Publication Date:
2018-09-27
Description:
Long-term (from 2005 to 2016) trends in wet SO4 2− deposition across China are assessed using Ozone Monitoring Instrument (OMI) SO2 columns within the planetary boundary layer. The models for estimating monthly SO4 2− 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 −0.1/0.3 kg S · ha−1 · month−1). In terms of spatial distribution, SO4 2− deposition shows substantial variations across China, ranging from 0.9 to 63.9 kg S · ha−1 · year−1, with an average of 10.4 kg S · ha−1 · year−1. Additionally, wet SO4 2− deposition shows significant seasonal variations, increasing from January to July and then decreasing thereafter. Regarding long-term trends, the wet SO4 2− deposition in northern, central, and southern China decreased at rates of 0.009, 0.001, and 0.0009 kg S · ha−1 · month−1, respectively. In contrast, Inner Mongolia, Qinghai-Tibet, and northwest and northeast China showed increasing deposition trends. In general, the wet SO4 2− 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 SO4 2− deposition. ©2018. American Geophysical Union. All Rights Reserved.
Print ISSN:
2169-897X
Electronic ISSN:
2169-8996
Topics:
Geosciences
,
Physics
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