用双矩阵法和积分方程模型估算地表的亮度温度

提出了一种估计覆盖植被的地表亮度温度模型。模型中的植被看作是不同大小和朝向的离散散射体如叶、茎、杆构成。植被层内的体散射以及植被与地表之间的多次散射采用了双矩阵法(M atrix Doub ling)计算,地表辐射采用了积分方程模型(Integral Equation M ethod)。较高频率上的模拟结果显示植被的辐射是主要的,植被对地表辐射的衰减作用较明显。模拟的亮度温度跟SGP99机载C波段以及AMSR-E的X和Ku波段实测数据相比接近一致。

An Estimation of Brightness Temperature for Vegetated Surface by Matrix Doubling Method and IEM

In this paper, a model is proposed to estimate the brightness temperature of vegetated surface based on ray tracing technique to account for increasing multiple scattering effects as frequencies goes higher. The vegetation layer is composed of discrete scatters such as leaf, branch and stalk. The multiple scattering inside the vegetation layer and that between the vegetation and soil surface is accounted for by Matrix Doubling. The surface emission is calculated by IEM(Integral Equation Method) algorithm. Simulation results at higher frequency show that the emission from vegetation layer is dominant, and that the vegetation has obvious extinction to surface. A good agreement is obtained by comparison of the simulation with air-bone PSR(Polarimetric Scanning Radiometer) C\|band data, and X- and Ku-band data from AMSR-E.