2009年大连春季强对流雨雪天气过程分析  

Analysis on Severe Convection Rain and Snow Weather Processes in Dalian in Spring of 2009

作　　者：李燕 石小龙 王树雄 吴杞平 

机构地区：[1]大连市气象台,辽宁大连116001

出　　处：《高原气象》2011年第4期961-968,共8页Plateau Meteorology

基　　金：大连市科技局科技计划项目"大连地区低温雨雪冰冻灾害的研究及预警系统"(2009E12SF167)资助

摘　　要：2009年4月15日大连出现了春季最晚的降雪天气。利用常规资料、自动气象站和雷达等多种资料及中尺度模式MM5对这次强对流雨雪天气过程进行了分析和模拟,结果表明,200hPa急流、500hPa贝加尔湖冷槽南压形成的冷涡、中低层南支槽前水汽输送以及地面冷锋是产生大连春季强对流雨雪天气的环流背景;中层干冷空气叠加在低层暖湿层上,有利于不稳定层结的形成,低层较充沛的水汽输送叠加于近地层冷空气之上,在锋面动力抬升作用下,为强对流雨雪天气的产生创造了条件;低层逆温层,不稳定能量配合明显的抬升运动,有利于不稳定降水产生;冷锋云系中多个中-β尺度对流云团是造成这次过程的直接中尺度系统;在多普勒雷达回波中,强带状回波及块絮状回波、速度场零速度线反"S"型和清晰的低空"牛眼"及模糊的高空"牛眼"显示出中高层冷、低层暖的不稳定层结配置,以及中小尺度对流辐合体回波系统的产生;温度分析表明,高层冷空气的侵入使中低层和地面温度在短时间内发生大幅度降温现象,是造成降水性质发生变化的直接原因。There was the latest spring snowfall weather process on 15 April 2009.The rain and snow weather processes of severe convection are analyzed using the conventional observation data,automatic meteorological station data,MM5 model,radar data and so on.The results show that the circulation background of the severe convection event is composed of many parts which include 200 hPa jet stream,500 hPa cold trough,vapor transportation in middle-low levels and surface cold front.In addition,the dry and cold air of middle level overlay the humid and warm air at lower level to make for instability stratification.On the dynamical uplift of front,more abundant vapor transportation at lower level overlay the cold air to be favorable for the severe convection snow and rain occurring.Otherwise,the temperature inversion of lower level and instability energy with obvious uplift results in instability precipitation.The much meso-β scale convection cloud clusters in the cold front cloud system is direct mesoscale system.In the echo of Doppler radar,the high intensity in different shapes,＇S＇ style zero rapidity line,and also ＇Bulls-eye＇ in different levels can all indicate the instability stratification positioning and the cause of meso-and micro-scales of convection convergence system.The analyzed temperature show that the incursion of cold air at upper level induces a large range of temperature decrease over middle-lower levels and surface,which is direct reason of convection event.

关 键 词：大连 春季降雪 强对流雨雪 MM5模式 逆温层 冷锋云系 

分 类 号：P458.121[天文地球—大气科学及气象学]