An Estimation-Based Precipitation Retrieval Algorithm for Attenuating Radars
An Estimation-Based Precipitation Retrieval Algorithm for Attenuating Radars
复制标题
基于估计的衰减雷达降水反演算法
DOI：
10.1175/1520-0450(2002)041
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
G. Stephens
中科院分区：
文献类型：
--
作者：
T. L’Ecuyer;G. Stephens
摘要介绍了一种利用星载雷达反演降雨剖面的新方法。由于星载雷达应用中所需的频率，降雨和液云粒子的衰减是不可忽视的，必须在做出定量降雨估计之前准确计算。所提出的方法基于最小化代价函数，该代价函数允许人们在迭代过程中直接考虑每一级的衰减。此外，该算法不调用瑞利近似，因此适用于星载雷达的波长特性。该方法对于要反演的参数是灵活的，并且非常适合于添加来自其他传感器的测量，例如被动微波辐射计，以限制反演。采用简化的液滴尺寸分布和颗粒形状假设的初步结果表明，在衰减不是很大的情况下，算法是有效的。
Abstract A new method for retrieving rainfall profiles from a spaceborne radar is introduced. As a result of the frequencies necessary in spaceborne radar applications, attenuation by both rainfall and liquid cloud particles is nonnegligible and must be accurately accounted for before quantitative rainfall estimates can be made. The proposed method is based on the minimization of a cost function that allows one to account for attenuation at each level directly in the iteration process. In addition, the algorithm does not invoke the Rayleigh approximation and is, therefore, applicable at wavelengths characteristic of spaceborne radars. The method is flexible with regard to the parameters to be retrieved and is well-suited for the addition of measurements from other sensors, such as a passive microwave radiometer, to constrain the retrieval. Preliminary results, using simplified assumptions of drop size distribution and particle shape, illustrate the utility of the algorithm provided the attenuation is not ...