HR: 0800h
AN: OS11A-0499    [Abstracts]
TI: Canyon Effects on Nearshore Infragravity Waves During NCEX
AU: * reniers, a
EM: ad@dutcvmm.ct.tudelft.nl
AF: Delft University of technology, stevinweg 1, delft, 2628CN Netherlands
AU: MacMahan, J
EM: jmacmah@nps.edu
AF: Naval Postgraduate School, Sloat av., Monterey, ca 94943 United States
AU: Thornton, E
EM: thornton@nps.edu
AF: Naval Postgraduate School, Sloat av., Monterey, ca 94943 United States
AU: Stanton, T
EM: stanton@nps.edu
AF: Naval Postgraduate School, Sloat av., Monterey, ca 94943 United States
AB: Infragravity waves become increasingly important as the water depth gets shallower and wind generated waves become saturated due to wave breaking. Infragravity wave energy is composed of wave-group forced long waves and reflected leaky waves and trapped edge waves. Typically conditions on a approximately alongshore uniform beach are consisdered (e.g. Herbers et al., 1994, van Dongeren et al., 2003). Here we examine the alongshore variability in the infragravity conditions induced by nearby canyons utilizing a 2D-surfbeat model (Reniers et al., 2004). The model simulates the propagation of both leaky and trapped infragravity waves that are generated by directionally spread wave groups. Model computations are used to examine the potential reflection (Inman et al., 1976, Huntley et al., 1981) of shore-trapped edge waves from the canyon walls by considering various model-scenarios with and without the canyons. Computational results will be compared with observations of infragravity conditons obtained from an alongshore array of pressure and velocity meters situated just north of the canyon (MacMahan et al., 2004, this conference). References Herbers, T.H.C., Steve Elgar and R.T. Guza, 1994: Infragravity-frequency (0.005 0.05 Hz) motions on the shelf. Part 1: Forced waves. J. Phys. Oc., 25, 1063-1079. Huntley, D. A., R. T. Guza and E. B. Thornton, 1981, "Field Observations of Surf Beat: Part I, Progressive Edge Waves", J. Geophys. Res., 86, 6451-6466. Inman, D.L., C.E. Nordstrom and R.E. Flick, 1976: Currents in sub-marine canyons: An air-sea-land interaction, Ann. Rev. Fluid Mech., 8, 275-310. MacMahan, J., E.B. Thornton, A. Reniers and T.P. Stanton, 2004, The Torrey Pines Rip-currents, this conference. Reniers, A.J.H.M., E.B. Thornton and J.A. Roelvink, 2004: Morphodynamic modeling of an embayed beach under wave-group forcing, J. Geophys. Res., 109, C01030, doi:10.1029/2002JC001586. Van Dongeren, A.R., A.J.H.M. Reniers, J.A. Battjes and I.A. Svendsen, 2003, "Numerical modeling of infragravity wave response during Delilah." J. Geoph. Res, 108 (C9), 4-1-19
DE: 4546 Nearshore processes
DE: 4560 Surface waves and tides (1255)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting