scholarly journals Statistical Characteristics of Wave Breakings and their Relation with the Wind Waves’ Energy Dissipation Based on the Field Measurements

2020 ◽  
Vol 27 (5) ◽  
Author(s):  
A. E. Korinenko ◽  
V. V. Malinovsky ◽  
V. N. Kudryavtsev ◽  
V. A. Dulov ◽  
◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Wind Speed ◽  
Wave Breaking ◽  
Wind Waves ◽  
Field Measurements ◽  
Sea Surface ◽  
Breaking Wave ◽  
Movement Velocity ◽  
Wide Range ◽  
The Waves

Purpose. The work is aimed at studying geometric similarity of wind wave breakings in natural conditions, estimating the Duncan constant which connects the wave energy dissipation conditioned by wave breakings, with distribution of the lengths of a breaking wave fronts Λ(с). Methods and Results. The field measurements of the wave breaking characteristics were carried out at the stationary oceanographic platform located in the Golubaya Bay near the Katsiveli village. Geometric dimensions of the wave breakings’ active phase, velocities and directions of their movement were determined from the video records of the sea surface; simultaneously, the meteorological information was recorded and the surface waves’ characteristics were measured. Altogether 55 video recordings (duration 40–50 mins) of the sea surface were obtained. The measurements were carried out in a wide range of meteorological conditions and wave parameters (wind speed varied from 9.2 to 21.4 m/s). Conclusions. It is found that the probability densities of the ratio between the maximum length of a breaking and the length of a breaking wave, obtained in various wind and wave conditions are similar. The average value of this ratio is 0.1. Distributions of the wave breakings’ total length are constructed in the movement velocity intervals on a surface unit. It is shown that the experimental estimates of dependence of these distributions upon the wind speed and the wave breaking movement velocity are consistent with the theoretical predictions of O.M. Phillips (1985); at that no dependence on the waves’ age was found. Quantitative characteristics of the relation between the wave lengths’ distribution and the energy dissipation are obtained. The Duncan constant was estimated; it turned out to be equal to 1.8·10-3 and independent upon the waves’ and atmosphere parameters.

scholarly journals Statistical Characteristics of Wave Breakings and their Relation with the Wind Waves’ Energy Dissipation Based on the Field Measurements

2020 ◽  
Vol 36 (5) ◽  
Author(s):  
A. E. Korinenko ◽  
V. V. Malinovsky ◽  
V. N. Kudryavtsev ◽  
V. A. Dulov ◽  
◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Wind Speed ◽  
Wave Breaking ◽  
Wind Waves ◽  
Field Measurements ◽  
Sea Surface ◽  
Breaking Wave ◽  
Movement Velocity ◽  
Wide Range ◽  
The Waves

Purpose. The work is aimed at studying geometric similarity of wind wave breakings in natural conditions, estimating the Duncan constant which connects the wave energy dissipation conditioned by wave breakings, with distribution of the lengths of a breaking wave crests Λ(с). Methods and Results. The field measurements of the wave breaking characteristics were carried out at the stationary oceanographic platform located in the Golubaya Bay near the village Katsiveli. Geometric dimensions of the wave breakings’ active phase, velocities and directions of their movement were determined from the video records of the sea surface; simultaneously, the meteorological information was recorded and the surface waves’ characteristics were measured. Altogether 55 video records of the sea surface were obtained; duration of each of them was 40–60 minutes. The measurements were performed in a wide range of meteorological conditions and wave parameters (wind speed varied from 9.2 to 21.4 m/s). Conclusions. It is found that the probability densities of the ratio between the maximum length of a breaking and the length of a breaking wave, obtained in various wind and wave conditions are similar. The average value of this ratio is 0.1. Distributions of the wave breakings’ total length are constructed in the movement velocity intervals on a surface unit. It is shown that the experimental estimates of dependence of these distributions upon the wind speed and the wave breaking movement velocity are consistent with the theoretical predictions of O.M. Phillips (1985); at that no dependence on the waves’ age was found. Quantitative characteristics of the relation between the wave lengths’ distribution and the energy dissipation are obtained. The Duncan constant was estimated; it turned out to be equal to 1.8⋅10-3 and independent upon the waves’ and atmosphere parameters.

