Measurements of the Directional Spectrum across the Equilibrium Saturation Ranges of Wind-Generated Surface Waves
Measurements of the Directional Spectrum across the Equilibrium Saturation Ranges of Wind-Generated Surface Waves
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DOI：
10.1175/jpo-d-17-0017.1
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发表时间：
2017-08-01
影响因子：
3.5
通讯作者：
Melville, W. Kendall
中科院分区：
文献类型：
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作者：
Lenain, Luc;Melville, W. Kendall
为了更好地理解大气和海洋之间的耦合，改进海洋-大气耦合模式，需要考虑表面波过程，这一点现在已被广泛接受。在这里，整个平衡和饱和范围内的表面波场的方向分布的属性进行了研究，从机载激光雷达数据收集在ONR南加州2013年（SoCal 2013）的实验，在南加州海岸外进行的2013年11月。在现场工作中，海洋大气边界层的详细表征是从研究平台（R/P）浮动仪器平台（FLIP）进行的，该平台系泊在飞机操作域的中心。在分析中考虑的10天数据收集期间，风速范围约为1-2至11 ms（-1），而有效波高范围为0.8至2.5 m。定向波数谱显示出清晰的双峰分布，远远超出了先前研究中的报道，对于可以分辨的最高波数，波瓣之间的方位角间隔接近π：约10-12 rad m（-1）。结果表明，相反的波分量可以在一个风暴系统中找到，而不是需要从相反的风暴波，海洋声学的影响。由于激光雷达获得的方向谱的波数范围很宽，当k（n）u（*）（2）/g近似为1-2 × 10（-3）时，在一定范围的风强迫条件下，从平衡区到饱和区的转变发生了，其中k（n）是平衡区上限的波数，u* 是摩擦速度，g是重力加速度。结果进行了讨论的背景下，菲利普斯模型的平衡范围的风产生的重力波。
It is now well accepted that to better understand the coupling between the atmosphere and the ocean, and improve coupled ocean-atmosphere models, surface wave processes need to be taken into account. Here, properties of the directional distributions of the surface wave field across the equilibrium and saturation ranges are investigated from airborne lidar data collected during the ONR Southern California 2013 (SoCal2013) experiment, conducted off the coast of Southern California in November 2013. During the field effort, detailed characterization of the marine atmospheric boundary layer was performed from Research Platform (R/P) Floating Instrument Platform (FLIP), moored at the center of the aircraft operational domain. The wind speed ranged from approximately 1-2 to up to 11ms(-1), while the significant wave height varied from 0.8 to 2.5m during the 10 days of data collection considered in the analysis. The directional wavenumber spectrum exhibits a clear, bimodal distribution that extends well beyond what was reported in previous studies, with the azimuthal separation between the lobes reaching approximate to pi for the highest wavenumbers that could be resolved: approximately 10-12 rad m(-1). The results demonstrate that opposing wave components can be found in one storm system rather than requiring waves from opposing storms, with implications for ocean acoustics. With the broad wavenumber range of the directional spectra obtained from the lidar, the transition from the equilibrium to saturation ranges over a range of wind forcing conditions is found to occur for k(n)u(*)(2)/g approximate to 1-2 x 10(-3), where k(n) is the wavenumber at the upper limit of the equilibrium range, u* the friction velocity, and g the gravitational acceleration. The results are discussed in the context of Phillips' model of the equilibrium range of wind-generated gravity waves.