沙丘粗糙面的二次极化电磁散射

研究了新月形沙丘粗糙面的二次极化电磁散射. 结合射线追踪理论, 由一次散射面元的反射场照射到二次散射面元, 采用基尔霍夫近似推导了二次散射面元的二次极化散射场. 计算结果表明二次极化散射结果在特定的角度和类型范围内有显著影响. 在电磁波射向背风坡时可以发现其同极化散射截面在入射角较大时大于其他入射方向的结果, 入射角在休止角附近时的交叉极化散射截面出现峰值, 以及前后狭长沙丘之间的二次极化散射特别突出. 本文结果可用于反演分析沙漠地区的风场信息. 关键词： 新月形沙丘 二次极化散射 射线追踪 休止角

Secondary electromagnetic polarimetric scattering from dune surface

Secondary electromagnetic polarimetric scattering from a barchan dune is studied. The secondary polarimetric scattering field from the secondary scattering facet is deduced in the Kirchhoff approximation with the waves reflecting from the first scattering facet based on the Ray-tracing theory. The results show that secondary scattering plays an important role in specific range of angle. The co-polarized backscattering coefficients of the lee slope have a local peak value when the incident angle equals the repose angle. Cross-polarized bistatic coefficient of the lee slope near the backscattering region is enhanced when the incident angle is close to the repose angle. The secondary polarimetric scattering between two dunes in line is especially noticeable. The information about wind field in desert region can be retrieved and analyzed by the results in this paper.
Keywords： barchan dune secondary polarimetric scattering ray tracing repose angle