Hostname: page-component-7479d7b7d-fwgfc Total loading time: 0 Render date: 2024-07-15T15:49:17.686Z Has data issue: false hasContentIssue false

Shoaling gravity waves: comparisons between field observations, linear theory, and a nonlinear model

Published online by Cambridge University Press:  20 April 2006

Steve Elgar
Affiliation:
Scripps Institution of Oceanography, A-022, University of California, La Jolla. California 92093
R. T. Guza
Affiliation:
Scripps Institution of Oceanography, A-022, University of California, La Jolla. California 92093

Abstract

Observed statistics of non-breaking ocean-surface gravity waves shoaling between 4 and 1 m depths are compared with the predictions of linear finite-depth theory and a nonlinear model. The linear theory included effects of the directional distribution of energy within each frequency component. The nonlinear model, which does not consider directional effects, is based on Boussinesq-type equations for a sloping bottom (Freilich & Guza 1984). Given initial conditions in 4 m depth, the nonlinear model more accurately predicts the evolution of energy spectra, coherence and phase speed between sensors, and lengths of runs of high waves than does the linear theory. In four out of five cases, observed trends in the evolution of sea-surface-elevation skewness are predicted by the nonlinear model, while linear theory predicts zero skewness. Neither model can explain changes in the directional spectra observed between 9 and 4 m depths.

Type
Research Article
Copyright
© 1985 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Barber N. F. 1963 The directional resolving power of an array of wave detectors. In Ocean Wave Spectra, pp. 137150. Prentice-Hall.
Büsching F. 1978 Anomalous dispersion of Fourier components of surface gravity waves in the nearshore area. Proc. 16th Coastal Engineering Conf., pp. 247267. New York: Amer. Soc. Civil Engng.
Elgar S., Guza, R. T. & Seymour R. J. 1984 Groups of waves in shallow water. J. Geophys. Res. 89, 36233634.Google Scholar
Esteva, D. & Harris D. L. 1970 Analysis of pressure wave records and surface wave records. Proc. 12th Coastal Engng Conf. pp. 101116.
Freilich, M. H. & Guza R. T. 1984 Nonlinear effects on shoaling surface gravity waves Phil. Trans. R. Soc. Lond. A 311, 141.Google Scholar
Gable, C. G. (ed.) 1981 Report on data from the Nearshore Transport Study experiment at Leadbetter Beach, Santa Barbara, California, January-February, 1980. IMR Ref. 80-5. Univ. of Calif., Inst. of Marine Resources, La Jolla, CA.
Guza, R. T. & Thornton E. B. 1980 Local and shoaled comparisons of sea surface elevations, pressures and velocities. J. Geophys. Res. 85, 15241530.Google Scholar
Guza, R. T. & Thornton E. B. 1985a Velocity moments in the nearshore. J. Waterway, Port, Coastal & Ocean Engng 111, 235256.Google Scholar
Guza, R. T. & Thornton E. B. 1985b Observations of surf beat. J. Geophys. Res. 90, 31613172.Google Scholar
Holman R. A. 1981 Infragravity energy in the surf zone. J. Geophys. Res. 86, 64426450.Google Scholar
Huang N. E. 1981 Comment on ‘Modulation characteristics of sea surface waves’ by A. Ramamonjiarisoa and E. Mollo-Christensen. J. Geophys. Res. 86, 20732075.Google Scholar
Huang, N. E. & Tung C. C. 1977 The influence of the directional energy distribution on the nonlinear dispersion relation in a random gravity wave field. J. Phys. Oceanogr. 7, 403414.Google Scholar
Inman D. L., Tait, R. J. & Nordstrom C. E. 1971 Mixing in the surf zone. J. Geophys. Res. 76, 34933514.Google Scholar
Le Méhauté B. & Wang, J. D. 1982 Wave spectrum changes on a sloped beach. J. Waterway, Port, Ocean and Coastal Div., Amer. Soc. Civil Eng. 108, 3347.Google Scholar
Munk W. H., Miller G. R., Snodgrass, F. E. & Barber N. F. 1963 Directional recording of swell from distant storms Phil. Trans. R. Soc. Lond. A 255, 505584.Google Scholar
Munk W. H., Snodgrass, F. E. & Gilbert F. 1964 Long waves on the continental shelf: an experiment to separate trapped and leaky modes. J. Fluid Mech. 20, 529554.Google Scholar
Oltman-Shay, J. & Guza R. T. 1985 A data adaptive ocean wave directional spectrum estimator for pitch and roll type measurements. J. Phys. Oceanogr. 14, 18001810.Google Scholar
Peregrine D. H. 1967 Long waves on a beach. J. Fluid Mech. 27, 815827.Google Scholar
Ramamonjiarisoa, A. & Coantic M. 1976 Loi expérimentale de dispersion des vagues produits par le vent sur une faible longueur d'action C. R. Acad. Sci. Paris B 282, 111113.Google Scholar
Snodgrass F. E., Groves G. W., Hasselmann K. F., Miller G. R., Munk, W. H. & Powers W. H. 1966 Propagation of ocean swell across the Pacific Phil. Trans. R. Soc. Lond. A 259, 431497.Google Scholar
Suhayda J. S. 1974 Standing waves on beaches. J. Geophys. Res. 79, 30653071.Google Scholar
Thornton, E. B. & Guza R. T. 1982 Energy saturation and phase speeds measured on a natural beach. J. Geophys. Res. 87, 94999508.Google Scholar
Yefimov V. V., Solov'yev, Y. P. & Khristoforov G. N. 1972 Observational determination of the phase velocities of spectral components of wind waves. Isv. Atmos. Oceanic Phys. 8, 435446.Google Scholar