2014年10月京津冀地区一次PM_(2.5)污染过程的数值模拟  

Simulation of a Heavy PM_(2.5) Pollutant Event over Beijing-Tianjin-Hebei Region in October 2014

作　　者：何心河 马建中[1] 徐敬[2] 马志强[2] 薛敏[1] 靳军莉[1] 

机构地区：[1]中国气象科学研究院,北京100081 [2]中国气象局京津冀环境气象预报预警中心,北京100089

出　　处：《气象》2016年第7期827-837,共11页Meteorological Monthly

基　　金：国家自然科学基金重点项目(41330422)资助

摘　　要：近年来我国东部尤其是华北地区的PM2.5污染逐年加重,引起广泛关注。本文利用WRF-Chem模拟了2014年10月京津冀地区一次PM2.5重度污染过程,研究造成此次过程的天气形势、污染物的时空分布特征以及一次、二次PM2.5对总浓度的贡献率,并对污染最严重当日的PM2.5垂直分布进行详细分析。结果表明：造成本次污染过程的是弱高压控制下的静稳天气系统,地面主导风向为南风,垂直方向上有逆温层,抑制了污染物垂直方向上的扩散。发生污染时,PM2.5的高浓度主要分布在北京南部、天津北部与河北接壤的区域,二次PM2.5的贡献率大于一次PM2.5,在清洁大气中则一次PM2.5的贡献更大。垂直方向上,PM2.5中的一次颗粒物只在近地面有高浓度中心,1.2~1.6 km的上空高值区以二次生成的颗粒物为主,是由前体物上升到高空后再通过氧化反应生成的,当这部分颗粒物随着边界层落回近地面时会加重污染。随着时间的变化,污染物的分布高度和边界层高度呈明显的正相关。In recent years, the eastern part of China, especially the Jing-Jin-Ji （shortly for Beijing-Tianjin- Hebei Region） has suffered increasingly severe pollution of PM2.5. A case of PM2.5 pollution over the Jing- Jin-Ji Region during the autumn of 2014 is studied with WRF-Chem model in this paper. The results show that the pollution was caused by a stable weak-high pressure system with the dominant southerly wind on the surface. The temperature inversion layer further suppressed the diffusion of pollutants in the vertical direction. High concentration of PM2.5 mainly spread in southern Beijing, Tianjin and northern Hebei Province, where the contribution of secondary PM2.5 was higher than that of primary PM2.5 to most of the pollution areas. Vertically, the secondary inorganic particles accumulated around Beijing, then became a high concentration region affixed to the ground surface. On the other hand, there was a zone of high pollu- tants over 1.2-1.6 km, and primary pollutants only had one high value area near the surface. The vertical distribution height of PM2.5 showed a similar trend with the boundary layer height.

关 键 词：气溶胶 PM2.5 大气污染 京津冀 WRF-Chem模式 

分 类 号：P402[天文地球—大气物理学与大气环境] P435[天文地球—大气科学及气象学]