Quantitative analysis of radar signatures of underwater bottom topography according to a Bragg-based composite surface model

Abstract

The authors have recently developed a calibrated composite surface model for the calculation of normalized radar backscattering cross sections (NRCS) of the ocean surface. Using an optimized parameterization of the wave height spectrum, the measured dependence of the mean NRCS on radar parameters and on the wind speed vector is reproduced quite well. In this paper the sensitivity of the NRCS to intensity variations of different wave spectral components is analyzed, and theoretical radar signatures associated with spatial surface roughness variations over underwater bottom topography in tidal waters are investigated. The composite surface model yields comparable radar signatures at high (10 GHz, X-band) and low (1 GHz, L-band) radar frequencies. However, measured NRCS variations at high radar frequencies appear to be still underestimated in some cases. Possible reasons and further improvements of the theory are discussed.