Radar sea-clutter at low grazing angles

An analysis of sea-clutter data obtained in conditions typical of sea state 2 at X-, S-, L- bands, UHF and VHF is presented. Results show that sea-clutter exhibits very different spectral characteristics at higher frequencies compared to those at low frequencies. Experimental sea-clutter coefficients as a function of grazing angle at various frequency bands were obtained for upswell and cross-swell conditions. These results were contrasted with those calculated from two sea-clutter (the GIT and Sittrop) models, assuming an upwind and a crosswind condition. The data were quite dissimilar in the low-grazing-angle regions to those predicted by the two models. Sea-clutter amplitude statistics provide evidence that the K-distribution serves as a limiting distribution for sea clutter