Model for coherent scattering from a network of buried river channels in a stratified ocean waveguide

Abstract

A theoretical model of three-dimensional bistatic scattering from a network of buried river channels in a continental shelf waveguide is presented. The scattered field on the river channel walls is estimated to be locally specular using the Kirchhoff approximation. This field is then propagated out to a distant receiving array using Green’s theorem and the waveguide Green function, so that it is also valid for scattering in the near field of the river channel network. This model is applied to calculate the scattered and beamformed field from a network of buried river channels in the East Coast strataform area, whose geomorphology was mapped out by numerous geophysical surveys. The modeled scattered field is found to be dependent upon the bistatic orientation and projected area of the river channel walls relative to the source and receiver. To verify the modeling, the result of the simulation is compared with data from the Geoclutter 2001 acoustic experiment where images of buried river channel networks were acquired from long-range using a bistatic sonar system.