Dynamics Of Eddy-induced Kuroshio Variability In The Luzon Strait

The dynamics of eddy-induced Kuroshio variability in the Luzon Strait are studied using a reduced-gravity quasi-geostrophic model. The model experiments suggest that when the Kuroshio is close to the critical states of hysteresis, both cyclonic and anti-cyclonic mesoscale eddies can induce transition of the Kuroshio path from an anti-cyclonic intrusion to a gap-leaping state in the Luzon Strait, whereas only cyclonic eddies can force the Kuroshio from the leaping path to an penetrating path. The experiments also show that the transition is sensitive to the strength, radius and initial position of the eddy. The dynamics of the path transition is related to the hysteresis of the Kuroshio in the Luzon Strait, whereby multiple steady states exist in the nonlinear system so that the path of the Kuroshio cannot return to its initial state after the external force is removed. When the Kuroshio is far away from the critical states of hysteresis, its path is not sensitive to eddy perturbation. In this case, the Kuroshio blocks the westward propagation of mesoscale eddies in the Luzon Strait and pushes the eddies to migrate northward along the eastern side of the Luzon Strait.