Wave-Follower Field Measurements of the Wind-Input Spectral Function. Part III: Parameterization of the Wind-Input Enhancement due to Wave Breaking

2007 ◽  
Vol 37 (11) ◽  
pp. 2764-2775 ◽  
Author(s):  
Alexander V. Babanin ◽  
Michael L. Banner ◽  
Ian R. Young ◽  
Mark A. Donelan
Keyword(s):  
Energy Flux ◽  
Water Waves ◽  
Wave Breaking ◽  
Field Measurements ◽  
Mean Value ◽  
Breaking Wave ◽  
Strong Wind ◽  
Local Wave ◽  
Wind Input ◽  
The Waves

Abstract This is the third in a series of papers describing wave-follower observations of the aerodynamic coupling between wind and waves on a large shallow lake during the Australian Shallow Water Experiment (AUSWEX). It focuses on the long-standing problem of the aerodynamic consequences of wave breaking on the wind–wave coupling. Direct field measurements are reported of the influence of wave breaking on the wave-induced pressure in the airflow over water waves, and hence the energy flux to the waves. The level of forcing, measured by the ratio of wind speed to the speed of the dominant (spectral peak) waves, covered the range of 3–7. The propagation speeds of the dominant waves were limited by the water depth and the waves were correspondingly steep. These measurements allowed an assessment of the magnitude of any breaking-induced enhancement operative for these field conditions and provided a basis for parameterizing the effect. Overall, appreciable levels of wave breaking occurred for the strong wind forcing conditions that prevailed during the observational period. Associated with these breaking wave events, a significant phase shift is observed in the local wave-coherent surface pressure. This produced an enhanced wave-coherent energy flux from the wind to the waves with a mean value of 2 times the corresponding energy flux to the nonbreaking waves. It is proposed that the breaking-induced enhancement of the wind input to the waves can be parameterized by the sum of the nonbreaking input and the contribution due to the breaking probability.

scholarly journals Skewness and Kurtosis of the Surface Wave in the Coastal Zone of the Black Sea

2021 ◽  
Vol 37 (4) ◽  
Author(s):  
A. S. Zapevalov ◽  
A. V. Garmashov ◽  
◽  
Keyword(s):  
Black Sea ◽  
Wind Waves ◽  
Correlation Coefficients ◽  
Sea Surface ◽  
Statistical Moments ◽  
Surface Elevation ◽  
The Black Sea ◽  
Sea Waves ◽  
Wide Range ◽  
The Waves

Purpose. The aim of the study is to analyze variability of the statistical moments characterizing deviations of the sea surface elevation distributions from the Gaussian one. Methods and Results. Field studies of the sea waves’ characteristics were carried out from the stationary oceanographic platform located in the Black Sea near the Southern coast of Crimea. The data obtained both in summer and winter, were used. The statistical moments were calculated separately for wind waves and swell. The measurements were performed in a wide range of meteorological conditions and wave parameters (wind speed varied from 0 to 26 m/s, wave age – from 0 to 5.2 and steepness – from 0.005 to 0.095). For wind waves, the coefficients of skewness correlation with the waves’ steepness and age were equal to 0.46 and 0.38. The kurtosis correlation coefficients with these parameters were small (0.09 and 0.07), but with the confidence level 99.8% – significant. For swell, the correlation coefficients were 1.5 – 2.0 times lower. Conclusions. The statistical moments of the sea surface elevations of the third and higher orders are the indicators of the wave field nonlinearity, which should be taken into account when solving a wide range of the applied and fundamental problems. The deviations of the surface elevation distributions from the Gaussian one are not described unambiguously by the waves’ steepness and age. At the fixed values of these parameters, a large scatter in the values of the surface elevations’ asymmetry and kurtosis is observed. This imposes significant limitations on the possibility of applying the nonlinear wave models based on the wave profile expansion by small parameter (steepness) degrees, in engineering calculations.

