Vertical Profiles of the Wave-Induced Airflow above Ocean Surface Waves
Vertical Profiles of the Wave-Induced Airflow above Ocean Surface Waves
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DOI：
10.1175/jpo-d-18-0121.1
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发表时间：
2018-12-01
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：
Grare, Laurent;Lenain, Luc;Melville, W. Kendall
分析了2013年11月在南加州海岸附近的R/P翻转期间收集的ONR南加州2013(SoCal2013)计划期间收集的风和海浪的相干测量数据。部署了安装在伸缩桅杆上的超声波风速计阵列，以解析海浪对海洋大气边界层调制的垂直剖面。数据的频谱分析提供了各种风浪条件下由波浪引起的风速分量。结果表明，波浪引起的脉动与波龄c(Omega)/U(Z)和归一化高度kz有关，其中c是波数为k的波线相速度，U(Z)是在高度z处测得的平均风速。谱波龄的依赖关系表示了波生气流对U(Z)=c的临界层的敏感性。在临界层上，波动的幅度和相位都发生了显著变化。在临界层以下，相位保持不变，而幅度随归一化高度呈指数衰减。考虑到这种双重依赖关系，表面轨道速度AKC对波浪引起的波动的幅度进行无量纲化，使声波风速计阵列测量的所有数据崩溃，其中a是波的幅度。
An analysis of coherent measurements of winds and waves from data collected during the ONR Southern California 2013 (SoCal2013) program from R/P FLIP off the coast of Southern California in November 2013 is presented. An array of ultrasonic anemometers mounted on a telescopic mast was deployed to resolve the vertical profile of the modulation of the marine atmospheric boundary layer by the waves. Spectral analysis of the data provides the wave-induced components of the wind velocity for various wind-wave conditions. Results show that the wave-induced fluctuations depend both on the spectral wave age c(omega)/U(z) and the normalized height kz, where c is the linear phase speed of the waves with wavenumber k and U(z) is the mean wind speed measured at the height z. The dependence on the spectral wave age expresses the sensitivity of the wave-induced airflow to the critical layer where U(z) = c. Across the critical layer, there is a significant change of both the amplitude and phase of the wave-induced fluctuations. Below the critical layer, the phase remains constant while the amplitude decays exponentially depending on the normalized height. Accounting for this double dependency, the nondimensionalization of the amplitude of the wave-induced fluctuations by the surface orbital velocity akc collapses all the data measured by the array of sonic anemometers, where a is the amplitude of the waves.