Impact of the South China Sea throughflow on the pacific low-latitude western boundary current: A numerical study for seasonal and interannual time scales

ABSTRACTThe trajectory of the Kuroshio, the western boundary current in the north Pacific, influences regional climate. It intrudes into the South China Sea (SCS) through the Luzon Strait, resulting in the exchange of water, nutrients, heat, and salt between the Pacific and SCS. It has been reported that the trajectory of the Kuroshio has varied with decadal climate changes. However, there has been no report of an observation-based estimate of the variation in the Luzon Strait transport. Here, a 50-year, high-resolution coral skeletal radiocarbon (Δ14C) dataset from 1946 to 1994 is reported from Currimao, northwest of Luzon Island. Δ14C has been used as a sensitive tracer of seawater, and our data indicates a significant increase in Δ14C from 1946 to 1994 related to atmospheric nuclear bomb testing, with more rapid increase in the SCS than in the Pacific. The unusual, rapid Δ14C increase in the 1950s found in our SCS corals together with seasonal variation in Δ14C will helps constrain physical oceanographic models for the western Pacific, including the SCS.

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Weakest winter South China Sea western boundary current caused by the 2015-2016 El Niño event

Journal of Geophysical Research Oceans ◽

10.1002/2016jc012252 ◽

2016 ◽

Vol 121 (10) ◽

pp. 7673-7682 ◽

Cited By ~ 13

Author(s):

Ruixiang Zhao ◽

Xiao-Hua Zhu

Keyword(s):

South China Sea ◽

South China ◽

El Niño ◽

El Nino ◽

Western Boundary Current ◽

Western Boundary ◽

Boundary Current ◽

China Sea ◽

El Niño Event

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The Eddy–Mean Flow Interaction and the Intrusion of Western Boundary Current into the South China Sea–Type Basin in an Idealized Model

Journal of Physical Oceanography ◽

10.1175/jpo-d-15-0220.1 ◽

2016 ◽

Vol 46 (8) ◽

pp. 2493-2527 ◽

Cited By ~ 4

Author(s):

Linhao Zhong ◽

Lijuan Hua ◽

Dehai Luo

Keyword(s):

South China Sea ◽

South China ◽

Relative Vorticity ◽

Western Boundary Current ◽

The South China Sea ◽

Western Boundary ◽

Loop Current ◽

Subgrid Scale ◽

Boundary Current ◽

China Sea

AbstractIn this paper, an ideal model of the role of mesoscale eddies in the Kuroshio intruding into the South China Sea (SCS) is developed, which represents the northwestern Pacific and the SCS as two rectangular basins connected by a gap. In the case of considering only intrinsic ocean variability, a time-dependent western boundary current (WBC) driven by steady wind is modeled under both eddy-resolving and noneddy-resolving resolutions. Almost all simulated WBCs intrude into the adjacent sea in the form of the Loop Current with multiple-state transitions and eddy-shedding processes, which have aperiodic variations on intraseasonal or interannual scales, determined by the eddy-induced WBC variation. For the parameters considered in this paper, the WBC intrusion exhibits a 30–90-day cycle in the presence of the subgrid-scale eddy forcing (SSEF) but a 300–500-day cycle in the absence of SSEF. Moreover, the roles of the grid-scale and subgrid-scale eddies in the WBC intrusion are studied by using the dynamically consistent decomposition developed by Berloff. Based on the large-sample composite analysis of the intrusion events, it is found that the Loop Current intensity is mainly determined by baroclinic processes through grid-scale, eddy–eddy interaction and subgrid-scale, eddy–flow interaction. The intrusion position and period are mainly regulated by the SSEF to the west of gap, where the balance between relative vorticity and isopycnal thickness SSEFs determines eddy detachment. Generally, the relative vorticity SSEF therein tends to induce WBC intrusion. However, the isopycnal thickness SSEF tends to induce eddy shedding, and WBC retreat thus determines the intrusion cycle through counteracting relative vorticity SSEF.

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