Record Details
Infragravity waves over a natural barred profile
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Infragravity waves over a natural barred profile |
| Names |
Sallenger, Asbury H. Jr.
(creator) Holman, Robert A. (creator) |
| Date Issued | 1987-08-15 (iso8601) |
| Note | Copyrighted by American Geophysical Union. |
| Abstract | Measurements of cross-shore flow were made across the surf zone during a storm as a nearshore bar became better developed and migrated offshore. Measured infragravity band spectra were compared to synthetic spectra calculated numerically over the natural barred profile assuming a white run-up spectrum of leaky mode or high-mode edge waves. As in earlier studies, the spectra compared closely; however, for some frequencies the energy of the measured spectrum exceeded the energy of the synthetic spectrum, suggesting that the run-up spectrum was not white but had dominating frequencies. Utilizing cross-shore flow data and synthetic spectra from a number of cross-shore locations, an equivalent run-up spectrum was calculated for each day. On the first day of the storm, the equivalent run-up spectrum indicated a dominant wave that had a node in velocity reasonably close to the bar crest. Later during the storm, when the bar had migrated farther offshore, there was no evidence for a dominant motion having a velocity node at the bar crest. The structure of the equivalent run-up spectrum compared well with spectra of direct measurements of run-up obtained several hundred meters away. We have no clear evidence in support of the theory that infragravity waves might form or force the offshore migration of a bar. To confirm this finding, longer records obtained synoptically over a developing bar are required. The dominant wave observed early in the storm was consistent with Symond and Bowen’s (1984) theoretical prediction of resonant amplification of discrete frequencies over a barred profile. |
| Genre | Article |
| Identifier | Sallenger, A., Jr., and R. Holman (1987), Infragravity Waves Over a Natural Barred Profile, J. Geophys. Res., 92(C9), 9531-9540. |
