沈阳市冬季一次严重污染天气过程成因分析

Analysis of the Causes for Heavy Air Pollution in the Winter of Shenyang

为探讨沈阳市冬季重污染天气的初步成因.以2013年1月11日～16日沈阳市发生的一次严重污染天气为例,利用中国气象局的MICAPS系统和美国的HYSPLT模式,从污染形成的天气背景、污染物扩散受地形的影响情况以及外来污染物输送的气流轨迹等几方面综合分析,从而探讨此次严重污染过程的成因：长白山小高压和西部倒槽双重系统的控制下,地面吹东北风,风速较小,湿度大,不利于污染物的水平扩散;有较强接地逆温存在时,不利于污染物的垂直扩散,导致近地面污染物累积;受来自于北部和东北部低层气流的影响,将内蒙古、辽宁东北部的污染物携带到沈阳地区汇聚.

In this paper,causes for heavy air pollution in the winter of Shenyang are initially analyzed.Based on the occurrence of heavy air pollution in Shenyang from January 11 to 16,2013,by utilization of the MICAPS system of China Meteorological Administration and the American HYSPLT model,a comprehensive analysis is performed from the aspects of weather conditions for pollution formation,topographic effects on pollutant diffusion and air trajectory of external pollutant transmission for discussion of the causes for such heavy air pollution.The results show that under the control of Changbai Mountain anticyclone and western inverted trough,the northeast wind velocity near the ground is small with high humidity,not favorable for horizontal diffusion of the pollutants.Moreover,the existence of relatively strong ground inversion is also not helpful for vertical diffusion of the pollutants,resulting in near-surface pollutant accumulation.Additionally,influenced by the north and northeast air streams,pollutants are brought from the Inner Mongolia and the northeast of Liaoning Province to Shenyang together.