SU\G(𝔸)/K·U
Sign Up for free Log In
Earth and Planetary Sciences › Oceanography

Ocean Waves and Remote Sensing

Works Count: 42975

Description

This cluster of papers explores the dynamics of ocean surface waves, their interaction with wind, and the associated phenomena such as rogue waves, tropical cyclones, and Langmuir turbulence. It covers topics such as wave modeling, wind stress, satellite altimetry, and the impact of surface waves on air-sea interaction.

Keywords

Ocean Waves; Wind Stress; Wave Climate; Rogue Waves; Tropical Cyclones; Wave Modeling; Surface Turbulence; Satellite Altimetry; Langmuir Turbulence; Air-Sea Interaction

<i>Wave Propagation in a Turbulent Medium</i>

1961-12-01
V. I. Tatarski , R. A. Silverman , Nicholas Chako

Thermo-fluid dynamic theory of two-phase flow

1976-12-01
M. Ishii

Theories for the interaction of electromagnetic and oceanic waves ? A review

1978-01-01
Gaspar R. Valenzuela

Directional spectra of wind-generated ocean waves

1985-09-26
Mark A. Donelan , J. H. Hamilton , W. H. Hui
From observations of wind and of water surface elevation at 14 wave staffs in an array in Lake Ontario and in a large laboratory tank, the directional spectrum of wind-generated … From observations of wind and of water surface elevation at 14 wave staffs in an array in Lake Ontario and in a large laboratory tank, the directional spectrum of wind-generated waves on deep water is determined by using a modification of Barber’s (1963) method. Systematic investigations reveal the following: ( a ) the frequency spectrum in the rear face is inversely proportional to the fourth power of the frequency w, with the equilibrium range parameter and the peak enhancement factor clearly dependent on the ratio of wind speed to peak wave speed; ( b ) the angular spreading 0 of the wave energy is of the form sech 2 (fid), where /? is a function of frequency relative to the peak; ( c ) depending on the gradient of the fetch, the direction of the waves at the spectral peak may differ from the mean wind direction by up to 50°, but this observed difference is predictable by a similarity analysis; ( d ) under conditions of strong wind forcing, significant effects on the phase velocity caused by amplitude dispersion and the presence of bound harmonics are clearly observed and are in accordance with the Stokes theory, whereas ( e ) the waves under natural wind conditions show amplitude dispersion, but bound harmonics are too weak to be detected among the background of free waves.

Air-sea bulk transfer coefficients in diabatic conditions

1975-08-01
Junsei Kondo

Toward the true near‐surface wind speed: Error modeling and calibration using triple collocation

1998-04-15
Ad Stoffelen
Wind is a very important geophysical variable to accurately measure. However, a statistical phenomenon important for the validation or calibration of winds is the small dynamic range relative to the … Wind is a very important geophysical variable to accurately measure. However, a statistical phenomenon important for the validation or calibration of winds is the small dynamic range relative to the typical measurement uncertainty, i.e., the generally small signal‐to‐noise ratio. In such cases, pseudobiases may occur when standard validation or calibration methods are applied, such as regression or bin‐average analyses. Moreover, nonlinear transformation of random error, for instance, between wind components and speed and direction, may give rise to substantial pseudobiases. In fact, validation or calibration can only be done properly when the full error characteristics of the data are known. In practice, the problem is that prior knowledge on the error characteristics is seldom available. In this paper we show that simultaneous error modeling and calibration can be achieved by using triple collocations. This is a fundamental finding that is generally relevant to all geophysical validation. To illustrate the statistical analysis using triple collocations, in situ, ERS scatterometer, and forecast model winds are used. Wind component error analysis is shown to be more convenient than wind speed and direction error analysis. The anemometer winds from the National Oceanic and Atmospheric Administration (NOAA) buoys are shown to have the largest error variance, followed by the scatterometer and the National Centers for Environmental Prediction (NCEP) forecast model winds proved the most accurate. When using the in situ winds as a reference, the scatterometer wind components are biased low by −4%. The NCEP forecast model winds are found to be biased high by −6%, After applying a higher‐order calibration procedure an improved ERS scatterometer wind retrieval is proposed. The systematic and random error analysis is relevant for the use of nearsurface winds to compute fluxes of momentum, humidity, or heat or to drive ocean wave or circulation models.

Quasi-linear Theory of Wind-Wave Generation Applied to Wave Forecasting

1991-11-01
Peter A. E. M. Janssen
The effect of wind-generated gravity waves on the airflow is discussed using quasi-linear theory of wind-wave generation. In this theory, both the effects of the waves and the effect of … The effect of wind-generated gravity waves on the airflow is discussed using quasi-linear theory of wind-wave generation. In this theory, both the effects of the waves and the effect of air turbulence on the mean wave profile are taken into account. The main result of this theory is that for young wind sea most of the stress in the boundary layer is determined by momentum transfer from wind to waves, therefore, resulting in a strong interaction between wind and waves. For old wind sea there is, however, hardly any coupling. As a consequence, a sensitive dependence of the aerodynamic drag on wave age is found, explaining the scatter in plots of the experimentally observed drag as a function of the wind speed at 10-m height. Also, the growth rate of waves by wind is found to depend on wave age. All this suggests that a proper description of the physics of the momentum transfer at the air–sea interface can only be given by coupling an atmospheric (boundary-layer) model with an ocean-wave prediction model. Here, results are presented of the coupling of a simple surface-layer model with a third-generation wave model. First, results obtained with a single gridpoint coupled model are discussed, and the evolution in time of wave height, wave stress, and the aerodynamic drag is investigated. Next, results obtained from a hindcast with the coupled model on the North Sea are discussed. In both cases, the wave-induced stress is found to have some impact on the results for wave height, while the impact on the stress in the surface layer is significant.
View PDF Chat

On the generation of surface waves by shear flows

1957-11-01
John W. Miles
A mechanism for the generation of surface waves by a parallel shear flow U(y) is developed on the basis of the inviscid Orr-Sommerfeld equation. It is found that the rate … A mechanism for the generation of surface waves by a parallel shear flow U(y) is developed on the basis of the inviscid Orr-Sommerfeld equation. It is found that the rate at which energy is transferred to a wave of speed c is proportional to the profile curvature -U"(y) at that elevation where U = c. The result is applied to the generation of deep-water gravity waves by wind. An approximate solution to the boundary value problem is developed for a logarithmic profile and the corresponding spectral distribution of the energy transfer coefficient calculated as a function of wave speed. The minimum wind speed for the initiation of gravity waves against laminar dissipation in water having negligible mean motion is found to be roughly 100cm/sec. A spectral mean value of the sheltering coefficient, as defined by Munk, is found to be in order-of-magnitude agreement with total wave drag measurements of Van Dorn. It is concluded that the model yields results in qualitative agreement with observation, but truly quantitative comparisons would require a more accurate solution of the boundary value problem and more precise data on wind profiles than are presently available. The results also may have application to the flutter of membranes and panels.

Semiempirical Dissipation Source Functions for Ocean Waves. Part I: Definition, Calibration, and Validation

2010-07-19
Fabrice Ardhuin , W. Erick Rogers , Alexander V. Babanin +7 more
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 … 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.
View PDF Chat

A model for non-Rayleigh sea echo

1976-11-01
E. Jakeman , P. N. Pusey
A mathematical model for non-Rayleigh microwave sea echo is developed which describes explicitly the dependence of statistical properties of the radar cross section on the area of sea surface illuminated … A mathematical model for non-Rayleigh microwave sea echo is developed which describes explicitly the dependence of statistical properties of the radar cross section on the area of sea surface illuminated by the radar. In addition to the first probability distribution of the scattered radiation, its temporal and spatial correlation functions are also considered. It is shown that, in general, these correlation functions decay on at least two scales, the second, non-Rayleigh, contributions being strongly dependent on the properties of a "single scatterer." Predictions of the model are found to be in qualitative agreement with existing experimental data. A new class of probability distributions, the " <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</tex> -distributions," is introduced, which may prove useful for fitting such data.

