Impacts of atmospheric circulation patterns and cloud inhibition on aerosol radiative effect and boundary layer structure during winter air pollution in Sichuan Basin, China

作者：Hua Lu, Min Xie, Bingliang Zhuang, Danyang Ma, Bojun Liu, Yangzhihao Zhan, Tijian Wang, Shu Li, Mengmeng Li, Kuanguang Zhu · 发表于：Atmospheric chemistry and physics · 年份：2024 · DOI：10.5194/acp-24-8963-2024 · 被引用次数：18 · 研究领域：Atmospheric chemistry and aerosols、Atmospheric aerosols and clouds、Atmospheric Ozone and Climate

Abstract. Persistent winter aerosol pollution frequently occurs in the Sichuan Basin (SCB) due to its unfavourable weather conditions, such as low wind, wetness, and cloudiness. Based on long-term observational data analyses from 2015–2021, it has been found that the four representative stations in the SCB often simultaneously experience PM2.5 pollution accompanied by variations in meteorological conditions above 850 hPa, which indicates a connection between regional winter air pollution in the SCB and large-scale synoptic patterns. The dominant 850 hPa synoptic patterns of winter in the SCB were classified into six patterns using T-model principal component analysis: (1) strong high pressure in the north, (2) east high–west low (EHWL) pressure, (3) weak high pressure in the north, (4) a weak ridge of high pressure after the trough, (5) a low trough (LT), and (6) strong high pressure. Pattern 2 characterized by the EHWL pressure system, and Pattern 5, featured with LT, was identified as having key synoptic patterns for the beginning and accumulation of pollution processes. Pattern 1, characterized by a strong high pressure in the north, was the cleanest pattern associated with reduced PM2.5 concentrations. The EHWL and LT patterns were associated with a remarkably high cloud liquid content attributed to upper southerly winds introducing humid air. Clouds reduce solar radiation through reflection and scattering, resulting in more stable stratification and aerosol accumulation....