成都地区一次暴雨诊断分析

Diagnostic Analysis on the Precipitation Process of Rainstorm in Chengdu Country

针对2012年8月16-19日成都地区出现短时、局地暴雨、特大暴雨的异常强降水天气，利用常规气象资料、1°×1°NCEP再分析资料和客观物理量场、卫星云图等资料，对造成此次强降水主要集中在成都地区西部沿山一带的原因进行了分析。分析得出：在有利的环流背景下，中小尺度系统发生发展和演变是这次暴雨产生的直接原因；中低层维持偏南气流，暖湿气流西进北抬，低空急流为这次暴雨提供了大量的水汽和不稳定能量；中低空的水平风切变不仅为暴雨提供了强烈的辐合上升运动，同时对水汽的水平辐合和垂直输送非常有利；另外，强对流云团的生成、移动与强降水的发生密切相连相关。

According to the intensive Heavy Rainfall was produced over the Chengdu country on 16- 19 August, 2012. By using the conventional observation, 1°×1°NCEP reanalysis data and objective physical, satellite image data, analysis the main reason why the strong rainfall mainly concentrated in the west mountain of Chengdu area. Based on the results of prognostic analysis, we found that the generation, development and evolution of me so-small is immediate factor of this heavy rainfall under the favorable synoptic situation. Maintenance of south low jet stream and the warm wet air move in northwest; and the low-level jet supplies abundant water vapor and convective available potential energy（CAPE） for intensive convection; strong convergence contributing to horizontal wind shear is located on the both sides of mid/low-level wind shear axis, which not only provides strong vertical ascending, but also transports the low-level water to level of free convection（LEC）, and releases the CAPE in water vapor to enhance the vertical motion.