A Simple Model for Marine Radar Images of the Ocean Surface

This letter describes a simple model for the backscattered signal received from the ocean surface by a horizontal-polarization marine radar operating at low grazing angles, including the effects of the logarithmic amplifiers conventionally used in these radars. Shadowing is accounted for via geometric optics. The range dependence of the mean radar signal predicted by this model compares well with that observed in two marine radar data sets collected under different environmental conditions. The model also indicates that the radar signal modulation (the deviation from the mean normalized by the mean) is proportional to the radial component of the surface slope in unshadowed regions. This suggests the possibility of direct quantitative wave observations using marine radar modulation data, without the need for calibration.