Rip current spacing in relation to wave energetics and directional spreading
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Authors
Holt, Robert D.
Subjects
Oceanography
Nearshore
Rip currents
Directional spreading
Beach cusps
Coastal video imaging
Nearshore
Rip currents
Directional spreading
Beach cusps
Coastal video imaging
Advisors
Thornton, Edward B.
Stanton, Timothy
Date of Issue
2003-06
Date
June 2003
Publisher
Monterey, California. Naval Postgraduate School
Language
Abstract
Rip current spacings are compared with wave energetics and directional spreading in the Southern Monterey Bay. Southern Monterey Bay affords a unique environment to study rip currents owing to their prevalence created by near-normally incident waves on a sandy shoreline. It is hypothesized that rip current spacing is a function of wave directional spreading and energy flux, based on the morphodynamic modeling by Reniers et al. 2003. A gradient of wave energy flux exists due to headlands and refraction over Monterey Canyon. Rip currents are shown to occur between cusps in the shoreline, allowing cusp spacing to be a surrogate for rip spacing. Rip current spacing was inferred from beach morphology surveys, LIDAR imagery, and Argus cameras, and found to be O(150m) at Sand City and O(300m) at Marina, separated by 6km . Measured waves during a two month period using wave-rider buoys, show a gradient of across-shore energy flux between Sand City, 2 28000( / ) F Jm x . , and Marina, 2 33000( / ) F Jm x . . The two sites have the same peak directional spreading of energy value, 14 peak ̤= o , and slightly different bulk values for Sand City, 18 bulk ̤= o , and Marina, 20 bulk ̤= o . Therefore, the variations in rip current spacing could not be attributed to directional spreading but appear related to variations in energy flux.
Type
Thesis
Description
Series/Report No
Department
Oceanography
Organization
Identifiers
NPS Report Number
Sponsors
Funder
Format
xiv, 65 p. : ill. (some col.)
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.