河北中南部连续12d重霾污染天气过程特征及影响因素分析

Analysis on the Characters and Influencing Factors of a 12 d Heavy Haze Pollution Weather Process

2013年12月14—25日,河北中南部地区发生了一次长达12 d的重霾污染天气过程。本文通过对同期气象条件、流场、污染物特征进行分析,探讨了这次过程的成因。此次污染过程与霾密切相关,具有持续时间长、范围广及强度大的特点;在静稳的大尺度气象条件和近地面大气层结下,污染物沿近地面风场的弱辐合区迅速积累,是重覆污染天气形成的关键;此次重霾污染天气过程中有两次弱冷空气活动,两次冷空气影响层次有所不同但影响时间均较短,不能彻底改变静稳大气层结,对污染物的扩散能力有限,重霾污染天气得以长时间持续。

From 14 to 25 December 2013,a heavy haze pollution process occurred in the central and southern part of Hebei.By analyzing the meteorological conditions,flow field and characteristics of pollutants,the causes of this process are discussed.This pollution process which was closely related to haze presented such features as long duration,wide range and great intensity.With large-scale stagnant meteorological condition and near-surface atmospheric stratification,pollutants accumulated rapidly in the convergence zone of surface wind,leading to the formation of this heavy pollution process.There were two weak cold air activities during this period,but they were too weak to change the stagnant atmospheric stratification.Thus,the heavy pollution process,this time lasted a long time.