The Kuroshio large meander formation in 2004 analyzed by an eddy‐resolving ocean forecast system

Abstract

The recent formation of the Kuroshio large meander southeast of the Kii Peninsula during the period from May to July 2004 has been simulated successfully in an eddy‐resolving ocean forecast system (Japanese Coastal Ocean Predictability Experiment). The formation process was examined from the viewpoint of eddy‐Kuroshio interactions using sensitivity experiments that had various initial conditions for eddies in March and May 2004. We confirmed that the large meander does not occur when the trigger meander southeast of the Kyushu Island has small amplitude and that the cyclonic eddy on the offshore side of the Kuroshio contributes to the large meander formation. Our results show that the large amplitude of the trigger meander southeast of Kyushu Island in April 2004 was caused by downstream advection of anticyclonic eddies along the Kuroshio in the East China Sea from east of Taiwan. The results suggest that the successive westward propagation of strong anticyclonic eddies in the subtropical frontal region from 2003 to 2004 was the origin of the formation of the Kuroshio large meander south of Japan in summer 2004.