关键词: 暴雨, 热点, 辐合, 雨影

Abstract: In this article. we analyse the influence of complex mountain surface layer on the formation and distribution of storm rainfall. The results show that topographically induced convergence and upward motion is one of the most important mechanism that may cause and strengthen storm rainfall. In moist regions, precipitation of storm rainfall caused by topography is much more than in less moist regions.In the humid region. leeward slope is usually dry with little or no rainfall, that is the so called rain shadow. In the semi-humid region with strong stable air passing over niountain. there is a high frenquency of leeward wave storm rainfall. In this srtuation. leeward wave storm rainfall is about eight times of that of windword slope. In the arid region. local gale may occur on leeward slope with little or no rainfall.Local thermal circulation and land-water circulation may cause cyclonic convergence with violent convective motion which can motivate nocturnal storm rainfall in the semi-humid region. In humid region, however. it may cause storm rainfall which is very strong but only lasts a short time.This kind of storm rainfall is dangerous but difficult to predict.In the mountain valleys. the moist warm air flows more paralell to the valley. storm rainfall is more easy to form or become strong. On the contrary. with air flow direction perpendicular to valley direction, the valley will be filled by dry and relatively hot air with no rainfall.

Key words: storm rainfall, heatspot, convergence, rain shadow