Polarization Orientation Angle and Scattering Characteristics of Steep Terrain

In this paper, we address polarimetric radar scattering from steep terrain and its relation to polarization orientation angle (POA) by adopting a tilted surface model based on Bragg scattering. We found that, as the azimuthal slope increases, |VV| decreases at a faster rate than |HH|, they become equal, when POA is ±45°, and |HH|>|VV| afterwards. Contrasting to the general perception, the cross-pol |HV| does not always increase with azimuth slope, but reaches a maximum then decreases to zero. In addition, we investigate the effect of soil moisture on PolSAR scattering characteristics of steep terrain and the effect of vegetation over surface on POA estimation. The latter is demonstrated with NASA/JPL TOPSAR L-band PolSAR data and C-band InSAR data.