Space-time scales of internal waves: A progress report

1975-01-20
Christopher Garrett , Walter Munk

Coefficients for sea surface wind stress, heat flux, and wind profiles as a function of wind speed and temperature

1988-12-15
Stuart D. Smith
Surface layer coefficients for wind profiles, wind stress, and heat flux in typical open sea conditions are briefly reviewed. Businger‐Dyer flux‐gradient relationships and a Charnock wind stress formula fit the … Surface layer coefficients for wind profiles, wind stress, and heat flux in typical open sea conditions are briefly reviewed. Businger‐Dyer flux‐gradient relationships and a Charnock wind stress formula fit the empirical data and are dimensionally consistent. These have been solved by an iterative method, and the results are presented in a tabular form suitable for climatological calculations from marine wind and temperature data.

The deformation of steep surface waves on water - I. A numerical method of computation

1976-07-30
M. S. Longuet‐Higgins , Edward D. Cokelet
Plunging breakers are beyond the reach of all known analytical approximations. Previous numerical computations have succeeded only in integrating the equations of motion up to the instant when the surface … Plunging breakers are beyond the reach of all known analytical approximations. Previous numerical computations have succeeded only in integrating the equations of motion up to the instant when the surface becomes vertical. In this paper we present a new method for following the time-history of space-periodic irrotational surface waves. The only independent variables are the coordinates and velocity potential of marked particles at the free surface. At each time-step an integral equation is solved for the new normal component of velocity. The method is faster and more accurate than previous methods based on a two dimensional grid. It has also the advantage that the marked particles become concentrated near regions of sharp curvature. Viscosity and surface tension are both neglected. The method is tested on a free, steady wave of finite amplitude, and is found to give excellent agreement with independent calculations based on Stokes’s series. It is then applied to unsteady waves, produced by initially applying an asymmetric distribution of pressure to a symmetric, progres­sive wave. The freely running wave then steepens and overturns. It is demonstrated that the surface remains rounded till well after the over­turning takes place.

Global Trends in Wind Speed and Wave Height

2011-03-25
Ian R. Young , Stefan Zieger , Alexander V. Babanin
Studies of climate change typically consider measurements or predictions of temperature over extended periods of time. Climate, however, is much more than temperature. Over the oceans, changes in wind speed … Studies of climate change typically consider measurements or predictions of temperature over extended periods of time. Climate, however, is much more than temperature. Over the oceans, changes in wind speed and the surface gravity waves generated by such winds play an important role. We used a 23-year database of calibrated and validated satellite altimeter measurements to investigate global changes in oceanic wind speed and wave height over this period. We find a general global trend of increasing values of wind speed and, to a lesser degree, wave height, over this period. The rate of increase is greater for extreme events as compared to the mean condition.
View PDF Chat

The parameters of atmospheric turbidity

1964-01-01
Anders Ångström
The methods for evaluating the atmospheric turbidity parameters, introduced by the present author in 1929-30, are subjected to a critical examination. A method first suggested by M. HEROVANU (1959) is … The methods for evaluating the atmospheric turbidity parameters, introduced by the present author in 1929-30, are subjected to a critical examination. A method first suggested by M. HEROVANU (1959) is here simplified and expanded, and used for deriving the named parameters in adherence to a procedure described by the present author in a previous paper in this journal (1961). The procedure is applied to the pyrheliometric observations at Potsdam in 1932-36, published by HOELPER (1939) A comparison between the frequency distribution of the coefficient of wave-length dependence α at the high level station Davos and the low level station Potsdam gives results which are discussed in detail. In all the figures of the present paper, where the turbidity coefficients occur, they are multiplied by 103.
View PDF Chat

On the non-linear energy transfer in a gravity-wave spectrum Part 1. General theory

1962-04-01
Klaus Hasselmann
The energy flux in a finite-depth gravity-wave spectrum resulting from weak non-linear couplings between the spectral components is evaluated by means of a perturbation method. The fifth-order analysis yields a … The energy flux in a finite-depth gravity-wave spectrum resulting from weak non-linear couplings between the spectral components is evaluated by means of a perturbation method. The fifth-order analysis yields a fourth-order effect comparable in magnitude to the generating and dissipating processes in wind-generated seas. The energy flux favours equidistribution of energy and vanishes in the limiting case of a white, isotropic spectrum. The influence on the equilibrium structure of fully developed wave spectra and on other phenomena in random seas is discussed briefly.
View PDF Chat

Finite bandwidth, finite amplitude convection

1969-09-03
Alan C. Newell , J. A. Whitehead
The main purpose of this work is to show how a continuous finite bandwidth of modes can be readily incorporated into the description of post-critical Rayleigh-Bénard convection by the use … The main purpose of this work is to show how a continuous finite bandwidth of modes can be readily incorporated into the description of post-critical Rayleigh-Bénard convection by the use of slowly varying (in space and time) amplitudes. Previous attempts have used a multimodal discrete analysis. We show that in addition to obtaining results consistent with the discrete mode approach, there is a larger class of stable and realizable solutions. The main feature of these solutions is that the amplitude and wave-number of the motion is that of the most unstable mode almost everywhere, but, depending on external and initial conditions, the roll couplets in different parts of space may be 180° out of phase. The resulting discontinuities are smoothed by hyperbolic tangent functions. In addition, it is clear that the mechanism for propagating spatial nonuniformities is diffusive in character.

On the Existence of a Fully Developed Wind-Sea Spectrum

1984-08-01
G. J. Komen , Klaus Hasselmann
We consider the energy transfer equation for well-developed ocean waves under the influence of wind, and study the conditions for the existence of an equilibrium solution in which wind input, … We consider the energy transfer equation for well-developed ocean waves under the influence of wind, and study the conditions for the existence of an equilibrium solution in which wind input, wave-wave interaction and dissipation balance each other. For the wind input we take the parameterization proposed by Snyder and others, which was based on their measurements in the Bight of Abaco and which agrees with Miles's theory. The wave-wave interaction is computed with an algorithm given recently by S. Hasselmann and others. The dissipation is less well-known, but we will make the general assumption that it is quasi-linear in the wave spectrum with a factor coefficient depending only on frequency and integral spectral parameters. In the first part of this paper we investigate whether the assumption that the equilibrium spectrum exits and is given by the Pierson-Moskowitz spectrum with a standard type of angular distribution leads to a reasonable dissipation function. We find that this is not the case. Even if one balances the total rate of change for each frequency (which is possible), a strong angular imbalance remains. Thus the assumed source terms are not consistent with this type of asymptotic spectrum. In the second part of the paper we choose a different approach. We assume that the dissipation is given and perform numerical experiments simulating fetch-limited growth, to see under which conditions a stationary solution can be reached. For the dissipation we take K. Haseelmann's form with two unknown parameters. From our analysis it follows that for a certain range of values of these parameters, a quasi-equilibrium solution results. We estimate the relation between dissipation parameters and asymptotic growth rates. For equilibrium spectra, the input, dissipation and nonlinear-transfer source functions are all significant in the energy-containing range of the spectrum. The energy balance proposed by Zakharov and Filonenko in 1966 and Kitaigorodskii in 1983, in which dissipation is assumed to be significant only at high frequencies, yields a spectrum that grows too rapidly and does not approach equilibrium. One of our equilibrium solutions has a one-dimensional spectrum that lies close to the Pierson-Moskowitz spectrum. However, the angular distribution differs in some important features from standard spreading functions. The energy balance of this equilibrium spectrum is analysed in detail.
View PDF Chat

On three-dimensional packets of surface waves

1974-06-04
A. Davey , K. Stewartson
In this note we use the method of multiple scales to derive the two coupled nonlinear partial differential equations which describe the evolution of a three-dimensional wave-packet of wavenumber k … In this note we use the method of multiple scales to derive the two coupled nonlinear partial differential equations which describe the evolution of a three-dimensional wave-packet of wavenumber k on water of finite depth. The equations are used to study the stability of the uniform Stokes wavetrain to small disturbances whose length scale is large compared with 2π/ k . The stability criterion obtained is identical with that derived by Hayes under the more restrictive requirement that the disturbances are oblique plane waves in which the amplitude variation is much smaller than the phase variation.

