Island sheltering of surface gravity waves: model and experiment

Pawka, S. S.; Inman, Douglas L.; Guza, R. T.

doi:10.1016/0278-4343(84)90042-6

Cited by 21 publications

(21 citation statements)

References 8 publications

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“…There is Northwest swell generated along the California coast, tropical storms formed off Mexico (Inman et al, ; Inman & Jenkins, ), Southern Hemisphere swell during summer months with small wave height and long period, sea‐breeze waves, and Santa Ana wind waves (Adams et al, ; Guzman‐Morales et al, ). The complexity is further compounded by wave refraction, diffraction, and sheltering by Point Conception, at the northern end of the SCB, which blocks waves from >315°, the complex bathymetry of the California Borderlands, and the Channel Islands (Adams et al, ; Pawka, ; Pawka et al, ). It is therefore logical to have high average ν in the region (Figure ), confirming that the role of instability in forming the rogues in the SCB is likely minimal.…”

Section: Resultsmentioning

confidence: 99%

Can Rogue Waves Be Predicted Using Characteristic Wave Parameters?

et al. 2018

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Rogue waves are ocean surface waves larger than the surrounding sea that can pose a danger to ships and offshore structures. They are often deemed unpredictable without complex measurement of the wavefield and computationally intensive calculation, which is infeasible in most applications; consequently, there a need for fast predictors. Here we collate, quality control, and analyze the largest data set of single‐point field measurements from surface following wave buoys to search for predictors of rogue wave occurrence. We find that analysis of the sea state parameters in bulk yields no predictors, as the subset of seas containing rogue waves sits within the set of seas without. However, spectral bandwidth parameters of rogue seas display different probability distributions to normal seas, but these parameters are rarely provided in wave forecasts. When location is accounted for, trends can be identified in the occurrence of rogue waves as a function of the average sea state characteristics at that location. These trends follow a power law relationship with the characteristic sea state parameters: mean significant wave height and mean zero upcrossing wave period. We find that frequency of occurrence of rogue waves and their generating mechanism is not spatially uniform, and each location is likely to have its own unique sensitivities, which increase in the coastal seas. We conclude that forecastable predictors of rogue wave occurrence will need to be location specific and reflective of their generation mechanism. Therefore, given location and a sufficiently long historical record of sea state characteristics, the likelihood of occurrence can be obtained for mariners and offshore operators.

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Section: Resultsmentioning

confidence: 99%

Can Rogue Waves Be Predicted Using Characteristic Wave Parameters?

et al. 2018

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“…A numerical solution of the three wave collision integral is developed, and the steady state wave Boltzmann equation is integrated using a piecewise ray method. The model is tested using the high resolution frequency-directional wave spectrum of Freilich, Guza and Elgar (1990) (Longuet-Higgins, 1957;Collins, 1972;LeMehaute and Wang, 1982;Pawka et al . , 1984;Izumiya and Horikawa, 1987) , with reasonable success in predicting the directional characteristics of the waves in shallow water.…”

Section: Report Documentation Pagementioning

confidence: 99%

Nonlinear transformation of directional wave spectra in shallow water

Abreu¹,

Larraza²,

Thornton³

1992

J. Geophys. Res.

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A shallow water, nonlinear spectral wave transformation model is developed for conditions of a mild sloping bottom (μ = ∇h/kh ≪ 1) and small amplitude effects (ε = ζ/h ≪ 1). Nonlinearities and combined shoaling and refraction effects act on the same time and length scales. The evolution equation of the wave action is prescribed by the wave Boltzmann equation, whereby resonant collinear triad interactions transfer energy among Fourier components. Combined shoaling and refraction effects are taken into account through the geometrical optics approximation. A numerical solution of the three‐wave collision integral is presented, and the steady state wave Boltzmann equation is integrated using a piece wise ray method. The model is tested using the high‐resolution frequency‐directional wave spectra of Freilich, Guza, and Elgar (1990) that show nonlinear transfers of energy between both harmonic and nonharmonic frequencies. A digitized version of the measured frequency‐directional spectrum at 10‐m depth is evolved 246 m shoreward over a bathymetry of straight and parallel bottom contours to 4‐m depth. The model predicts the prominent spectral features in the measured wave field. The model results are in general superior to estimates using linear, finite depth wave theory, and they compare well with the observations in the region of the spectrum dominated by nonlinear effects.

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“…Pawka et al () show that low‐frequency waves have a strong refraction effect near the island in the SCB using a numerical model. O'Reilly et al () use a spectral analysis of buoy data to study the dissipation of wave energy by the reflection from cliffs on the coast of California.…”

Section: Discussionmentioning

confidence: 99%

“…The water depth is the deepest in the southwest and decreases steeply around the islands and near the coast. Wave climate in the region is affected by the prevailing northwest winds along the California coast, tropical storms, and swell propagating from the west and northwest, with associated wave refraction and diffraction (Adams et al, ; Arthur & Siple, ; Dong et al, ; O'Reilly et al, ; O'Reilly & Guza, ; Pawka et al, ). The sea surface wave plays an important role in the air‐sea exchange, such as the momentum and carbon dioxide exchanges.…”

Section: Introductionmentioning

confidence: 99%

Multiple‐Scale Variations of Wind‐Generated Waves in the Southern California Bight

et al. 2018

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A numerical wave model is applied to study the wind‐generated wave in the Southern California Bight (SCB). Observational data available in this area are used to validate the numerical model results. The model is integrated for 10 years (2004–2013). The comparison of the model results with observations shows that the model well reproduces the wave variations in the SCB. The multiple‐scale variations in the wavefield are examined: interannual, seasonal, intraseasonal, and diurnal. The significant wave height and swell wave height distributions display distinct patterns during different seasons. On the interannual scale, the wave variation in the SCB is influenced by El Niño–Southern Oscillation activities. Intraseasonal scale events occur frequently. Land/sea breezes cause the diurnal variation. The effects of topography (especially islands) and currents on waves are analyzed. The islands in the SCB provide significant sheltering effects to the coast from deep‐ocean waves. The effect of background currents on waves is discussed.

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Island sheltering of surface gravity waves: model and experiment

Cited by 21 publications

References 8 publications

Can Rogue Waves Be Predicted Using Characteristic Wave Parameters?

Can Rogue Waves Be Predicted Using Characteristic Wave Parameters?

Nonlinear transformation of directional wave spectra in shallow water

Multiple‐Scale Variations of Wind‐Generated Waves in the Southern California Bight

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