Kuroshio water intrusion into the subarctic region in the western North Pacific Ocean and analyses of the Lagrangian coherent structure

Abstract Previous studies have suggested that the quasi-stationary jets, sometimes called “Isoguchi jets” in western North Pacific Ocean, regulate warm and salty conditions transition domain between Subarctic Boundary Front. Here, we show mesoscale eddies interannual/decadal modulations are responsible for Kuroshio water intrusion into domain. A case study using Lagrangian coherent structure suggests northward shift of Extension forms a favorable velocity field around Boundary, while geometric inside Isoguchi jet is quasi-permanent.