地形坡面对被动微波遥感影响的试验研究

地表起伏所形成的倾斜表面,特别是在山区,受地形坡度和坡向变化的影响,地表的微波辐射特征较之平坦地表发生明显变化。基于地基微波辐射地形试验,模拟星载被动微波辐射计AMSR\|E的观测参数,通过建立地形坡面的地貌微缩景观进行观测,探索地表斜坡对被动微波辐射特征的影响,用AIEM模型 和 Fresnel 方程分别模拟裸土地形坡面的微波辐射特征。结果表明,倾斜坡面对被动微波辐射的亮度温度产生了10~15 K的偏差,由坡度形成的本地入射角改变了地表的有效发射率,并随坡向的变化发生微波极化旋转。经试验数据和模型模拟结果对比,认为AIEM 在考虑了表面粗糙度影响时可以较好地模拟地形坡面的被动微波辐射特征。

Measurement and Simulation of Hill\|slope Effects on Passive Microwave Remote Sensing

Hill\|slope terrain has an essential influence on microwave radiation due to slope angles and aspects.It is necessary to experiment in the field by observed different topographic landscapes we designed based on the trunk\|mounted microwave radiometer.In the configuration of AMSR\|E,the observed data compared with simulations of relief effects modeled by AIEM and Fresnel equation.The result shows there are 10~15K bias of brightness temperatures affected by tilted angles between flat terrain and mountainous terrain.When frequencies less than 10 GHz,the relief effect of terrain elevation becomes weakened.And we certified that microwave polarization path and direction changed for surface geometrical property,such as shape and the orientation of hills.