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Showing papers on "Wave height published in 2009"


Journal ArticleDOI
TL;DR: In this paper, the wave energy balance is verified in a wide range of conditions and scales, from gentle swells to major hurricanes, from the global ocean to coastal settings using in situ and remote sensing data.
Abstract: New parameterizations for the spectra dissipation of wind-generated waves are proposed. The rates of dissipation have no predetermined spectral shapes and are functions of the wave spectrum and wind speed and direction, in a way consistent with observation of wave breaking and swell dissipation properties. Namely, the swell dissipation is nonlinear and proportional to the swell steepness, and dissipation due to wave breaking is non-zero only when a non-dimensional spectrum exceeds the threshold at which waves are observed to start breaking. An additional source of short wave dissipation due to long wave breaking is introduced to represent the dissipation of short waves due to longer breaking waves. Several degrees of freedom are introduced in the wave breaking and the wind-wave generation term of Janssen (J. Phys. Oceanogr. 1991). These parameterizations are combined and calibrated with the Discrete Interaction Approximation of Hasselmann et al. (J. Phys. Oceangr. 1985) for the nonlinear interactions. Parameters are adjusted to reproduce observed shapes of directional wave spectra, and the variability of spectral moments with wind speed and wave height. The wave energy balance is verified in a wide range of conditions and scales, from gentle swells to major hurricanes, from the global ocean to coastal settings. Wave height, peak and mean periods, and spectral data are validated using in situ and remote sensing data. Some systematic defects are still present, but the parameterizations yield the best overall results to date. Perspectives for further improvement are also given.

420 citations


Journal ArticleDOI
TL;DR: The response of the circulation of a coral reef system in Kaneohe Bay, Hawaii, to incident wave forcing was investigated using field data collected during a 10-month experiment as mentioned in this paper.
Abstract: The response of the circulation of a coral reef system in Kaneohe Bay, Hawaii, to incident wave forcing was investigated using field data collected during a 10-month experiment. Results from the study revealed that wave forcing was the dominant mechanism driving the circulation over much of Kaneohe Bay. As predicted theoretically, wave setup generated near the reef crest resulting from wave breaking established a pressure gradient that drove flow over the reef and out of the two reef channels. Maximum reef setup was found to be roughly proportional to the offshore wave energy flux above a threshold root-mean-square wave height of 0.7 m (at which height setup was negligible). On the reef flat, the wave-driven currents increased approximately linearly with incident wave height; however, the magnitude of these currents was relatively weak (typically <20 cm s−1) because of (i) the mild fore-reef slope of Kaneohe Bay that reduced setup resulting from a combination of frictional wave damping and its re...

188 citations


Journal ArticleDOI
TL;DR: In this article, a long-term analysis of the accuracy and stability of the wave height and wind speed derived from the following satellites: European Remote Sensing-1 (ERS-1), ERS-2, Environmental Satellite (Envisat), Geosat, GFO, Jason-1, and the Ocean Topography Experiment (TOPEX).
Abstract: Since 1985, for a period of more than 23 yr, seven altimeter missions have provided global coverage of significant wave height and wind speed. This study undertakes a long-term analysis of the accuracy and stability of altimeter-derived values of significant wave height and wind speed from the following satellites: European Remote Sensing-1 (ERS-1), ERS-2, Environmental Satellite (Envisat), Geosat, Geosat Follow-On (GFO), Jason-1, and the Ocean Topography Experiment (TOPEX). This study is a necessary step in developing a quality-controlled and fully calibrated and validated dataset from the combined satellites. Calibration of all altimeters is performed against National Oceanographic Data Center (NODC) buoy data over the extended period. These calibrations are validated using intercomparisons between satellite missions at crossover ground points. This analysis shows that, for a number of the satellites, small ‘‘step like’’ changes occur during the missions. These inconsistencies are removed by subdividing these missions and undertaking a partial calibration for each section of the mission. The analysis also highlights that care is necessary when attempting to apply relationships between radar cross section and wind speed derived for one altimeter to other platforms. Before undertaking such steps, it is first necessary to apply a platform-specific radar crosssectional offset to the data.

