一次强对流风暴成因探析及CINRAD回波特征

Reason Analysis of A Severe Convective Storm and the Featurer of CINRAD Echoes

用常规天气图、卫星云图和CINRAD产品资料，分析2005年3月22日影响华南地区的中尺度对流风暴过程，揭示中尺度对流风暴的环流背景及其成因：500hPa槽前西南急流和850hPa低涡切变东移南压及低空西南急流为对流风暴生成发展提供了有利条件；边界层华南西部低涡切变系统和地面中气旋及冷空气南下影响的共同作用是此次对流风暴的触发机制；垂直风切变分析，“3·22”中尺度对流风暴是在中等偏强的垂直风切变条件下，有利于发展成组织性完好的多单体风暴和超级单体风暴。CINRAD回波特征：中尺度对流风暴表征为飑线回波带，强回波区呈弓状，其后侧有弱回波通道（入流槽口），预示有灾害性大风；弓状强回波头部及其带上出现了中气旋，表明飑线回波带是由多单体和超单体组成；径向速度图上有逆风区、辐合区和气旋性辐合等特征。

We analyze the process of mesoscale convection storm which has an impact on southregion on twentysecond, March, 2005 by means of regulations climate outlook, cloud diagrams andthe CINRAD product datas to reveal the circulation background and causes of mesoscale convectionstorm.The 500hPa trough southwest jetsteam and 850hPa vortex which shears south pressure from the east and the low level southwest jetsteam make a great condition for the form of convectionstorm.The trigger mechanism is made up of three factors.That is boundary layer south westernvortex shear system and the mesocyclone on surface plus the cold air comes＇ off to the south.The three one makes the combined effect to the convection storm. Accoding to the analysis verticalwind which shears, the convection storm is good to the development of muhicell storm and supercellstorm which has perfect constructive in the condition of turning moderate to strong.The characteristic of CINRAD echoes is： the mesoscale convection storm takes on squall line wave whose strong echoes show bow form and its afterward side has an echoes passage （that is the trough area for entrance） and that indicates the disaster strong wind.If the mesocyclone appears on the head of the strong bow form echoes and its zoster, it means the squall line echoes strip is constituted by muhicell and supercell while the radial velocity chart has the characteristic of wind inversion area, convergence area and cyclonic convergence.