The Generation of Nonlinear Internal Waves in the South China Sea: A Three-Dimensional, Nonhydrostatic Numerical Study
The Generation of Nonlinear Internal Waves in the South China Sea: A Three-Dimensional, Nonhydrostatic Numerical Study
复制标题
南海非线性内波的产生：三维非静水数值研究
DOI：
10.1029/2019jc015283
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发表时间：
2019
影响因子：
3.6
通讯作者：
Xiong Xuejun
中科院分区：
文献类型：
--
作者：
Lai Zhigang;Jin Guangzhen;Huang Yongmao;Chen Haiyun;Shang Xiaodong;Xiong Xuejun
孤立地形上分层潮流产生的非线性内波是多年来的研究课题。然而，作为两个地形特征的流动的结果的动力学的增强的复杂性已经较少的研究和理解。在这里，我们报告的结果产生的类型-A和类型-B NLIW在中国南海，起源于一个双脊系统。基于真实三维非静力模拟，发现A类NLIW是通过内潮释放机制在西部洋脊生成的，而B类NLIW是由于内波相互作用在东部洋脊生成的。与脊的高度，分离距离，调制潮汐强迫，B型NLIW的产生强烈修改的两个脊之间的共振过程。因此，A型和B型NLIW出现在具有交替的大振幅和小振幅的观测中。此外，通过对这些波的产生时间的详细了解，还发现这些波的不同到达时间可能是由于它们的产生时间不同。最后，B型NLIW在亚临界西脊的反射/透射被认为是共振的一个关键特征。然而，它是由水力控制的流量，而不是当地地形坡度的内部波束角的比率。
The generation of nonlinear internal waves (NLIWs) by stratified tidal flow over an isolated topography has been a subject of research for many years. However, the enhanced complexity of the dynamics as a consequence of flow over two topographical features has been less studied and understood. Here, we report results of the generation of type‐A and type‐B NLIWs in the South China Sea that originate from a double‐ridge system. Based on a realistic three‐dimensional nonhydrostatic simulation, it is found that type‐A NLIWs are generated at the western ridge through the mechanism of internal tide release, while the generation of type‐B NLIWs occurs at the eastern ridge as a consequence of internal wave interaction. Associated with the ridge height, separation distance, and modulated tidal forcing, the generation of type‐B NLIWs is strongly modified by the resonant process between the two ridges. As a result, type‐A and type‐B NLIWs appear in the observations with alternating large and small amplitudes. In addition, with a detailed knowledge of the generation, it is also found that the different arrival time of these waves could be due to their different generation times. Finally, the reflection/transmission of type‐B NLIWs at the subcritical western ridge is suggested as a key feature of resonance. However, it is governed by hydraulically controlled flow instead of the ratio of the local topographic slope to the internal wave beam angle.