Record Details
Field | Value |
---|---|
Title | Longshore structure of infragravity wave motions |
Names |
Holman, R. A.
(creator) Bowen, A. J. (creator) |
Date Issued | 1984 (iso8601) |
Note | copyrighted by American Geophysical Union |
Abstract | Synchronous runup records were collected from 14 locations spaced irregularly over a 7 km stretch of a low-slope beach. The significant runup height, herein defined as the significant vertical excursion of water level at the shoreline, was typically 2 m, 60% of the incident significant wave height at the breakpoint. The runup spectra were dominated by the energy at low frequencies, with 99.9% of the variance in motions with periods longer than 20 s and 83% for periods longer than 50 s. A peak between 0.005 and 0.010 Hz was present in all spectra. Analysis of this band showed the motion to be a standing edge wave with wavelength between 5 and 10 km and significant edge wave height at the antinode of 1.3 m, accounting for half of the local significant runup height. The edge wave period was approximately 140 s and the mode number in the range 3-7. An apparently linear sand bar was present 175 m offshore, roughly the same location as the first node of cross-shore velocity for the edge wave. While the edge wave could not have been the cause of the bar (a standing edge wave does not create a linear bar), the opposite may be true, with the bar potentially providing a topographic resonance. As the local headlands extend only a small fraction of the offshore distance of the edge wave, they are unlikely to be significant reflectors. The single rip current observed occurred at the edge wave node. |
Genre | Article |
Identifier | Bowen, A. J., and Holman, R. A. (1984), Longshore structure of infragravity wave motions. J. Geophys. Res., 89, C4. |