Vertical and horizontal length scales of suspended sediment in the nearshore
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Authors
Huck, Michael P.
Subjects
Suspended sediment length scales
Suspended sediment
Nearshore
Suspended sediment
Nearshore
Advisors
Thornton, Edward B.
Stanton, Timothy P.
Date of Issue
1998-09-01
Date
September 1998
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
Suspended sediment measurements acquired using acoustic and optical sensors are analyzed to determine the vertical and horizontal coherence length scales in the nearshore zone across a barred beach during the SandyDuck experiment. Suspended sediments over the vertical, from the seafloor to approximately 65 cm above the bed, are inferred from acoustical backscatter of a 1.3 MHz signal at discrete 1.7 cm bins. The height of the bedload layer ranged from 1.7 - 3.4 cm above the bed floor for all stations investigated, which is twice the height of the theoretical wave boundary layer. The vertical coherence length was found to be an order of magnitude greater than the wave boundary layer and had a weak dependence with wave height, depth of water and orbital excursion (linear correlation coefficient of 0.6 statistically significant at 95% confidence). The cross-shore horizontal coherence length scale of suspended sediment was determined using a two meter lagged array of six optical backscatter sensors at an elevation of approximately 18 cm above the bed. The horizontal coherence length scale was approximately 0.8 times the rms wave orbital excursion length for all cross shore stations. Both the vertical and horizontal coherence length scales are longest for infragravity waves and decrease with increasing frequency.
Type
Thesis
Description
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
viii, 45 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.