Reverberation and biological clutter in continental shelf waveguides

Abstract

Seafloor reverberation in continental shelf waveguides is the primary limiting factor in active sensing of biological clutter in the ocean for noise unlimited scenarios. The detection range of clutter is determined by the ratio of the intensity of scattered returns from clutter versus the seafloor in a resolution cell of an active sensing system. We have developed a Rayleigh-Born volume scattering model for seafloor scattering in an ocean waveguide. The model has been tested with data collected from a number of Ocean Acoustic Waveguide Remote Sensing (OAWRS) experiments in distinct US Northeast coast continental shelf environments, and has shown to provide accurate estimates of seafloor reverberation over wide areas for various source frequencies. We estimate scattered returns from fish clutter by combining ocean-acoustic waveguide propagation modeling that has been calibrated in a variety of continental shelf environments for OAWRS applications with a model for fish target strength. Our modeling of seafloor reverberation and scattered returns from fish clutter is able to explain and elucidate OAWRS measurements along the US Northeast coast.