TRMM卫星微波成像仪资料的陆面降水反演

RETRIEVAL OF PRECIPITATION OVER LAND USING TRMM MICROWAVE IMAGE

关键词:  TRMM卫星  资料匹配  反演降水  算式  比较

Key words:  TRMM satellite  data matching  retrieval of precipitation  algorithms  comparison

摘要:

为了探讨微波亮温与降水的关系,用TRMM卫星上微波降水雷达PR、微波辐射计TMI资料和973资料组提供的2002年6～7月120站的每小时自记降水记录,采用逐步回归方法,反演陆面降水。通过资料匹配分析显示,由于时空匹配问题,站点降水与微波辐射计亮温及亮温的组合因子的相关性并不高,明显低于TRMM卫星的测雨雷达PR与微波辐射计亮温及其组合因子的相关程度,因此仅用微波亮温和站点降水难以建立较好的反演算式。结合时空匹配较好的TRMM卫星降水雷达PR、微波辐射计TMI资料,建立新的算式,并且和其它算式进行比较。就反演降水结果而言,新算式比原有算式有一定改善,但对6～10mm/h的降水来说,新算式与原有算式反演结果都较差。

Abstract:

In this paper,precipitation over land was retrieved using collocated data from a precipitation radar(PR),TMI on the Tropical Rainfall Measuring Mission satellite(TRMM) and the hourly surface rainfall measurements of 120 stations from June to July in 2002 provided by the "973" data group.Through data matching and analysis,It is shown that the hourly rainfall from the stations do not correlate well with corresponding brightness temperatures and their combination factors,but are much lower than the correlation of the precipitation radar(PR) with corresponding brightness temperatures and their combination factors,due to the poor match between time and space.So it is hard to establish a retrieval algorithm if only the hourly rainfall from stations and the corresponding brightness temperatures are used.A new statistical algorithm was built with the precipitation radar data from the PR and the corresponding brightness temperatures data from TMI,and then compared with the old algorithm.As far as the retrieved result of precipitation is concerned,the new retrieval algorithm has certain improvements compared with the original one.But for precipitation of 6～10 mm/h,neither the new retrieval algorithm nor the original retrieval algorithm performs well.