Variability of internal tides and near-inertial waves on the continental slope of the northwestern South China Sea

2013 ◽  
Vol 118 (1) ◽  
pp. 197-211 ◽  
Author(s):  
Zhenhua Xu ◽  
Baoshu Yin ◽  
Yijun Hou ◽  
Yongsheng Xu
Keyword(s):  
South China Sea ◽  
Continental Slope ◽  
South China ◽  
Internal Tides ◽  
Inertial Waves ◽  
China Sea

scholarly journals Influence of Remote Internal Tides on the Locally Generated Internal Tides upon the Continental Slope in the South China Sea

2021 ◽  
Vol 9 (11) ◽  
pp. 1268
Author(s):  
Zheng Guo ◽  
Anzhou Cao ◽  
Shuya Wang
Keyword(s):  
South China Sea ◽  
Continental Slope ◽  
South China ◽  
Maximum Energy ◽  
The South China Sea ◽  
Internal Tides ◽  
The South ◽  
China Sea ◽  
The Taiwan Strait ◽  
Local Generation

In this paper, the M2 internal tides (ITs) originating from the continental slope in the South China Sea are studied using the CROCO model. The simulation results show that there are two origins of ITs on the continental slope: at 118°–119.5° E along 22° N near the southern entrance of the Taiwan Strait and at 117°–118° E along 20° N near Dongsha Island. The local generation of ITs is greatly influenced by the ITs that radiate from the Luzon Strait (LS). The integrated conversion at the first generation site is increased by 31% to 0.42 GW compared to the case where the LS is excluded from the simulation region. Its maximum energy flux almost doubles to 2.5 kW/m, which is 10% of the westward component. The existence of the other IT beams from Dongsha Island is attributed to the ITs from the LS. The local generation on the continental slope changes when remotely generated ITs alter the amplitudes and phases of the bottom pressure perturbation. These results indicate that the ITs originating from the LS contribute to the spatial variation of ITs in the SCS by modulating the IT generation on the continental slope.

Disintegration of the K1 internal tide in the South China Sea due to parametric subharmonic instability

2021 ◽  
Author(s):  
Kun Liu ◽  
Zhongxiang Zhao
Keyword(s):  
South China Sea ◽  
South China ◽  
Internal Tide ◽  
The South China Sea ◽  
Internal Tides ◽  
Upper Ocean ◽  
The South ◽  
China Sea ◽  
Parametric Subharmonic Instability ◽  
Critical Latitude

<p>The disintegration of the equatorward-propagating K<sub>1</sub> internal tide in the South China Sea (SCS) by parametric subharmonic instability (PSI) at its critical latitude of 14.52ºN is investigated numerically. The multiple-source generation and long-range propagation of K<sub>1</sub> internal tides are successfully reproduced. Using equilibrium analysis, the internal wave field near the critical latitude is found to experience two quasi-steady states, between which the subharmonic waves develop constantly. The simulated subharmonic waves agree well with classic PSI theoretical prediction. The PSI-induced near-inertial waves are of half the K<sub>1</sub> frequency and dominantly high modes, the vertical scales ranging from 50 to 180 m in the upper ocean. From an energy perspective, PSI mainly occurs in the critical latitudinal zone from 13–15ºN. In this zone, the incident internal tide loses ~14% energy in the mature state of PSI. PSI triggers a mixing elevation of O(10<sup>-5</sup>–10<sup>-4</sup> m<sup>2</sup>/s) in the upper ocean at the critical latitude, which is several times larger than the background value. The contribution of PSI to the internal tide energy loss and associated enhanced mixing may differ regionally and is closely dependent on the intensity and duration of background internal tide. The results elucidate the far-field dissipation mechanism by PSI in connecting interior mixing with remotely generated K<sub>1</sub> internal tides in the Luzon Strait.</p>

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