利用TRMM/TMI资料提取地表层湿度信息试验

Retrieving Soil Moisture from TRMM/TMI

模拟分析了地表层湿度反演过程中地表及大气各种因素(卫星扫描角、地表粗糙度、地表植被覆盖和大气)对反演结果的影响情况;应用正演模拟技术得到了利用TMI低频10GHz通道微波极化比反演地表层湿度信息时,斜率和截距随像元植被覆盖度可调的反演方程;确定了反演方程中斜率、截距系数随像元植被覆盖度变化的对数关系和线性关系;反演技术中综合应用了多种途径获取到的被动微波像元中动态的植被覆盖信息;尝试了将这些因子用于地表层湿度反演的可行性;对于反演结果,研究工作中利用地表HUBEX外场观测资料进行了对比分析,得到了空间分布特征和时间演变趋势比较一致的对比分析结果。

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, a new approach to retrieve surface layer soil moisture is accomplished in this paper, in which the passive microwave data of TRMM/TMI and ground observation data have been used to retrieve surface soil moisture. Surface and atmosphere microwave radiance transfer models have been applied to analyze the effects of surface and atmosphere, e. g. scan angle, surface roughness, and canopy layer. In the retrieval technique for TMI low frequency, variable gain and intercept appeared. Multi-spectrum remote sensing information, surface digital elevation measurement data, and mixed-pixel information were involved. The consistency was obtained between the retrieval results and ground observation or HUBEX IOP data.