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dc.contributor.authorAustin, Martin
dc.contributor.authorScott, Tim
dc.contributor.authorBrown, Jeff
dc.contributor.authorBrown, Jenna
dc.contributor.authorMacMahan, Jamie
dc.contributor.authorMasselink, Gerd
dc.contributor.authorRussell, Paul
dc.date.accessioned2014-05-16T18:34:30Z
dc.date.available2014-05-16T18:34:30Z
dc.date.issued2010
dc.identifier.citationContinental Shelf Research 30 (2010) 1149–1165
dc.identifier.urihttp://hdl.handle.net/10945/41263
dc.description.abstractA field experiment was conducted on a high energy macro-tidal beach (Perranporth, UK) to examine rip current dynamics over a low-tide transverse bar/rip system in response to changing tide and wave conditions. Hydrodynamic data were collected using an array of in situ acoustic doppler current meters and pressure transducers, as well as 12 GPS-tracked Lagrangian surf zone drifters. Inter-tidal and subtidal morphology were measured through RTK-GPS and echo-sounder surveys. Data were collected for eight consecutive days (15 tides) over a spring-neap tidal cycle with tidal ranges of 4–6.5m and offshore significant wave heights of 1–2m and peak periods of 5–12 s. The hypothesis that rip current dynamics in a macro-tidal setting are controlled by the combination of variations in wave dissipation and morphological flow constriction, modulated by changes in tidal elevation was tested. During the measurement period, rip circulation was characterised by a large rotational surf zone eddy O(200 m) extending offshore from the inner-surf zone to the seaward face of the inter-tidal transverse bar. During high- and mid-tide, water depth over the bars was too deep to allow wave breaking, and a strong longshore current dominated the surf zone. As the water depth decreased towards low-tide, wave breaking was concentrated over the bar crests initiating the rotational rip current eddy. Peak rip flow speeds of 1.3ms!1 were recorded around low-tide when the joint effects of dissipation and morphological constriction were maximised. At low tide, dissipation over the bar crests was reduced by partial bar-emergence and observations suggested that rip flows were maintained by morphological constriction and the side-drainage of water from the transverse bars.en_US
dc.rightsThis 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.en_US
dc.titleTemporal observations of rip current circulation on a macro-tidal beachen_US
dc.typeArticleen_US
dc.contributor.departmentOceanography
dc.subject.authorRip currenten_US
dc.subject.authorMacro-tidalen_US
dc.subject.authorsurf zoneen_US
dc.subject.authorintermediate beachen_US
dc.subject.authorDriftersen_US
dc.subject.authorCell circulationen_US


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