Tests of some radar backscatter models with multifrequency, polarimetric SAR data from the 1989 Noordwijk experiment

Simultaneous images in different frequencies and polarisations were obtained from the NASA/JPL airborne synthetic aperture radar (SAR) at a shallow-water site off the Dutch coast (Noordwijk) in 1989. The properties of the mean backscatter and backscatter statistics are analysed to compare the predictions of a Kirchhoff-based scattering model with Bragg and composite-surface models. The frequency dependence is particularly sensitive to assumptions about the description of the sea-surface roughness. Although the composite-surface model provides the most realistic behaviour of the models tested, the results suggest that models which include the polarisation dependence as a correction to the Kirchhoff model are also appropriate