一次滇西南秋季暴雨的中尺度分析与诊断

The Meso-Scale Diagnostic Study on a Heavy Rain in Southwest Yunnan Autumn

应用大尺度物理量场诊断分析和中尺度带通滤波处理技术,对2001年10月25日发生在云南西南部的一次暴雨过程机制进行了分析。结果表明,在副热带高压(下称副高)外围大尺度西南气流环境场中,中尺度系统是此次暴雨产生的直接原因;大尺度环境场为暴雨的发生提供了充沛的水汽来源,而中尺度系统则在水汽的强烈辐合、向上输送,使对流层中下层达到准饱和状态扮演了十分重要的角色。

By using the diagnostic methods of largescale circulation and the mesoscale bandpass filter, the mechanism of the storm rainfall occurring in the southwest region of Yunnan province on 25 October 2001 are analysied in this paper. The results show that the mesoscale weather system is the direct cause of the storm rainfall occurring in the southwest flow outside the subtropical high; The largescale circulation provide an abundance of vapour source for storm rainfall occurring, but the mesoscale weather system act as an important factor in which the vapour has the strong convergence and upward transport, and make the midlower troposphere to get at quasisaturation state.