Bottom friction and wind drag for wave models

Zijlema, Marcel; Vledder, G.P. Van; Holthuijsen, L.H.

doi:10.1016/j.coastaleng.2012.03.002

Cited by 191 publications

(151 citation statements)

References 40 publications

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“…Choosing the JONSWAP bottom friction coefficient equal to C f,J ON = 0.038 m 2 s −3 , as recommended by Zijlema et al (2012), also seems a better choice than the previously recommended value for wind seas of C f,J ON = 0.067 m 2 s −3 , as originally recommended by Bouws and Komen (1983). It turned out that bottom friction is more effective for lower frequency components than for higher frequency components of the wave spectrum.…”

Section: Discussionmentioning

confidence: 96%

“…Hasselmann et al 1973). Zijlema et al (2012), however, showed that there is no reason to have different values for the JON-SWAP bottom friction coefficient, one for wind seas and one for swell. The results shown in the Fig.…”

Section: Results Of the Wave Hindcastmentioning

confidence: 99%

“…the Komen type dissipation using δ = 1 as recommended by Rogers et al (2003) and a constant JONSWAP bottom friction coefficient of C f,J ON = 0.038 m 2 s −3 as recommended by Zijlema et al (2012). Hereafter, model runs were applied using the Komen-type whitecapping with δ = 0, the saturation-based whitecapping formulation of Van der Westhuysen et al (2007) and the recently developed ST6 whitecapping formulation, all with a bottom friction coefficient of C f,J ON = 0.038 m 2 s −3 .…”

Section: Results Of the Wave Hindcastmentioning

confidence: 99%

“…in which f is frequency, θ is direction, k is wave number, d is depth, and the bottom friction coefficient χ = 0.038 m 2 s −3 as recommended by Zijlema et al (2012). We chose the latter value for most of our computations.…”

Section: The Swan Wave Modelmentioning

confidence: 99%

“…For the North Sea, the source term balance was investigated by Bouws and Komen (1983) to arrive at an estimate of JONSWAP type bottom friction during storm conditions. The January 1976 storm considered by Bouws and Komen (1983) was reanalysed by Zijlema et al (2012) who showed that one value for the JONSWAP bottom friction rate suffices for both wind sea and swell conditions in combination with a wind speed dependent wind drag coefficient. In shallow water or close to the coast, this balance may change.…”

Section: Introductionmentioning

confidence: 99%

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Source term balance in a severe storm in the Southern North Sea

Vledder

Hulst²,

McConochie

2016

Ocean Dynamics

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This paper presents the results of a wave hindcast of a severe storm in the Southern North Sea to verify recently developed deep and shallow water source terms. The work was carried out in the framework of the ONR funded NOPP project (Tolman et al. 2013) in which deep and shallow water source terms were developed for use in third-generation wave prediction models. These deep water source terms for whitecapping, wind input and nonlinear interactions were developed, implemented and tested primarily in the WAVEWATCH III model, whereas shallow water source terms for depth-limited wave breaking and triad interactions were developed, implemented and tested primarily in the SWAN wave model. So far, the new deepwater source terms for whitecapping were not fully tested in shallow environments. Similarly, the shallow water source terms were not yet tested in large inter-mediate depth areas Shell Global Solutions International B.V, Rijswijk, The Netherlands like the North Sea. As a first step in assessing the performance of these newly developed source terms, the source term balance and the effect of different physical settings on the prediction of wave heights and wave periods in the relatively shallow North Sea was analysed. The December 2013 storm was hindcast with a SWAN model implementation for the North Sea. Spectral wave boundary conditions were obtained from an Atlantic Ocean WAVEWATCH III model implementation and the model was driven by hourly CFSR wind fields. In the southern part of the North Sea, current and water level effects were included. The hindcast was performed with five different settings for whitecapping, viz. three Komen type whitecapping formulations, the saturation-based whitecapping by Van der Westhuysen et al. (2007) and the recently developed ST6 whitecapping as described by Zieger et al. (2015). Results of the wave hindcast were compared with buoy measurements at location K13 collected by the Dutch Ministry of Transport and Public Works. An analysis was made of the source term balance at three locations, the deep water location North Cormorant, the inter-mediate depth location K13 and at location Wielingen, a shallow water location close to the Dutch coast. The results indicate that at deep water the source terms for wind input, whitecapping and nonlinear four-wave interactions are of the same magnitude. At the inter-mediate depth location K13, bottom friction plays a significant role, whereas at the shallow water location Wielingen also depth-limited wave breaking becomes important.

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Section: Discussionmentioning

confidence: 96%

Section: Results Of the Wave Hindcastmentioning

confidence: 99%

Section: Results Of the Wave Hindcastmentioning

confidence: 99%

Section: The Swan Wave Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Source term balance in a severe storm in the Southern North Sea

Vledder

Hulst²,

McConochie

2016

Ocean Dynamics

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Modeled dependence of wind and waves on ocean temperature in tropical cyclones

Phibbs

Toumi

2014

Geophysical Research Letters

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Typhoon air‐sea drag coefficient in coastal regions

Zhao

Liu

et al. 2015

JGR Oceans

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The air-sea drag during typhoon landfalls is investigated for a 10 m wind speed as high as U 10 % 42 m s 21 , based on multilevel wind measurements from a coastal tower located in the South China Sea.The drag coefficient (C D ) plotted against the typhoon wind speed is similar to that of open ocean conditions; however, the C D curve shifts toward a regime of lower winds, and C D increases by a factor of approximately 0.5 relative to the open ocean. Our results indicate that the critical wind speed at which C D peaks is approximately 24 m s 21 , which is 5-15 m s 21 lower than that from deep water. Shoaling effects are invoked to explain the findings. Based on our results, the proposed C D formulation, which depends on both water depth and wind speed, is applied to a typhoon forecast model. The forecasts of typhoon track and surface wind speed are improved. Therefore, a water-depth-dependence formulation of C D may be particularly pertinent for parameterizing air-sea momentum exchanges over shallow water.

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Bottom friction and wind drag for wave models

Cited by 191 publications

References 40 publications

Source term balance in a severe storm in the Southern North Sea

Source term balance in a severe storm in the Southern North Sea

Modeled dependence of wind and waves on ocean temperature in tropical cyclones

Typhoon air‐sea drag coefficient in coastal regions

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