17:15 〜 18:45
[ACG44-P01] Effects of eddy kinetic energy over the Kuroshio large meander region on the Kuroshio extension bimodality
キーワード：Ocean, Kuroshio, Kuroshio extension, Eddy
The eddy kinetic energy (EKE) in the Kuroshio Extension (KE) region may be affected by EKE in the Kuroshio large meander (KLM) region and the North Pacific Gyre Oscillation (NPGO). Previous studies reported that the Kuroshio path variations south of Japan may affect the low-frequency variability of the KE jet and related EKE, but the linear correlation between these phenomena derived from long time series is low and not significant. This may be because their relationship is nonlinear. As such, we investigate the causal effects of the KLM EKE and NPGO on the KE EKE using the nonlinear convergent cross mapping approach based on satellite sea surface height observations. The analysis shows that the KLM EKE only affects the EKE only in the KE upstream area (west of 146°E), with no significant effect on the EKE in the downstream area. Instead, the NPGO plays a remarkable role on the EKE in both areas. The effect of the KLM EKE on the KE EKE depends on the Kuroshio latitudinal position over the Izu Ridge. The KLM EKE can affect the downstream advection of eddies and induce changes in the Kuroshio position over the ridge, causing different EKE levels in the KE upstream region. The NPGO affects the KE EKE through the westward propagation of sea surface height anomalies remotely forced by wind stress anomalies associated with the North Pacific Oscillation.