Locating strong acoustic scattering on the seafloor using wedge diffraction theory

Abstract

The challenge of rapidly and accurately assessing the potential acoustic scattering from bathymetric features requires a physics based solution to the rough surface scattering problem that captures the essential behavior of the scattering while still retaining a level of simplicity that allows for fast computation. A very common and simple geometric proxy (derived from the Kirchhoff approximation) associates the degree to which local tangent-plane surfaces are oriented to provide specular reflection in the direction of the receiver with the strength of the scattering. Such an approach is bound to fail for almost all natural rough surfaces simply because diffraction not reflection is the dominant scattering mechanism. In this paper, the capacity of rough surface scattering models based on wedge diffraction theory to accurately model the scattering from bathymetric shapes is reviewed. Easily computed geometric metrics, derived from the wedge diffraction modeling approach, that can act as proxies for the full scattering calculation are proposed and a demonstrated.