Scanning laser wave recorder with registration of “instantaneous” sea surface profiles

2021 ◽  
Author(s):  
V.V. Sterlyadkin ◽  
K.V. Kulikovsky ◽  
A.V. Kuzmin ◽  
E.A. Sharkov ◽  
M.V. Likhacheva
Keyword(s):  
Spatial Scales ◽  
Wind Waves ◽  
Single Point ◽  
Video Recording ◽  
Surface Profile ◽  
Weather Conditions ◽  
Sea Surface ◽  
Sea Waves ◽  
Wide Range ◽  
Wave Recorder

AbstractA direct optical method for measuring the “instantaneous” profile of the sea surface with an accuracy of 1 mm and a spatial resolution of 3 mm is described. Surface profile measurements can be carried out on spatial scales from units of millimeters to units of meters with an averaging time of 10−4 s. The method is based on the synchronization of the beginning of scanning a laser beam over the sea surface and the beginning of recording the radiation scattered on the surface onto the video camera matrix. The heights of all points of the profile are brought to a single point in time, which makes it possible to obtain “instantaneous” profiles of the sea surface with the frequency of video recording. The measurement technique and data processing algorithm are described. The errors of the method are substantiated. The results of field measurements of the parameters of sea waves are presented: amplitude spectra, distribution of slopes at various spatial averaging scales. The applied version of the wave recorder did not allow recording capillary oscillations, but with some modernization it will be possible. The method is completely remote, does not distort the properties of the surface, is not affected by wind, waves and sea currents, it allows you to measure the proportion of foam on the surface. The possibility of applying the proposed method at any time of the day and in a wide range of weather conditions has been experimentally proved.

scholarly journals A Modified k – ε Turbulence Model for a Wave Breaking Simulation

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2282
Author(s):  
Giovanni Cannata ◽  
Federica Palleschi ◽  
Benedetta Iele ◽  
Francesco Gallerano
Keyword(s):  
Energy Dissipation ◽  
Turbulence Model ◽  
Wave Breaking ◽  
A Priori ◽  
Time Dependent ◽  
Breaking Wave ◽  
Vertical Coordinate ◽  
Initial Wave ◽  
Proposed Model ◽  
Curvilinear Coordinate

We propose a two-equation turbulence model based on modification of the k − ε standard model, for simulation of a breaking wave. The proposed model is able to adequately simulate the energy dissipation due to the wave breaking and does not require any “a priori” criterion to locate the initial wave breaking point and the region in which the turbulence model has to be activated. In order to numerically simulate the wave propagation from deep water to the shoreline and the wave breaking, we use a model in which vector and tensor quantities are expressed in terms of Cartesian components, where only the vertical coordinate is expressed as a function of a time-dependent curvilinear coordinate that follows the free surface movements. A laboratory test is numerically reproduced with the aim of validating the turbulence modified k − ε model. The numerical results compared with the experimental measurements show that the proposed turbulence model is capable of correctly estimating the energy dissipation induced by the wave breaking, in order to avoid any underestimation of the wave height.

An Investigation of the Stability Dependence of SST-Induced Vertical Mixing over the Ocean in the Operational Met Office Model

2017 ◽  
Vol 30 (1) ◽  
pp. 91-107 ◽  
Author(s):  
Qingtao Song ◽  
Dudley B. Chelton ◽  
Steven K. Esbensen ◽  
Andrew R. Brown
Keyword(s):  
Wind Speed ◽  
Weather Prediction ◽  
Surface Wind ◽  
Vertical Mixing ◽  
Surface Wind Speed ◽  
Satellite Observations ◽  
Sea Surface ◽  
Stable Conditions ◽  
Wide Range ◽  
The Impact

