应用先进微波探测器AMSU资料遥感反演春季陆地表层湿度

Spring Soil Moisture Retrieving by AMSU-AMicrowave Remote Sensing Data

利用先进微波探测器 (AMSU)正演快速微波辐射传输模型 ,完成了AMSU窗区通道亮温与地表温湿特征的相关性分析 ,根据模拟计算结果改进了现有业务上反演地表微波辐射率的统计分析方法 ,得到适用于我国非冻土积雪覆盖地区地表微波辐射率反演的指数分析模型 ;进一步通过地表微波辐射传输模型迭代反演得到土壤体积含水量信息。2 0 0 1年相互匹配的AMSU资料和地面农业气象观测站地表相对湿度观测结果的对比分析表明二者间具有一定的相关性。利用 2 0 0 2年 3月和 2 0 0 3年 3月的AMSU资料 ,反演了我国陆地区域地表湿度 ;连续两年春季地表湿度反演结果的对比分析表明 ,与 2 0 0 2年春季相比 ,2 0 0 3年我国北方沙尘暴发生源区地表湿度反演值普遍偏高 ,潮湿的下垫面特征与沙尘暴发生频次的减少之间有一定的对应关系。试验结果表明 ,利用AMSU遥感资料可以获取大范围陆地表层湿度信息 ,进行区域尺度陆地表层湿度特征的动态分析 ,为我国沙尘暴监测分析提供陆地表层湿度基础信息。

Remote sensing of soil moisture by microwave radiometry has been a subject of intensive studies in the past two decades. Following the studies done before, retrieval of the terrain surface microwave emissivity from the remote sensing data of the AMSU-A is studied. Based on radiance transfer simulation, the AMSU-A brightness temperature index is defined for emissivity retrieval. The surface emissivity retrieved is applicable to the soil moisture retrieval on regional scale. Surface moisture information of regional scale over North China in March 2003 and March 2002 was retrieved by use of semi-empirical method based on the results of surface microwave radiance forward simulation. Good results were obtained by the comparison with surface observation data. The algorithm can be used to detect the surface moisture dynamically. The retrieval results can be a new data source of land surface physical parameters for sand storm simulation.