Accession Number:

ADA625493

Title:

Monitoring Air-Sea Exchange Processes Using the High Frequency Ambient Sound Field

Descriptive Note:

Annual rept.

Corporate Author:

WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB

Personal Author(s):

Report Date:

2001-09-30

Pagination or Media Count:

8.0

Abstract:

The ambient sound field contains information about the processes generating the sound and the intervening media modifying the sound. This research seeks to demonstrate measurement of useful ocean surface processes using passive measurements of the high frequency underwater ambient sound field. This will allow passive monitoring of environmental conditions from simple and robust sensors, namely hydrophones. In turn, given environmental weather conditions, predictive Naval ocean ambient noise models will be improved. This technique introduces no acoustic disturbance to the environment, and is hence covert and poses no potential harm to marine mammals or other forms of life in the ocean. The frequency range of interest is from 200 Hz to 50 kHz. In this frequency range, the dominant natural sources of sound are breaking wind waves and precipitation. The sound generated by these phenomena can be subsequently modified through attenuation by ambient bubbles. These features of the air-sea interface breaking waves, precipitation and bubbles, are an important part of the exchange of momentum, heat, water and gas between the ocean and the atmosphere. Coupled air-sea models are currently the weakest of the numerical models needed to analyze and forecast environmental weather conditions. Modelers have identified the need for data, especially of wind and rain, to develop and verify these models. Acoustical inversion of the sound field should be able to provide these data, even in remote and difficult regions where more conventional measurements are unavailable.

Subject Categories:

  • Meteorology
  • Physical and Dynamic Oceanography
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE