使用物理方法反演中国陆地雨强和水凝物垂直结构

The retrieval of the rainfall intensity and the vertical structure of hydrometers over land in China using the physical algorithm

中文关键词:  MM5模式，蒙特卡罗辐射传输模式，微波成像仪（TMI），云-辐射数据集，GPROF算法

英文关键词:MM5 mesoscale model, Monte Carlo radiative transfer model, TMI, Cloud radiation database, GPROF algorithm

中文摘要:

      使用MM5模式模拟了11个降水个例，获得中国陆地的降水廓线，由蒙特卡罗辐射传输模式计算其上行辐射亮温，构成初始云 辐射数据库。采用对照表方法从中获得Db_m1和Db_m2两个数据集，作为GPROF反演算法的先验数据集。对2007年7月的3次强降水过程的地面雨强进行反演，与微波成像仪（TMI）及NESDIS、GSCAT、PCT-SI 3种经验算法反演的雨强比较，发现Db_m2参与反演的地面雨强和TMI的反演结果比较接近，效果明显优于Db_m1获得的反演结果，甚至优于3种经验算法的反演结果。使用测雨雷达、地面S波段雷达反演的雨强分别检验上述各算法反演雨强的综合效果，表明Db_m2和TMI反演的结果综合效果较好，经验算法中以PCT SI综合指数法效果比较好。数据集Db_m2参与反演的可降水在垂直分布和含量上与TMI反演的结果非常一致，与地面雷达反演的液态水含量也较接近；而云水、云冰和可降冰与TMI反演结果在垂直高度分布上较接近，含量上高于TMI的结果。使用数据集Db_m1反演的4种水凝物垂直结构与使用Db_m2的结果在垂直分布上基本一致，可降水含量略低一些，云水含量有时偏低。综上，研究使用数据集Db_m1和Db_m2对地面雨强的反演具有一定的准确性，反演的水凝物结构与TMI反演的结果有相近之处，可作为发展适用于中国的由微波亮温反演地面雨强和水凝物廓线的一种物理方法。

英文摘要:

      In order to construct the cloud radiation database, 11 precipitating systems were simulated by the MM5 to obtain the rainfall profiles whose upwelling radiative brightness temperatures were computed by the Monte Carlo radiative transfer model. Then as the priori databases, the Db_m1 and Db_m2 were extracted from the cloud radiation database by using check list. The rain rates of three precipitation systems during July 2007 were retrieved by importing Db_m1 and Db_m2 to the GPROF algorithm respectively. Comparing with the results from the TMI and three statistic algorithms, the rain rate from Db_m2 was close to the TMI's and better than that from Db_m1 obviously, even better than those from NESDIS, GSCAT and PCT SI algorithms sometimes. The rainfall intensities from the PR and the Doppler radar on land surface were used to inspect the results calculated by the aforementioned methods. It is found that the Db_m2 and TMI are preferable and the result from the PCT SI algorithm is better than the other statistic algorithms. Among the 4 kinds of hydrometeors retrieved by Db_m2, the precipitable water (pw) displays consistent with that from the TMI or Doppler radar on land surface. The vertical distributions of the other three hydrometeors including cloud water (cw), cloud ice (ci) and precipitable ice (pi) are close to those from the TMI. However the contents of those 3 kinds of hydrometeors are several times as large as those from the TMI respectively. The hydrometeor structures obtained from the Db_m1 are consistent to those from the Db_m2, except that the content of pw is lower, and so does cw sometimes. Thus, the algorithm constructed in this study has a positive effect on retrieving rainfall intensity and the structures of hydrometeors to some extent. It can be regarded as a successful attempt to improve the physical algorithm applied in China with which the rainfall intensity and hydrometeor structures can be retrieved from brightness temperatures. 