长江上游暴雨的边界层动力诊断研究

本文应用诊断分析方法研究了大气边界层动力特征与长江上游暴雨天气的关系。结果表明:大气边界层对暴雨天气有重要影响，成都边界层风场分量u，v＜０时，对应暴雨天气，u，v＞０时，无降水天气；边界层内正涡度、辐合、上升运动的出现、增强、减弱与暴雨的发生、发展、结束相联系；与青藏高原东部边缘东北－西南走向地势相关的边界层动力激发作用是长江上游暴雨产生的一种物理机制。

The PBL Dynamic Diagnosis of Heavy Rain over the Upper Reaches of the Changjiang River

In this paper,characteristics of the planetary boundary layer(PBL) and its relations with heavy rains in the upper reaches of the Changjiang myer are studied by the diagnostic analysis method The result shows that the PBL has important influence on heavy rains.Heavy rains happen when u,v components in the PBL in Chengdu are negative and it will be clear when the u,v components are positive.The appearance,strengthening and weakening if positive vorticity,convergence and ascending motion in the PBL are connected with the occurrence,development and end of heavy rains.Dynamical trigger in the PBL relating to the topography in the northeast-southwest direction at the eastern edge of Tibetan Plateau is one kind of physical mechanism for heavy rains in the upper reaches of the Changjiang River.