| A salient features of the Kuroshio found by recent currents measurements east of Okinawa and Amami Island is a north-eastward current with a subsurface maximum at about 500 m depth and the volume transport of about 20 Sv which explains the missing link of the Kuroshio net transport between the Kuroshio south of Japan(about 40 Sv) and that in the East China Sea(about 20 Sv).The time mean structures of the Kuroshio reproduced by a 3-D Pacific Ocean model with 1/6 degree horizontal resolution driven by NCEP reanalysis data show good agreements with the observed features. The model results reveal that the Kuroshio east of Taiwan bifurcates into two branches. One (upper portion of the Kuroshio shallower than about 600 m) enters into the East China Sea through the strait east of Taiwan and flows north-eastward along the continental shelf break with a volume transport of about 25 Sv. The other branch (lower portion of the Kuroshio deeper than about 600 m), which cannot enter the East China Sea due to the shallowness of the strait east of Taiwan, flow northeastward along the Pacific side of the Ryukyu Islands with a subsurface maximum of velocity at about 600m depth. The subsurface maximum disappears by meeting of two branches at the Tokara Strait. The volume transport of the Kuroshio east of Ryukyu Islands increases gradually from 20 Sv at the beginning to 25 Sv near the Tokara Strait. The weak westward flow in the interior of the Pacific Ocean feeds partly the Kuroshio along the Ryukyu Islands. |
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