2004-07-16河南大暴雨过程的湿位涡分析

Analysis on the Moist Potential Vorticity of the Heavy Rainstorm Process in Henan in July 16,2004

应用涅位涡理论，分析了2004年7月16—17日的强暴雨个例，发现有利于强降水发生的湿位涡场分布特征：对流低层MPV1〈0、同时MPV2〉0，有利于强降水发生。暴雨发生时，对流高层表现对流稳定，即MPV1〉0，低层MPV1〈0，为湿对流不稳定区；当两者相互作用时，即当高层干冷空气下滑与上升的低空高温高湿的空气交汇，容易储存和释放对流不稳定能量，利于暴雨的发生。低层西南急流不仅为暴雨的发生提供了丰沛的水汽，也为暴雨的发生提供了足够的热力和动力，因而使MPV2增大，垂直涡度得到发展，降水加剧。湿位涡在夏季可以作为河南省预报暴雨的一个有效辅助工具。

A process of heavy rain occurred on July,16th,2004 in henan province of moist potential vorticity （MPV） are analyzed. The relationship between MPV and this heavy rainstorm is discussed. The results show that there are favourable distributions of MPV in the heavy rainstorm occurred in Summer in Henan province. The change of MPV corresponds to the heavy rainstorm. When MPV1 〈 0 in the low tropospheric and MPV2 ≥0 ,there are advantageous fields of heavy rainstorm. On the other hands when the dry and cold air from the high level interacts the warm and moist air from the low level ,it is easy to store and release the convective instability energy , and it is useful for heavy rainstorm occurring.