Interannual and decadal variations of the Kuroshio axis in the East China Sea

Abstract

Much work has been focused on the variability and climatic effect of the Kuroshio Extension, but little focus on the Kuroshio variation in the East China Sea(ECS). This study, investigates the interannual and decadal migrations of Kuroshio axis(KA) in the ECS and its relationships to large-scale climate signals. On interannual timescale, variability of the KA in the ECS is closely related to El Niño-Southern Oscillation (ENSO) cycle. The shifting of the main axis in ECS presents a dipolar pattern with the offshore (onshore) shift of the south (north) part KA in ECS under the El Niño events and onshore (offshore) shift under the La Niña events. The interannual variation (IVAR) is modulated dominantly by wind stress curl (WSC) and surface relative vorticity advection associated with the ENSO. On the decadal timescale, the Pacific Decadal Oscillation (PDO) and North Pacific Gyre Oscillation (NPGO) could cause the WSC and relative vorticity (RV) anomalies, and in turn modulates the fluctuation of KA. The PDO is the main factor and the NPGO is secondary factor for the decadal variation (DVAR) of the KA in ECS.