Whitecap Coverage Dependence on Wind and Wave Statistics as Observed during SO GasEx and HiWinGS
Whitecap Coverage Dependence on Wind and Wave Statistics as Observed during SO GasEx and HiWinGS
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DOI：
10.1175/jpo-d-17-0005.1
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发表时间：
2017-09-01
影响因子：
3.5
通讯作者：
Cifuentes-Lorenzen, Alejandro
中科院分区：
文献类型：
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作者：
Brumer, Sophia E.;Zappa, Christopher J.;Cifuentes-Lorenzen, Alejandro
在南大洋(SO)气体交换(GASEX)和高风速气体交换研究(HiWinGS)项目期间获得的同时波场和湍流通量测量允许评估白冠覆盖W与风速、波龄、波浪陡度、均方斜率以及风浪和破碎雷诺数的关系。W是从600多个高频可见图像记录中确定的，每个记录时间为20分钟。波浪统计数据是从现场和遥感数据以及WaveWatch III后播中计算出来的。在HiWinGS期间，首次获得了在持续10米中性风速U10N为25ms(-1)的情况下W的船载估计。这些测量表明，W在高风速时稳定，当平均风速超过20分钟时，W不超过10%。将风速和海浪高度以风浪雷诺数的形式组合在一起，使得两个数据集的模型非常一致，无论是单独的还是合并的。这些也与之前的两项研究相一致。当仅用波场统计或波年龄来表示W时，观察到更大的散射和/或在SOGAS、HiWinGS和先前发表的数据之间几乎没有一致性。从SOGASEX和HiWinGS数据集导出的仅考虑风速的参数模式与观测到的W变率非常接近，并且比雷诺数参数模式捕捉到更多的观测W变率。然而，这些仅考虑风速的模型与前人的研究相比，与风浪雷诺数的一致性更差。
Concurrent wavefield and turbulent flux measurements acquired during the Southern Ocean ( SO) Gas Exchange (GasEx) and the High Wind Speed Gas Exchange Study (HiWinGS) projects permit evaluation of the dependence of the whitecap coverage W on wind speed, wave age, wave steepness, mean square slope, and wind-wave and breaking Reynolds numbers. The W was determined from over 600 high-frequency visible imagery recordings of 20min each. Wave statistics were computed from in situ and remotely sensed data as well as from a WAVEWATCH III hindcast. The first shipborne estimates of W under sustained 10-m neutral wind speeds U10N of 25ms(-1) were obtained during HiWinGS. These measurements suggest that W levels off at high wind speed, not exceeding 10% when averaged over 20 min. Combining wind speed and wave height in the form of the wind-wave Reynolds number resulted in closely agreeing models for both datasets, individually and combined. These are also in good agreement with two previous studies. When expressing W in terms of wavefield statistics only or wave age, larger scatter is observed and/or there is little agreement between SO GasEx, HiWinGS, and previously published data. The wind speed-only parameterizations deduced from the SO GasEx and HiWinGS datasets agree closely and capture more of the observed W variability than Reynolds number parameterizations. However, these wind speed- only models do not agree as well with previous studies than the wind-wave Reynolds numbers.