173 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a simple method to estimate sediment erosion potential in shallow tidal basins caused by wind wave events, combining in a simple framework the contribution from different landscape units.
Abstract: [1] Wave-generated shear stresses are the main mechanism responsible for sediment erosion on tidal flats and regulate both sediment concentrations in the water column and, together with tidal currents, sediment export to salt marshes and to the ocean. We present herein a simple method to estimate sediment erosion potential in shallow tidal basins caused by wind wave events. The method determines the aggregate response of the entire basin, combining in a simple framework the contribution from different landscape units. The method is applied to a system of shallow tidal basins along the Eastern Shore of Virginia, USA. Our analysis unravels the interplay of basin morphology, tidal elevation, and wind direction on water depth, fetch, and the resulting wave-generated shear stresses. We identify four bottom shear stress regimes as a function of water elevation produced by wind waves in shallow micromesotidal systems. For water elevations below mean lower low water (MLLW), an increase in fetch is counteracted by an increase in depth, so that the average bottom shear stress and erosion potential is maintained constant. For elevations between MLLW and mean sea level (MSL), the increase in water depth dominates the increase in wave height, thus reducing the bottom shear stresses. For elevations between MSL and mean higher high water (MHHW), the range associated with stable salt marsh platforms, flooding of salt marshes increases fetch, wave height, and bottom shear stresses, producing the largest resuspension events in the bay. For elevations above MHHW, the increase in depth once again dominates increases in wave height, thereby reducing average bottom shear stresses and potential erosion.

169 citations


Journal ArticleDOI
TL;DR: A coupled wave-circulation numerical model was used to simulate the distribution of wave energy, as well as the circulation induced by wave breaking, wind, and tidal forcing, within a coral reef system in Kaneohe Bay, Oahu, Hawaii as discussed by the authors.
Abstract: [1] A coupled wave-circulation numerical model was used to simulate the distribution of wave energy, as well as the circulation induced by wave breaking, wind, and tidal forcing, within a coral reef system in Kaneohe Bay, Oahu, Hawaii. Modeled wave, current, and wave setup fields were compared with field measurements collected on the forereef, reef flat, and reef channels and in the lagoon over a 4-week period. The predicted wave height transformation across the reef-lagoon system was in good agreement with field observations, using single-parameter (spatially uniform) values to describe both wave-breaking and frictional dissipation. The spatial distribution of the resulting wave setup field drove a persistent wave-driven flow across the reef flat that returned to the ocean through two deeper channels in the reef. Both the magnitude and direction of these currents were well described using a spatially uniform hydraulic roughness length scale. Notably, the model lends support to field observations that setup within the coastally bounded lagoon was a substantial fraction of the maximum setup on the reef (∼60–80%), which generated relatively weak cross-reef wave-driven flows (∼10–20 cm s−1) compared with reefs having mostly unbounded lagoons (e.g., many atolls and barrier reefs). Numerical experiments conducted using Lagrangian particle tracking revealed that residence times within Kaneohe Bay are extremely heterogeneous, typically ranging from 1 month within its sheltered southern lagoon.

166 citations


Journal ArticleDOI
TL;DR: Model trees as a new soft computing method was invoked for prediction of significant wave height and error statistics of model trees and feed-forward back propagation (FFBP) ANNs were similar, while model trees was marginally more accurate.

164 citations


Journal ArticleDOI
TL;DR: In this paper, the authors review the existing capability for combined modelling of tides, surges and waves, their interactions and the development of coupled models, and their interactions with surface wind-stress and bottom friction as well as depth and current refraction of waves by surge water levels and currents.
Abstract: Wind waves and elevated water levels together can cause flooding in low-lying coastal areas, where the water level may be a combination of mean sea level, tides and surges generated by storm events. In areas with a wide continental shelf a travelling external surge may combine with the locally generated surge and waves and there can be significant interaction between the propagation of the tide and surge. Wave height at the coast is controlled largely by water depth. So the effect of tides and surges on waves must also be considered, while waves contribute to the total water level by means of wave setup through radiation stress. These processes are well understood and accurately predicted by models, assuming good bathymetry and wind forcing is available. Other interactions between surges and waves include the processes of surface wind-stress and bottom friction as well as depth and current refraction of waves by surge water levels and currents, and some of the details of these processes are still not well understood. The recent coastal flooding in Myanmar (May 2008) in the Irrawaddy River Delta is an example of the severity of such events, with a surge of over 3 m exacerbated by heavy precipitation. Here, we review the existing capability for combined modelling of tides, surges and waves, their interactions and the development of coupled models.

