Measurements and modelling of high-frequency acoustic scattering by a rough seafloor and sea surface

Abstract

Acoustic scattering by a rough, possibly dynamic interface is experimentally studied by insonifying the seabed and the sea surface at high frequency at various incidentangles. A directional source working at 300 kHz was placed at the top of a 3.5 m high tower deployed on the seabed. A vertical array of 3 omnidirectional hydrophones was suspendedfrom a portable frame, which was deployed in bistatic configuration at a variable range between 30 and 70 m. A selection of the results is presented to evaluate the sea surface andseabed scattering amplitude in the nominal specular reflection direction. Scattering by thesea surface was measured during relatively long periods of time in order to correlate its value with the sea state. Model-data comparison was conducted between the scattering data and a time-domain, three-dimensional rough surface scattering model (BORIS-SSA). Model based analysis allows for a better understanding of some aspects of high-frequency multipath reverberation in shallow water.