Response of the Internal Wave Field to Remote Wind Forcing by Tropical Cyclones
Response of the Internal Wave Field to Remote Wind Forcing by Tropical Cyclones
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DOI：
10.1175/jpo-d-17-0112.1
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发表时间：
2018-02-01
影响因子：
3.5
通讯作者：
Walter, Maren
中科院分区：
文献类型：
--
作者：
Koehler, Janna;Voelker, Georg S.;Walter, Maren
在热带北大西洋，平均风引入相对较少的能量到内波场，但飓风作为近惯性波的非常有活力的来源。除了类似事件的通过这样的热带气旋，在信风系统北部的风速变化引起的季节性周期的表面膨胀，与潜在的影响的高频部分的内波场。使用5年系泊时间序列在热带北大西洋的内部在16 ° N，内波能量的时间变化的主要飓风路径以南的不同频带的研究，其变化的幅度，沿着与可能的能量传输机制，进行了分析。结果表明，近惯性能量的变化主要是由以系泊点以北几百公里为中心的飓风产生的内波通过所决定的。飓风在产生近惯性波的主要作用也被认为是在一个扩展的平板模型，考虑到在混合层基地的近惯性流场的水平发散。在内波频谱的高频端（频率高于6cpd）的能量中观察到季节性周期。它与近惯性能量变化不同相，但与当地表面波的变化协变。这些高频内波是最有活力的时候，大幅度的表面隆起与长周期和相应的长波长的观察。
In the tropical North Atlantic, mean winds introduce relatively little energy into the internal wave field, but hurricanes act as very energetic sources for near-inertial waves. In addition to the eventlike passage of such tropical cyclones, changes in the wind speed north of the trade wind system induce a seasonal cycle in surface swell, with potential implications for the high-frequency part of the internal wave field. Using a 5-yr mooring time series in the interior of the tropical North Atlantic at 16 degrees N, the temporal variability of internal wave energy south of the main hurricane track in different frequency bands is studied, and the magnitude of its variability, along with possible energy transfer mechanisms, is analyzed. The results show that changes in near-inertial energy are dominated by the passage of internal waves generated by hurricanes centered several hundred kilometers north of the mooring. The major role of hurricanes in the generation of near-inertial waves is also seen in an extended slab model that takes the horizontal divergence of the near-inertial current field at the mixed layer base into account. A seasonal cycle is observed in the energy at the high-frequency end (frequencies above 6 cpd) of the internal wave spectrum. It is not in phase with the near-inertial energy variability but covaries with changes in the local surface waves. These high-frequency internal waves are most energetic at times when large-amplitude surface swell with long periods and correspondingly long wavelengths is observed.