scholarly journals Relationship between Sea Surface Drag Coefficient and Wave State

2021 ◽  
Vol 9 (11) ◽  
pp. 1248
Author(s):  
Jian Shi ◽  
Zhihao Feng ◽  
Yuan Sun ◽  
Xueyan Zhang ◽  
Wenjing Zhang ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Momentum Flux ◽  
Sea Surface ◽  
Sea Spray ◽  
Wave Age ◽  
High Wind ◽  
Surface Drag ◽  
Wave State ◽  
Wind Speeds ◽  
Strong Winds

The sea surface drag coefficient plays an important role in momentum transmission between the atmosphere and the ocean, which is affected by ocean waves. The total air–sea momentum flux consists of effective momentum flux and sea spray momentum flux. Sea spray momentum flux involves sea surface drag, which is largely affected by the ocean wave state. Under strong winds, the sea surface drag coefficient (CD) does not increase linearly with the increasing wind speed, namely, the increase of CD is inhibited by strong winds. In this study, a sea surface drag coefficient is constructed that can be applied to the calculation of the air–sea momentum flux under high wind speed. The sea surface drag coefficient also considers the influence of wave state and sea spray droplets generated by wave breaking. Specially, the wave-dependent sea spray generation function is employed to calculate sea spray momentum flux. This facilitates the analysis not only on the sensitivity of the sea spray momentum flux to wave age, but also on the effect of wave state on the effective CD (CD, eff) under strong winds. Our results indicate that wave age plays an important role in determining CD. When the wave age is >0.4, CD decreases with the wave age. However, when the wave age is ≤0.4, CD increases with the wave age at low and moderate wind speeds but tends to decrease with the wave age at high wind speeds.

The impact of ocean waves on spray stress and surface drag coefficient

2019 ◽  
Vol 29 (2) ◽  
pp. 523-535
Author(s):  
Zhanhong Wan ◽  
Luping Li ◽  
Zhigen Wu ◽  
Jiawang Chen ◽  
Xiuyang Lü
Keyword(s):  
Drag Coefficient ◽  
Momentum Flux ◽  
Sea Surface ◽  
Sea Spray ◽  
Wave Age ◽  
Surface Drag ◽  
Content Type ◽  
Flux Formula ◽  
Hurricane Prediction ◽  
Windsea Reynolds Number

Purpose The behaviors of sea surface drag coefficient should be well understood for an accurate hurricane prediction. The speed of wind has been applied to characterize the spray production; however, this could result in inaccurate spray productions compared to the experimental or field data if the influence of wave state is not considered. This paper aims to integrate a new sea spray generation function, described by windsea Reynolds number, into the spray momentum flux formula to calculate the spray momentum. Design/methodology/approach On the basis of this spray momentum, this study proposes the new formulas of spray stress and drag coefficient when the wind speed is high. Findings Results of the revised formulas show that wave status had significant effects on the spray stress and sea surface drag coefficient. Also, wave age was found to be an important parameter that affects the drag coefficient. The drag coefficient decreased with the increasing wave age. Comparison between this study’s theoretical and observation values of drag coefficient shows that the study results are close to the measured values. Research limitations/implications The research findings can enhance the understanding of the behaviors of sea surface drag for an accurate hurricane prediction. Originality/value A new sea spray generation function, described by windsea Reynolds number, is integrated into the spray momentum flux formula to calculate the spray momentum. On the basis of this spray momentum, this study proposes the new formulas of spray stress and drag coefficient when the wind speed is high.

The Influence of wave state and sea spray on drag coefficient from low to high wind speeds

2016 ◽  
Vol 15 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Jian Shi ◽  
Zhong Zhong ◽  
Xunqiang Li ◽  
Guorong Jiang ◽  
Wenhua Zeng ◽  
...  
Keyword(s):  
Drag Coefficient ◽  
Sea Spray ◽  
High Wind ◽  
Wave State ◽  
Wind Speeds

scholarly journals A Novel Sea Surface Roughness Parameterization Based on Wave State and Sea Foam

2021 ◽  
Vol 9 (3) ◽  
pp. 246
Author(s):  
Difu Sun ◽  
Junqiang Song ◽  
Xiaoyong Li ◽  
Kaijun Ren ◽  
Hongze Leng
Keyword(s):  
Surface Roughness ◽  
Wind Speed ◽  
Drag Coefficient ◽  
Sea Surface ◽  
High Wind Speed ◽  
Wave State ◽  
Wind Speeds ◽  
Sea Surface Roughness ◽  
Extreme Wind ◽  
The Impact

A wave state related sea surface roughness parameterization scheme that takes into account the impact of sea foam is proposed in this study. Using eight observational datasets, the performances of two most widely used wave state related parameterizations are examined under various wave conditions. Based on the different performances of two wave state related parameterizations under different wave state, and by introducing the effect of sea foam, a new sea surface roughness parameterization suitable for low to extreme wind conditions is proposed. The behaviors of drag coefficient predicted by the proposed parameterization match the field and laboratory measurements well. It is shown that the drag coefficient increases with the increasing wind speed under low and moderate wind speed conditions, and then decreases with increasing wind speed, due to the effect of sea foam under high wind speed conditions. The maximum values of the drag coefficient are reached when the 10 m wind speeds are in the range of 30–35 m/s.