143 citations


Journal ArticleDOI
TL;DR: This paper presents a pragmatic automated, simple and computationally inexpensive threshold selection method based on the distribution of the difference of parameter estimates when the threshold is changed, and applies it to a published rainfall and a new wave height data set.

135 citations


Journal ArticleDOI
TL;DR: In this paper, combined wave overtopping and storm surge overflow of a levee with a trapezoidal cross section was studied in a two-dimensional laboratory wave/flow flume at a nominal prototype-to-model length scale of 25 to 1.

107 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present the coastal observatory in the Spanish Catalan coast and its contribution to a better understanding of processes that take place in this area, including the most important variations in sea level in the Catalan coast are due to meteorological conditions and in some areas the resonant effect of bays and harbours.

87 citations


Journal ArticleDOI
TL;DR: In this article, a time-dependent generalized extreme value (GEV) model for monthly significant wave heights maxima is developed and applied to several 3-hour time series from the Spanish buoy network.

Journal ArticleDOI
TL;DR: In this article, the role of waves, tide, wind and freshwater discharges over the sea level in Obidos Lagoon, a coastal system connected to the sea through a narrow and shallow mobile inlet, was evaluated.

Book
10 Mar 2009
TL;DR: In this article, the authors introduce the concept of nearly-horizontal flows and the theory of turbulence in the physical environment of coastal, estuarial, and harbour regions, as well as the physical and mathematical models in the optimisation of breakwater layout.
Abstract: Introduction. Part 1: The dynamic environment. The deep-water origins of the physical environment of coastal, estuarial and harbour regions. An introduction to nearly-horizontal flows. Element of the theory of turbulence. Diffusion, dispersion and sub-grid parametization. Elements of non-cohesive sediment transport. Elements of cohesive sediment deposition, consolidation and erosion. Three-dimensional hydrodynamic models. Quasi-three-dimensional modelling using mixed finite difference and spectral models. Two-dimensional nearly-horizontal flow models. One-dimensional nearly-horizontal flow models. Numerical modelling of short-period waves. Three-dimensional advection-diffusion models. Two-dimensional advection-diffusion models. One-dimensional transport-dispersion and water quality. Three-dimensional sediment-transport models. Two-dimensional models of sediment transport due to waves and currents. One-dimensional models of sediment-transport under the influence of currents. Physical short-period-wave models. Hydraulic-structure interaction. Part 2: The physical environment. Groynes, offshore breakwaters and artifical islands. Beach response modelling. Beach nourishment, offshore dredging and sand bypassing. Marinas. Physical and mathematical models in the optimisation of breakwater layout. Design of breakwaters and selected design wave height. Rock for maritime structures. Wave forces on structures. Wave loads on sea dikes. Coastal pollution and water quality. Hydromechanics of porous media in the maritime. Geotextiles in coastal and harbour engineering. Dredging and dredgers. Disposal of dredged material at sea. Field studies and the analysis of data. Coastal management. Construction of maritime works. Materials in the marine environment. Maintenance of coastal structures. Economic appraisal of coastal engineering works. Cohesive sediments. Hydraulic behaviour of fine sediment. Contamination in estuarine sendiments. Cohesive sediments in coastal engineering applications. Determining depth and navigability. Maintenance dredging. Estuarial problems. Barrages and barriers. Tendering, coastal management, site supervision and control. Arbitration. Index.

Journal ArticleDOI
TL;DR: In this paper, the role of mangrove forests in mitigating the Andaman tsunami is assessed by analytical model and numerical simulations by incorporating the Morison Equation to represent friction provided by the mangroves for the coasts of Penang.

Journal ArticleDOI
TL;DR: In this article, a strong positive power correlation between sediment wave height and spacing was observed: Δ s ǫ = 0.0692 λ 0.8020 (N Â = 935; r Â= 0.853).

