基于降雨率的GMF+RAIN模型构建及在台风风场反演中的应用

首先选取2006年QuikSCAT散射计扫描的3次台风个例("珊珊"、"摩羯"及"象神"),分析其获取的台风区域雷达后向散射截面值(σ^o)在降雨影响下的分布特征.然后依据大气辐射传输理论,考虑降雨对雷达后向散射截面值的影响,引进两个不同形式的降雨辐射传输模型(简称为SY和AMSR模型),并将这两个降雨辐射传输模型分别与NSCAT2模型函数相结合,构建了适合降雨情况的地球物理模型函数(简称为GMF+RAIN).最后,在GMF+RAIN模型的基础上,采用二维变分结合多解方案

New GMF+RAIN model based on rain rate and application in typhoon wind retrieval

This paper firstly selects three typhoon cases (SHANSHAN, YAGI, XANGSANE) which occurred in 2006, and analyzes the distribution characteristic of the normalized radar cross-section (NRCS, σ^o), which were received by QuikSCAT scatterometer in the case of rain effect. Secondly, in order to account for the effects of rain to σ^o, we follow the theory of atmospheric radiation transfer and introduce two different types of rain radiation transfer models (called SY model and AMSR model, respectively), then combine these two models with NSCAT2 GMF to produce an improved GMF suitable for the case of rain effect (called GMF+RAIN). Lastly, based on this GMF+RAIN, we use the ambiguity removal method which integrates 2DVAR (two-dimensional variational assimilation) with MSS (multiple solution scheme) to retrieve the YAGI and XANGSANE typhoon wind fields which had different intensity. The new approach which combines GMF+RAIN with 2DVAR+MSS improves the result, which further verifies the effectiveness of GMF+RAIN. This new approach also makes the scatterometer data more effective and valuable for application in the research of typhoon.