Water waves, nonlinear Schrödinger equations and their solutions

1983-07-01
D. H. Peregrine
Abstract Equations governing modulations of weakly nonlinear water waves are described. The modulations are coupled with wave-induced mean flows except in the case of water deeper than the modulation length … Abstract Equations governing modulations of weakly nonlinear water waves are described. The modulations are coupled with wave-induced mean flows except in the case of water deeper than the modulation length scale. Equations suitable for water depths of the order the modulation length scale are deduced from those derived by Davey and Stewartson [5] and Dysthe [6]. A number of ases in which these equations reduce to a one dimensional nonlinear Schrödinger (NLS) equation are enumerated. Several analytical solutions of NLS equations are presented, with discussion of some of their implications for describing the propagation of water waves. Some of the solutions have not been presented in detail, or in convenient form before. One is new, a “rational” solution describing an “amplitude peak” which is isolated in space-time. Ma's [13] soli ton is particularly relevant to the recurrence of uniform wave trains in the experiment of Lake et al .[10]. In further discussion it is pointed out that although water waves are unstable to three-dimensional disturbances, an effective description of weakly nonlinear two-dimensional waves would be a useful step towards describing ocean wave propagation.
View PDF Chat

Mass transport in water waves

1953-03-31
M. S. Longuet‐Higgins
It was shown by Stokes that in a water wave the particles of fluid possess, apart from their orbital motion, a steady second-order drift velocity (usually called the mass-transport velocity). … It was shown by Stokes that in a water wave the particles of fluid possess, apart from their orbital motion, a steady second-order drift velocity (usually called the mass-transport velocity). Recent experiments, however, have indicated that the mass-transport velocity can be very different from that predicted by Stokes on the assumption of a perfect, non-viscous fluid. In this paper a general theory of mass transport is developed, which takes account of the viscosity, and leads to results in agreement with observation. Part I deals especially with the interior of the fluid. It is shown that the nature of the motion in the interior depends upon the ratio of the wave amplitude a to the thickness d of the boundary layer: when a 2 / d 2 is small the diffusion of vorticity takes place by viscous ‘conduction’; when a 2 / d 2 is large, by convection with the mass-transport velocity. Appropriate field equations for the stream function of the mass transport are derived. The boundary layers, however, require separate consideration. In part II special attention is given to the boundary layers, and a general theory is developed for two types of oscillating boundary: when the velocities are prescribed at the boundary, and when the stresses are prescribed. Whenever the motion is simple-harmonic the equations of motion can be integrated exactly. A general method is described for determining the mass transport throughout the fluid in the presence of an oscillating body, or with an oscillating stress at the boundary. In part III, the general method of solution described in parts I and II is applied to the cases of a progressive and a standing wave in water of uniform depth. The solutions are markedly different from the perfect-fluid solutions with irrotational motion. The chief characteristic of the progressivewave solution is a strong forward velocity near the bottom. The predicted maximum velocity near the bottom agrees well with that observed by Bagnold.

On the generation of waves by turbulent wind

1957-07-01
O. M. Phillips
A theory is initiated for the generation of waves upon a water surface, originally at rest, by a random distribution of normal pressure associated with the onset of a turbulent … A theory is initiated for the generation of waves upon a water surface, originally at rest, by a random distribution of normal pressure associated with the onset of a turbulent wind. Corrlations between air and water motions are neglected and the water is assumed to be inviscid, so that the motion of the water, starting from rest, is irrotational. It is found that waves develop most rapidly by means of a resonance mechanism which occurs when a component of the surface pressure distribution moves at the same speed as the free surface wave with the same wave-number.The development of the waves is conveniently considered in two stages, in which the time elapsed is respectively less or greater than the time of development of the pressure fluctuations. An expression is given for the wave spectrum in the initial stage of development (§ 3.2), and it is shown that the most prominent waves are ripples of wavelength λcr = 1·7 cm, corresponding to the minimum phase velocity c = (4gT/ρ)1/4 and moving in directions cos-1(c/Uc) to that of the mean wind, where Uc is the 'convection velocity' of the surface pressure fluctuations of length scale λcr or approximately the mean wind speed at a height λcr above the surface. Observations by Roll (1951) have shown the existence under appropriate conditions, of waves qualitatively similar to those predicted by the theory.Most of the growth of gravity waves occurs in the second, or principal stage of development, which continues until the waves grow so high that non-linear effects become important. An expression for the wave spectrum is derived (§ 4.1), from which follows the result where the mean square turbulent pressure on the water surface, t the elapsed time, Uc the convection speed of the surface pressure fluctuations, and ρ the water density. This prediction is consistent with published oceanographic measurements (§ 4.3).It is suggested that this resonance mechanism is more effective than those suggested by Jeffreys (1924, 1925) and Eckart (1953), and may provide the principal means whereby energy is transferred from the wind to the waves.

A Cross-calibrated, Multiplatform Ocean Surface Wind Velocity Product for Meteorological and Oceanographic Applications

2010-10-08
Robert Atlas , Ross N. Hoffman , J. Ardizzone +4 more
The ocean surface wind mediates exchanges between the ocean and the atmosphere. These air–sea exchange processes are critical for understanding and predicting atmosphere, ocean, and wave phenomena on many time … The ocean surface wind mediates exchanges between the ocean and the atmosphere. These air–sea exchange processes are critical for understanding and predicting atmosphere, ocean, and wave phenomena on many time and space scales. A cross-calibrated multiplatform (CCMP) long-term data record of satellite ocean surface winds is available from 1987 to 2008 with planned extensions through 2012. A variational analysis method (VAM) is used to combine surface wind data derived from conventional and in situ sources and multiple satellites into a consistent nearglobal analysis at 25-km resolution, every 6 h. The input data are cross-calibrated wind speeds derived from the Special Sensor Microwave Imager (SSM/I; F08–F15), the Tropical Rainfall Measuring Mission Microwave Imager (TMI), and the Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E), and wind vectors from SeaWinds on the NASA Quick Scatterometer (QuikSCAT) and on the second Japanese Advanced Earth Observing Satellite (ADEOS- 2; i.e., the Midori-2 satellite). These are combined with ECMWF reanalyses and operational analyses by the VAM. VAM analyses and derived data are currently available for interested investigators through the Jet Propulsion Laboratory (JPL) Physical Oceanography Distributed Active Archive Center (PO.DAAC). This paper describes the methodology used to assimilate the input data along with the validation and evaluation of the derived CCMP products. A supplement to this article is available online: DOI: 10.1175/2010BAMS2946.2
View PDF Chat

The applied dynamics of ocean surface waves

1983-10-01
Chiang C. Mei

Radiation stress and mass transport in gravity waves, with application to ‘surf beats’

1962-08-01
M. S. Longuet‐Higgins , R. W. Stewart
This paper studies the second-order currents and changes in mean surface level which are caused by gravity waves of non-uniform amplitude. The effects are interpreted in terms of the radiation … This paper studies the second-order currents and changes in mean surface level which are caused by gravity waves of non-uniform amplitude. The effects are interpreted in terms of the radiation stresses in the waves. The first example is of wave groups propagated in water of uniform mean depth. The problem is solved first by a perturbation analysis. In two special cases the second-order currents are found to be proportional simply to the square of the local wave amplitude: (a) when the lengths of the groups are large compared to the mean depth, and (b) when the groups are all of equal length. Then the surface is found to be depressed under a high group of waves and the mass-transport is relatively negative there. In case (a) the result can be simply related to the radiation stresses, which tend to expel fluid from beneath the higher waves. The second example considered is the propagation of waves of steady amplitude in water of gradually varying depth. Assuming no loss of energy by friction or reflexion, the wave amplitude must vary horizontally, to maintain the flux of energy constant; it is shown that this produces a negative tilt in the mean surface level as the depth diminishes. However, if the wave height is limited by breaking, the tilt is positive. The results are in agreement with some observations by Fairchild. Lastly, the propagation of groups of waves from deep to shallow water is studied. As the mean depth decreases, so the response of the fluid to the radiation stresses tends to increase. The long waves thus generated may be reflected as free waves, and so account for the 'surf beats’ observed by Munk and Tucker. Generalle speaking, the changes in mean sea level produced by ocean waves are comparable with those due to horizontal wind stress. It may be necessary to allow for the wave stresses in calculating wind stress coefficients.

