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A comparison of near-bed acoustic backscatter and laser diffraction measurements of suspended sediments

March 25, 2007

As part of the U.S. Office of Naval Research (ONR, Arlington, VA) mine burial program, an experiment was conducted off the pier at Santa Cruz, CA, to measure the near-bed suspended sediment reference concentration under waves and currents. Two tripods were deployed to carry out the measurements; one consisting mainly of acoustical instrumentation and the other solely of optical instruments. The tripods were located within 15 m of one another on a sandy bed and measurements of the suspended sediment were made using acoustics and optics. Although the experiment was not primarily designed to conduct an intercomparison of acoustical and optical measurements, it was considered interesting to take advantage of the situation and to examine if these two techniques gave comparable results. In particular, measurements of particle size and concentration, obtained using a triple frequency acoustic backscatter system (ABS) have been compared with the commercially available laser miniature scattering and transmissometry instrument (MSCAT). It was found that the mean grain size estimated by the two methods was consistent; however, in contrast, the concentration time series showed differences, both in magnitude and form. 

Citation Information

Publication Year 2007
Title A comparison of near-bed acoustic backscatter and laser diffraction measurements of suspended sediments
DOI 10.1109/JOE.2007.890978
Authors P.D. Thorne, Yogesh C. Agrawal, D. A. Cacchione
Publication Type Article
Publication Subtype Journal Article
Series Title IEEE Journal of Oceanic Engineering
Series Number
Index ID 70209258
Record Source USGS Publications Warehouse
USGS Organization Pacific Coastal and Marine Science Center