Three dimensional underwater acoustic modeling on continental slopes and submarine canyons

Abstract

Underwater sound propagation on slopes and canyons is influenced jointly and strongly by the complexity of topographic variability and ocean dynamics. Some integrated ocean and acoustic models have been developed and implemented to investigate such joint acoustic effects. In this talk, an integrated numerical model employing a time-stepping three-dimensional (3D) parabolic-equation (PE) acoustic modeling method and the Regional Ocean Modeling System (ROMS) is presented. Numerical examples of sound propagation and ambient noise in Mid-Atlantic Bight area with realistic environmental conditions are demonstrated. The sound propagation model reveals the focusing of sound due to concave canyon seafloor and the different level of temporal variability of focused and unfocused sound. The ambient noise model is constructed for surface wind generated noise, and the model shows the azimuthal dependency of noise field and its spatial coherence structure. Lastly, a simple sonar performance prediction is made to investigate the variability of the probability of detection in these complex underwater environments. [Work supported by the ONR.]