Three‐dimensional, nonhydrostatic numerical simulation of nonlinear internal wave generation and propagation in the South China Sea
Three‐dimensional, nonhydrostatic numerical simulation of nonlinear internal wave generation and propagation in the South China Sea
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DOI：
10.1029/2010jc006424
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发表时间：
2011-05
影响因子：
--
通讯作者：
Z. Zhang;O. Fringer;S. Ramp
中科院分区：
文献类型：
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作者：
Z. Zhang;O. Fringer;S. Ramp
[1]本文利用SUNTANS模式对南海内潮和波浪进行了三维非静力模拟。模型结果准确地预测了观测到的波到达时间在两个系泊位置在南海。内波振幅预测不足，由于缺乏振幅分散，导致内波速度预测不足。我们发现，著名的A和B波产生的半日内潮，由于强烈的正压流在吕宋海峡的山脊上产生的陡峭。A波的生成是强大的吕宋海峡南部的一部分，因为昼夜内潮梁的半日A波的振幅增加。B波在北方部分产生较强，在那里东西脊之间的距离近似等于一个内潮波长，并导致半日内潮共振。海脊的方位产生了传播到南海西部盆地北方的大A波和传播到南部的较强的B波。当沿沿着线性特征追溯时，A波始终与落潮（东向）正压气流峰值接近，而B波始终与涨潮（向西向）正压气流峰值一致。这加强了背风波机制和相关的水力或非线性效应很弱的概念，正如一个简单的线性模型所证明的那样，该模型将模拟波的振幅与山脊处的偏移参数相关联。
[1] We present the results of three-dimensional, nonhydrostatic simulations of internal tides and waves in the South China Sea (SCS) using the SUNTANS model. Model results accurately predict the observed wave arrival times at two mooring locations in the SCS. Internal wave amplitudes are underpredicted which causes underprediction of internal wave speeds due to a lack of amplitude dispersion. We show that the well-known A and B waves arise from the steepening of semidiurnal internal tides that are generated due to strong barotropic flow over ridges in the Luzon Strait. A wave generation is stronger in the southern portion of the Luzon Strait because diurnal internal tidal beams augment the amplitude of the semidiurnal A waves. B wave generation is stronger in the northern portion where the distance between the eastern and western ridges is approximately equal to one internal tidal wavelength and leads to semidiurnal internal tidal resonance. The orientation of the ridges produces large A waves that propagate into the northern portion of the western SCS basin and stronger B waves that propagate into the southern portion. When traced back in time along linear characteristics, A waves consistently line up close to peak ebb (eastward) barotropic currents, while B waves consistently line up with peak flood (westward) barotropic currents. This reinforces the notion that the lee wave mechanism and associated hydraulic or nonlinear effects are weak, as demonstrated by a simple linear model relating the amplitude of the simulated waves to the excursion parameter at the ridges.