Stability of periodic waves of finite amplitude on the surface of a deep fluid

1972-01-01
В. Е. Захаров

Oceanic Rogue Waves

2008-01-01
K. B. Dysthe , Harald E. Krogstad , Peter Müller
Oceanic rogue waves are surface gravity waves whose wave heights are much larger than expected for the sea state. The common operational definition requires them to be at least twice … Oceanic rogue waves are surface gravity waves whose wave heights are much larger than expected for the sea state. The common operational definition requires them to be at least twice as large as the significant wave height. In most circumstances, the properties of rogue waves and their probability of occurrence appear to be consistent with second-order random-wave theory. There are exceptions, although it is unclear whether these represent measurement errors or statistical flukes, or are caused by physical mechanisms not covered by the model. A clear deviation from second-order theory occurs in numerical simulations and wave-tank experiments, in which a higher frequency of occurrence of rogue waves is found in long-crested waves owing to a nonlinear instability.

A unified directional spectrum for long and short wind‐driven waves

1997-07-15
T. Elfouhaily , Bertrand Chapron , K. B. Katsaros +1 more
Review of several recent ocean surface wave models finds that while comprehensive in many regards, these spectral models do not satisfy certain additional, but fundamental, criteria. We propose that these … Review of several recent ocean surface wave models finds that while comprehensive in many regards, these spectral models do not satisfy certain additional, but fundamental, criteria. We propose that these criteria include the ability to properly describe diverse fetch conditions and to provide agreement with in situ observations of Cox and Munk [1954] and Jähne and Riemer [1990] and Hara et al . [1994] data in the high‐wavenumber regime. Moreover, we find numerous analytically undesirable aspects such as discontinuities across wavenumber limits, nonphysical tuning or adjustment parameters, and noncentrosymmetric directional spreading functions. This paper describes a two‐dimensional wavenumber spectrum valid over all wavenumbers and analytically amenable to usage in electromagnetic models. The two regime model is formulated based on the Joint North Sea Wave Project (JONSWAP) in the long‐wave regime and on the work of Phillips [1985] and Kitaigorodskii [1973] at the high wavenumbers. The omnidirectional and wind‐dependent spectrum is constructed to agree with past and recent observations including the criteria mentioned above. The key feature of this model is the similarity of description for the high‐ and low‐wavenumber regimes; both forms are posed to stress that the air‐sea interaction process of friction between wind and waves (i.e., generalized wave age, u/c ) is occurring at all wavelengths simultaneously. This wave age parameterization is the unifying feature of the spectrum. The spectrum's directional spreading function is symmetric about the wind direction and has both wavenumber and wind speed dependence. A ratio method is described that enables comparison of this spreading function with previous noncentrosymmetric forms. Radar data are purposefully excluded from this spectral development. Finally, a test of the spectrum is made by deriving roughness length using the boundary layer model of Kitaigorodskii. Our inference of drag coefficient versus wind speed and wave age shows encouraging agreement with Humidity Exchange Over the Sea (HEXOS) campaign results.
View PDF Chat

A NEW VIEW OF NONLINEAR WATER WAVES: The Hilbert Spectrum

1999-01-01
Norden E. Huang , Zhengwei Shen , Steven Long
▪ Abstract We survey the newly developed Hilbert spectral analysis method and its applications to Stokes waves, nonlinear wave evolution processes, the spectral form of the random wave field, and … ▪ Abstract We survey the newly developed Hilbert spectral analysis method and its applications to Stokes waves, nonlinear wave evolution processes, the spectral form of the random wave field, and turbulence. Our emphasis is on the inadequacy of presently available methods in nonlinear and nonstationary data analysis. Hilbert spectral analysis is here proposed as an alternative. This new method provides not only a more precise definition of particular events in time-frequency space than wavelet analysis, but also more physically meaningful interpretations of the underlying dynamic processes.
View PDF Chat

Scattering of GPS signals from the ocean with wind remote sensing application

2000-03-01
Valery U. Zavorotny , Alexander G. Voronovich
A theoretical model that describes the power of a scattered Global Positioning System (GPS) signal as a function of geometrical and environmental parameters has been developed. This model is based … A theoretical model that describes the power of a scattered Global Positioning System (GPS) signal as a function of geometrical and environmental parameters has been developed. This model is based on a bistatic radar equation derived using the geometric optics limit of the Kirchhoff approximation. The waveform (i.e., the time-delayed power obtained in the delay-mapping technique) depends on a wave-slope probability density function, which in turn depends on wind. Waveforms obtained for aircraft altitudes and velocities indicate that altitudes within the interval 5-15 km are the best for inferring wind speed. In some regimes, an analytical solution for the bistatic radar equation is possible. This solution allows converting trailing edges of waveforms into a set of straight lines, which could be convenient for wind retrieval. A transition to satellite altitudes, together with satellite velocities, makes the peak power reduction and the Doppler spreading effect a significant problem for wind retrieval based on the delay-mapping technique. At the same time, different time delays and different Doppler shifts of the scattered GPS signal could form relatively small spatial cells on sea surface, suggesting mapping of the wave-slope probability distribution in a synthetic-aperture-radar (SAR) fashion. This may allow more accurate measurements of wind velocity and wind direction.

Radiation stresses in water waves; a physical discussion, with applications

1964-08-01
M. S. Longuet‐Higgins , R. W. Stewart

Water waves of finite amplitude on a sloping beach

1958-05-01
G. F. Carrier , H. P. Greenspan
In this paper, we investigate the behaviour of a wave as it climbs a sloping beach. Explicit solutions of the equations of the non-linear inviscid shallow-water theory are obtained for … In this paper, we investigate the behaviour of a wave as it climbs a sloping beach. Explicit solutions of the equations of the non-linear inviscid shallow-water theory are obtained for several physically interesting wave-forms. In particular it is shown that waves can climb a sloping beach without breaking. Formulae for the motions of the instantaneous shoreline as well as the time histories of specific wave-forms are presented.

Spectral and statistical properties of the equilibrium range in wind-generated gravity waves

1985-07-01
O. M. Phillips
Recent measurements of wave spectra and observations by remote sensing of the sea surface indicate that the author's (1958) conception of an upper-limit asymptote to the spectrum, independent of wind … Recent measurements of wave spectra and observations by remote sensing of the sea surface indicate that the author's (1958) conception of an upper-limit asymptote to the spectrum, independent of wind stress, is no longer tenable. The nature of the equilibrium range is reexamined, using the dynamical insights into wave–wave interactions, energy input from the wind and wave-breaking that have been developed since 1960. With the assumption that all three of these processes are important in the equilibrium range, the wavenumber spectrum is found to be of the form , where p ∼ ½ and the frequency spectrum is proportional to u*gσ−4. These forms have been found by Kitaigorodskii (1983) on a quite different dynamical basis; the latter is consistent with the form found empirically by Toba (1973) and later workers. Various derived spectra, such as those of the sea-surface slope and of an instantaneous line traverse of the surface, are also given, as well as directional frequency spectra and frequency spectra of slope.The theory also provides expressions for the spectral rates of action, energy and momentum loss from the equilibrium range by wave-breaking and for the spectrally integrated rates across the whole range. These indicate that, as a wave field develops with increasing fetch or duration, the momentum flux to the underlying water by wave-breaking increases asymptotically to a large fraction of the total wind stress and that the energy flux to turbulence in the water, occurring over a wide range of scales, increases logarithmically as the extent of the equilibrium range increases. Interrelationships are pointed out among different sets of measurements such as the various spectral levels, the directional distributions, the total mean-square slope and the ratio of downwind to crosswind mean-square slopes.Finally, some statistical characteristics of the breaking events are deduced, including the expected length of breaking fronts (per unit surface area) with speeds of advance between c and c+dc and the number of such breaking events passing a given point per unit time. These then lead to simple expressions for the density of whitecapping, those breaking events that produce bubbles and trails of foam, the total number of whitecaps passing a given point per unit time and, more tenuously, the whitecap coverage.

