A general circulation model study of the dynamics of the upper ocean circulation of the South China Sea

2002 ◽  
Vol 107 (C7) ◽  
Author(s):  
Haijun Yang
Keyword(s):  
South China Sea ◽  
General Circulation Model ◽  
Ocean Circulation ◽  
South China ◽  
General Circulation ◽  
Circulation Model ◽  
The South China Sea ◽  
Upper Ocean ◽  
China Sea ◽  
Model Study

scholarly journals The South China Sea Throughflow Retrieved from Climatological Data*

2009 ◽  
Vol 39 (3) ◽  
pp. 753-767 ◽  
Author(s):  
Max Yaremchuk ◽  
Julian McCreary ◽  
Zuojun Yu ◽  
Ryo Furue
Keyword(s):  
South China Sea ◽  
General Circulation Model ◽  
South China ◽  
General Circulation ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Luzon Strait ◽  
The South China Sea ◽  
China Sea ◽  
Ocean General Circulation

Abstract The salinity distribution in the South China Sea (SCS) has a pronounced subsurface maximum from 150–220 m throughout the year. This feature can only be maintained by the existence of a mean flow through the SCS, consisting of a net inflow of salty North Pacific tropical water through the Luzon Strait and outflow through the Mindoro, Karimata, and Taiwan Straits. Using an inverse modeling approach, the authors show that the magnitude and space–time variations of the SCS thermohaline structure, particularly for the salinity maximum, allow a quantitative estimate of the SCS throughflow and its distribution among the three outflow straits. Results from the inversion are compared with available observations and output from a 50-yr simulation of a highly resolved ocean general circulation model. The annual-mean Luzon Strait transport is found to be 2.4 ± 0.6 Sv (Sv ≡ 106 m3 s−1). This inflow is balanced by the outflows from the Karimata (0.3 ± 0.5 Sv), Mindoro (1.5 ± 0.4), and Taiwan (0.6 ± 0.5 Sv) Straits. Results of the inversion suggest that the Karimata transport tends to be overestimated in numerical models. The Mindoro Strait provides the only passage from the SCS deeper than 100 m, and half of the SCS throughflow (1.2 ± 0.3 Sv) exits the basin below 100 m in the Mindoro Strait, a result that is consistent with a climatological run of a 0.1° global ocean general circulation model.

scholarly journals A Three-Layer Alternating Spinning Circulation in the South China Sea

2016 ◽  
Vol 46 (8) ◽  
pp. 2309-2315 ◽  
Author(s):  
Jianping Gan ◽  
Zhiqiang Liu ◽  
Chiwing Rex Hui
Keyword(s):  
South China Sea ◽  
Ocean Circulation ◽  
South China ◽  
Three Dimensional ◽  
Circulation Model ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Vorticity Flux ◽  
Intrinsic Dynamic

AbstractUnderstanding of the three-dimensional circulation in the South China Sea (SCS) is crucial for determining the transports of water masses, energy, and biogeochemical substances in the regional and adjacent larger oceans. The circulation’s kinematic and dynamic natures, however, are largely unclear. Results from a three-dimensional numerical ocean circulation model and geostrophic currents, derived from hydrographic data, reveal the existence of a unique, three-layer, cyclonic–anticyclonic–cyclonic (CAC) circulation in the upper (<750 m), middle (750–1500 m), and deep (>1500 m) layers in the SCS with differing seasonality. An inflow–outflow–inflow structure in Luzon Strait largely induces the CAC circulation, which leads to vortex stretching in the SCS basin because of a lateral planetary vorticity flux in each of the respective layers. The formation of joint effects of baroclinicity and relief (JEBAR) is an intrinsic dynamic response to the CAC circulation. The JEBAR arises from the CAC flow–topography interaction in the SCS.

scholarly journals Low-Frequency Variability of Monsoon-Driven Circulation with Application to the South China Sea

2015 ◽  
Vol 45 (6) ◽  
pp. 1632-1650 ◽  
Author(s):  
Haiyuan Yang ◽  
Lixin Wu ◽  
Sun Shantong ◽  
Chen Zhaohui
Keyword(s):  
South China Sea ◽  
Ocean Circulation ◽  
South China ◽  
Low Frequency ◽  
The South China Sea ◽  
Upper Ocean ◽  
China Sea ◽  
Low Frequency Variability ◽  
Gyre System ◽  
Double Gyre

AbstractThe interannual variability of the upper-ocean circulation forced by seasonally varying monsoonal wind is investigated in a two-layer quasigeostrophic (QG) model, with the aim to understand the low-frequency variability of the South China Sea (SCS) circulation. It is demonstrated that the seasonally varying monsoonal wind can force the upper-ocean circulation with significant internal variability, which is mainly associated with the intrinsic nonlinear dynamics of the summer double-gyre system. This arises from the fact that the intrinsic variability, characterized by the Rossby wave adjustment in the winter single-gyre system, is much weaker than that in the summer double-gyre system driven by the intergyre eddy potential vorticity flux through barotropic 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

&lt;p&gt;The disintegration of the equatorward-propagating K&lt;sub&gt;1&lt;/sub&gt; internal tide in the South China Sea (SCS) by parametric subharmonic instability (PSI) at its critical latitude of 14.52&amp;#186;N is investigated numerically. The multiple-source generation and long-range propagation of K&lt;sub&gt;1&lt;/sub&gt; 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&lt;sub&gt;1&lt;/sub&gt; 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&amp;#8211;15&amp;#186;N. In this zone, the incident internal tide loses ~14% energy in the mature state of PSI. PSI triggers a mixing elevation of O(10&lt;sup&gt;-5&lt;/sup&gt;&amp;#8211;10&lt;sup&gt;-4&lt;/sup&gt; m&lt;sup&gt;2&lt;/sup&gt;/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&lt;sub&gt;1&lt;/sub&gt; internal tides in the Luzon Strait.&lt;/p&gt;

scholarly journals The impact of the planetary β-effect on the tilting vertical structure of a mesoscale eddy

2018 ◽  
Author(s):  
Shengmu Yang ◽  
Jiuxing Xing ◽  
Shengli Chen ◽  
Jiwei Tian ◽  
Daoyi Chen
Keyword(s):  
South China Sea ◽  
South China ◽  
General Circulation ◽  
Vertical Structure ◽  
Mesoscale Eddy ◽  
Maximum Velocity ◽  
Circulation Model ◽  
Mesoscale Eddies ◽  
China Sea ◽  
The Impact

Abstract. Tilting mesoscale eddies in the South China Sea have been reported recently from observed field data. The mechanism of the dynamic process of the tilt, however, is not well understood. In this study, the influence of planetary β on the vertical structure of mesoscale eddies and its mechanism is investigated using theoretical analysis and numerical model experiments based on the MIT General Circulation Model (MITgcm). The results of the both approaches show that vertical motion due to the planetary β effect and nonlinear dynamics causes a pressure anomaly in the horizontal domain which triggers the tilt of the eddy axis. The tilting distance extends to be the radius of the eddy maximum velocity. In addition, the vertical stratification is another key factor in controlling the tilt of a mesoscale eddy. External forcings such as wind and inflow current are not considered in this study, and topography is included only in a realistic South China Sea model. Therefore, mesoscale eddies with large vertical depth should have the similar axis tilt character in open oceans under the β-effect.

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