Ambient noise measurements from 100 Hz to 80 kHz in an Alaskan fjord

J Acoust Soc Am. 1992 Apr;91(4 Pt 1):1990-2003. doi: 10.1121/1.403683.


Measurements covering a broad frequency range from 100 Hz to 80 kHz have been made in Behm Canal, Alaska. This site represents a fairly deep embayment (400 m) with a soft bottom (porosity of about 0.8) and, hence, the noise detected at the hydrophones is affected negligibly by multipath contributions except possibly at the lowest frequencies. Data were gathered over a wide range of wind speeds (0 to 15 m/s) and during periods of rain and snow. Several unique and noteworthy results were obtained. Foremost was the observation that the wind-generated noise level measured during the winter was approximately 5 dB lower than during the summer for the same wind speeds and air-sea temperature differences (air temperature about the same as or colder than the sea surface). The summer data agree well with the most recent published measurements and are approximately 2 dB higher than the standard Knudsen/Wenz reference spectra. It appeared that below-freezing air temperatures and snow were responsible for the 5 dB offset between the summer and winter data. Most reported wind noise measurements are restricted to frequencies less than 20 kHz. Those that go beyond this frequency display a noticeable hump above the usual--17 dB/decade power-law slope, and the Behm Canal measurements show that this hump continues to 80 kHz where the spectrum rejoins the extension of the canonical power-law slope.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustics
  • Alaska
  • Humans
  • Noise*
  • Oceans and Seas
  • Seasons
  • Signal Processing, Computer-Assisted / instrumentation*
  • Sound Spectrography / instrumentation*
  • Water*
  • Weather*
  • Wind*


  • Water