Journal ArticleDOI
TL;DR: In this article, the authors made measurements at six locations around a small reef platform island in the Maldives during both westerly and northeast monsoon conditions and found that windward reefs and shorelines are dominated by waves at wind and swell frequencies, whereas windwave energy is absent from leeward shorelines.

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate that the sensitivity of model-predicted wave height and flow to variations in bathymetric resolution had different characteristics, and that errors between observed and modeled flow and wave heights are well predicted by comparing model simulation results using progressively filtered bathymetry to results from the highest resolution simulation.

Journal ArticleDOI
TL;DR: In this article, the performance of a porous breakwater was evaluated with normal incidence by a non-breaking monochromatic wave train and a characteristic friction diagram was obtained considering wave energy balance in a control volume, minimising the error between the numerical model and the experimental results for the wave transmission coefficient.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the variability of wake conditions for the coasts of Tallinn Bay, the Baltic Sea, a sea area with very intense fast ferry traffic and found that the spatial extent of the wake patterns is very sensitive to small variations in sailing conditions.
Abstract: . High-speed ferries are known to generate wakes with unusually long periods, and occasionally large amplitudes which may serve as a qualitatively new forcing factor in coastal regions that are not exposed to a sea swell. An intrinsic feature of such wakes is their large spatial variation. We analyze the variability of wake conditions for the coasts of Tallinn Bay, the Baltic Sea, a sea area with very intense fast ferry traffic. The modelled ship wave properties for several GPS-recorded ship tracks reasonably match the measured waves in terms of both wave heights and periods. It is shown that the spatial extent of the wake patterns is very sensitive to small variations in sailing conditions. This feature leads to large variations of ship wave loads at different coastal sections with several locations regularly receiving high ship wave energy. The runup of the largest ship wakes on the beach increases significantly with an increase in wave height whereas shorter (period

Journal ArticleDOI
TL;DR: In this article, a Takagi-Sugeno-rule-based Fuzzy Inference System (FIS) was developed aiming at forecasting wave parameters based on the wind speed and direction, and the lagged-wave characteristics.

Journal ArticleDOI
TL;DR: Based on wind data from the Vilsandi meteorological station and a 5-month calibration measurement with a bottom-mounted Recording Doppler Current Profiler (RDCP), a semi-empirical hindcast of wave parameters near the quickly developing accumulative Kelba Spit is presented for the period 1966-2006 as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this paper, the optical intensity signals from surf zone waves in a laboratory flume are analyzed using several different phase-averaging techniques, and a methodology is developed for estimating wave roller lengths and local wave dissipation.
Abstract: [1] The optical intensity signals from surf zone waves in a laboratory flume are analyzed using several different phase-averaging techniques, and a methodology is developed for estimating wave roller lengths and local wave dissipation The intensity signals (ie, phase-averaged intensity profiles) of individual breaking waves are compared with the wave profiles measured by in situ wave gauges, and the optical signal of the wave roller is shown to ramp up from the toe of the wave roller on the front face of the wave to a maximum intensity at the wave crest The remote sensing observations capture the growth, equilibrium, and decay phases of the roller as it propagates over a fixed bed arranged in a bar/trough morphology Next, for the regular wave conditions considered here, the local maxima of the phase-averaged intensities are shown to better indicate the initial onset of wave breaking and the occurrence of wave breaking in the bar trough, as compared to the more commonly used time-averaged mean intensity In addition, the phase-averaged profiles are used to measure the size of the roller, and these measurements are compared to previous observations of smaller-scale rollers in equilibrium The observed roller lengths are shown to agree with predictions from a wave roller model and to provide a new physical link between the remotely sensed signal and roller dissipation Finally, as an example application of these new data, a simple wave height inversion model is presented that allows an estimation of surf zone wave heights from the remotely sensed roller lengths

Journal ArticleDOI
TL;DR: In this paper, a high-resolution nested WAM/SWAN wave model suite aimed at rapidly establishing nearshore wave forecasts as well as a climatology and return values of the local wave conditions with Rapid Environmental Assessment (REA) in mind is described.

Journal ArticleDOI
TL;DR: In this article, the vertically integrated effect of interaction between waves and wave-induced currents on wave transformation over a submerged elliptic shoal was investigated based on numerical simulations of the Vincent and Briggs experiment.

