Role of the South China Sea in Regulating the North Pacific Double-Gyre System

TitleRole of the South China Sea in Regulating the North Pacific Double-Gyre System
Publication TypeJournal Article
Year of Publication2017
AuthorsYang H.Y, Wu L.X, Sun S.T, Chen Z.H
JournalJournal of Physical Oceanography
Date Published2017/07
Type of ArticleArticle
ISBN Number0022-3670
Accession NumberWOS:000405111400007
Keywordscurrents; eddy; gap; inertial recirculation; kuroshio; low-frequency variability; model; Ocean circulation; oceanography; western boundary current; wind-driven

The role of the South China Sea (SCS) in regulating the North Pacific circulation is investigated using a two-layer quasigeostrophic (QG) model. The double-gyre circulations in the North Pacific with and without the SCS are compared and analyzed. It is found that the SCS acts as a sink of both potential vorticity (PV) and energy in the Pacific-SCS system for the mean state. Consequently, the Kuroshio and the upstream Kuroshio Extension (KE) are weaker in the presence of the SCS. Moreover, the eddy activity is also lower in the North Pacific Ocean because the barotropic instability is suppressed for a weaker circulation. In terms of low-frequency variations at interannual to decadal time scale, the presence of the SCS is found to enhance the variability of the latitudinal position and intensity of the KE jet. This is explained by a positive feedback process that is associated with the negative correlation between the inertia of the Kuroshio and its intrusion into the SCS.

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