中文摘要：

利用自动站降水资料、卫星综合降水CMORPH资料、卫星TBB资料、雷达回波资料以及NCEP再分析资料等,分析了2007年5月26日发生在华南地区的一次暴雨过程,主要研究了与暴雨过程相关的中β尺度对流系统（Mβcss）的发展演变特征。结果表明：（1）本次暴雨过程形成于地面低压倒槽及西南低空急流的左侧,暴雨区斜压特征不明显,是一次比较典型的暖区暴雨过程 （2）暴雨至少与三个连续生消的Mβcss的活动直接相关,不同暴雨落区中降水峰值出现的时间与相应Mβcss发展强盛期对应关系良好 （3）Mβcss的发展演变表现为后向次第发展的形式,与华南另一种较为常见的前向次第发展类型不同,即新的对流系统主要在原Mβcss的后部形成 （4）引发暴雨的中β尺度对流系统形成于850hPa西南低空急流左侧的辐合区,高层200hPa有明显辐散气流。但与典型华南前汛期暴雨区上空对应为南亚高压东侧向外辐散的类型不同,本次暖区暴雨位于入海南亚高压西侧的偏东和偏南气流的辐散区下方。（5）低空急流不仅为暴雨区输送了丰富的暖湿空气,有利于中低层高不稳定能量存储区形成,相应的暖空气平流对对流系统的形成可能有更直接的作用。从地面中尺度流场出发,对这些暖区暴雨对流系统形成和发展的可能触发机制进行了有意义的讨论。

英文摘要：

With multiple meteorological data, including those of precipitation from automatic stations, integrated satellite-based precipitation（CMORPH）, brightness temperature（TBB）, radar echoes and NCEP reanalysis data, analysis is performed of a heavy rainfall event that occurred on 26 May 2007 over South China with the focus on the evolution characteristics of associated meso-βconvective systems（M βcss）. The results are shown as follows. （1） The heavy rain presents itself as a typical warm sector event, for it occurs within a surface inverted low trough and on the left side of a southwesterly low level jet（LLJ）, which shows no obvious features of baroclinicity. （2） The heavy rainfall event is directly related to at least three M βcss with peak precipitation corresponding well to their mature stages. （3） The M βscss manifest a backward propagation, which is marked with a new form of downstream convection different from the more usual type of forward propagation over South China, i.e. new convective systems mainly form in the rear part of older M βscss. （4） Heavy-rain-causing M ,Scss form near the convergence region on the left side of an 850 hPa southwesterly LLJ, over which at 200 hPa there are dominantly divergent air flows. Different from the typical flow pattern of outward divergence off the east side of South Asia High, which is usually found to be over zones of heavy rains during the annually first rainy season of South China, this warm sector heavy rain is below the divergence region formed between the easterly and southerly flows west to the South Asian High that is moving out to sea. （5） The LLJ transports abundant amount of warm and moist air to the heavy rainfall area, providing advantageous conditions for highly unstable energy to generate and store at middle and high levels, where corresponding low level warm advection may be playing a more direct role in the development of M βcss. As a triggering mechanism for organized convective systems, the effect of low level wa