2013-2018年冬季成都市9次大气重污染过程的天气形势及逆温特征

Study on the weather conditions and inversion characteristics of nine sessions of atmospheric heavy pollution in Chengdu in the winter from 2013 to 2018

利用2013年1月-2018年12月成都地区气象探空资料、空气质量指数(AQI)和欧洲中期天气预报中心ERA-Interim再分析资料,研究了成都市9次大气重污染过程中的天气形势和逆温特征,结合重污染过程期间的AQI及各类污染物质量浓度变化,讨论了不同天气形势和逆温特征与空气污染的内在关系.结果表明, 9次大气重污染过程中,在低槽天气型且风向主要为西南风、南风和西风时,污染较严重.白天贴地逆温的层数、厚度和强度与气态污染物呈正相关,对流层低层逆温的发展对各类污染物的扩散有抑制作用;晚上脱地逆温层数越多,厚度与强度越大时,颗粒污染物越难扩散.逆温层数与空气污染的正相关性相对于逆温厚度和逆温强度更明显, AQI对逆温总层数和总厚度具有一定的滞后性.

Meteorological sounding data, air quality index(AQI) data on the Chengdu area from January2013 to December 2018, and the ERA-Interim reanalysis data of the European Centre for medium-range weather forecasts were used to explore the nine atmospheric weights in Chengdu. The weather conditions and inversion characteristics in the pollution processes, combined with the AQI and various pollutant concentrations during the heavy pollution process were utilized to discuss the intrinsic relationship between different weather conditions and inversion characteristics and air pollution. The results showed that during the nine periods of heavy atmospheric pollution, the low-slot weather type and wind direction were mainly southwest, south and west, and the pollution was more serious. During the daytime, the number, thickness and intensity of the inversion of the ground were positively correlated with the gaseous pollutants, while the development of the inversion of the lower troposphere had an inhibitory effect on the diffusion of various pollutants. When the number of layers of the inversion temperature at night was higher, and the thickness and strength were larger, the particle pollutants were more difficult to diffuse.The positive correlation between the number of inversion layers and air pollution was more obvious than the inversion thickness and the inversion strength. AQI had a certain hysteresis for the total number of inversions and the total thickness.