Bulk Parameterization of Air–Sea Fluxes: Updates and Verification for the COARE Algorithm

2003-02-01
C. W. Fairall , E. F. Bradley , J. E. Hare +2 more
In 1996, version 2.5 of the Coupled Ocean–Atmosphere Response Experiment (COARE) bulk algorithm was published, and it has become one of the most frequently used algorithms in the air–sea interaction … In 1996, version 2.5 of the Coupled Ocean–Atmosphere Response Experiment (COARE) bulk algorithm was published, and it has become one of the most frequently used algorithms in the air–sea interaction community. This paper describes steps taken to improve the algorithm in several ways. The number of iterations to solve for stability has been shortened from 20 to 3, and adjustments have been made to the basic profile stability functions. The scalar transfer coefficients have been redefined in terms of the mixing ratio, which is the fundamentally conserved quantity, rather than the measured water vapor mass concentration. Both the velocity and scalar roughness lengths have been changed. For the velocity roughness, the original fixed value of the Charnock parameter has been replaced by one that increases with wind speeds of between 10 and 18 m s−1. The scalar roughness length parameterization has been simplified to fit both an early set of NOAA/Environmental Technology Laboratory (ETL) experiments and the Humidity Exchange Over the Sea (HEXOS) program. These changes slightly increase the fluxes for wind speeds exceeding 10 m s−1. For interested users, two simple parameterizations of the surface gravity wave influence on fluxes have been added (but not evaluated). This new version of the algorithm (COARE 3.0) was based on published results and 2777 1-h covariance flux measurements in the ETL inventory. To test it, 4439 new values from field experiments between 1997 and 1999 were added, which now dominate the database, especially in the wind speed regime beyond 10 m s−1, where the number of observations increased from 67 to about 800. After applying various quality controls, the database was used to evaluate the algorithm in several ways. For an overall mean, the algorithm agrees with the data to within a few percent for stress and latent heat flux. The agreement is also excellent when the bulk and directly measured fluxes are averaged in bins of 10-m neutral wind speed. For a more stringent test, the average 10-m neutral transfer coefficients were computed for stress and moisture in wind speed bins, using different averaging schemes with fairly similar results. The average (mean and median) model results agreed with the measurements to within about 5% for moisture from 0 to 20 m s−1. For stress, the covariance measurements were about 10% higher than the model at wind speeds over 15 m s−1, while inertial-dissipation measurements agreed closely at all wind speeds. The values for stress are between 8% (for inertial dissipation) and 18% (for covariance) higher at 20 m s−1 than two other classic results. Twenty years ago, bulk flux schemes were considered to be uncertain by about 30%; the authors find COARE 3.0 to be accurate within 5% for wind speeds of 0–10 m s−1 and 10% for wind speeds of between 10 and 20 m s−1.

A third‐generation wave model for coastal regions: 2. Verification

1999-04-15
R.C. Ris , L.H. Holthuijsen , N. Booij
A third‐generation spectral wave model (Simulating Waves Nearshore (SWAN)) for small‐scale, coastal regions with shallow water, (barrier) islands, tidal flats, local wind, and ambient currents is verified in stationary mode … A third‐generation spectral wave model (Simulating Waves Nearshore (SWAN)) for small‐scale, coastal regions with shallow water, (barrier) islands, tidal flats, local wind, and ambient currents is verified in stationary mode with measurements in five real field cases. These verification cases represent an increasing complexity in two‐dimensional bathymetry and added presence of currents. In the most complex of these cases, the waves propagate through a tidal gap between two barrier islands into a bathymetry of channels and shoals with tidal currents where the waves are regenerated by a local wind. The wave fields were highly variable with up to 3 orders of magnitude difference in energy scale in individual cases. The model accounts for shoaling, refraction, generation by wind, whitecapping, triad and quadruplet wave‐wave interactions, and bottom and depth‐induced wave breaking. The effect of alternative formulations of these processes is shown. In all cases a relatively large number of wave observations is available, including observations of wave directions. The average rms error in the computed significant wave height and mean wave period is 0.30 m and 0.7 s, respectively, which is 10% of the incident values for both.
View PDF Chat

A proposed spectral form for fully developed wind seas based on the similarity theory of S. A. Kitaigorodskii

1964-12-15
Willard J. Pierson , Lionel I. Moskowitz

The disintegration of wave trains on deep water Part 1. Theory

1967-02-24
T. Brooke Benjamin , J. E. Feir
The phenomenon in question arises when a periodic progressive wave train with fundamental frequency ω is formed on deep water—say by radiation from an oscillating paddle—and there are also present … The phenomenon in question arises when a periodic progressive wave train with fundamental frequency ω is formed on deep water—say by radiation from an oscillating paddle—and there are also present residual wave motions at adjacent side-band frequencies ω(1 ± δ), such as would be generated if the movement of the paddle suffered a slight modulation at low frequency. In consequence of coupling through the non-linear boundary conditions at the free surface, energy is then transferred from the primary motion to the side bands at a rate that, as will be shown herein, can increase exponentially as the interaction proceeds. The result is that the wave train becomes highly irregular far from its origin, even when the departures from periodicity are scarcely detectable at the start. In this paper a theoretical investigation is made into the stability of periodic wave trains to small disturbances in the form of a pair of side-band modes, and Part 2 which will follow is an account of some experimental observations in accord with the present predictions. The main conclusion of the theory is that infinitesimal disturbances of the type considered will undergo unbounded magnification if \[ 0 &lt; \delta \leqslant (\sqrt{2})ka, \] where k and a are the fundamental wave-number and amplitude of the perturbed wave train. The asymptotic rate of growth is a maximum for δ = ka .

Sonic Anemometer Tilt Correction Algorithms

2001-04-01
James M. Wilczak , Steven Oncley , Steven A. Stage

Physical mechanisms of the rogue wave phenomenon

2003-10-27
Christian Kharif , Efim Pelinovsky
View PDF Chat

Linear and Nonlinear Waves

1975-11-01
K. J. Whiteman
G B Whitham Chichester: J Wiley 1974 pp xvi + 636 price £12.15 Professor Whitham's book can be highly recommended as a comprehensive account of the mathematics of wave motion … G B Whitham Chichester: J Wiley 1974 pp xvi + 636 price £12.15 Professor Whitham's book can be highly recommended as a comprehensive account of the mathematics of wave motion written with great knowledge and enthusiasm. It grew out of a course given to postgraduate mathematicians and physicists and contains material that one would expect in such a text; a discussion of characteristics and the formation of shocks; application to water waves and gas dynamics; group velocity, dispersion and wave patterns; the classical nonlinear results.

On the statistical distribution of the heights of sea waves

1952-01-01
M. S. Longuet‐Higgins

Microwave Radar and Radiometric Remote Sensing

2014-01-01
F.T. Ulaby , David G. Long
Introduction Electromagnetic Wave Propagation Remote-Sensing Antennas Microwave Dielectric Properties of Natural Earth Materials Radar Scattering Microwave Radiometry and Radiative Transfer Microwave Radiometric Systems Microwave Interaction with Atmospheric Constituents Radiometric Sounding … Introduction Electromagnetic Wave Propagation Remote-Sensing Antennas Microwave Dielectric Properties of Natural Earth Materials Radar Scattering Microwave Radiometry and Radiative Transfer Microwave Radiometric Systems Microwave Interaction with Atmospheric Constituents Radiometric Sounding of the Atmosphere Surface-Scattering Models and Land Observations Volume-Scattering Models and Land Observations Emission Models and Land Observations Radar Measurements and Scatterometers Real- and Synthetic-Aperture Side-Looking Airborne Radar Interferometric SAR Radar Remote Sensing of the Ocean Spaceborne Altimetry Radiometric Remote Sensing of the Ocean.

