用GPROF算法反演降水强度和水凝物垂直结构

THE RETRIEVALOF RAINFALL INTENSITY AND VERTICAL STRUCTURE OF HYDROMETERS USING GPROF ALGORITHM

  • 摘要: 对NASA应用于TMI的业务降水反演算法(GPROF算法)作了简单分析,并对采用该算法反演的2002年夏季我国湖南常德地区的暴雨结构和2001年7月上旬袭击中国香港地区的尤特台风结构进行了分析。对常德暴雨个例,用地面雷达数据作为实况资料进行了真实性检验。检验结果表明:该算法的整体反演效果较好,可较好地反演常德地区的地面雨强及降水结构,雨区的反演精度与降水性质有关。对尤特台风个例,将反演结果与测雨雷达的反演产品进行了定性比较,结果表明:二者反映的降水结构基本一致;GPROF算法反演的潜热垂直结构也较好地反映了台风的热力结构。最后对算法可能的改进方向进行了讨论。

     

    Abstract: The framework of GPROF algorithm, used as operational rainfall retrieval algorithm for TMI by NASA is introduced. GPROF algorithm is used to retrieve the rainfall intensity and vertical structure of hydrometers for some rainfall cases, including rain cases of Changde area in the summer of 2002 and a case of Utor typhoon attacking Hongkong on 5 July 2001, in terms of TMI 1B11 data. Comparison of GPROF algorithm retrievals with ground-based radar shows that GPROF algorithm retrievals can retrieve rain intensity well and indicate vertical structure of hydrometers mainly. As far as retrieved rain area, it is better for convective precipitation type than stratified precipitation type. Namely, GPROF algorithm can describe no-raining information better than infrared method especially for convective rainfall but it would leave some stratified precipitation areas out. Similarly, Comparison of GPROF algorithm retrievals with PR 2A25 products on ocean show that the results of GPROF algorithm can catch major rain information of typhoon and show that the results of GPROF algorithm can catch major rain information of typhoon and indicate vertical structure of hydrometers mainly. At same time, the retrieved latent heat can give some thermodynamic characters of typhoon, which ulteriorly help to understand climatic change and general circulation on earth. If an improvement of GPROF algorithm is made according to the precipitation characters of China, such as building a cloud-radiation database using the realistic profiles from measurement of models, considering it is a global algorithm, the precision of retrieval over China may be improved。

     

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