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Acoustic signature

Acoustic signature

Typical acoustic signatures of bottomfish, mostly snappers and approximately 30-60 cm long, at 70 kHz frequency during day and nighttime surveys. Figure by Réka Domokos. Source: NOAA Typical acoustic signatures of bottomfish, mostly snappers and approximately 30-60 cm long, at 70 kHz frequency during day and nighttime surveys. Figure by Réka Domokos. Source: NOAA
Published:
Updated: December 12, 2011, 5:37 pm
Topics: Oceans and seas Physics & Chemistry Animal Behavior Technology Meteorology Zoology
This article has been reviewed by the following Topic Editor: Peter Saundry

An acoustic signature is a set of characteristics used to describe a sound signal which is being observed.

This article is written at a definitional level only. Authors wishing to improve this entry are inivited to expand the present treatment, which additions will be peer reviewed prior to publication of any expansion.

The acoustic signature may present itself in a gas, liquid or solid medium; furthermore, its temporal nature may be of a repeating waveform, be intermittent, or manifest as a single burst.

The signature may arrive directly from an emission source, or may include sound echos from targets, radiated and ambient noise, with salient echo characteristics including target strength, spectral reflectivity versus frequency, doppler shift, doppler spread and target range extent.

Characteristics of the signature

The acoustical signature generally may be characterized by its:

  • Energy content or amplitude

  • Frequency spectrum content

  • Intermittence or continuity

  • Transmission medium

  • Directional vector of the transmission

  • Presence or absence of echoes

Applications

There are countless applications of an acoustical signature, some of the prominent ones being:

  • Voice recognition (identification of a specific person or animal producing an acoustic signature)

  • Navigation of certain marine mammals or other aquatic fauna (use of echolocation via underwater topography)

  • Prey location of certain marine mammals or other aquatic fauna (echolocation using prey backscatter)

  • Military intercept systems (passive monitoring of missile launches, telemetry communications, etc.)

References

  • C.S.Clay and H.Medwin. 1977. Acoustical Oceanography. Wiley, New York
  • National Research Council of the National Academies (U.S.) 2003. Ocean Noise and Marine Mammals. The National Academies Press, Washington DC
  • D.Simmonds and J.MacLennan. 2005. Fisheries Acoustics: Theory and Practice, 2nd edition. Blackwell, Oxford.

See also

 

Citation

C Michael Hogan, Steve Baum (Lead Author);Peter Saundry (Topic Editor) "Acoustic signature". In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth March 28, 2010; Last revised Date December 12, 2011; Retrieved May 19, 2013 <http://www.eoearth.org/article/Acoustic_signature>

The Authors

C Michael Hogan Standing within a gentoo penguin colony on King George Island, Antarctica, Dr. C. Michael Hogan served a term as Editor in-Chief of the Encyclopedia of Earth which ended in 2012. In addition to authoring a number of papers for the Encyclopedia of Earth, he is a physicist who has published over 1220 peer reviewed articles in other journals and government monographs in the fields of molecular biology, quantum spinwaves, atmospheric physics, biogeochemistry, hydrological modeling, species populat ... (Full Bio)

Steve Baum Assistant Research Scientist, Physical Section Department of Oceanography Texas A&M University   ... (Full Bio)

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