Journal Article
TL;DR: Farrer et al. as discussed by the authors designed and implemented a field experiment at Belinho, Portugal, to assess the attenuation and transformation of waves across this surface as a result of shoaling and breaking, derived spectral estimates of wave height and period through each high tide series.
Abstract: ^MHI^HHH^HHBII^^HH^HHHi^H!iH!^BIHMH Farrell, E.J.., Granja, H., Cappietti, L., Ellis, J.T., Li, B., and Sherman, D.J., 2009 . Wave transformation across a rock platform, Belinho, Portugal. Journal of Coastal Research, SI 56 (Proceedings of the 10th International Coastal Symposium), 44 48. Lisbon, Portugal, ISSN 0749-0258. Much is known about wave attenuation across sandy nearshore environments or coral reef platforms. Limited field work has aimed to measure and assess attenuation across rock platforms. We designed and implemented a field experiment at Belinho, Portugal, to address this need. Field work was conducted in June, 2006, over a sequence of five tidal cycles. We deployed a shore-normal array of seven KPSI pressure transducers, installed 0.15 m above the bed and spaced between 10 and 15 m apart, to measure surface water levels. When all instruments were submerged by the rising tide, they were sampled at 20Hz.. The instrument array spanned the inter-tidal platform composed of schist. The surface, about 70 m wide, is irregular and cut by many shore perpendicular channels. To assess the attenuation and transformation of waves across this surface as a result of shoaling and breaking, we derived spectral estimates of wave height and period through each high tide series. Wave heights at the outermost PT ranged between about 0. 4 to 0.9 m. At the innermost PT, corresponding values were 0.5 to 1.14 m. Wave periods averaged about 10 s through the study. Our results showed that a breaking criterion of 0.42 + c fit our data. additional index words: breaking criterion, surf zone, wave attenuation, wave steepness

Journal ArticleDOI
TL;DR: In this paper, a two-dimensional spectral wave model is applied at high temporal resolution to time slices from 12 ka BP to present using paleobathymetries of the NW European shelf seas.
Abstract: [1] Because of the depth attenuation of wave orbital velocity, wave-induced bed shear stress is much more sensitive to changes in total water depth than tidal-induced bed shear stress. The ratio between wave- and tidal-induced bed shear stress in many shelf sea regions has varied considerably over the recent geological past because of combined eustatic changes in sea level and isostatic adjustment. In order to capture the high-frequency nature of wind events, a two-dimensional spectral wave model is here applied at high temporal resolution to time slices from 12 ka BP to present using paleobathymetries of the NW European shelf seas. By contrasting paleowave climates and bed shear stress distributions with present-day conditions, the model results demonstrate that, in regions of the shelf seas that remained wet continuously over the last 12,000 years, annual root-mean-square (rms) and peak wave heights increased from 12 ka BP to present. This increase in wave height was accompanied by a large reduction in the annual rms wave-induced bed shear stress, primarily caused by a reduction in the magnitude of wave orbital velocity penetrating to the bed for increasing relative sea level. In regions of the shelf seas which remained wet over the last 12,000 years, the annual mean ratio of wave- to (M2) tidal-induced bed shear stress decreased from 1 (at 12 ka BP) to its present-day value of 0.5. Therefore compared to present-day conditions, waves had a more important contribution to large-scale sediment transport processes in the Celtic Sea and the northwestern North Sea at 12 ka BP.

01 Jan 2009
TL;DR: In this article, an algorithm for modeling natural entrainment of spilled oil at sea, extending the range of application beyond the 100-1000 cP limit of the earlier work, is presented.
Abstract: The purpose of this project has been to extend earlier work on the entrainment of oil into higher viscosity, non-Newtonian regions. The key deliverable is an algorithm for modeling natural entrainment of spilled oil at sea, extending the range of application beyond the 100 – 1000 cP limit of the earlier work. Equations were developed for droplet size distribution as a function of oil film thickness, wave amplitude, oil viscosity, and oil-water interfacial tension. Combined with equations for wave height and period as a functions of wind speed (plus fetch, depth and duration if desired), and whitecap coverage, an algorithm for natural dispersion is presented. This algorithm differs substantially from earlier work in that it is built up from a dimensional analysis of the problem, incorporating both the Weber number and a non-dimensional viscosity group.

