Models for seafloor roughness and volume scattering

Models for seabed volume and roughness scattering at high and lower frequencies are presented. The sediment is considered as a fluid medium with rough interfaces and spatial fluctuations of the density and sound speed. At high frequencies, the mean parameters of bottom medium are considered as independent from spatial coordinates due to small penetration of sound into the sediment. At lower frequencies, seabeds are assumed as statistically stratified (plane-layered on the average) with the mean parameters taken as various functions of depth. As numerical examples, angular dependencies of the scattering strength are calculated for seabeds of various types