一次华东地区大范围持续雾过程的诊断分析  

Diagnostic and Analysis of Consecutive Fog Process on Large-Scale in East China Region

作　　者：张恒德 饶晓琴 乔林[2] 

机构地区：[1]国家气象中心,北京100081 [2]北京市气象台,北京100089

出　　处：《高原气象》2011年第5期1255-1265,共11页Plateau Meteorology

基　　金：国家自然科学基金委青年基金项目(40805021);中国气象局气象新技术推广项目(CMATG2010Y26)共同资助

摘　　要：利用地面观测资料、高空探测资料以及NCEP/NCAR再分析资料,分析了2009年1月30日～2月10日华东地区大范围持续雾形成过程的特点、性质及环流背景;诊断分析了该雾过程中的水汽、动力等条件;同时还对比分析了该过程与2008年1月上旬我国中东部地区雾霾过程的差异。结果表明,该过程雾的性质主要为辐射雾,每天05:00～08:00最严重,整个过程分为3个时段,较严重的几天分别为1月31日和2月1,5,10日。该雾过程发生在中高纬处于纬向型环流背景下,西风气流平直,不利于冷空气南下影响我国中东部地区,华东地区基本上处于地面高压内的均压场中,气压梯度力小,近地面风速小,有利于雾的形成和维持。风及湿度等各物理量分布均利于此次雾的发生,即:地面风速维持在1～3 m.s-1、低层辐散、负涡度及垂直上升运动弱是形成雾的动力条件;低层相对湿度大、温度露点差小,对流层中层相对较干;低层逆温层的存在和大气层结稳定构成了稳定性条件。与2008年1月上旬我国中东部地区雾霾天气过程相比,此次雾过程以辐射雾为主,近地面风更小,相对湿度更大。Using the surface observation data,upper probe data and NCEP/NCAR reanalysis data,the characteristic,property and circulation of consecutive fog process on large-scale in East China from 30 January to 10 February 2009 are analyzed,and the water vapor and dynamic conditions are diagnosed,then the difference between the processes of fog and haze in middle-east China in the first ten days of January 2008 is briefly compared.The progress mainly belongs to radiation fog,and the fog is the most serious during 05：00～08：00 in the morning.The whole process is divided three stages,while it is the more serious on January 31,February 1,5,10.There is zonal-type circulation in middle-high latitudes,and westerly flow is relative flat and straight,so it is difficult for cold air moving southward to middle-east China.East China is basically controlled by the equal high pressure field,so the pressure gradient force and near-surface wind are very small,and it is beneficial to the formation and maintenance of fog.Interpretation of the physical quantity distribution is very good for the occurrence and maintenance conditions of fog.1～3 m·s-1 surface wind,divergence,negative vorticity,weak vertical movement in lower level are the dynamical conditions of fog formation.The configurations of small relative humidity,little difference of dew point to air temperature on lower level,and relative dry in middle troposphere constitutes water vapor condition of the fog.Inversion layer on lower level and stratified stable atmospheric stratification stability compose of stable condition.The process is significant different to the fog and haze in middle-east China in the first ten days of January 2008.

关 键 词：华东地区 辐射雾 高空纬向环流 地面均压场 中层干低层湿 

分 类 号：P426.4[天文地球—大气科学及气象学]