辽宁一次区域持续性雾霾的气象成因分析  

Meteorological Causes of a Regional Persistent Fog and Haze Event in Liaoning

作　　者：侯亚红[1] 徐方姝 张蕊[2] 赵淼[1] 明惠青[1] Hou Yahong Xu Fangshu Zhang Rui Zhao Miao Ming Huiqing(Liaoning Meteorological Service Center, Shenyang 110166 Meteorological Service in Dongling District of Shenyang, Shenyang 110168)

机构地区：[1]辽宁省气象服务中心,沈阳110166 [2]沈阳市东陵区气象局,沈阳110168

出　　处：《气象科技》2017年第4期710-716,共7页Meteorological Science and Technology

基　　金：辽宁省科技厅基金项目(辽宁省大气灰霾的污染形成机制及预报预警技术研究2013229031)资助

摘　　要：近年来,雾霾天气频发,加剧了空气质量的恶化。研究雾霾天气的成因,加强雾霾的预报能力,对指导公众出行和保护身体健康有着重要的意义。本文利用辽宁62个国家级自动站观测资料和NCEP再分析资料,对2015年11月7—14日辽宁一次持续性雾霾天气过程的环流背景、形成条件和持续原因进行分析,结果表明:(1)高层西南偏西气流,低层暖脊及地面倒槽和弱气压场的环流背景为雾霾天气的发生提供了有利的天气形势。(2)逆温是这次雾霾天气持续的重要原因。雾和霾天气逆温表现形式不同,大雾过程中,逆温层高度低,厚度小;霾过程中,逆温层高度高,厚度大,且表现为多个逆温层同时存在。(3)水汽条件是雾和霾转换的关键因素。当近地层空气相对湿度大于95%时,有利于雾的生成;而相对湿度在60%~70%时,有利于霾的形成。雾向霾转换时,比湿增大;霾向雾转换时,比湿下降。(4)近地面弱的上升运动、中高层弱的下沉运动是此次雾霾加强的动力机制。(5)雾霾出现前后气象要素特征差异明显,可为雾霾天气的预报提供重要参考。Foggy and hazy weather occurred frequently and worsened air quality dramatically during recent years.Investigating the causes and improving the prediction for fog and haze are essential to guide the public and protect public health.This paper utilizes the observational data from 62 national-level automatic weather stations in Liaoning and the reanalysis data from NCEP to analyze the general-circulation background,forming conditions and persistency causes for the fog and haze process occurred from 7 to 14 November 2015 in Liaoning.Results indicate：（1）The general circulation,including an upper-level westsouthwest flow,a low-level warm ridge,a reversed surface trough,and a weakened surface pressure,provided favorable synoptic conditions for the fog and haze event.（2）Temperature inversion was the critical cause for this persistent fog and haze event.The inversion had different structures for foggy and hazy stages,with a lower top and thinner layer for intense fog but a higher top,a thicker layer and even multiple simultaneous inversion layers for haze.（3）Water vapor content was the key factor for the conversion between fog and haze.A 95% relative humidity near the surface favors fog genesis,while a 60% to 70% is optimal for haze.The specific humidity increased when fog turns into haze,whilst it decreased with a reversed conversion.（4）The weak rising motion near the surface and the weak sinking at middle-upper layers dynamically intensified this fog-haze event.（5）The characteristics of meteorological elements differ substantially before and after the fog and haze,which provides references for predicting fog and haze.

关 键 词：雾霾 环流背景 逆温 稳定层结 湿度 动力条件 

分 类 号：P458[天文地球—大气科学及气象学]