重庆市“5·29”暴雨天气过程诊断分析与数值模拟

Diagnostic Analysis and Numerical Simulation of a Heavy Rainfall in Chongqing

在天气分析的基础上,利用非静力中尺度数值预报模式MM5和双向二重嵌套网格技术,对2004年5月29～30日重庆市暴雨天气过程进行数值模拟.诊断分析表明,高空低槽产生的冷锋云系发展东移是产生此次暴雨天气过程的主要大尺度天气系统,由高空槽诱发产生的中尺度涡旋是产生此次暴雨天气的主要中尺度系统.模拟结果与观测结果的对比显示表明,MM5中尺度数值预报模式能够成功模拟四川盆地东部的暴雨天气过程,同时揭示了高空槽东移过程中在重庆地区范围内产生的较强中尺度气旋性辐合和强烈上升运动促使了暴雨的产生.

Based on the synoptic analysis for a rainstorm event occurred in Chongqing on 29, 30 May 2004, the nonhydrostatic version of mesoscale numerical model MM5 was used to simulate this case with two nested domains. The diagnostic analysis results show that the moving cold-front cloud system produced by a high-level trough is the main synoptic system of this rainstorm, and a meso-vortex produced by the trough is the main mesoscale system. The comparison between simulated and observed data shows that MM5 can successfully simulate the rainstorm event in the east of the Sichuan plain. It is pointed out that the meso-vortex convergence and the intense ascending movement produced by the east-moving trough in the Chongqing area engendered the rainstorm.