Summary

Large-scale, interannual changes of the Kuroshio Extension are characterized by oscillation between an elongated and a contracted state.

In the elongated state, the Kuroshio Extension has a larger eastward surface transport, a greater zonal penetration, and a more northerly zonal-mean path. These characteristics are connected to the presence of an intenser southern recirculation gyre.

Large-scale, interannual changes of the Kuroshio Extension affect the regional wintertime SST field.

Nonseasonal geostrophic advection of the Kuroshio Extension works to reduce (increase) the wintertime SST anomalies when the Kuroshio Extension changes from the elongated (contracted) state to the contracted (elongated) state.

SST anomalies associated with the large-scale changes of the KE have a peak-to-peak amplitude of > 1.5°C and are independent of the interannual SST changes in the tropical Pacific Ocean.