TheKyucho in Uwajima Bay

The phenomenon of rapid increase in water temperature accompanied by a sudden, swift current (Kyucho) in Uwajima Bay is described on the basis of results of long term observations from July 1985 to September 1986. This phenomenon occurs somewhat periodically with an interval of about 15 days in summer, although it does not occur in winter. The increase in water temperature occasionally reaches about 5°C. This phenomenon results from the intrusion of a warm water mass into the bay. NOAA-9 satellite images show that the warm water mass originates from the Pacific Ocean south of the Bungo Channel.