河南省冬季3次重污染过程的数值模拟及输送特征分析

利用WRF-Chem模式模拟2015年11月27日—12月1日、12月5—14日、12月19—25日河南3次重污染过程,结合空气污染资料和ERA-Interim再分析资料,对比分析了这3次重污染过程的开始、持续和结束及污染物的输送特征.结果表明,静稳天气有利于污染的发展持续,3次重污染过程的结束均是由西路冷空气入侵造成的.第1次重污染过程平均风场上的风速均为小风或静风,从湖北到河南南部风向为偏南风;而第2和第3次重污染过程平均风场分别以偏东和偏北风为主.第2和第3次重污染过程中均存在明显的由北向南的污染物输送过程.3次重污染过程中,河南省本地排放对本省PM_(2.5)浓度的平均贡献率最大,而河南省周边区域对河南PM_(2.5)浓度的平均贡献率在这3次过程中不一样,第1次重污染过程,河南南部主要受偏南风影响,湖北对河南PM_(2.5)浓度的平均贡献率最大,为20.7%;第2和第3次重污染过程主要受偏东风影响,安徽和江苏对河南PM_(2.5)浓度的平均贡献率最大,分别为17.7%和18.5%.3次重污染过程中,安阳的主要污染输送源均不相同,分别来自河北、江苏和安徽、本省.

Numerical simulation and transport analysis of three heavy air pollution processes in Henan Province in winter

The WRF-Chem model has been utilized to simulate the three heavy air pollution processes in Henan Province which occurred from 27 November to 1 December, from 5 to 14 December, and from 19 to 25 December 2015, respectively. The air pollution modeling output and ERA-Interim reanalysis data were employed to investigate the pollutant transport characteristics associated with these processes through comparison of the pollutant transport at the beginning, the development and the end stages of the three heavy pollution processes. The results show that the stable weather was conducive to the development of air pollution conditions. Additionally, the invasion of cold westerly flow ceased these three air pollution processes. During the first process, the averaged wind speed was relatively small and the weather condition was stable. The southward wind blew from Hubei Province to the southern part of Henan Province. During the other two processes, the easterly and northerly flows played an important role to transport considerable pollutants from the north vicinities to Henan Province. In these three processes, the local emission made a largest contribution to PM_2.5 concentration in Henan Province while the local contributions to PM_2.5 concentration were significantly different in the adjacent provinces. The PM_2.5 contamination transported by prevailing southerly wind from Hubei Province contributed to the PM_2.5 pollutants at a rate of 20.7% in Henan Province during the first process. In the second process, the average contribution rates of PM_2.5 carried by easterly wind from Jiangsu and Henan were 17.7% and 18.5% respectively. Besides, the main pollutant sources at Anyang city came from Hebei, Jiangsu, Anhui and Henan Provinces during these three processes.