基于静止锋的强对流过程个例诊断分析

A CASE DIAGNOSIS OF SEVERE CONVECTION IN THE SOUTHEAST COAST REGION

本文利用常规天气图、中尺度暴雨 η模式输出的物理量场和红外卫星云图资料对 1999年 7月 18日 0 8时～ 7月 19日 0 8时东南沿海 2 1～ 30°N ,110～ 12 2°E范围内的强对流过程进行了分析 ,并仔细考察了对流云团强烈发展的前期条件。结果表明 :此次强对流过程与副高边缘的强暖湿不稳定及准静止锋的活动有关 ,静止锋活动是产生雷暴的直接原因 ,同时也与午后的热对流运动有关。对流不稳定和惯性不稳定是这次雷暴的触发机制 ,相对湿度和对流有效位能的大值中心附近未来可能将有雷暴出现。

Using the usual historical synoptic charts, the mesoscal η storm rainfall model output diagnostic fieldsand thedata of infrared satellite images, this paper analyzes a severe convective weather event in the range of 21～30°N,110～122°Ealong the southeast coast of ChinaonJuly 18 and 19,1999, and investigates the prophetic conditions of convective cloud suddenly grown in detail. The results show that this severe convective weather is related to the strong warm and wet instability at the edge of subtropical high and the qusai-stationary front activity as well as the thermal convection in the afternoon. Before the storm the diagnostic fields, such as relative humidity,CAPEetc. are revealed obviously.