Topography Effects on Brightness Temperature in Remote Sensing at L-band

Current retrieval algorithms for microwave remote sensing of soil moisture, generally assume a two-dimensional geometry (horizontal plane) possibly with small scale roughness appropriate for agriculture. However, for accurate retrievals of soil moisture on a global scale, the impact of earth’s topography on the sensor output needs to be investigated. In this paper, an analytical study of the impact of topography on antenna temperature is presented using Digital Elevation Maps (DEM) for the site of the Soil Moisture Experiment (SMEX04). The results predict a large impact for rough terrain at large incidence angles. 1