Abstract: The effects of topography on the surface layer winds were diagnosed by using a one-level mesoscale model. Some convergence lines forced by complex terrain were found in the leeside of mountains and coinsided with the heavy rainfall. Theresults of these experiments indicate that the influence created bythe deflection of low-level flow around the mountains would be seriously considered in the mesoscale diagnostic analys is of the heavy rainfall, especially in the leeward side.

Key words: terrain-covergence zone, detour flow, covergence area in the leeside of mountain

摘要： 本文的目的是为了研究复杂地形中的中尺度环流特征。在统计分析黑龙江省地形－环流－暴雨关系的基础上，应用一层σ坐标中尺度模式对局部复杂地形进行数值模拟。选取的个例是一次北上台风和西风带冷空气相结合的暴雨过程。模拟结果表明，有一些明显的中尺度地形辐合带（100～200km）与暴雨中心相对应。最强的辐合带出现在喇叭口地形附近。另外，在一些山包背风坡也有较强的辐合带。理想的椭圆形孤立山地的试验，更清楚看出地形周围的气流分布。绕流作用造成的迎风坡辐散和背风坡辐合非常明显。这说明，在暴雨中尺度诊断分析中，除了考虑地形爬坡作用外，还必须重视地形的绕流作用。

关键词: 地形辐合带, 绕流作用, 背风坡辐合区