Fig.9. Correlation between the position of the Kuroshio axis measured due southward from Cape Shionomisaki (in km) and the sea level difference between Kushimoto and Uragami (in cm). The distance was determined from Prompt Report of the Oceanographic Condition published bimonthly by Hydrographic Department, Maritime Safety Agency of Japan, and the sea level difference averaged for each half month is used. Black circles indicated the data which were taken at the time of the large meander and white circles those taken at the time of the straight path (Fujita, 1997)
The intrusion of the offshore Kuroshio water into the coastal region to the west of the cape (namely, off the Kushimoto tide gauge station) would enhance the sea level difference. However, the short-time leave of the current zone of the Kuroshio from the coast may allow water exchange between the coastal regions to the west and to the east of the cape in some degree. The large scattering of the sea level difference at the time of the straight path suggests that the separation of the coastal waters may be partly destroyed depending on the current structures very near to the cape. It is very understandable that the large sea level difference is not created if the Kuroshio axis is apart far enough from the coast so as that the water exchange of the coastal waters between to the west and to the east of the cape takes place. Uchida et al. (2000) discussed the structure and its variability of the Kii Bifurcation Current with reference to the short period (a few days to several days) variability of the sea level difference between Kushimoto and Uragami, and gave an evidence of water exchange between the coastal waters to the east and to the west of Cape Shionomisaki at the time of the straight path of the Kuroshio.
Acknowledgements. We would like to thank to Mr. Yasuhiro Kaku of Wakayama Research Center of Agriculture, Forestry and Fisheries, Prof. Takashi Koike of Mie University and Dr. Koichi Fujita of Fisheries Research Center of Mie for their kind supports and valuable discussions. We are also thank the officers and crews of the R/V Seisui-maru of Mie University and of the R/V Wakayama of Wakayama Prefectural Fisheries Experimental Station for their help in making the observations.