scholarly journals Experimental Study of High Wind Sea Surface Drag Coefficient

2015 ◽  
Author(s):  
I.A. Repina ◽  
A.Yu. Artamonov ◽  
M.I. Varentsov ◽  
A.V. Kozyrev ◽  
◽  
...  
Keyword(s):  
Experimental Study ◽  
Drag Coefficient ◽  
Sea Surface ◽  
High Wind ◽  
Surface Drag ◽  
Wind Sea

scholarly journals Influence of Wave State and Sea Spray on the Roughness Length: Feedback on Medicanes

Atmosphere ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 301 ◽  
Author(s):  
Umberto Rizza ◽  
Elisa Canepa ◽  
Antonio Ricchi ◽  
Davide Bonaldo ◽  
Sandro Carniel ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Single Case ◽  
Wind Waves ◽  
Wave Model ◽  
Atmospheric Model ◽  
Sea Surface ◽  
Sea Spray ◽  
High Wind ◽  
Wave State ◽  
Sea Surface Roughness

Occasionally, storms that share many features with tropical cyclones, including the presence of a quasi-circular “eye” a warm core and strong winds, are observed in the Mediterranean. Generally, they are known as Medicanes, or tropical-like cyclones (TLC). Due to the intense wind forcings and the consequent development of high wind waves, a large number of sea spray droplets—both from bubble bursting and spume tearing processes—are likely to be produced at the sea surface. In order to take into account this process, we implemented an additional Sea Spray Source Function (SSSF) in WRF-Chem, model version 3.6.1, using the GOCART (Goddard Chemistry Aerosol Radiation and Transport) aerosol sectional module. Traditionally, air-sea momentum fluxes are computed through the classical Charnock relation that does not consider the wave-state and sea spray effects on the sea surface roughness explicitly. In order to take into account these forcing, we implemented a more recent parameterization of the sea surface aerodynamic roughness within the WRF surface layer model, which may be applicable to both moderate and high wind conditions. The implemented SSSF and sea surface roughness parameterization have been tested using an operative model sequence based on COAWST (Coupled Ocean Atmosphere Wave Sediment Transport) and WRF-Chem. The third-generation wave model SWAN (Simulating Waves Nearshore), two-way coupled with the WRF atmospheric model in the COAWST framework, provided wave field parameters. Numerical simulations have been integrated with the WRF-Chem chemistry package, with the aim of calculating the sea spray generated by the waves and to include its effect in the Charnock roughness parametrization together with the sea state effect. A single case study is performed, considering the Medicane that affected south-eastern Italy on 26 September 2006. Since this Medicane is one of the most deeply analysed in literature, its investigation can easily shed some light on the feedbacks between sea spray and drag coefficients.

scholarly journals Experimental Study of High Wind Sea Surface Drag Coefficient

2015 ◽  
Author(s):  
I.A. Repina ◽  
A.Yu. Artamonov ◽  
M.I. Varentsov ◽  
A.V. Kozyrev ◽  
◽  
...  
Keyword(s):  
Experimental Study ◽  
Drag Coefficient ◽  
Sea Surface ◽  
High Wind ◽  
Surface Drag ◽  
Wind Sea

scholarly journals Cyclonic Wave Simulations Based on WAVEWATCH-III Using a Sea Surface Drag Coefficient Derived from CFOSAT SWIM Data

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1610
Author(s):  
Weizeng Shao ◽  
Tao Jiang ◽  
Yu Zhang ◽  
Jian Shi ◽  
Weili Wang
Keyword(s):  
Drag Coefficient ◽  
Numerical Models ◽  
Sea Surface ◽  
Surface Drag ◽  
Wavewatch Iii ◽  
Sea Surface Roughness ◽  
Typhoon Wave ◽  
Strong Winds ◽  
Remote Sensing Techniques ◽  
High Winds

It is well known that numerical models are powerful methods for wave simulation of typhoons, where the sea surface drag coefficient is sensitive to strong winds. With the development of remote sensing techniques, typhoon data (i.e., wind and waves) have been captured by optical and microwave satellites such as the Chinese-French Oceanography SATellite (CFOSAT). In particular, wind and wave spectra data can be simultaneously measured by the Surface Wave Investigation and Monitoring (SWIM) onboard CFOSAT. In this study, existing parameterizations for the drag coefficient are implemented for typhoon wave simulations using the WAVEWATCH-III (WW3) model. In particular, a parameterization of the drag coefficient derived from sea surface roughness is adopted by considering the terms for wave steepness and wave age from the measurements from SWIM products of CFOSAT from 20 typhoons during 2019–2020 at winds up to 30 m/s. The simulated significant wave height (Hs) from the WW3 model was validated against the observations from several moored buoys active during three typhoons, i.e., Typhoon Fung-wong (2014), Chan-hom (2015), and Lekima (2019). The analysis results indicated that the proposed parameterization of the drag coefficient significantly improved the accuracy of typhoon wave estimation (a 0.49 m root mean square error (RMSE) of Hs and a 0.35 scatter index (SI)), greater than the 0.55 RMSE of Hs and >0.4 SI using other existing parameterizations. In this sense, the adopted parameterization for the drag coefficient is recommended for typhoon wave simulations using the WW3 model, especially for sea states with Hs < 7 m. Moreover, the accuracy of simulated waves was not reduced with growing winds and sea states using the proposed parameterization. However, the applicability of the proposed parameterization in hurricanes necessitates further investigation at high winds (>30 m/s).

