Journal of Oceanography, Vol. 54, pp. 217 to 226. 1998 217 Copyright  The Oceanographic Society of Japan. Keywords: ⋅ Kuroshio east of Taiwan, ⋅ three branches, ⋅ Ryukyu Current, ⋅ recirculating gyre, ⋅ modified inverse method, ⋅ velocity measure- ment. The Kuroshio East of Taiwan and in the East China Sea and the Currents East of Ryukyu Islands during Early Summer of 1996 YAOCHU YUAN 1 , ARATA KANEKO 2 , JILAN SU 1 , XIAOHUA ZHU 2 , YONGGANG LIU 1 , NORIAKI GOHDA 2 and HONG CHEN 1 1 Second Institute of Oceanography, SOA, Hangzhou 310012, China 2 Department of Environmental Sciences, Faculty of Engineering, Hiroshima University, Higashi-Hiroshima 739, Japan (Received 25 July 1997; in revised form 19 January 1998; accepted 20 January 1998) Using hydrographic data and moored current meter records and the ADCP observed current data during May–June 1996, a modified inverse method is applied to calculate the Kuroshio east of Taiwan and in the East China Sea and the currents east of Ryukyu Islands. There are three branches of the Kuroshio east of Taiwan. The Kuroshio in the East China Sea comes from the main (first) and second branches of the Kuroshio east of Taiwan. The easternmost (third) branch of the Kuroshio flows northeastward to the region east of Ryukyu Islands. The net northward volume transports of the Kuroshio through Section K 2 southeast of Taiwan and Section PN in the East China Sea are 44.4 × 10 6 and 27.2 × 10 6 m 3 s –1 , respectively. The western boundary current east of Ryukyu Islands comes from the easternmost branch of the Kuroshio east of Taiwan and an anticyclonic recirculating gyre more east, making volume transports of 10 to 15 × 10 6 m 3 s –1 . At about 21°N, 127°E southeast of Taiwan, there is a cold eddy which causes branching of the Kuroshio there. 1. Introduction The region east of Taiwan is very important for un- derstanding the Kuroshio, the Kuroshio Countercurrent and other subgyres in Western North Pacific because all western ends of the subgyres merge together there, as pointed out by Hasunuma and Yoshida (1978). There have been some studies on the Kuroshio east of Taiwan (Chu, 1974; Guan, 1978, 1985; Liu et al., 1986; Yuan ia, 1988; Yuan et al., 1996, 1998) and the currents east of Ryukyu Islands (Nitani, 1972; Yuan et al., 1990, 1991, 1994, 1995). There are some im- portant current characteristics of the Kuroshio east of Tai- wan. For example, (1) Chu (1974) pointed out fluctuations of the Kuroshio Current axis and pattern, and changes of its maximum velocity east of Taiwan on the basis of CSK data obtained during several cruises; (2) part of the Kuroshio made a cyclonic meander on the eastern side of a cold eddy northeast of Lanyu Island during the winter season (Guan, 1985; Yuan and Xia, 1988); (3) Guan (1978) reported the anticyclonic deflection of the Kuroshio across a submarine ridge adjacent to the northern coast of Taiwan; (4) based on a dynamic calculation, Liu et al . (1986) pointed out that there is evidence of the band structure southeast of Taiwan; (5) Yuan et al. (1996, 1998) showed that there are multi-core structures of the Kuroshio current and several branches of the Kuroshio east of Taiwan. Furthermore, Yuan et al. (1998) pointed out that there is an easternmost branch of the Kuroshio east of Taiwan, flowing northeastward to the east of Ryukyu Islands and becoming part of the western boundary current east of Ryukyu Islands during October 1995. However, no branch of the Kuroshio flowed into the region east of Ryukyu Islands during early summer of 1985 (Yuan et al., 1996). Yuan et al. (1996, 1998) further pointed out that the above Kuroshio current patterns are closely related to the strengths and positions of cyclonic and anticyclonic gyres in the adjacent region. In this paper, using hydrographic data, moored current meter records and towed-ADCP current data obtained during the early summer of 1996, a modified inverse method is applied to calculate the Kuroshio east of Taiwan and in the East China Sea and the currents east of Ryukyu Islands (Ryukyu Current). The current features of the Kuroshio east of Taiwan and in the East China Sea and the problem of the origin of the western boundary current east of Ryukyu Islands are also discussed. Furthermore, we make a com- parison between results obtained during the present and the previous cruises.