A Characterization of Underwater Sound Produced by Heavy Precipitation

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 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 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 m/s), 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 form the surface.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1990
Accession Number
ADA242429

Entities

People

  • Chih-lung Tan

Organizations

  • Naval Postgraduate School

Tags

Communities of Interest

  • Materials and Manufacturing Processes
  • Sensors
  • Space

DTIC Thesaurus Topics

  • Acoustic Measurement
  • Acoustic Signals
  • Acquisition
  • Algorithms
  • Computer Programs
  • Computers
  • Data Acquisition
  • Data Analysis
  • Data Processing
  • Data Sets
  • Frequency Bands
  • Measurement
  • Meteorological Radar
  • Observation
  • Rain Gages
  • Recording Systems
  • Surface Properties

Fields of Study

  • Environmental science

Readers

  • Aerosol Science/Aerosol Physics
  • Mathematics or Statistics
  • Oceanography.