A characterization of underwater sound produced by heavy precipitation
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Authors
Tan, Chih-Lung
Subjects
Rainfall rate
Underwater sound Spectrum
Sonogram
Underwater sound Spectrum
Sonogram
Advisors
Nystuen, Jeffrey A.
Date of Issue
1990-12
Date
December 1990
Publisher
Monterey, California. Naval Postgraduate School
Language
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 conditons. During the first stage of the experiment, nine data sets were obtained with rainfall rates up to 300 mm/hr. 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 acoustical measurement of rainfall rate at sea is possible. The correlation is best at lower frequencies (2-10 kHz). At higher frequencies (12-22 kI-Iz) low spectral levels are observed in conditions of high wind (> 10 ns), presumably due to sound absorption by ambient bubble clouds from breaking waves. At very high rainfall rates (>200 mm/hr), 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 from the surface.
Type
Thesis
Description
Series/Report No
Department
Oceanography
Organization
Identifiers
NPS Report Number
Sponsors
Funder
Format
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
Copyright is reserved by the copyright owner