Sensitivity Of High Frequency Surface-Generated Noise To Sonar And Environmental Parameters

This paper investigates the sensitivity of high frequency (6 to 60 kHz) surface-generated ambient noise to sonar and environmental parameters. A simulation model for the vertical directionality and depth dependence of noise originating at the ocean surface is developed. The use of the model is demonstrated when sonar beam elevation angle, receiver depth, water depth, and sound velocity profile are varied at a relatively high frequency (23.5 kHz). Results show a high level of sensitivity to these parameters. In deep water, it is predicted that volume absorption is the dominant contributor to the anisotropic character of the noise field. In shallow water, it is shown that the received noise levels are limited primarily by two environmental parameters of the ocean: (1) sound speed profile (SSP) and (2) bottom porosity.