Influence of ice and snow properties on ice ridge mapping by SAR

Effects of different ice and snow properties on the signature of ice ridges in ERS-1 SAR images are investigated. Scattering models based on the physical optics approximation are applied to surface backscatter from ice ridges and frozen brash ice. In situ ice properties are used as input and the results are compared with SAR image signatures and radar scatterometer measurements. The results indicate that C-band backscattering from ice ridges composed of blocks is mainly dependent on the slope distribution of the ice blocks. The agreement between model and measurements is good for cases with slopes less than 0.4. The observed backscattering coefficients of frozen brash ice are almost as high as for ridged ice. The scattering model for brash ice is sensitive to the shape of the surface height correlation function and to the dielectric properties of the snow layer.