Variability of the Kuroshio in the East China Seain 1993 and 1994

Based on hydrographic data obtained by R/V Chofu Maru during eight cruises of 1993-1994, a modified inverse method is used to compute the velocity, volume and heat transports of the Kuroshio in the East China Sea. The calculated results show that:(1) at Section PN, there are two current cores of the Kuroshio in autumn, one or two cores in other seasons. The main core always lies over the shelf break. Countercurrent always exists east of and in the deep layer under the Kuroshio;(2) at Section TK, the velocity distribution is more complicated, and it may have one, two or three current cores of the Kuroshio. Current cores often appear in the middle and northern parts of the Tokara Strait. There are westward countercurrents in the southern end and deep layer of the strait, and the countercurrent in the southern end of the strait is stronger in autumn;(3) at Section A, the Tsushima Warm Current(hereafter TSWC) core lies in the shelf break area, and its V_max varies between 26-46 cm/s. The Huanghai Warm Current lies to the west of the TSWC, and it is weaker;(4) in 1993 and 1994 the volume transport(hereafter VT) of the Kuroshio is the smallest in spring, but it is the largest or has a larger value in summer. The average net northward VT of the Kuroshio during four seasons each year, for example through Section PN, almost has the same value for 1993 and 1994, but both is smaller than that in 1992. The average net northward VT through Sections PN and TK during the eight cruises is 27.1×10⁶ and 25.0×10⁶m³/s;(5) the average heat transports through Sections PN and TK are 1.99×10¹⁵ and 1.78×10¹⁵W, respectively and(6) at the computation area, heat transfer is from the ocean to the atmosphere in autumn and winter, but the direction reverses in summer, and the direction of heat transfer is uncertain in spring. The average rate of heat transfer is the largest in winter, but smaller in spring and summer.