HR: 16:30h
AN: OS14B-03    [Abstracts]
TI: Wave Propagation Over a Submarine Canyon: Model-Data Comparisons
AU: * Magne, R
EM: rmagne@shom.fr
AF: Laboratoire de Sondages Electromagn‚tique de l'Environnement Terrestre, Universit{\'e} de Toulon et du Var cedex, La Garde cedex, 83957 France
AU: * Magne, R
EM: rmagne@shom.fr
AF: Centre Militaire d'Oc{\'e}anographie, Service Hydrographique et Oc{\'e}anographique de la Marine, 13, rue du Chatellier, Brest cedex, 29609 France
AU: Herbers, T
EM: thherber@nps.edu
AF: Department of Oceanography, Naval Postgraduate School, Monterey, CA 93943 United States
AU: Belibassakis, K
EM: kbel@fluid.mech.ntua.gr
AF: Department of Naval Architecture and Marine Engineering, National Technical University of Athens, PO Box 64033 Zografos, Athens, 15710 Greece
AU: Ardhuin, F
EM: ardhuin@shom.fr
AF: Centre Militaire d'Oc{\'e}anographie, Service Hydrographique et Oc{\'e}anographique de la Marine, 13, rue du Chatellier, Brest cedex, 29609 France
AU: O'Reilly, W
EM: bor@coast.ucsd.edu
AF: Integrative Oceanography Division, Scripps Institution of Oceanography, La Jolla,, CA 92093 United States
AB: Observations of the transformation of ocean swell over Scripps Canyon, collected during the NCEX experiment, are compared with predictions of a three-dimensional coupled-mode model for wave propagation over steep topography (Athanasoullis and Belibassakis, J. Fluid Mech., 389, 275-301,1999; Belibassakis et al., Appl. Ocean Res., 23, 319-336, 2001). To examine the importance of steep bottom slope effects, which are fully accounted for in this model, results are compared with two earlier models which assume a gently sloping bottom: a parabolic refraction/diffraction model (Kirby, J. Geophys. Res., 91, 933-952, 1986) and a spectral refraction model based on backward ray tracing (O'Reilly and Guza, Coast. Eng., 19, 263-282, 1993). Preliminary results are presented for long period swell arriving from the west at the canyon at a large oblique angle. Model results are compared with data from directional wave buoys and bottom pressure gauges deployed around the rim of the canyon and over the canyon. The coupled-mode model yields accurate results over and behind the canyon where the parabolic refraction/diffraction model and the ray model overestimate and underestimate the wave height, respectively. These differences suggest that diffraction effects are important in the region behind the canyon that is sheltered by the topography from direct swell arrivals. At some locations seaward of the canyon both the refraction/diffraction and coupled-mode models overpredict the wave height. This reseach is supported by the Office of Naval Research and the National Science Foundation.
DE: 4546 Nearshore processes
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting