Accession Number:

ADA242429

Title:

A Characterization of Underwater Sound Produced by Heavy Precipitation

Descriptive Note:

Master's thesis

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

Report Date:

1990-12-01

Pagination or Media Count:

70.0

Abstract:

An experiment by the Naval Postgraduate School and the National Data Buoy Center was performed in the Gulf of Mexico to investigate the underwater sound generated by heavy precipitation under a variety of conditions. During the first stage of the experiment, nine data sets were obtained with rainfall rates up to 300 mmhr. The characteristic fifteen kilohertz peak in the underwater sound spectrum generated by small raindrops in light rain is absent during heavy rain. These data sets show a good correlation between rainfall rate and underwater sound levels, suggesting that acoustic measurement of rainfall rate at sea is possible. The correlation is best at lower frequencies 2-10 kHz. At higher frequencies 12-22 kHz low spectral levels are observed in conditions of high wind 10 ms, presumably due to sound absorption by ambient bubble clouds from breaking waves. At very high rainfall rates 200 mmhr, low levels at higher frequencies are also observed suggesting that the rain itself is capable of producing large populations of bubbles which absorb the sound radiated form the surface.

Subject Categories:

  • Meteorology
  • Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE