双层植被电磁散射模型分析及实验对比

Computation of a two-layer canopy model and comparison with measured data

基于矢量辐射输运理论,根据广义瑞利 金斯近似理论计算了单个植被叶片的后向散射系数随着入射角和尺寸参数的变化曲线.采用矢量辐射输运方程的零阶和一阶迭代解,考虑了地面相干散射的影响,详细描述并计算了双层植被散射模型的后向散射系数,并与文献实测数据对比分析,得到了较好的吻合结果.

A canopy layer is usually modeled as a random medium composed of many discrete scatters such as circular disks, needles and cylinders. The scattering field of a disk is estimated by the generalized RayleighGans approximation and that of a finite length cylinder is estimated by the field of the same cylinder of infinite length. The effect of different methods on the backscattering cross section is compared numerically for a disk, a needle and a cylinder as the incidence angle and wave number. Finally the backscattering cross section of a canopy layer is obtained and compared with measurements. Good agreement is obtained.