On the wave age dependent drag coefficient and roughness length at sea

1991 ◽  
Vol 96 (C4) ◽  
pp. 7167 ◽  
Author(s):  
Thor Erik Nordeng
Keyword(s):  
Drag Coefficient ◽  
Roughness Length ◽  
Wave Age ◽  
Age Dependent

scholarly journals On the Linear Parameterization of Drag Coefficient over Sea Surface

2004 ◽  
Vol 34 (12) ◽  
pp. 2847-2851 ◽  
Author(s):  
Changlong Guan ◽  
Lian Xie
Keyword(s):  
Wind Speed ◽  
Drag Coefficient ◽  
Linear Function ◽  
Sea Surface ◽  
Wave Steepness ◽  
Wave Age ◽  
Age Dependent ◽  
Logarithmic Law ◽  
Linear Parameterization ◽  
Charnock Relation

Abstract Combining the logarithmic law with the Charnock relation yields a drag coefficient that is a function of wind speed with the Charnock coefficient as a parameter. It is found that the function is nearly linear within the typically measured range of the drag coefficient. The slope of the linear function is dominated by the Charnock coefficient. When the Charnock relation is extended to a wave age–dependent function, the drag coefficient remains a near-linear function of wind speed after invoking the 3/2 power law. The slope of the linear function is dominated by wave steepness.

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.

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 Form drag on pressure ridges and drag coefficient in the northwestern Weddell Sea, Antarctica, in winter

2013 ◽  
Vol 54 (62) ◽  
pp. 133-138
Author(s):  
Tan Bing ◽  
Lu Peng ◽  
Li Zhijun ◽  
Li Runling
Keyword(s):  
Sea Ice ◽  
Drag Coefficient ◽  
Roughness Length ◽  
Weddell Sea ◽  
Neutral Stability ◽  
Form Drag ◽  
Laser Altimeter ◽  
Dominant Component ◽  
Elevation Data ◽  
Ice Surfaces

AbstractSurface elevation data for sea ice in the northwesternty - Weddell Sea, Antarctica, collected by a helicopter-borne laser altimeter during the Winter Weddell Outflow Study 2006, were used to estimate the form drag on pressure ridges and its contribution to the total wind drag, and the air-ice drag coefficient at a reference height of 10 m under neutral stability conditions (Cdn(10)). This was achieved by partitioning the total wind drag into two components: form drag on pressure ridges and skin drag over rough sea-ice surfaces. The results reveal that for the compacted ice field, the contribution of form drag on pressure ridges to the total wind drag increases with increasing ridging intensity Ri (where Ri is the ratio of mean ridge height to spacing), while the contribution decreases with increasing roughness length. There is also an increasing trend in the air-ice drag coefficient Cdn(10) as ridging intensity Ri increases. However, as roughness length increases, Cdn(10) increases at lower ridging intensities (Ri < 0.023) but decreases at lower ridging intensities (0.023 < Ri < 0.05). These opposing trends are mainly caused by the dominance of the form drag on pressure ridges and skin drag over rough ice surfaces. Generally, the form drag becomes dominant only when the ridging intensity is sufficiently large, while the skin drag is the dominant component at relatively larger ridging intensities. These results imply that a large value of Cdn(10) is caused not only by the form drag on pressure ridges, but also by the skin drag over rough ice surfaces. Additionally, the estimated drag coefficients are consistent with reported measurements in the northwestern Weddell Sea, further demonstrating the feasibility of the drag partition model.

scholarly journals Study of the relationship between non-dimensional roughness length and wave age, effected by wave directionality

2002 ◽  
Vol 111 (3) ◽  
pp. 305-313 ◽  
Author(s):  
Naoya Suzuki ◽  
Naoto Ebuchi ◽  
Chaofang Zhao ◽  
Isao Watabe ◽  
Yasuhiro Sugimori
Keyword(s):  
Roughness Length ◽  
Wave Age ◽  
Wave Directionality ◽  
The Relationship
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