中文摘要：

利用TRMM卫星测雨雷达探测反演的降水廓线、红外辐射温度、微波高频辐射亮温和闪电资料，并结合数字地形资料和NCEP再分析资料，分析研究了1999年5月4日13：05（UTC，下同）青藏高原东南部某山谷及附近地区（29．49°N-30．13°N，95．08°E～96．89°E）的降水云结构。结果表明，该降水云团为特殊地形强迫而引起的一强对流降水；强对流降水云团水平范围约20km，它自谷地向上呈“蘑菇”状向上水平展开；最大降水率位于谷中云体下部，超过100mm·h；在谷地上方该强对流降水云团云体向下风方向延伸，形成下风方向大范围的弱降水。结果还表明，强对流降水云团中剧烈变化的地表降水率也反映在云团云顶红外辐射温度和云体微波辐射亮温的变化上。此外，虽然闪电附近云顶高度和云中的含冰量相差甚小，但闪电发生次数、持续时间和发出的辐射能量却十分不均。降水事件的天气背景分析表明，降水发生前13h内，高原500hPa一弱低压槽东移引起的大气低层辐合、中高层辐散及大气不稳定性增加，是此次降水事件发生的大气内在因素。

英文摘要：

The precipitation cloud structures of a rain event in a valley area （29.49°-30.13°N, 95.08° -96.89°E）of southern Tibetan Plateau detected by TRMM satellite at 13：05 （UTC） on May 4, 1999 are studied by using standard TRMM data sets of precipitation profile, infrared radiant temperature, microwave brightness temperature at high frequent channel and flash together with topographic data as well as NCEP data. Results indicate that this precipitation cloud is a strong local convective precipitation system induced by the topographic forcing effect. The horizontal scale of the precipitation cloud is about 20 km. In vertical direction, the cloud shape extends outwards from the bottom of the valley to the upper like ＂mushroom＂. Results also show that the maximum rain rate is more than 100 mm·h^-1 , which is located in the lower level of the cloud within the valley. Above the valley, the strong convective cloud body stretches in the wide downwind region where weak precipitation is produced. The studies expose consuming variations of IR radiant temperature from cloud top and microwave brightness temperature from cloud body corresponding to intensive surface rain rates of the strong convective precipitation cloud： Furthermore, the analysis illustrates the very inhomogenous distributions of flash frequency, duration and radiance energy in the cloud although relative small differences of cloud tops and ice contents near each flash location. Synoptic analysis shows that the rain event is produced by a weak low pressure trough eastward moving in 500 hPa over the Plateau 13 hours before the rain event detected by TRMM satellite, which induces convergence in the lower atmosphere, divergence in the middle and upper atmosphere, as well as increases of atmospheric instability.