Near-Surface Reflection and Nonlinear Effects of Low-Mode Internal Tides on a Continental Slope
Near-Surface Reflection and Nonlinear Effects of Low-Mode Internal Tides on a Continental Slope
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大陆坡上低模内潮汐的近地表反射和非线性效应
DOI：
10.1175/jpo-d-20-0197.1
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发表时间：
2021-01
影响因子：
3.5
通讯作者：
Dake Chen
中科院分区：
文献类型：
--
作者：
Xie Xiaohui;Dake Chen
在中国南海东北部陆坡的一个横坡剖面上沿着的两个站点（MA和MB）采集了两组系泊数据。这些数据被用来调查的低模式半日（M2）内潮的亚临界斜率相对于M2的演变和能量衰减。在斜坡的深部（~1250 m; MA），M2内潮显示向上的能量传播，而在浅MB（~845 m）处经常观察到垂直站立的M2内潮。一个二维的线性内潮模型与现实的地形和分层再现的意见，表明低模式M2内潮事件亚临界斜坡演变成垂直传播的内波由于地形散射，向上传播到边界，并从海面反射。反射点在很大程度上取决于入射通量的模态分量之间的相位。在近地表反射区，观测到两种非线性效应对入射内潮能量的衰减。一种是共振参数次谐波不稳定，它将M2内潮转换为周日次谐波M1（=M2/2），但不稳定性主要取决于入射波。另一种是非共振波-波相互作用，产生两条垂直方向相反的高次谐波M4（= 2 M2）射线。在相互作用区域观察到一个强的向西平均流，其振幅与入射波的振幅相当。这种平均流量似乎也是由M2内潮的非线性反射产生的。
Two sets of mooring data were collected at two sites (MA and MB) along a cross-slope section on the northeastern continental slope in the South China Sea (SCS). These data are used to investigate evolution and energy decay of low-mode semidiurnal (M2) internal tides on a subcritical slope with respect to M2. At the deep portion of the slope (~1250 m; MA), the M2 internal tides show upward energy propagation, while vertically standing M2 internal tides are often observed at shallow MB (~845 m). A two-dimensional linear internal tide model with realistic topography and stratification reproduces the observations, suggesting that low-mode M2 internal tides incident on subcritical slopes evolve into vertically propagating internal waves due to topographic scattering, propagate upward to the boundary, and reflect from the sea surface. The reflection point largely depends on the phase between the modal components of the incoming flux. In the near-surface reflection region, two kinds of nonlinear effects are observed to decay energy of the incoming internal tides. One is the resonant parametric subharmonic instability which transfers M2 internal tides to diurnal subharmonics M1 (=M2/2), but the instability is found to mainly depend on the incident waves. The other one is the nonresonant wave–wave interaction, producing two higher-harmonic M4 (=2M2) rays with opposite vertical propagation. A strong westward mean flow is observed in the interacting region, with amplitude comparable to that of the incident waves. This mean flow also appears to be generated by the nonlinear reflection of the M2 internal tides.
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影响因子：
3.5
作者：
K. Martini;M. Alford;E. Kunze;S. Kelly;J. Nash
通讯作者：
K. Martini;M. Alford;E. Kunze;S. Kelly;J. Nash
影响因子：
3.6
作者：
ERIKSEN, CC
通讯作者：
ERIKSEN, CC
影响因子：
--
作者：
B. Gayen;S. Sarkar
通讯作者：
B. Gayen;S. Sarkar
影响因子：
3.5
作者：
Zhong‐Kuo Zhao;M. Alford
通讯作者：
Zhong‐Kuo Zhao;M. Alford
DOI：
--
发表时间：
2013
期刊：
--
影响因子：
--
作者：
A. J.;Mackinnon;H. M.;Alford;O. Sun;R. Pinkel;Zhong‐Kuo Zhao;J. Klymak
通讯作者：
A. J.;Mackinnon;H. M.;Alford;O. Sun;R. Pinkel;Zhong‐Kuo Zhao;J. Klymak