成都一次持续性污染天气过程的气象条件分析

Meteorological Conditions of Persistence Polluted Event in Chengdu

本文利用气象台站资料和NCEP再分析资料对2017年12月18日~2018年1月2日成都出现的一次持续性污染天气过程的气象条件进行了分析。结果表明,此次污染过程是一次中到重度污染,局部时段出现了严重污染。500hPa环流形势及其调整与此次污染状况的发展有着密切的联系,其中500hPa高压脊前西北气流下沉区所产生的下沉逆温层和等温层是导致此次污染过程的主要因素。随着环流调整,低槽东移,受槽前西南气流影响,污染状况得到了改善,并最终结束了此次污染过程。此次污染天气过程中,贴地逆温及静风的稳定大气抑制了污染物的扩散,但对污染天气的生成及演变并未起主导作用。此外,有四次冷空气进入盆地的过程出现。冷空气主要来自四川盆地北部和东部,使污染状况得到缓解,但并未对污染过程的结束起到决定性的作用。

The meteorological conditions of a persistent polluted weather process in Chengdu from December 18,2017 to January 2,2018 are analyzed by using meteorological station data and NCEP reanalysis data.The results show that the pollution process is a moderate to severe pollution event.The circulation situation of 500 hPa and its adjustment are closely related to the development of this pollution situation.The subsidence inversion layer and isothermal layer associated with 500 hPa high pressure ridge are the main factors leading to the pollution process.With the adjustment of circulation,the low trough moved eastward,the pollution situation was improved,and finally the pollution process ended.In the process of polluted weather,the surface inversion and stable atmosphere restrained the diffusion of pollutants,but did not play a leading role in the generation and evolution of polluted weather.In addition,there are cold air entering the basin for four times.The cold air mainly comes from the north and east of Sichuan Basin,which alleviates the pollution,but does not play a decisive role in the end of the pollution process.