An investigation of the effects of rough seas and bubble injections on high frequency propagation using a parabolic equation method

Abstract

High frequency underwater acoustic transmissions (>10 kHz) are heavily influenced by scattering from both rough surfaces and bubbles. These interactions are recorded through the prevalence of micro multi-paths in observed data. To study these scattering effects, a rough-surface variant of the Monterey Miami parabolic equation model was combined with a hydrodynamic surface model that produces non-linear waves along with depth- and range-dependent bubble distributions. Parabolic equation setup parameters were taken from collected environmental data, while a wave-rider buoy was used for time-evolving sea surface generation. Bubble plume densities were calculated using surface white-cap distributions along with a bubble evolution scheme. Comparisons of the simulated results are made against collected acoustic data for calm and rough sea states [Work supported by ONR Code 322OA.]