摘要
利用常规气象观测资料、探空资料、NECP再分析资料以及大气环境监测数据,对2018年冬季常州市一次典型污染过程进行分析,结果表明:这次连续污染过程可分为污染发生、加强和减弱三个阶段,过程主要污染物为PM 2.5,期间伴随三次污染物浓度的“爆发性”增长。高空环流呈纬向型,地面长时间受均压场控制,是此次污染过程的基本环流形势。期间有两次地面弱冷锋南下,是造成空气污染加重的重要原因。污染过程期间风速小,多静风,风向乱,无主导风向,有利于污染物的积聚;弱冷空气和弱降水的发生对污染物没有明显的清除作用,反而造成污染物吸湿增长。绝对值0.2 hPa/s以内弱垂直运动和绝对值4×10-5/s以内弱散度也为此次污染过程提供了良好的动力条件。近地面持续的强逆温层覆盖和较低的混合层高度,抑制了污染物在垂直方向上的输送扩散,使大气污染得以维持或加强。污染物浓度的变化较混合层高度的变化有一定的滞后性。
Based on conventional meteorological observation data,sounding data,NECP reanalysis data and atmospheric environmental monitoring data,an analysis of one typical pollution process in Changzhou in the winter of 2018 is conducted,which shows that the continuous pollution process could be divided into three stages(pollution occurrence,strengthening and weakening).The main pollutant in the process is PM 2.5,which is accompanied by an explosive increase in the concentration of the three pollutants.Zonal high-altitude circulation and ground controlled by a constant pressure field for a long time are the basic circulation situation of the pollution process.The two weak cold fronts on the ground are important causes of increased air pollution.During the process,the low or calm wind,rough wind direction are conducive to the accumulation of pollutants;the occurrence of weak cold air and weak precipitation has no obvious effect on the clearing of pollutants,but this causes the moisture absorption of pollutants to grow.Weak vertical motion and divergence also provide good dynamic conditions for this pollution process.The continuous strong inversion layer coverage and the lower mixed layer height near the ground inhibit the transport and diffusion of pollutants in the vertical direction,so that the air pollution is maintained or strengthened.The change in pollutant concentration has a certain hysteresis compared to the change in the height of the mixed layer.
作者
吴建秋
刘端阳
沈沛丰
吴晶璐
温静
WU Jian-qiu;LIU Duan-yang;SHEN Pei-feng;WU Jing-lu;WEN Jing(Changzhou Meteorological Observatory of Jiangsu Province,Changzhou 213022,China;Observatory of Jiangsu Province,Nanjing 210008,China;Suzhou Meteorological Observatory of Jiangsu Province,Suzhou 215100,China)
出处
《环境生态学》
2019年第2期41-46,共6页
Environmental Ecology
基金
国家重点研发计划资助(JFYS2016YFC0201903)
江苏省气象局重点项目(KZ201902)共同资助
关键词
大气环流
气象要素
逆温层
混合层高度
atmospheric circulation
meteorological elements
inversion layer
mixed layer height
