Modelling of VHF radar backscattering from forests based on radiative transfer

The CARABAS system is a wide band SAR, that operates at VHF frequencies (20-90 MHz). The image information includes a higher dynamic range in the radar backscattering from forested areas of varying stem volume, than what has been found using conventional microwave SAR. A modified MIMICS model has been used to model the radar backscattering at VHF. The various terms in the solution have been added coherently, taking the variation with height above ground and the phase shift of the ground reflection into account. The results show an improved agreement with measured data.