Study on Generation Process of Kyucho

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Kyucho, a coastal stormy current, often has destroyed fishing gear nets along the southeastern coast of the central Japan, facing to the Kuroshio. The purpose of this study is to clarify a generation process of a Kyucho in Sagami Bay as a model sea.On January 9, 1994, a Kyucho rushed along the Sagami Bay coast having the maximum velocity of 0.65ms^<-1> with a steep temperature rise, and the strong current continued for about half a day. NOAA-IR image showed that the warm water intrusion of the Kuroshio water through the Oshima west channel, and the water moving along the Sagami Bay coast cyclonically. The Kyucho occurred during the transition period from the non-large meander nearshore path of the Kuroshio to the non-large meander offshore path. On June 1,1998, the Kyucho rushed through the Oshima east channel with high temperature water and also moved along the Sagami Bay coast cyclonically. The current records at 10m, 35m and 60m depths at the northwest of the bay showed the several-days period fluctuation before the Kyucho and were suddenly amplified on June 1. The sea level fluctuations around Izu Islands and the sea level difference between Kushimoto and Uragami and the other data indicated that the Kyucho occurred during the Kuroshio path transition from non-large meander nearshore path to large meander path.This study proposes that the warm water intrusion is induced by the baroclinic instability of the Kuroshio. So, we are carrying out to clarify the generation mechanism of the Kyucho induced by the transition of the Kuroshio path by the numerical experiment.