This study presents an assessment of the impact of a March 2006 change in the Met Office operational global numerical weather prediction model through the introduction of a nonlocal momentum mixing scheme. From comparisons with satellite observations of surface wind speed and sea surface temperature (SST), it is concluded that the new parameterization had a relatively minor impact on SST-induced changes in sea surface wind speed in the Met Office model in the September and October 2007 monthly averages over the Agulhas Return Current region considered here. The performance of the new parameterization of vertical mixing was evaluated near the surface layer and further through comparisons with results obtained using a wide range of sensitivity of mixing parameterization to stability in the Weather Research and Forecasting (WRF) Model, which is easily adapted to such sensitivity studies. While the new parameterization of vertical mixing improves the Met Office model response to SST in highly unstable (convective) conditions, it is concluded that significantly enhanced vertical mixing in the neutral to moderately unstable conditions (nondimensional stability [Formula: see text] between 0 and −2) typically found over the ocean is required in order for the model surface wind response to SST to match the satellite observations. Likewise, the reduced mixing in stable conditions in the new parameterization is also relatively small; for the range of the gradient Richardson number typically found over the ocean, the mixing was reduced by a maximum of only 10%, which is too small by more than an order of magnitude to be consistent with the satellite observations.

scholarly journals Observations of Steep Wave Statistics in Open Ocean Waters

2005 ◽  
Vol 22 (3) ◽  
pp. 258-271 ◽  
Author(s):  
Nicholas Scott ◽  
Tetsu Hara ◽  
Edward J. Walsh ◽  
Paul A. Hwang
Keyword(s):  
Wind Speed ◽  
Ocean Waves ◽  
Open Ocean ◽  
Breaking Wave ◽  
Wave Statistics ◽  
Analysis Methodology ◽  
Wide Range ◽  
Wave Slope ◽  
Steep Waves ◽  
Steep Wave

Abstract A new wavelet analysis methodology is proposed to estimate the statistics of steep waves. The method is applied to open ocean wave height data from the Southern Ocean Waves Experiment (1992) and from a field experiment conducted at Duck, North Carolina (1997). Results show that high wave slope crests appear over a wide range of wavenumbers, with a large amount being much shorter than the dominant wave. At low wave slope thresholds, all wave fields have roughly the same amount of wave crests regardless of wind forcing. The steep wave statistic decays exponentially with the square of the wave slope threshold, with a decay rate that is larger for the low wind cases than the high wind cases. Comparison of the steep wave statistic with independent measurements of the breaking wave statistic suggests a breaking wave slope threshold of about 0.12. The steep wave statistic does not scale with the cube of the wind speed, suggesting that other factors besides the wind speed also affect its level. Comparison of the steep wave statistic to the saturation spectrum reveals a reasonable correlation at moderate wave slope thresholds.

scholarly journals STUDY FOR ESTIMATION OF AIR-SEA C02 GAS TRANSFER BY WAVE BREAKING MODEL USING SATELLITE DATA — ESTIMATION OF THE FRICTION VELOCITY CONSIDERING WAVE EFFECT

2010 ◽  
Vol 1 (1) ◽  
Author(s):  
NAOYA SUZUKI ◽  
NAOTO EBUCHI ◽  
CHAO FANG ZHAO ◽  
TAKAHIRO OSAWA ◽  
TAKASHI MORIYAMA
Keyword(s):  
Wind Speed ◽  
Satellite Data ◽  
Wave Breaking ◽  
Friction Velocity ◽  
Roughness Length ◽  
North Pacific Ocean ◽  
Wind Waves ◽  
Wave Age ◽  
Exchange Coefficient ◽  
Noaa Avhrr

The determination of wind friction velocity from satellite-derived wind data will take an important role of key factors for computation of C02 flux transfer. It is necessary for relation between wind speed and wind friction velocity to determine that of relation between nondimensional roughness length and wave age, included with all parameters (wind, wave). In this study, we proposed a new method to estimate u„, which is based on the new relationship between non-dimensional roughness and wave velocity, after considering fetch and wave directionality. Consequently, we obtained the new relationship between friction velocity and wind speed. Using this relationship, we estimated the wave frequency from two methods: 3 per 2 powers law (Toba, 1972) and WAM model (WAMDI, 1988). The results arc compared with the results estimated from Charnock formula (1955) and the above influence of wave effects on the wind stress is also discussed. A new relationship was established to determine CO. exchange coefficient based on whitecap model (Monahan and Spillane 1984), using U|0-u, relationship in North Pacific Ocean, satellite data of NOAA-AVHRR (SST) and DMSP-SSM-I (wind speed) in Oct., Nov., and Dec. 1991. The C02 exchange coefficient estimated by other models (Wanninkhof, 1992; Liss and Merlivat, 1986; Tans et al., 1990) are also compared with these results. The results show the importance of wave breaking effect. Key words: wind waves, friction velocity, C02 exchange coefficient, roughness length, wave age.

