Angular dependence of SAR backscatter around Mt Taranaki, New Zealand

An L-band SAR image from the Japanese JERS-1 satellite has been analysed for the effects of local surface orientation relative to the viewing angle. A high resolution digital terrain model is used to determine the local surface orientation and to orthorectify the SAR imagery. It is shown that the major variation in backscatter due to local incidence angle is accurately corrected for over a wide variety of slopes by simply accounting for the expected change in distributed scatterer density. Residual orientation effects are found to be dependent on the ground cover class. Backscatter from the indigenous forest was more isotropic than that from the farmland. Accurate registration was required for this study and a method of identifying control points in the rectified imagery is described