| The volume transport of the Kuroshio throughflow in the top 1000m layer has been estimated to be 42 Sv (1 Sv = 106 m3/s) in the south of Japan while it is estimated to be 23 Sv in the East China Sea. In order to clarify the source of this large difference of Kuroshio volume transports, the vertical section of current velocity in the southeast of Amami-Ohshima Island in the northern Ryukyu Islands Arc was examined with combined use of the moored current-meter data during four years from December 1998 to October 2002 along the ground track of TOPEX/Poseidon (T/P) satellite and the absolute seasurface geostrophic current data derived from T/P altimeter data and ship-mounted ADCP data. The mean surface absolute geostrophic current is found to be northeastward between 26.8o N and 28.1o N with maximum value of 20 cm/s at 27.5o N. The volume transport in the top 1500m layer between 26.6o N and 28.2o N is estimated to be 20.3 Sv notheastward. This result suggests that about 50% of the Kuroshio volume transport south of Japan is supplied by the northeastward current outside of the East China Sea. In the 400m - 700m depth range over the slope of 2000m water depth in the north of 27.6o N, there is a northward undercurrent velocity maximum with a mean velocity core of 23 cm/s at 27.9o N. |
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