rates of 0.009, 0.001, and 0.0009kgSha(-1)month(-1), respectively. In contrast, Inner Mongolia, Qinghai-Tibet, and northwest and northeast China showed increasing deposition trends. In general, the wet SO42- deposition in 2016 decreased by 4.3% from that in 2005 on a national scale, indicating that air quality policies to control SO2 emissions have had some effects on wet SO42- deposition.