一次梅雨期暴雨的中尺度数值模拟分析

利用常规气象资料、AREM模式输出资料，对发生在2005年梅雨期湖北的一次暴雨过程进行了中尺度数值模拟分析。分析结果表明，强降水发生时，在对应的中尺度对流系统中存在两个分别位于300hPa和600hPa附近的强上升运动中心，低层辐合、高层辐散的单模态分布是上升运动得以维持的重要条件；环境风场并不能控制中尺度对流系统的移动方向，中尺度对流系统向低层涡度增加的地方移动；强降水形成可概括为低层切变线东移诱发地面低压发展、引起垂直上升运动迅速增加、触发低层水汽的垂直输送和高不稳定能量强烈释放等过程。

Numerical Simulation Analysis of a Heavy Rain During Meiyu Season

By using the conventional observations and AREM model data, a rainstorm is analyzed based on the event in Hubei province during Meiyu season in 2005. It is found that there are two strong rising centers located respectively near 300 hPas and 600 hPas in the convection system when the strong rainfall happened. The single model distribution with low layer convergence matching the high layer divergence is the key condition to keep the rising movements, Environment wind can＇t control the moving direction of mesoscale convection system which moves to the place where the low layer vorticity is increasing. The forming process of rainstorm can be summarized as follows： the low pressure on ground caused by the low layer shear line east moving, the vertical rising movement increasing quickly, the low layer abundant vapor transport and the high and instability energy release.