2003年秋季华北地区一次区域性大暴雨分析

通过对2003年10月10～12日发生在华北地区的一场罕见大范围暴雨、区域性大暴雨天气的分析发现，生成于孟加拉湾的季风云团及其向东北方向扩展的西南季风云系与高空急流云系的结合为区域性大暴雨的形成打下了基础；高、低空急流的耦合及中、低空系统的上下叠加为大暴雨的形成创造了良好的动力场；多支低空急流的形成为大暴雨提供了有利的水汽条件。

Cause Analysis of a Heavy Rainfall Eventin North China in Autumn 2003

Based on the synoptic theory, a heavy rain event in East China during 10-12, Oct. 2003 is studied. Results show that the monsoon cloud system generated in the Bay of Bengal and the spreading northeastward monsoon cluster and the upper-level jet cloud are the main synoptic systems. The interaction of low-level jet and upper-level jet attributes the good dynamic condition. After the analysis of the cloud images data and numerical products, it is found that the heavy precipitation is located in the area with characters both low-level strong convergence and strong vapor supplement.