scholarly journals Observed Internal Tides and Near‐Inertial Waves in the Northern South China Sea: Intensified f ‐Band Energy Induced by Parametric Subharmonic Instability

2020 ◽  
Vol 125 (10) ◽  
Author(s):  
Junqiang Shen ◽  
Wendong Fang ◽  
Shanwu Zhang ◽  
Yun Qiu ◽  
Junpeng Zhang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Internal Tides ◽  
Inertial Waves ◽  
Band Energy ◽  
China Sea ◽  
Parametric Subharmonic Instability

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>

Observed Near Inertial Waves in the Wake of Typhoon Linfa (2015) in the Northern South China Sea

2019 ◽  
Vol 18 (5) ◽  
pp. 1013-1021
Author(s):  
Guanlin Wang ◽  
Dawei Li ◽  
Zexun Wei ◽  
Shujiang Li ◽  
Yonggang Wang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Inertial Waves ◽  
China Sea

Features of internal tides observed near the shelf break in the northern South China Sea

2019 ◽  
Vol 69 (3) ◽  
pp. 353-365 ◽  
Author(s):  
Shengli Chen ◽  
Daoyi Chen ◽  
Jiuxing Xing ◽  
Jianyu Hu ◽  
Zhenyu Sun
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Shelf Break ◽  
Internal Tides ◽  
China Sea

Polarity Variations of Internal Solitary Waves over the Continental Shelf of the Northern South China Sea: Impacts of Seasonal Stratification, Mesoscale Eddies, and Internal Tides

2018 ◽  
Vol 48 (6) ◽  
pp. 1349-1365 ◽  
Author(s):  
Xiaojiang Zhang ◽  
Xiaodong Huang ◽  
Zhiwei Zhang ◽  
Chun Zhou ◽  
Jiwei Tian ◽  
...  
Keyword(s):  
South China Sea ◽  
Continental Shelf ◽  
South China ◽  
Northern South China Sea ◽  
Internal Tides ◽  
Thermocline Depth ◽  
China Sea ◽  
Seasonal Stratification ◽  
Anticyclonic Eddies ◽  
The Impact

AbstractSpatiotemporal variations in internal solitary wave (ISW) polarity over the continental shelf of the northern South China Sea (SCS) were examined based on mooring-array observations from October 2013 to June 2014. Depression ISWs were observed at the easternmost mooring, where the water depth is 323 m. Then, they evolved into elevation ISWs at the westernmost mooring, with a depth of 149 m. At the central mooring, with a depth of 250 m, the ISWs generally appeared as depression waves in autumn and spring but were elevation waves in winter. Seasonal variations in stratification caused this seasonality in polarity. On the intraseasonal time scales, anticyclonic eddies can modulate ISW polarity at the central mooring by deepening the thermocline depth for periods of approximately 8 days. During some days in autumn and spring, depression ISWs and ISWs in the process of changing polarity from depression to elevation appeared at time intervals of 10–12 h because of the thermocline deepening caused by internal tides. Isotherm anomalies associated with eddies and internal tides have a more significant contribution to determining the polarity of ISWs than do the background currents. The observational results reported here highlight the impact of multiscale processes on the evolution of ISWs.

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