Dominant synoptic patterns during wintertime and their impacts on aerosol pollution in Central China

Abstract

Abstract Meteorological conditions are largely driven by synoptic circulations, affecting pollutant transport, dispersion, and even emissions. Partly due to the lack of systematic investigations of meteorological impact at large- and local-scale, aerosol pollution in Central China is not yet fully understood. This study conducted synoptic classification based on the obliquely rotated principal component analysis in T-mode, and investigated the relationship between aerosol pollution and the prevailing synoptic patterns over Wuhan during wintertime from 2014 to 2018. Among five identified patterns, three driven by the northerly high-pressure systems, accompanied by weak surface winds, low boundary layer height, and high relative humidity, were found to be closely related to heavy pollution. Notably, the winter aerosol pollution in Wuhan showed a declining trend in recent years, which also slightly benefited from the interannual variation of synoptic patterns besides emission control. However, with the increase in humidity, pollution caused by secondary particles cannot be ignored. The oxidation rate of sulfur and nitrogen in the atmosphere was about 0.1 higher in 2018 than in 2014. This study is significant for pollution control in Wuhan and its surrounding areas of Central China.