Wave height

About: Wave height is a research topic. Over the lifetime, 5920 publications have been published within this topic receiving 100257 citations.

A 2-d random wave transformation model with gradational breaker index

Abstract: Random wave transformations with breaking in shallow water of 2-D bathymetry are computed with the parabolic equation. A new system of gradational breaker index, the value of which gradually decreases as the level of wave height within a wave group is lowered, is introduced to simulate gradual shape variations of wave height distribution in the surf zone. Wave attenuation in the trough area of a barred beach is treated with a secondary gradational breaker index, which is applied for locations in water of constant or increasing depth. Its empirical coefficients are assigned values different from those in water of decreasing depth. The wave attenuation factor due to bottom friction is formulated by evaluating the rate of energy dissipation by shear stress along the sea bottom. Computation is made for directional spectral components with multiple levels of wave heights under the Rayleigh distribution, and the results are synthesized for the calculation of wave height distributions. The new computational scheme succeeds in reproducing the random wave breaking diagrams by Goda (1975), and shows good agreements with several experimental results on wave transformations over horizontal shelves, barred beaches, and an elliptical shoal. The scheme also yields wave height predictions in good agreement with several field measurements across the surf zone.

Suspended Sediment in Breaking Waves.

Abstract: : Suspended sediment concentration was measured in 235 breaking waves on undeveloped beaches near Price Inlet, South Carolina, U.S.A., using portable in situ bulk water samplers. The purpose of the study was to determine what factors control the distribution of suspended sediment in the breaker zone. The final conclusion inferred from accumulated data is that sediment transport is highly dependent on breaker type. Net offshore movement and equilibrium profiles can be qualitatively explained on the basis of variations in wave form, beach slope and suspended sediment concentration. Longshore transport rates are dependent not only on wave height, but on breaker type, which can be quantified to reasonable certainty by the simple ratio, d sub b/H sub b, relative wave height. (Author)

Wave Attenuation Through an Arctic Marginal Ice Zone on 12 October 2015: 1. Measurement of Wave Spectra and Ice Features From Sentinel 1A

Abstract: A storm with significant wave heights exceeding 4 m occurred in the Beaufort Sea on 11-13 October 2015. The waves and ice were captured on 12 October by the Synthetic Aperture Radar (SAR) on board Sentinel-1A, with Interferometric Wide swath images covering 400 x 1,100 km at 10 m resolution. This data set allows the estimation of wave spectra across the marginal ice zone (MIZ) every 5 km, over 400 km of sea ice. Since ice attenuates waves with wavelengths shorter than 50 m in a few kilometers, the longer waves are clearly imaged by SAR in sea ice. Obtaining wave spectra from the image requires a careful estimation of the blurring effect produced by unresolved wavelengths in the azimuthal direction. Using in situ wave buoy measurements as reference, we establish that this azimuth cutoff can be estimated in mixed ocean-ice conditions. Wave spectra could not be estimated where ice features such as leads contribute to a large fraction of the radar backscatter variance. The resulting wave height map exhibits a steep decay in the first 100 km of ice, with a transition into a weaker decay further away. This unique wave decay pattern transitions where large-scale ice features such as leads become visible. As in situ ice information is limited, it is not known whether the decay is caused by a difference in ice properties or a wave dissipation mechanism. The implications of the observed wave patterns are discussed in the context of other observations. Plain Language Summary Our work entitled Wave attenuation through an Arctic marginal ice zone on 12 October 2015. 1. Measurement of wave spectra and ice features from Sentinel-1A, uses a newly developed method to extract wave spectra from radar imagery over sea ice. This is possible since the sea ice rapidly removes the short waves which usually distort the radar imagery. We are able to estimate thousands of wave spectra across several hundred kilometers at kilometer-scale resolution for the first large-scale view of wave attenuation across the marginal ice zone. Our results show a unique wave attenuation pattern described by a piecewise exponential decay that changes by a factor of 10. The transition between the different wave attenuation regions occurs near a change in sea ice conditions we estimate from the SAR backscatter. This suggests the wave-ice interaction mechanisms are indeed changing over these large scales.