scholarly journals A New Approach for Modeling Dissipation due to Breaking in Wind Wave Spectra

2020 ◽  
Vol 50 (2) ◽  
pp. 439-454
Author(s):  
Dorukhan Ardag ◽  
Donald T. Resio
Keyword(s):  
Wave Breaking ◽  
Wind Wave ◽  
Wind Waves ◽  
Random Phase ◽  
Detailed Balance ◽  
Sea Surface ◽  
Random Wave ◽  
Dissipation Term ◽  
Sensing Applications ◽  
Spectral Models

AbstractA robust spectral dissipation term for wind waves has long been a goal of detailed-balance spectral modeling and is represented by many different approximations in spectral models of random wave fields. A Monte Carlo approach is employed here to create a random-phase sea surface that is used to simulate the distribution of horizontal surface velocities at the sea surface and to relate these velocities to deep-water wind wave breaking. Results are consistent with many recent studies that show a kinematic-based breaking criterion can provide a consistent depiction of the onset of wave breaking. This criterion is combined with the calculated nonlinear flux rates to estimate a transition point within a spectrum at which a spectrum changes from an f−4 equilibrium-range form to an f−5 region dominated by dissipation, potentially an important factor within several air–sea interaction mechanisms, turbulence at the sea surface, and remote sensing applications. It also has the potential to improve operational modeling capabilities.

scholarly journals Wind Speed Retrieval Based on Sea Surface Roughness Measurements from Spaceborne Microwave Radiometers

2013 ◽  
Vol 52 (2) ◽  
pp. 507-516 ◽  
Author(s):  
Sungwook Hong ◽  
Inchul Shin
Keyword(s):  
Surface Roughness ◽  
Wind Speed ◽  
Data Assimilation ◽  
Thermal Emission ◽  
Surface Wind ◽  
Sea Surface ◽  
Retrieval Algorithm ◽  
Surface Emissivity ◽  
Wide Range ◽  
Global Data

AbstractWind speed is the main factor responsible for the increase in ocean thermal emission because sea surface emissivity strongly depends on surface roughness. An alternative approach to estimate the surface wind speed (SWS) as a function of surface roughness is developed in this study. For the sea surface emissivity, the state-of-the-art forward Fast Microwave Emissivity Model, version 3 (FASTEM-3), which is applicable for a wide range of microwave frequencies at incidence angles of less than 60°, is used. Special Sensor Microwave Imager and Advanced Microwave Scanning Radiometer (AMSR-E) observations are simulated using FASTEM-3 and the Global Data Assimilation and Prediction System operated by the Korea Meteorological Administration. The performance of the SWS retrieval algorithm is assessed by comparing its SWS output to that of the Global Data Assimilation System operated by the National Centers for Environmental Prediction. The surface roughness is computed using the Hong approximation and characteristics of the polarization ratio. When compared with the Tropical Atmosphere–Ocean data, the bias and root-mean-square error (RMSE) of the SWS outputs from the proposed wind speed retrieval algorithm were found to be 0.32 m s−1 (bias) and 0.37 m s−1 (RMSE) for the AMSR-E 18.7-GHz channel, 0.38 m s−1 (bias) and 0.42 m s−1 (RMSE) for the AMSR-E 23.8-GHz channel, and 0.45 m s−1 (bias) and 0.49 m s−1 (RMSE) for the AMSR-E 36.5-GHz channel. Consequently, this research provides an alternative method to retrieve the SWS with minimal a priori information on the sea surface.

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