“13·6·30”遂宁市特大暴雨成因的初探

利用自动气象站雨量资料、常规观测资料、雷达资料以及NCEP再分析资料,对2013年6月30日至7月2日四川遂宁地区特大暴雨过程中高原低涡和西南涡的耦合作用对本次特大暴雨的影响以及低空急流演化特征和强暴雨的关系进行初步探讨。结果表明:当高原涡和西南涡发生耦合时会使得高空低涡发展加强,并激发遂宁暴雨天气的产生。急流为高空低涡的发展提供不稳定能量。超低空急流和低空急流对强降水有提前2 h的指示意义,低空急流指数增大的过程和降水量的强度成正比关系。

Primary Study of the Extreme Rainfall Event in Suining City on 30 June 2013

Based on the rain gauge data from automatic weather stations, conventional observations and NCEP analysis data, the extreme rainstorm that hit Suining City from 30 June to 2 July 2013 and the relationship between the extreme rainstorm and the LLJ evolution are studied primarily. This extrem event was caused by the coupling interaction between plateau and southwest vortexes. The results show that the high level vortex development is strengthened when the coupling interaction occurs between plateau and southwest vortexes, stimulating the generation of rainstorms in Suining City. Jet stream provides unstable energy for the development of high level vortex. Ultra low level jet and low level jet cannot cause a strong rainfall immediately, and sometimes severe rainfall process may occur two hours later. The degree of increase in the low level jet index (I) and the intensity of rainfall have a direct proportional relationship.