中文摘要：

利用2000----2009年5月和6月的NCEP1°×1°再分析资料和气象台站常规资料，对产生华南暖区暴雨的500hPa及以下的环流特征进行统计分析，并将影响暖区暴雨的环流系统划分为三大类型，即切变线型、低涡型和偏南风风速切变辐合型（简称偏南风型）。切变线型在南海夏季风爆发前以冷式切变为主，季风爆发后以暖式切变为主；低涡型在季风爆发前的发生次数远少于季风爆发后，在低涡中心的东北．东南方向最易产生暖区暴雨；偏南风型总体以西风风速切变辐合为主，而南风风速切变辐合在季风爆发后的比例有所增加。对影响暖区暴雨的高空槽分析发现，高原槽对暖区暴雨影响明显，其次为南支槽。低涡型最易受高空槽影响。对各种类型暖区暴雨的合成分析发现，各类型暖区暴雨500hPa高空槽的位置特点均不相同，暴雨辐合中心均在850hPa以下的低层，副高脊线距雨区约6～8纬距是产生华南暖区暴雨的重要天气形势。

英文摘要：

The primary datasets used in this study include the NCEP 1°×1° reanalysis data and conventional surface data. A statistical analysis on the features of the circulation under 500 hPa and a classification on the formation system of warm-sector heavy rainfall over South China in May and June from 2005--2008 are performed. The formation system of warm-sector heavy rainfall in South China is divided into three types of shear lines, low vortexes and shear of southerly wind velocity. In the type of shear line, heavy rain is usually caused by cold shear lines before the onset of the South China Sea （SCS） summer monsoon but by warm shear lines after it. In the low vortex type, warm-sector heavy rainfall, usually taking place northeast and southeast of the vortex center, happens less before the monsoon onset than after it. In the southerly wind velocity shear type, warm-sector heavy rainfall mainly results from the shear and convergence of west wind velocity, but it is caused by increasing cases of shear and convergence of south wind velocity after the monsoon onset. Study of upper-level troughs which affect the warm-sector heavy rainfall shows that their impacts on the rainfall are most significant, followed by that of the southern-branch trough. Composite analysis of warm-sector heavy rainfall shows that the convergence center is below the level of 850 hPa. That the ridge of the subtropical high is about 6 - 8 latitudinal degrees away from the rainfall is an important situation for the generation of warm-sector heavy rainfall. Different types of warm-sector heavy rainfall correspond to different 500 hPa trough characteristics.