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Acoustic Measurement of Near-Bed Sediment Transport Processes

Thorne, P.D.; Bell, P.S.. 2009 Acoustic Measurement of Near-Bed Sediment Transport Processes. In: Steele, John H.; Turekian, Karl K.; Thorpe, Steve A., (eds.) Encyclopedia of Ocean Sciences, 2nd ed. Amsterdam, Elsevier, 38-51.

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Abstract/Summary

The use of acoustics to measure near-bed sediment transport processes has gained increasing acceptance within the sedimentological community over the past two decades. The idea of using sound to study fundamental sediment processes in the underwater environment is attractive, and, in concept, straightforward. A pulse of high-frequency sound is transmitted downward from a directional sound source usually mounted a meter or two above the bed. As the pulse propagates down toward the bed, sediment in suspension backscatters a proportion of the sound and the bed generally returns a strong echo. The signal backscattered from the suspended sediments can be used to obtain vertical profiles of the suspended concentration and particle size and profiles of the three orthogonal components of flow. The strong echo from the bed can be used to measure the bed forms. Further, the profiles can be obtained with sufficient spatial and temporal resolution to allow near-bed turbulence and intrawave sediment processes to be probed; this coupled with the bedform morphology observations provides sedimentologists and coastal engineers with an extremely powerful tool to advance understanding of sediment entrainment and transport. All of this is delivered with almost no influence on the processes being observed, because sound is the instrument of measurement.

Item Type: Publication - Book Section
Digital Object Identifier (DOI): 10.1016/B978-012374473-9.00736-0
Programmes: Oceans 2025
Oceans 2025 > Marine biogeochemical cycles
ISBN: 978-0-12-374473-9
NORA Subject Terms: Marine Sciences
Date made live: 06 Sep 2010 12:54
URI: http://nora.nerc.ac.uk/id/eprint/9760

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