Characteristics Of Convective System And Influence Of The Tibet Plateau Eastward Convective System On Precipitation In The Yangtze-Huaihe River Basin

The temporal and spatial distribution of Convection systems(CS) which influence the Yangtze-Huaihe River Basin and the parameter characteristics of convective systems (CS)from 1998 to 2007 were statistical analyzed by using Deep Convection Tracking Products Provided by the International satellite cloud Climate Program(ISCCP).The results showed that these CS are mainly concentrated in the spring and summer, mostly generated in the Yangtze-Huaihe River Basin and central and western regions of china. These CS present the zonal distribution characteristic of the center of the Yangtze-Huaih River Basin, and the closer to the area, the more dense. The number of CS is much larger than large scale convections. According to the source, these CS can be divided into 5 categories. Affected by climate conditions and topography, these CS are significantly different. Overall, the greater the horizontal scale of CS, the life cycle, the number of CCs and the cloud temperature gradient are greater.The mesoscale convective system (CS) of the eastern Qinghai Tibet Plateau,which can influenced the Yangtze-Huaihe River Basin, were extracted by the CT database. This paper analyzes the evolution of cloud physical properties of CS in the whole life history. And focuses on the analysis of the change of cloud physical properties and its contribution to the precipitation in the Yangtze-Huaihe River Basin after the eastward migration of CS into the Yangtze-Huaihe River Basin. The results show that the eastward CS which can influence the Yangtze-Huaihe River Basin source to 90 degrees E east of Tibet Plateau. These CS' life histories most concentrated within 150 h, the history of long life CS tend to have larger radius of convective system, and larger radius of convective clouds (CC) and the minimum radius of lower light cloud temperature. More than 90% of the plateau eastward into the Yangtze-Huaihe River Basin CS time are less than 12h, after entering the Yangtze River region CS has a new development.About 94.21% of these CS can precipitation in the Yangtze-Huaihe River Basin,the average precipitation intensity is about 1.64 mm/3h. The precipitation of the CS in the Yangtze-Huaihe River Basin is mainly in the southeastern regions and less in northwestern regions. The main precipitation area is in the middle section of the Yangtze River Basin, the Dabie Mountain and the Huangshan Mountains, and the northern plains are less. The diurnal variation of the plateau eastward into the Yangtze-Huaihe River Basin CS significantly changed, the precipitation is mainly concentrated from 11:00 pm to 23:00 pm, and the precipitation is less in early morning. The precipitation of the CS in the Yangtze-Huaihe River Basin is more times in spring, and the rainfall is small and the number in summer is small but the intensity is large. The disaster effect in the Yangtze-Huaihe River Basin is mainly due to the direct precipitation disaster caused by spring and summer.