The WAM Model—A Third Generation Ocean Wave Prediction Model

1988-12-01
The Wamdi Group
A third generation wave model is presented that integrates the basic transport equation describing the evolution of a two-dimensional ocean wave spectrum without additional ad hoe assumptions regarding the spectral … A third generation wave model is presented that integrates the basic transport equation describing the evolution of a two-dimensional ocean wave spectrum without additional ad hoe assumptions regarding the spectral shape. The three source functions describing the wind input, nonlinear transfer, and white-capping dissipation are prescribed explicitly. An additional bottom dissipation source function and refraction terms are included in the finite-depth version of the model. The model was calibrated against fetch-limited wave growth data. Only two tuning parameters am introduced in the white-capping dissipation source function. The model runs on a spherical latitude-longitude grid for an arbitrary region of the ocean. Hindcast results am shown for six North Atlantic-North Sea storms, three Gulf of Mexico hurricanes, and a global run for the SEASAT period. The agreement with measurements is encouraging.
View PDF Chat

A hybrid Gaussian and plane wave density functional scheme

1997-10-20
GERALD LIPPERT , Jürg Hutter , Michele Parrinello

Regional Wave Analysis in the East China Sea Based on the SWAN Model

2025-06-19
Shuyi Ma , Fuwu Ji , Qunhui Yang +2 more | Journal of Marine Science and Engineering
High-precision wave data serve as a foundation for investigating the wave characteristics of the East China Sea (ECS) and wave energy development. Based on the simulating waves nearshore (SWAN) model, … High-precision wave data serve as a foundation for investigating the wave characteristics of the East China Sea (ECS) and wave energy development. Based on the simulating waves nearshore (SWAN) model, this study uses the ERA5 (ECMWF Reanalysis v5) reanalysis wind field data and ETOPO1 bathymetric data to perform high-precision simulations at a resolution of 0.05° × 0.05° for the waves in the area of 25–35° N and 120–130° E in the ECS from 2009 to 2023. The simulation results indicate that the application of the whitecapping dissipation parameter Komen and the bottom friction parameter Collins yields an average RMSE of 0.374 m and 0.369 m when compared to satellite-measured data, demonstrating its superior suitability for wave simulation in shallow waters such as the ESC over the other whitecapping dissipation parameter, Westhuysen, and the other two bottom friction parameters, Jonswap and Madsen, in the SWAN model. The monthly average significant wave height (SWH) ranges from 0 to 3 m, exhibiting a trend that it is more important in autumn and winter than in spring and summer and gradually increases from the northwest to the southeast. Due to the influence of the Kuroshio current, topography, and events such as typhoons, areas with significant wave heights are found in the northwest of the Ryukyu Islands and north of the Taiwan Strait. The wave energy flux density in most areas of the ECS is &gt;2 kW/m, particularly in the north of the Ryukyu Islands, where the annual average value remains above 8 kW/m. Because of the influence of climate events such as El Niño and extreme heatwaves, the wave energy flux density decreased significantly in some years (a 21% decrease in 2015). The coefficient of variation of wave energy in the East China Sea exhibits pronounced regional heterogeneity, which can be categorized into four distinct patterns: high mean wave energy with high variation coefficient, high mean wave energy with low variation coefficient, low mean wave energy with high variation coefficient, and low mean wave energy with low variation coefficient. This classification fundamentally reflects the intrinsic differences in dynamic environments across various maritime regions. These high-precision numerical simulation results provide methodological and theoretical support for exploring the spatiotemporal variation laws of waves in the ECS region, the development and utilization of wave resources, and marine engineering construction.

Examination of the effect of wind drift on water wave packets in the forced nonlinear Schrödinger equation

2025-06-19
Montri Maleewong , Roger Grimshaw | Journal of Ocean Engineering and Marine Energy

Experimental research on drift of rescue targets in a basin under controllable wind-wave-current environment

2025-06-19
Jiaqian Wang , Hao Qin , Haiwen Tu +7 more | Ocean Engineering

Observing Ocean‐Atmosphere Fluxes From Autonomous Surface Vehicles

2025-06-19
Laurent Grare , Luc Lenain , J. Thomas Farrar | Geophysical Research Letters
Abstract With the increasing use of autonomous surface vehicles (ASVs) to characterize the marine atmospheric boundary layer, better understanding and evaluation of the observations collected from these platforms is needed. … Abstract With the increasing use of autonomous surface vehicles (ASVs) to characterize the marine atmospheric boundary layer, better understanding and evaluation of the observations collected from these platforms is needed. We present here unique comparisons of measurements of bulk properties and air‐sea fluxes collected from ASVs right above the sea surface to state‐of‐the‐art observations from R/P FLIP over a broad range of environmental conditions. We find good agreement between the two platforms, suggesting that near surface observations from such wave following vehicles are suitable to estimate air‐sea fluxes using bulk formulas. This result is somewhat surprising, because the relatively low measurement height (1 m) is often below the wave crests. Possible interpretations are that the presence of waves does not violate the assumptions of the Monin‐Obukhov theory inherent in the TOGA COARE bulk flux formulas, or that the empirical fit of the Monin‐Obukhov stability functions somehow accounts for the wave effects.

Generative AI for dangerous wave environments in marine dynamics

2025-06-19
Wenzhe Xu , Kevin J. Maki | Ocean Engineering

On the use of remote island data to reconstruct sea level spectra associated with the 2020 typhoons Maysak and Haishen and with the 2024 Noto Peninsula tsunami on the eastern Korean coast

2025-06-18
Daria A. Smirnova , А. Б. Рабинович | Ocean Engineering

Refining the Ochi–Hubble spectrum for mixed wave modeling: Two case studies in East China coastal waters

2025-06-16
Bingxian Liang , Zhaochen Sun , Shuxiu Liang +2 more | Ocean Engineering

Seasonal wave dynamics and model validation at Galesong Beach, south Sulawesi: Evaluating the accuracy of wave prediction

2025-06-16
Sakka Sakka , Cut Mauliditya Fachtya Rizky Mawnad , Alimuddin Hamzah Assegaf +2 more | Ecological Engineering & Environmental Technology

Deep learning model for predicting power spectral density of water column height in a fixed oscillating water column using remotely measured wave height

2025-06-13
Hyung-Jin Kim , Se-Yun Hwang , Su‐gil Cho +2 more | Ocean Engineering

Wave-by-wave analysis, spike removal, and NewWaves in GPS buoy data near the great barrier reef in tropical cyclone Nathan

2025-06-12
Kosuke Sando , Paul H. Taylor , Hugh Wolgamot +2 more | Ocean Engineering

Modulated wave train with oblique sidebands in finite water depths

2025-06-06
Jiacheng Yang , Xinshu Zhang , Jinyu Yao | Physical Review Fluids

Vortex-Carrying Solitary Gravity Waves of Large Amplitude

2025-06-02
Robin Ming Chen , Kristoffer Varholm , Samuel Walsh +1 more | Communications in Mathematical Physics

The late December 2024 North Pacific swells on South American coasts

2025-06-02
Patricio Winckler , Santiago Correa , René Garreaud +1 more | Natural Hazards

Numerical schemes for a fully nonlinear coagulation–fragmentation model coming from wave kinetic theory

2025-06-01
Arijit Das , Minh-Binh Tran | Proceedings of the Royal Society A Mathematical Physical and Engineering Sciences
This article introduces a novel numerical approach, based on finite-volume techniques, for studying fully nonlinear coagulation–fragmentation models, where both the coagulation and fragmentation components of the collision operator are nonlinear. … This article introduces a novel numerical approach, based on finite-volume techniques, for studying fully nonlinear coagulation–fragmentation models, where both the coagulation and fragmentation components of the collision operator are nonlinear. The models come from three-wave kinetic equations, a pivotal framework in wave turbulence theory. Despite the importance of wave turbulence theory in physics and mechanics, there have been very few numerical schemes for three-wave kinetic equations, in which no additional assumptions are manually imposed on the evolution of the solutions, and the current manuscript provides one of the first of such schemes. To the best of our knowledge, this also is the first numerical scheme capable of accurately capturing the long-term asymptotic behaviour of solutions to a fully nonlinear coagulation–fragmentation model. The scheme is implemented on some test problems, demonstrating strong alignment with theoretical predictions of energy cascade rates, rigorously obtained in the work (Soffer &amp; Tran. 2020 Commun. Math. Phys. 376 , 2229–2276. ( doi:10.1007/BF01419532 )). We further introduce a weighted finite-volume variant to ensure energy conservation across varying degrees of kernel homogeneity. Convergence and first-order consistency are established through theoretical analysis and verified by experimental convergence orders in test cases.