Journal ArticleDOI
15 Jun 2009
TL;DR: Xie et al. as mentioned in this paper examined the effects of wave-current interactions on ocean surface waves induced by Hurricane Hugo in and around the Charleston Harbor and its adjacent coastal waters by using a three-dimensional (3D) wavecurrent coupled modeling system.
Abstract: The effects of wave–current interactions on ocean surface waves induced by Hurricane Hugo in and around the Charleston Harbor and its adjacent coastal waters are examined by using a three-dimensional (3D) wave–current coupled modeling system. The 3D storm surge modeling component of the coupled system is based on the Princeton Ocean Model (POM), the wave modeling component is based on the third generation wave model, Simulating WAves Nearshore (SWAN), and the inundation model is adopted from [Xie, L., Pietrafesa, L. J., Peng, M., 2004. Incorporation of a mass-conserving inundation scheme into a three-dimensional storm surge model. J. Coastal Res., 20, 1209–1223]. The results indicate that the change of water level associated with the storm surge is the primary cause for wave height changes due to wave–surge interaction. Meanwhile, waves propagating on top of surge cause a feedback effect on the surge height by modulating the surface wind stress and bottom stress. This effect is significant in shallow coastal waters, but relatively small in offshore deep waters. The influence of wave–current interaction on wave propagation is relatively insignificant, since waves generally propagate in the direction of the surface currents driven by winds. Wave–current interactions also affect the surface waves as a result of inundation and drying induced by the storm. Waves break as waters retreat in regions of drying, whereas waves are generated in flooded regions where no waves would have occurred without the flood water.

Journal ArticleDOI
TL;DR: It is shown that a behavioral display trait, the maximum height that the tip of the claw reaches during a courtship wave, is a strong correlate of the subsequent likelihood that a female will visit a male's burrow (which is a prerequisite for a burrow mating).
Abstract: Claw size of male fiddler crabs, Uca perplexa appears to be a target of female choice that increases the likelihood a female will initially approach a male. Here we show that a behavioral display trait, the maximum height that the tip of the claw reaches during a courtship wave, is a strong correlate of the subsequent likelihood that a female will visit a male's burrow (which is a prerequisite for a burrow mating). We experimentally manipulated claw mass, to test whether there is a trade-off between claw mass and wave height. Males with a metal weight added to their claw showed a large reduction in wave height, whereas control males (plastic added) showed no net change in wave height. There is therefore a trade-off between these two sexually selected traits (claw size and wave display). More importantly, the greater the initial wave height the smaller the subsequent decline in wave height. Assuming that variation in wave height is an index of quality, this variation in the cost-benefit trade-off is consistent with the requirements of a signaling system that conforms to the handicap principle when fitness is the multiplicative product of different fitness components. We conclude by discussing the ongoing difficulties in testing the handicap principle.

Journal ArticleDOI
TL;DR: In this paper, the results of a weeklong field experiment carried out in September 2003 on the beach of Capbreton, in southwest France, are presented, where wave-induced pore pressures were measured at various depths below the sandy bed in front of a coastal structure.
Abstract: [1] Wave-induced pore pressures were measured at various depths below the sandy bed in front of a coastal structure. The results of a weeklong field experiment carried out in September 2003 on the beach of Capbreton, in southwest France, are presented. The coastal structure was located in the intertidal zone of the beach. The transmission of pressure variations inside the soil, as compared to the pressure variations produced by the waves in the water layer, are analyzed in terms of both amplitude decay and phase shifts and compared to theoretical models. The gas content inside the soil was also measured. The results confirm that the gas content is a key parameter affecting the transmission of pressure inside the soil. It is shown that a significant upward pressure gradient is generated during a wave period, which can liquefy a 30 cm deep superficial layer of the soil. This is interpreted in terms of momentary liquefaction events. The manner in which the phenomena change during the different tidal periods investigated is described. The dependence of the results on wave height and bed level is discussed. Whereas the soil properties were not modified over a tidal period when the wave activity was sufficiently low, a significant change in the transmission of pressure variations inside the soil was observed when the structure was subjected to larger waves. This is interpreted in terms of a change in the gas content in the superficial layer.