The Effect of Roughness on Bottom Loss from Elastic Ocean Bottoms

摘要

Acoustic interaction with the ocean bottom profoundly affects propagation in shallow waters. However, most forward ocean bottom interactions are modeled as if the bottom were a flat interface or use a simple model to quantify the additional loss. These assumptions either neglect or over-estimate the enhancement of ocean bottom loss due to scattering into the bottom. Scattering from and into elastic bottoms is particularly interesting since it can induce the production of an interface wave. In this study, finite element analysis is used to calculate acoustic scattering from elastic ocean bottoms with varying degrees of roughness. The forward scattering loss from these bottoms is calculated as a function of angle and then compared with the flat bottom reflection coefficient in order to gain insight on the conditions under which enhancement of bottom loss by rough interface scattering is significant.