Observations of Breaking Wave Dissipation and Their Relationship to Atmosphere‐Ocean Energy Transfer

2025-06-01
Lindsay Hogan , Christopher J. Zappa , Alejandro Cifuentes‐Lorenzen +3 more | Journal of Geophysical Research Oceans
Abstract Energy is transferred from the atmosphere to the ocean primarily through ocean surface waves, and the majority is dissipated locally in the near‐surface ocean. Observations of turbulent kinetic energy … Abstract Energy is transferred from the atmosphere to the ocean primarily through ocean surface waves, and the majority is dissipated locally in the near‐surface ocean. Observations of turbulent kinetic energy (TKE) in the upper ocean have shown dissipation rates exceeding law‐of‐the‐wall theory by an order of magnitude. The excess near‐surface ocean TKE dissipation rate is thought to be driven primarily by wave breaking, which limits wave growth and transfers energy from the surface wave field to the wave‐affected layer of the ocean. Here, the statistical properties of breaking wave dynamics in a coastal area are extracted from visible imagery and used to estimate TKE dissipation rates due to breaking waves. The statistical properties of whitecap dynamics are quantified with Λ(c), a distribution of total whitecap crest length per unit area as a function of crest speed, and used to compute energy dissipation by breaking waves, S ds . S ds approximately balances elevated subsurface dissipation in young seas but accounts for only a fraction of subsurface dissipation in older seas. The wind energy input is estimated from wave spectra from polarimetric imagery and laser altimetry. S ds balances the wind energy input except under high winds. Λ(c)‐derived estimates of TKE dissipation rates by breaking waves compare well with the atmospheric deficit in TKE dissipation, a measure of energy input to the wave field (Cifuentes‐Lorenzen et al., 2024). These results tie the observed atmospheric dissipation deficit and enhancement in subsurface TKE dissipation to wave driven energy transport, constraining the TKE dissipation budget near the air‐sea interface.

Retrieval of ocean surface wave parameters from ICESat-2 altimetry: validation and limitations

2025-06-01
Li Cao , Qingxiang Liu , Joey Voermans +2 more | Ocean Dynamics

Automatic Approach for Wind Vector Retrieval from Dual-Polarized 1mC-SAR Image Based on Machine Learning

2025-06-01
Shuguang Leng , Weizeng Shao , Q.J. Zhang +2 more | Advances in Space Research

Corrigendum to “Observed changes in significant wave heights derived from long-term homogenized measurements offshore mainland Portugal” [Applied Ocean Research Volume 158, May 2025]

2025-06-01
Rita Esteves , Diogo Mendes , M. G. Neves +2 more | Applied Ocean Research

A simple and accurate method for quantifying the area effect of unidirectional extreme ocean waves

2025-06-01
Zhao Zhao , Ying Min Low | Applied Mathematical Modelling

Bottom Wave Streaming Intensifies a Nearshore Upwelling Front

2025-06-01
Jiang Wu , Peng Wang | Estuarine Coastal and Shelf Science

Statistical representation of waves in free-surface elevation time series

2025-05-31
Hannah Mankle , Bryony DuPont , Bryson Robertson | Journal of Ocean Engineering and Marine Energy

Localized Trefftz method for wave generation and propagation in a two-dimensional numerical wave tank

2025-05-31
Xiran Lin , Liangbin Xu , Y. Liu +1 more | Ocean Engineering

Probabilistic wave forecast for week two and beyond based on NOAA’s Global Ensemble Forecast System

2025-05-30
Ricardo Martins Campos , Darin Figurskey , Avichal Mehra +1 more | Weather and Forecasting
Abstract In this paper we propose a new capability for an oceanic hazards outlook containing delineations of where winds and waves are expected to have the potential of posing a … Abstract In this paper we propose a new capability for an oceanic hazards outlook containing delineations of where winds and waves are expected to have the potential of posing a hazard to either life or property at sea. This new product is based on NOAA’s Global Ensemble Forecast System, focused on developing a probabilistic forecast of 10-meter wind speed (U10) and significant wave height (Hs) for week 2. The methodology involves defining temporal and spatial windows to post-process the ensemble members, analyzing the tail of the probability density function generated by the pooled dataset. Specific thresholds for U10 and Hs as well as probability levels are defined in the algorithm to generate probability maps. The performance is assessed through statistical validation using NDBC buoy data and reanalysis, followed by case studies. Results indicate that the probabilistic forecast is skillful in predicting waves up to 9 meters and winds up to 48 knots, particularly for extratropical systems. In addition, with weaker signals and lower probabilities forecasted, extreme extratropical events associated with hurricane-force winds could be in many cases successfully detected in the week 2 forecast. Therefore, the probability maps provide valuable guidance for practical applications, helping in decision-making for maritime operations.

VALIDATION OF A SPECTRAL WAVE MODEL USING WAVE HEIGHT MEASUREMENTS FROM SATELLITE MISSIONS

2025-05-29
Andrei Armani A. Adame , Eric C. Cruz , Edgardo P. Kasilag | Coastal Engineering Proceedings
In the use of coastal oceanography models, validation of a spectral wave model is imperative to assess its accuracy and reliability. This validation of the spectral wave model of the … In the use of coastal oceanography models, validation of a spectral wave model is imperative to assess its accuracy and reliability. This validation of the spectral wave model of the eastern Philippine seaboard is carried out by comparing the model's predictions to actual wave conditions—Copernicus Marine Service's Satellite Wave Measurements. Two representative grids from each dataset were used as points for comparison—one adjacent to the Philippines and one in the offshore Philippine Sea. The time series comparisons of the two grids over a 4-month window show that the timing of the high and low peaks was generally captured by the numerical model. However, the magnitude of the high and low peaks was underestimated. This can be attributed to the significant differences in the number of data points, sampling area, and sampling frequency between the two datasets. Therefore, the current iteration of satellite data is not yet optimal for validation purposes of the eastern Philippine seaboard. However, it is projected that the satellite data will be more appropriate for Philippine studies in the future. As more satellites are launched, the resolution and frequency of satellite observations are expected to increase which will enhance the utility of satellite data for validation purposes.

AN OVERVIEW OF MULTI-SCALE CAPABILITIES OF THE SPECTRAL WAVE MODEL (WAVEWATCH III) FOR GLOBAL AND COASTAL APPLICATIONS. CASE STUDY: 2022 ATLANTIC HURRICANE SEASON

2025-05-29
Ali Abdolali , Aron Roland , Ty Hesser +5 more | Coastal Engineering Proceedings
The third-generation spectral wave model WAVEWATCH III (WW3), has undergone significant advancements in its unstructured components. This recent enhancement of WW3 includes the implementation of modern parallelization algorithms based on … The third-generation spectral wave model WAVEWATCH III (WW3), has undergone significant advancements in its unstructured components. This recent enhancement of WW3 includes the implementation of modern parallelization algorithms based on Geographical domain decomposition and updated physics [2]. Notably, the advanced capabilities of WW3 have already been applied in several studies, while others are currently undergoing testing. This presentation aims to provide an overview of the model's development, highlighting select application studies. Particular emphasis will be placed on the 2022 hurricane season in Atlantic and Gulf of Mexico (GoM) basins, during which a rich set of observations is available, ranging from stationary NDBC buoys to moving Lagrangian drifter buoys and satellite altimeters. These observations will be instrumental in assessing the model's performance during this critical period.