scholarly journals A Physics-Based Parameterization of Air–Sea Momentum Flux at High Wind Speeds and Its Impact on Hurricane Intensity Predictions

2007 ◽  
Vol 135 (8) ◽  
pp. 2869-2878 ◽  
Author(s):  
Il-Ju Moon ◽  
Isaac Ginis ◽  
Tetsu Hara ◽  
Biju Thomas
Keyword(s):  
Drag Coefficient ◽  
Momentum Flux ◽  
Surface Wind ◽  
Wind Pressure ◽  
Central Pressure ◽  
Geophysical Fluid Dynamics Laboratory ◽  
High Wind ◽  
Wind Speeds ◽  
Gfdl Model ◽  
The Impact

Abstract A new bulk parameterization of the air–sea momentum flux at high wind speeds is proposed based on coupled wave–wind model simulations for 10 tropical cyclones that occurred in the Atlantic Ocean during 1998–2003. The new parameterization describes how the roughness length increases linearly with wind speed and the neutral drag coefficient tends to level off at high wind speeds. The proposed parameterization is then tested on real hurricanes using the operational Geophysical Fluid Dynamics Laboratory (GFDL) coupled hurricane–ocean prediction model. The impact of the new parameterization on the hurricane prediction is mainly found in increased maximum surface wind speeds, while it does not appreciably affect the hurricane central pressure prediction. This helps to improve the GFDL model–predicted wind–pressure relationship in strong hurricanes. Attempts are made to provide physical explanations as to why the reduced drag coefficient affects surface wind speeds but not the central pressure in hurricanes.

scholarly journals DEVELOPMENT OF AN INVERSE ESTIMATION METHOD OF SEA SURFACE DRAG COEFFICIENT UNDER STRONG WIND CONDITIONS

2011 ◽  
Vol 1 (32) ◽  
pp. 32 ◽  
Author(s):  
Masaki Yokota ◽  
Noriaki Hashimoto ◽  
Koji Kawaguchi ◽  
Hiroyasu Kawai
Keyword(s):  
Drag Coefficient ◽  
A Priori ◽  
Estimation Method ◽  
Sea Surface ◽  
Observation Data ◽  
Strong Wind ◽  
High Wind ◽  
Surface Drag ◽  
Inverse Estimation ◽  
The Given

For the purpose of clarifying the mechanism of energy transfer from high wind to waves, the ADWAM, a wave prediction model incorporating the data assimilation method, was modified to deduce the sea surface drag coefficients as its control variables. Validity of the model was verified through the identical twin experiment in deep sea conditions. Also, the behavior of the deduced parameter was examined through several experiments. As a result, it was confirmed that the drag coefficient deduced by the model is accurate enough when the number of the given observation data is sufficient compared with the number of the unknown parameter. It was also confirmed that the accuracy of the deduced coefficient can be improved by adding an a priori condition even if the number of the observation data is insufficient.

scholarly journals UNCERTAINTY OF EXTREME STORM SURGE ESTIMATION BY HIGH WIND SEA SURFACE DRAG COEFFICIENT AND FUTURE TYPHOON CHANGE

2011 ◽  
Vol 1 (32) ◽  
pp. 18 ◽  
Author(s):  
Hiroyasu Kawai ◽  
Noriaki Hashimoto ◽  
Masaru Yamashiro ◽  
Tomohiro Yasuda
Keyword(s):  
Drag Coefficient ◽  
Storm Surge ◽  
Return Period ◽  
Extreme Values ◽  
Research Output ◽  
Storm Surges ◽  
Sea Surface ◽  
High Wind ◽  
Surface Drag ◽  
Typhoon Vera

Japan has been constructing long coastal defense since the storm surge disaster with a loss of 5,000 lives by Typhoon Vera in 1959. The defense is designed for the storm water level including the storm surge of the standard typhoon based on Typhoon Vera. Stochastic typhoon model, simulating various typhoon track and intensity with Monte Carlo method, is one of useful tools to estimate the return period. According to recent research output the return period of the storm surge of the standard typhoon is near 100 years or more at three major bays in Japan. But there is uncer-tainty by some of parameters and models in the stochastic simulation. Sea surface drag coefficient under high wind speed and future change in typhoon intensity and track are critical to extreme values of the storm surges.

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