Shallow-water torpedo reverberation data modeling with the comprehensive acoustic system simulation

Abstract

The comprehensive acoustic system simulation (CASS) was used to track a 30-dB variability in the reverberation time series from 38 torpedo pings within a 4-km2 area of the shallow-water U.S. Navy SOCAL range. This data set was extremely well modeled with a fairly simple bottom description. A thorough survey of the bottom characteristics in this area showed that the region transitioned from a current-swept rough-rock bottom to a mud-filled depression. The Gaussian ray bundles (GRAB) model, a component of CASS, simulated the acoustic propagation in this range-dependent environment. With the exception of the forward bottom loss for rock, the component scattering models proposed by the Applied Physics Laboratory, University of Washington [APL-UW TR 9407, AEAS 9501, October 1994] were used in the simulation. Twenty-nine interleaving torpedo pings traversed the rough-rock conditions. The model predictions were internally consistent with the data and the environment when a 6-dB value was assumed for the rough-rock forward bottom loss. [Work supported by the Naval Sea Systems Command (PMS-402 and PMS-406) and the Office of Naval Research (ONR-321).]