On the Nonlinearity of the Kuroshio Current South of Japan

The Kuroshio south of Japan exhibits three stable paths: One with a meander centered at 138E, one without the meander following a straight path and a third with a large meander centered at 135E upstream of the Izu ridge. We have computed the bifurcation diagram of a limited area 2 layer quasi-geostrophic model of the Kuroshio south of Japan. The bifurcation diagram represents two of the three stable paths and one unstable path. The nature of the unstable path and the transition from a stable path to an unstable one is investigated by analyzing the leading eigenvectors and eigenvalues.