摘要
热带测雨卫星TRMM(TropicalRainfallMeasuringMission)于 1 997年 1 1月发射成功 ,其首次携带了空载雷达 ,有关资料已在网上对公众发布。利用热带测雨卫星上的微波成像仪TMI(TRMMMicrowaveImager)资料以及其和测雨雷达TRMM/PR(PrecipitationRadar)资料联合反演的地面瞬时降水产品 ,采用散射指数 (Is)法从理论上探讨了我国江淮、华南降水尤其是暴雨的微波特性 ,其中Is 表达式通过江淮、华南晴空TMI资料统计回归得到。以联合反演的地面瞬时降水产品为真值 ,用面积相当法对 1 4个降水个例求Is降水阈值 ,研究了阈值和降水面积以及 85 .5GHz垂直通道最低亮温的关系 ,并寻求了Is和降水的相关特征。研究表明 :Is降水阈值随降水面积的增大或 85 .5GHz垂直通道最低亮温的降低有增高的趋势 ;Is与强对流性降水瞬时雨强对应很好 ,Is≥ 60K是一个好的暴雨指标。最后进行了初步的雨强反演试验研究 ,由于TMI资料分辨率的提高以及时空配合较好的真值 。
TRMM (Tropical Rainfall Measurement Mission) was launched in December 1997, which carried a space radar for the first time and the related data have been made available to the public users since June 1998. The microwave characteristics of rainfall over South China and the Yangtze river basin are investigated by using TMI (TRMM Microwave Imager) data and TRMM derived precipitation products through I s (Scattering Index) algorithm. The expression of the I s is regressed by the TMI data on sunny days. For 14 rainfall cases, the relationship between the I s precipitation threshold obtained through the “area equal' method and the precipitation area and the coldest top temperature of 85.5 GHz vertical channel is investigated. At the same time, the correlation between I s and surface instantaneous rain intensity is studied. The result shows that the I s threshold has the increasing tendency when the precipitation area increases or the top temperature decreases, and I s ≥60 K is a good index of rainstorm. The instantaneous rain intensity is retrieved, and it is found that I s can be used to retrieve rain intensity better because of the improvement of data resolution and the temporal and spatial consistency of the data.
出处
《应用气象学报》
CSCD
北大核心
2003年第2期206-214,共9页
Journal of Applied Meteorological Science
基金
国家重点基础研究发展规划项目 (G19980 4 0 90 9)
优秀归国留学人员重点基金共同资助
