Wave-Breaking Turbulence in the Ocean Surface Layer

AbstractObservations of winds, waves, and turbulence at the ocean surface are compared with several analytic formulations and a numerical model for the input of turbulent kinetic energy by wave breaking and the subsequent dissipation. The observations are generally consistent with all of the formulations, although some differences are notable at winds greater than 15 m s−1. The depth dependence of the turbulent dissipation rate beneath the waves is fit to a decay scale, which is sensitive to the choice of vertical reference frame. In the surface-following reference frame, the strongest turbulence is isolated within a shallow region of depths much less than one significant wave height. In a fixed reference frame, the strong turbulence penetrates to depths that are at least half of the significant wave height. This occurs because the turbulence of individual breakers persists longer than the dominant period of the waves and thus the strong surface turbulence is carried from crest to trough with the wave orbital motion.

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Effect of Uni- and Bi-Directional Coupling of Ocean-Met Interaction on Significant Wave Height and Local Wind

Volume 7B: Ocean Engineering ◽

10.1115/omae2017-61681 ◽

2017 ◽

Author(s):

Adil Rasheed ◽

Jakob Kristoffer Süld ◽

Mandar Tabib

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Surface Wind ◽

Wave Model ◽

Ocean Surface ◽

Observation Data ◽

Local Wind ◽

Near Surface ◽

Significant Wave ◽

Bidirectional Coupling

Accurate prediction of near surface wind and wave height are important for many offshore activities like fishing, boating, surfing, installation and maintenance of marine structures. The current work investigates the use of different methodologies to make accurate predictions of significant wave height and local wind. The methodology consists of coupling an atmospheric code HARMONIE and a wave model WAM. Two different kinds of coupling methodologies: unidirectional and bidirectional coupling are tested. While in Unidirectional coupling only the effects of atmosphere on ocean surface are taken into account, in bidirectional coupling the effects of ocean surface on the atmosphere are also accounted for. The predicted values of wave height and local wind at 10m above the ocean surface using both the methodologies are compared against observation data. The results show that during windy conditions, a bidirectional coupling methodology has better prediction capability.

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Significant Wave Height and Bistatic Doppler Signals of Microwave Scattering From the Ocean Surface: With Emphasis on the Swell Factor

IEEE Transactions on Geoscience and Remote Sensing ◽

10.1109/tgrs.2021.3118995 ◽

2021 ◽

pp. 1-12

Author(s):

Paul A. Hwang ◽

Jeffrey D. Ouellette ◽

Jakov V. Toporkov ◽

Joel T. Johnson

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Ocean Surface ◽

Microwave Scattering ◽

Significant Wave ◽

Doppler Signals

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Dynamic and resuspension by waves and sedimentation pattern definition in low energy environments: guaíba lake (Brazil)

Brazilian Journal of Oceanography ◽

10.1590/s1679-87592013000100006 ◽

2013 ◽

Vol 61 (1) ◽

pp. 55-64 ◽

Cited By ~ 6

Author(s):

João Luiz Nicolodi ◽

Elirio E. Toldo Jr ◽

Leandro Farina

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Depositional Environments ◽

Maximum Height ◽

Significant Wave ◽

Suspended Particulate ◽

Propagating Waves ◽

Wind Intensity ◽

The Mathematical Model ◽

The Waves

Little research has been undertaken into sediment dynamics in lakes, and most of it only analyses particular aspects such as the texture of the sediments. In this study, the characteristics of the wave field in Guaíba Lake are investigated. The parameters significant wave height (Hs), period (T) and direction of wave propagation are examined together with their relation to the resuspension of sediments at the bottom. For this purpose, the mathematical model SWAN (Simulating Waves Nearshore) has been validated and employed. The results pointed out that the highest waves modeled reached 0.55 m at a few points in the lake, particularly when winds were blowing from the S and SE quadrants with an intensity over 7 m.s-1. Generally speaking, waves follow wind intensity and direction patterns, and reach maximum height in about 1 to 2 hours after wind speed peaks. Whenever winds were stronger, waves took some 2 hours to reach 0.10 m. However, with weak to moderate winds, the waves took around 3 hours to achieve this value in significant wave height. In addition to speed and direction, wind regularity proved relevant in generating and propagating waves on Lake Guaíba. In conclusion the lake's sediment environments were mapped and classified as follows: 1) Depositional Environments (51% of the lake); 2) Transitional Environments (41%); and 3) Erosional or Non-Depositional Environments (8%). As a contribution to the region's environmental management, elements have been created relating to the concentration of suspended particulate matter.

