2004年7月12日上海飑线天气过程分析

利用上海自动观测站资料、NCEP1°×1°的逐6小时分析资料、水汽云图和WSR88D多普勒雷达探测等资料,对2004年7月12日上海飑线天气过程进行天气动力学诊断分析。结果表明上海处在上干冷、下暖湿的不稳定大气层结中,对流层上层干冷空气的侵入和边界层暖湿气流强烈辐合是飑线天气的触发机制。飑线以断续线型与后续线型相结合的型式形成,在对流单体的右侧不断新生单体,最终连接成弓状回波带,给上海带来雷雨大风。

Dynamic Diagnosis of a Squall Line in Shanghai on 12 July 2004

A squall line weather process occurred in Shanghai on July 12 2004 is diagnosed with various kinds of observational data, such as the automatic meteorological station data, satellite water vapor image and Doppler radar echo, and NCEP reanalysis data of 1°×1°with 6h interval. The results show that Shanghai is located in an unstable stratification and the dry and cold intrusion down from the upper troposphere and the strong convergence of the moist and warm air in the boundary layer are the trigger mechanisms. The radar echo shows that the squall line is shaped by the joint type of line of discontinuity and line of rearward continuity. The bow echo belt causing thunderstorm and gust in Shanghai is the connection of the convective cells and the new ones appearing on the right of them.