HR: 13:40h
AN: OS13C-01 INVITED     [Abstracts]
TI: The Torrey Pines Rip Currents
AU: * MacMahan, J
EM: jhmacmah@nps.edu
AF: Naval Postgraduate School, Oceanography Dept., Monterey, CA 93943 United States
AU: Reniers, A J
EM: ad@dutcvmm.ct.tudelft.nl
AF: Delft University of Technology, Civil Engineering and Geosciences, Netherlands, 0000 Netherlands
AU: Thornton, E B
EM: thornton@nps.edu
AF: Naval Postgraduate School, Oceanography Dept., Monterey, CA 93943 United States
AU: Stanton, T P
EM: stanton@nps.edu
AF: Naval Postgraduate School, Oceanography Dept., Monterey, CA 93943 United States
AU: Symonds, G
EM: graham.symonds@adfa.edu.au
AF: University of New South Wales, Australian Defence Force Academy, School of Physical, Environmental and Mathematical Sciences, Canberra, 2600 Australia
AB: Field observations during the Nearshore Canyon Experiment documented the hydrodynamics of a morphologically-controlled migrating rip current utilizing a coherent cross- and alongshore array of 13 co-located pressure and velocity sensors on a near planar beach at Torrey Pines Beach, CA. The rip current morphology had $\sim 150m$ channel width and $\sim 300m$ rip spacing with a depth variation of 0.003m/m alongshore. The rip channel morphology is very broad with the bathymetric variation smaller than the camber of a football field. The rip currents obtain mean velocities up to 0.5m/s at lower tidal elevations for 0.5 m significant wave heights. Argus Images suggest that the rip channels were present prior to the instrument deployment on yearday 303. The rip channels migrated southerly at 12.5 m/day and migrated past our cross-shore array. The cross-shore velocity profile along the axis of a rip channel in the field has not been well documented. Preliminary analysis found that cross-shore velocity increased to a maximum inside the break point, and then decreased offshore. Velocity vectors suggest a flow reversal close to the shoreline, similar to laboratory measurements by Haller et al., 2002. We will discuss the flow dynamics of the morphologically-controlled, migrating Torrey Pines rip currents. This work was supported by the Office of Naval Research.
DE: 4546 Nearshore processes
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting