【摘要】 利用静止卫星云图和天气图,分析了1981—2004年6—8月发生在湖北省的14场特大暴雨过程。分析结果表明:在这些特大暴雨过程发生、发展中,不仅存在着大量的水汽输送,而且还存在着大量的液态水输送,表现为特大暴雨区的上游方向,在850 hPa和700 hPa存在一个或几个中尺度的水汽(近饱和)和液态水(饱和)源,在这些暴雨过程的形成过程中,这些源持续向暴雨区输送水汽和液态水。特大暴雨的触发系统对应的云系多为中尺度涡旋云系和准纬向斜压叶云系。文章还分析总结了湖北省特大暴雨过程的若干卫星云图环境云场特点和形成过程的物理图像特征,进而讨论了特大暴雨的形成机理,认为特大暴雨是由中尺度涡旋或高空急流东移叠置在"露点锋"上或暖湿空气上触发而成,CISK是其主要作用机理,"露点锋"在特大暴雨的触发中起到了重要作用。更多还原

【Abstract】 The geostationary satellite images and synoptic maps of 14 cases of excessive heavy rain occurred in Hubei Province from 1981 to 2003 were analyzed carefully.Not only water vapor but also liquid water transfer had been found in these cases.It was found that the triggering precipitation cloud systems of excessive heavy rain were quasi-zonal baroclinic leaf cloud system and mesoscale vortex cloud system.Ambient cloud fields characteristics of satellite cloud image and four image types of excessive heavy rain were deduced.The mechanism of excessive heavy rain was that the excessive heavy rain was triggered by mesoscale eddy or upper level jet stream moving eastward and covering the "dew point front" and warm moisture air mass.The "CISK" was the main mechanism.The "dew point front" played a key role in triggering and keeping the excessive heavy rain.更多还原