Volume transport analysis of the numerical simulation for the North Equatorial Current and Kuroshio Current System

Abstract

Relationships between the variations of volume transport in the North Equatorial Current, the Kuroshio and the Tsushima Current were analysed based on the high-resolution ocean general circulation model (RIAMOM) experiments. Model domain covers the area from 95°E to 70°W and 50°S to 65°N with the horizontal resolution of 1/6 degree and 70 levels in vertical. NCEP heat flux and monthly mean wind stress were adopted as surface forcing conditions. Model was integrated for 25 years. In the model simulation the volume transport of the NEC at the meridional section in the east of Philippine shows double local maxima(~76 Sv, including deep counter-currents and meso-scale eddies) in January and April, and a minimum(~44 Sv) in October with decreasing pattern in May to October and increasing pattern in November to next April. In the northeast section off Taiwan the Kuroshio transport shows an increasing pattern in March to May, while in the downstream section of the East China Sea continental shelf it increases during April to June, suggesting the northward propagation of increasing phase in transport. It seems that the volume transport of the Tsushima Current in the Korea Strait is contributed mainly by the Taiwan Current in spring and summer, and by the Kuroshio branched current in fall.