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Rogue waves in 2006–2010

Natural Hazards and Earth System Science ◽

10.5194/nhess-11-2913-2011 ◽

2011 ◽

Vol 11 (11) ◽

pp. 2913-2924 ◽

Cited By ~ 61

Author(s):

I. Nikolkina ◽

I. Didenkulova

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Rogue Wave ◽

World Ocean ◽

Rogue Waves ◽

Shallow Waters ◽

Extreme Waves ◽

Significant Wave ◽

The World ◽

The Waves

Abstract. The evidence of rogue wave existence all over the world during last five years (2006–2010) has been collected based mainly on mass media sources. Only events associated with damage and human loss are included. The waves occurred not only in deep and shallow zones of the World Ocean, but also at the coast, where they were manifested as either sudden flooding of the coast or high splashes over steep banks or sea walls. From the total number of 131 reported events, 78 were identified as evidence of rogue waves (which are expected to be at least twice larger than the significant wave height). The background significant wave height was estimated from the satellite wave data. The rogue waves at the coast, where the significant wave height is unknown or meaningless, were selected based on their unexpectedness and hazardous character. The statistics built on the selected 78 events suggests that extreme waves cause more damage in shallow waters and at the coast than in the deep sea and can be used for hazard assessment of the rogue wave phenomenon.

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Functional Data Analysis and Wave Profiles During a Storm

Volume 2: Structures, Safety and Reliability ◽

10.1115/omae2011-50320 ◽

2011 ◽

Cited By ~ 1

Author(s):

Joaqui´n Ortega ◽

Cristina Gorrostieta ◽

George H. Smith

Keyword(s):

Data Analysis ◽

Wave Height ◽

Functional Data Analysis ◽

Functional Data ◽

Significant Wave Height ◽

Functional Principal Component Analysis ◽

Time Interval ◽

Significant Wave ◽

Wave Profiles ◽

The Waves

Functional Data Analysis is a set of statistical tools developed to perform statistical analysis on data having a functional form. In our case we consider the one-dimensional wave profiles registered during a North-Sea storm as functional data. The waves are defined as the surface height between two consecutive downcrossings. Data is split into 20-minute periods and after registration of the waves to the interval [0,1], the mean wave is obtained along with the first two derivatives of this mean profile. We analyze the shape of these mean waves and their derivatives and show how they change as a function of the significant wave height for the corresponding time interval. We also look at the evolution of the energy, as represented by the phase diagram, as a function of significant wave height. The results show the asymmetry in vertical and horizontal scales for real data. To consider how the individual waves vary we perform a Functional Principal Component Analysis of wave profiles, dividing previously the waves into groups according to their height and comparing with waves measured during a non-storm period. The results suggest that the modes of variation of wave profiles do not depend on wave height or sea condition.

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Interannual variability of ocean surface waves in the Southeast Pacific

10.5194/egusphere-egu2020-11567 ◽

2020 ◽

Author(s):

Catalina Aguirre ◽

Diego Becerra ◽

Marcelo Godoy ◽

Diego Silva

Keyword(s):

South America ◽

Interannual Variability ◽

Wave Height ◽

Significant Wave Height ◽

Wind Waves ◽

Austral Summer ◽

Ocean Surface ◽

Positive Phase ◽

Significant Wave ◽

Southeast Pacific

<p>Ocean surface (wind-driven) waves continuously shape the coastal environment and play a relevant role in ocean-atmosphere interaction processes. They are also important in operational aspects of ports and have significant energy potential. This research is focused on the interannual variability of the wind waves in the Southeast Pacific, particularly its relationship with the Southern Annular Mode (SAM) and El Ni&#241;o Southern Oscillation (ENSO). We used a 38-year wave simulation (1979-2016) performed using the Wavewatch III model forced with surface winds and ice concentration from the ERA-Interim reanalysis. Additionally, a cyclone tracking software was used to analyze the trajectories of the extratropical storms which generate the wind waves that reach the coast of western South America. Time series statistics, such as correlation and composites analysis, have been applied to both wave parameters (such as significant wave height and mean period) and directional spectra. Results show a significant and positive correlation between the SAM and the significant wave height and the mean period of the wind waves. However, local storms in central Chile, which are the most damaging extreme wave events for coastal infrastructure, are less frequent during the positive phase of the SAM. Furthermore, a trend analysis shows an increase of the significant wave height during the last decades, which is consistent with the trend toward the positive phase experienced by the SAM. On the other hand, the wave energy of remote origin that travels from the North Pacific toward the Southeast Pacific, which is maximum during the austral summer, shows a significant relationship with the extreme El Ni&#241;o events. These energetic swells events that reach the coast of western South America during the austral summer are more intense and frequent during the warm phase of ENSO.</p>

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