Bottom reverberation modeling with limited bottom interaction information.

Abstract

Frequently, the only available information on bottom interaction is the reflection loss as a function of grazing angle. Here we explore a method of incorporating this information into a normal mode code, such as KRAKEN, via the mode cycle distance. We compare this approach with the perturbation method used by KRAKEN with a full geoacoustic description of the bottom. Results are also compared to an exact solution using a full-bottom characterization. This approach using the cycle distance generalizes to full reverberation calculations, allowing one to predict the spatial and temporal structure of the active sonar reverberation field. The resulting model provides a small trade-off in accuracy but provides the reverberant field extremely rapidly.