Energy transformations and dissipation of nonlinear internal waves over New Jersey's continental shelf
Energy transformations and dissipation of nonlinear internal waves over New Jersey's continental shelf
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新泽西大陆架非线性内波的能量转换和耗散
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
J. Nash
中科院分区：
文献类型：
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作者：
E. Shroyer;J. Moum;J. Nash
抽象的。根据2006年8月获得的船舶和系泊数据，总结了在新泽西大陆架观测到的大振幅、高频非线性内波（NLIWs）的能量学。NLIW的能量通常在105 Jm−1的量级，波耗散损耗接近50 W m−1。然而，在特定的一周时间内，波能（耗散）比这些值大~10（~2）倍。在一般情况下，领先的波在一个包增长的能量在整个外大陆架，达到峰值附近40公里的近岸的大陆架断裂，然后失去了能量的湍流混合。波浪增长归因于内潮的钻孔性质，因为表现出更大的长期（持续几个小时）位移的密度跃层离岸波群通常有更大的能量近岸。对于船舶观测的NLIW，衰减区域的平均耗散损失与波浪中的峰值能量成比例;将这种比例扩展到系泊数据，产生与使用波浪能量的通量发散所作的NLIW耗散损失估计一致的NLIW耗散损失估计。NLIWs的衰变时间尺度约为12 h，对应于35 km的长度尺度（O（100）波长）。强加在这些较大规模的充满活力的趋势，是短期的，快速的交流与波的相互作用和浅滩上的局部地形上升。这两个事件导致的剪切不稳定性和大的能量损失湍流混合的发病。
Abstract. The energetics of large amplitude, high-frequency nonlinear internal waves (NLIWs) observed over the New Jersey continental shelf are summarized from ship and mooring data acquired in August 2006. NLIW energy was typically on the order of 105 Jm−1, and the wave dissipative loss was near 50 W m−1. However, wave energies (dissipations) were ~10 (~2) times greater than these values during a particular week-long period. In general, the leading waves in a packet grew in energy across the outer shelf, reached peak values near 40 km inshore of the shelf break, and then lost energy to turbulent mixing. Wave growth was attributed to the bore-like nature of the internal tide, as wave groups that exhibited larger long-term (lasting for a few hours) displacements of the pycnocline offshore typically had greater energy inshore. For ship-observed NLIWs, the average dissipative loss over the region of decay scaled with the peak energy in waves; extending this scaling to mooring data produces estimates of NLIW dissipative loss consistent with those made using the flux divergence of wave energy. The decay time scale of the NLIWs was approximately 12 h corresponding to a length scale of 35 km (O(100) wavelengths). Imposed on these larger scale energetic trends, were short, rapid exchanges associated with wave interactions and shoaling on a localized topographic rise. Both of these events resulted in the onset of shear instabilities and large energy loss to turbulent mixing.