Wave refraction over complex nearshore bathymetry

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Authors
Peak, Scott Douglas
Subjects
Refraction
Swell transformation
Scripps Canyon
NCEX
Nearshore wave model
Advisors
Herbers, Thomas H.C.
Date of Issue
2004-12
Date
December 2004
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
Accurate predictions of nearshore wave conditions are critical to the success of military operations in the littoral environment. Although linear spectral-refraction theory is used by the main operational forecasting centers in the world for these predictions, owing to a lack of field studies its accuracy in regions of complex bathymetry such as steep shoals and submarine canyons is unknown. This study examines the accuracy of linear spectral-refraction theory in areas of complex nearshore bathymetry with three months of extensive wave data collected during the Nearshore Canyon Experiment (NCEX) held in the fall of 2003. The field site, off La Jolla California, is characterized by two submarine canyons that strongly affect the propagation of long period Pacific swell. Data from 7 directional waverider buoys, 17 bottom pressure recorders, and 12 pressure-velocity sensors, were examined and compared to predictions made by a high resolution spectral-refraction model. Analysis reveals large spatial variation in wave heights over the area especially in the vicinity of the canyon heads, where wave heights vary by as much as an order of magnitude over a few hundred meters. This extreme variation in wave conditions across the canyons is surprisingly well described by refraction theory with typical errors of nearshore wave height predictions of about 20 percent.
Type
Thesis
Description
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School (U.S.).
Identifiers
NPS Report Number
Sponsors
Funder
Format
xvi, 75 p. : ill. (chiefly col.), maps
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
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Copyright is reserved by the copyright owner
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