HR: 17:30h
AN: OS14B-07    [Abstracts]
TI: Wind Effects on Shoaling Wave Shape
AU: * Feddersen, F
EM: falk@coast.ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Drive 0209, La Jolla, CA 92093-0209
AB: In the nearshore, cross-shore winds strongly affect the location of the breakpoint and the breaking-wave height. From casual observation from the beach, wind direction (onshore or offshore) and speed also appears to affect wave shape (\ie skewness and asymmetry), although as of yet this has not been quantified in the nearshore. The effect of wind on shoaling wave shape is investigated with laboratory experiments using monochromatic waves and onshore directed wind. Wind increases the shoaling wave energy at discrete multiples of the primary frequency, and has a significant effect on the wave shape at both a deeper and shallower shoaling locations. At the shallower location, the ratio of wave energy at twice the primary frequency to the primary frequency is also a function of wind speed, indicating interaction between the wind and the nonlinear wave shoaling process. Nearshore wave models do not account for these wind effects. Incorrect predictions of $3^\mathrm{rd}$ order velocity moments (wave shape), believed to control wave driven sediment transport, would result in incorrect beach morphological evolution predictions.
DE: 4504 Air/sea interactions (0312)
DE: 4546 Nearshore processes
DE: 4560 Surface waves and tides (1255)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting