一次海风锋触发的多单体雹暴及合并过程的观测分析  

Observational analysis of a multicell hailstorm triggered by a sea-breeze front and its merging process

作　　者：易笑园[1,2] 张义军[3] 沈永海[4] 刘一玮[1] 孙晓磊[1] 

机构地区：[1]天津市气象台,天津300074 [2]南京信息工程大学大气科学学院,南京210044 [3]中国气象科学研究院雷电物理和防护工程实验室,北京100081 [4]北京市气象局大气探测技术保障中心,北京100085

出　　处：《气象学报》2012年第5期974-985,共12页Acta Meteorologica Sinica

基　　金：国家自然科学基金(41030960;41275044;41005006);公益性行业专项(GYHY20100605);中央级公益性科研院所专项(IUMKY201002);国家科技支撑计划重点项目(2008BAC37B05/B01)

摘　　要：综合利用雷达、SAFIR3000三维闪电定位系统、微波辐射仪和加密气象自动站等多种观测资料,针对一次与海风锋有关的多单体雷暴造成的大冰雹事件,通过雷达图像和多种雷达、闪电参量的定性、定量分析得到以下结论:(1)地面局地不稳定区配合湿冷的海风锋是触发雷暴并促进其发展的机制,局地背景条件对雹暴发生的预警时间达2h。(2)γ中尺度或小的β中尺度对流单体间的合并主要出现了2种类型,即独立型合并和喂养型合并。对流单体合并时,云桥有时在单体间的中空(4—6km)、有时在高空(9—10km),而二者成因的物理机制截然不同。(3)独立型合并的瞬间(约12min内),雷暴整体上升的发展趋势受到抑制;合并后,上升重新加强发展。降雹和云闪频数峰值出现在独立型合并之后,而喂养型合并处在雷暴消亡阶段,闪电频数平稳下降。(4)雷达参量Zmax、Zmean15、V40、V50等可以定量地描述雹暴三维结构变化,并且,能间接地反映云体发展空间大小、上升气流强弱、水成物粒子多少及其相态。雷达参量V40-Fup、V40-Fdown、SET11能描述合并、降雹、闪电活动时雷暴结构变化。The observational data from Doppler radar, SAFIR3000 three-dimensional lightning position system, microwave ra- diameter, and from high-density meteorology automatic stations were used to analyze a big hail ease caused by a multl.cell hail- storm which connected with a sea breeze front on the west coast of the Bohai bay. The characteristic of merger process, light- ning activity parameters and quantificational structures of hailstorm were studied. The results show that： Firstly, the humid and cold sea breeze convergence line in the local instable region on ground was the mechanism for storms＇ triggering and develo- ping with the time of early warning for hailstorms of 2 h. Secondly, there were two merger types of γ-mesoscale convective cells and small β-mesoscale convective cells, that is, the independence type, and the feeder type. As cells merging, the cloud bridge between two cells emerged at the height of 4 - 6 km or 9 - 10 kin. Thirdly, at the time of merging, the development of storm was lim- ited and hailfall and the peak of lightning emerged after merger. Fourthly, the relationship of the evolution of quantificational storm 3D- structure （time-height cross sections of the radar parameters of Zmax, Zmean15 ,V40 ,V50 etc. ） with lightning activity was investigated, with the result that the radar parameters of V40-Fup, V40-Fdown, SET11 were able to describe properly the feature of merger process and the change of hailstorm structures, and pulled ahead of the total lightning flash peak for 12 min.

关 键 词：海风锋 多单体雹暴 合并 观测分析 雷达参数 

分 类 号：P458.121.2[天文地球—大气科学及气象学]