Tidal energy conversion in a global hot spot: On the 3-D dynamics of baroclinic tides at the Celtic Sea shelf break
Tidal energy conversion in a global hot spot: On the 3-D dynamics of baroclinic tides at the Celtic Sea shelf break
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DOI：
10.1002/2013jc009708
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发表时间：
2014-06
影响因子：
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通讯作者：
V. Vlasenko;N. Stashchuk;M. Inall;J. Hopkins
中科院分区：
文献类型：
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作者：
V. Vlasenko;N. Stashchuk;M. Inall;J. Hopkins
在全球范围内，凯尔特海陆架断裂被列为潮汐能转换的最高能量“热点”，因此使其成为全球内部潮汐能通量的最重要贡献者。本文利用2012年6月“RRS发现号”RV第376次巡航收集的观测数据，数值研究了凯尔特海陆架斜坡区斜压潮汐的三维动力学。在陆架断裂系泊记录的时间序列表明，半日内波伴随着包的内部孤立波，最大振幅可达105米，最大的内波有史以来记录在凯尔特海，并在全球海洋中观察到的最大的排名。利用马萨诸塞州理工学院大气环流模式数值模拟了观测到的斜压波场。一个高分辨率的网格，115米的水平和10米的垂直步骤允许识别两类短尺度内波。第一个分类是在岬上产生的，类似于孤立的水下银行典型的螺旋型内波。第二个分类，在几个峡谷的区域内产生的，揭示了准平面内波包的属性。观察到的现场加剧的潮汐底流在陆架断裂系泊解释在超临界底部地形在系泊位置形成的潮汐梁。
Globally, the Celtic Sea shelf break is ranked highest as an energetic “hot spot” of tidal energy conversion, therefore making it the most significant contributor to global internal tidal energy flux. In this paper, the three-dimensional dynamics of baroclinic tides in the shelf-slope area of the Celtic Sea was investigated numerically and using observational data collected on the 376th cruise of the RV “RRS Discovery” in June 2012. The time series recorded at a shelf break mooring showed that semidiurnal internal waves were accompanied by packets of internal solitary waves with maximum amplitudes up to 105 m, the largest internal waves ever recorded in the Celtic Sea, and ranking among the largest observed in the global ocean. The observed baroclinic wavefields were replicated numerically using the Massachusetts Institute of Technology general circulation model. A fine-resolution grid with 115 m horizontal and 10 m vertical steps allowed the identification of two classes of short-scale internal waves. The first classification was generated over headlands and resembles spiral-type internal waves that are typical for isolated underwater banks. The second classification, generated within an area of several canyons, revealed properties of quasi-planar internal wave packets. The observed in situ intensification of tidal bottom currents at the shelf break mooring is explained in terms of a tidal beam that was formed over supercritical bottom topography at the mooring location.