Evaluating RANS and LES turbulence models in hybrid wave modelling of breaking waves

2025-05-29
Chengzhao Zhang , Eugeny Buldakov | Frontiers in Marine Science
Understanding the characteristics of breaking waves in deep and intermediate waters is crucial for air-sea interactions. Recent advancements in modelling these interactions have often relied on numerical wave tanks using … Understanding the characteristics of breaking waves in deep and intermediate waters is crucial for air-sea interactions. Recent advancements in modelling these interactions have often relied on numerical wave tanks using Stokes waves, which may not fully represent real-world conditions. To address this gap, we developed a numerical wave tank to investigate the effects of different turbulence models on the performance of our numerical wave model in simulating breaking waves under more realistic wave conditions. A hybrid model that couples a Lagrangian wave model with a VOF model based on OpenFOAM is developed to simulate breaking wave groups resulting from dispersive focussing, with a spectrum related to a modelled sea state. The numerical results obtained through the hybrid wave model without turbulence models are validated against experimental data, demonstrating a high level of accuracy. Then, four turbulence models including RANS standard k − ϵ , RNG k − ϵ models, LES Smagorinsky and LES k -equation turbulence models are applied to the hybrid wave model with peak-focussed wide band Gaussian (GW) spectrum. The effects of turbulence models on the prediction of breaking crests, the energy dissipation due to breakers and the estimation of the breaking strength parameter b are investigated. The findings demonstrate that the turbulence models can significantly affect the numerical results for weak breaking cases. Notably, the hybrid wave model with the LES k -equation turbulence model showed superior performance. This proposed numerical wave tank can be a promising tool for investigating air-sea interactions in 3D simulations under more realistic wave conditions.

A FIELD EXPERIMENT ON GRAVITY WAVES: EFFECTS OF THE WAVE STEEPNESS AND EFFECTIVE WATER DEPTH ON THE WAVE PROFILE AND BREAKING LIMIT

2025-05-29
George Spiliotopoulos , Vanessa Katsardi , Vincenzo Fiamma +3 more | Coastal Engineering Proceedings
This paper describes a series of field observations of large surface gravity waves, recorded at the Natural Ocean Engineering Laboratory (NOEL), Italy. The study involves a variety of sea states … This paper describes a series of field observations of large surface gravity waves, recorded at the Natural Ocean Engineering Laboratory (NOEL), Italy. The study involves a variety of sea states measured at a series of water depths, from deep to the shallowest limit of intermediate waters. The discussion is focused on the effect of the spectral and local wave parameters, described by the wave steepness and the effective water depth, on the wave profile, statistical properties and the breaking characteristics. The data presented show a transition in the dispersive properties of the wavefield as waves propagate from deep to shallower water. This is indicated both in the wave profiles as well as the wave height distributions. Leading roles, albeit competitive to each other, play the wave steepness and wave breaking.

IMPACT OF DATA ASSIMILATION FOR TYPHOON-GENERATED EXTREME WAVE BASED ON DRIFTING WAVE BUOY OBSERVATION

2025-05-29
Gota Yamasaki , Tomoya Shimura , Takuya Miyashita +1 more | Coastal Engineering Proceedings
Typhoon-generated extreme waves are a major factor to be considered for coastal disaster risk management in the mid- latitude of the North Western Pacific and the North Atlantic. Therefore, improving … Typhoon-generated extreme waves are a major factor to be considered for coastal disaster risk management in the mid- latitude of the North Western Pacific and the North Atlantic. Therefore, improving the accuracy of the spectral wave model for extreme waves around typhoons is important. Also, compact and inexpensive drifting buoys have been developing in recent years, and their number has increased globally. In this study, we developed a data assimilation system using drifting buoys for typhoon-generated extreme waves. First, we investigate the assimilation method of the significant wave heights into the wave spectral model. Second, the assimilation model of frequency spectra is developed. We show the effectiveness of the data assimilation of drifting buoy observations for the open ocean on extreme waves along the Japanese coast.

FUTURE WAVE CLIMATE IN THE MEDITERRANEAN SEA FROM AN ENSEMBLE OF 33 GCM-RCMS

2025-05-29
Tim Toomey , Andrea Lira‐Loarca , Marta Marcos +2 more | Coastal Engineering Proceedings
The generation and propagation of waves towards the coastal regions during storm events, in combination with storm surges, are a major coastal hazard. Although the Mediterranean Sea is characterized by … The generation and propagation of waves towards the coastal regions during storm events, in combination with storm surges, are a major coastal hazard. Although the Mediterranean Sea is characterized by a fetch-limited environment, the generation and/or passage of extra- tropical cyclones over its surface often originates powerful waves. An illustrative example includes recorded significant wave heights higher than 8 m during the Gloria storm in 2020 (Amores et al., 2020), that caused extensive damage in the eastern coasts of Spain. As climate numerical models consistently converged towards a global warming climate over the past few decades, it is thus crucial to evaluate how wave climate will be responding to future climate conditions. This study investigates the wave climate projected across the Mediterranean region using an ensemble of high- resolution wave numerical simulations of unprecedented size.

Caribbean Easterly Waves: Structure, Thermodynamics, and Instability Mechanisms

2025-05-29
Víctor C. Mayta , Ángel F. Adames , Qiao‐Jun Lin +1 more | Journal of the Atmospheric Sciences
Abstract Caribbean easterly waves (CEWs) propagate in an environment that is distinct from that of other easterly waves since it exhibits substantial westerly vertical wind shear. In spite of this … Abstract Caribbean easterly waves (CEWs) propagate in an environment that is distinct from that of other easterly waves since it exhibits substantial westerly vertical wind shear. In spite of this distinction, their structure, propagation and growth have not received much attention. A linear regression analysis reveals that these systems exhibit features consistent with moisture modes that are destabilized by moisture-vortex instability. They exhibit large moisture fluctuations, are in weak temperature gradient (WTG) balance, and moist static energy (MSE) growth is partly driven by meridional mean MSE advection by the anomalous winds. However, its circulation tilts vertically against the mean shear, a feature that is often associated with baroclinic instability. To reconcile these differences, a linear stability analysis employing a moist two-layer model is performed using a basic state that resembles the Caribbean Sea during boreal summer. The unstable wave solution from this analysis exhibits a structure that resembles observed CEWs. Excluding the upper troposphere from the stability analysis has little impact on the propagation and growth of the wave, and its circulation still exhibits a westward tilt in height. Thus, baroclinic instability is not the main growth mechanism of CEWs despite their structural similarity to baroclinic waves. Instead, the instability is largely rooted in how the lower tropospheric circulation interacts with water vapor, as expected from moisture mode theory. These results suggest that tilting against the shear should not be used as the sole diagnostic for baroclinic instability. Baroclinic instability is unlikely to be a primary driver of growth for most oceanic tropical depression-type waves, in agreement with previous work.

THEORY OF FIFTH-ORDER STOKES WAVES IN A LINEAR SHEAR CURRENT

2025-05-29
Philip L.‐F. Liu , Haiqi Fang , Pengzhi Lin | Coastal Engineering Proceedings
In coastal and deep-water areas, shear currents are often generated by wind action. This leads to a strong vertical shearing action within the upper layer of the water body. Therefore, … In coastal and deep-water areas, shear currents are often generated by wind action. This leads to a strong vertical shearing action within the upper layer of the water body. Therefore, the rotational characteristics of the flow motion play an essential role in affecting the wave-current interaction process. Analytical Stokes wave solutions on linear shear currents provide necessary information on wave properties and velocity fields for ocean and coastal engineering applications (see Fig.1). However, existing high-order (above third-order) Stokes wave solutions are not valid. Thus, in this paper, following the methodology introduced by Zhao and Liu (2022), a new fifth-order solution for Stokes wave in a linear shear current is derived. The new analytical solutions are checked with the exact numerical solutions by Francius and Kharif (2017).

EXPECTED WAVE ENERGY FLUX OF PREDICTED SEA STATES

2025-05-29
Paolo Pezzutto | Coastal Engineering Proceedings
Whether coupled into an earth-system model or as separate tool, third-generation wave models (e.g. WAVEWATCHIII, WAM, SWAN) are the tools used by weather centers and researchers to describe the evolution … Whether coupled into an earth-system model or as separate tool, third-generation wave models (e.g. WAVEWATCHIII, WAM, SWAN) are the tools used by weather centers and researchers to describe the evolution of expected sea-states. Due to the complicated nature of the wave generation process, wave phases are unpredictable, thus the sea states are represented by the distribution of the wave action density over a finite frequency range.

A nonlinear Schrödinger equation for capillary waves on arbitrary depth with constant vorticity

2024-04-06
Christian Kharif , Malek Abid , Yang-Yih Chen +1 more
View PDF Chat