Japan Geoscience Union Meeting 2023

Presentation information

[J] Online Poster

A (Atmospheric and Hydrospheric Sciences ) » A-CG Complex & General

[A-CG43] Kuroshio Large Meander

Mon. May 22, 2023 10:45 AM - 12:15 PM Online Poster Zoom Room (5) (Online Poster)

convener:Hatsumi Nishikawa(Atmosphere and Ocean Research Institute, University of Tokyo), Hidetaka Hirata(Rissho University), Toru Miyama(Japan Agency for Marine-Earth Science and Technology, Application Laboratory), KUSAKA AKIRA(National Research and Development Agency, Japan Fisheries Research and Education Agency. Fisheries Resources Institute)


On-site poster schedule(2023/5/21 17:15-18:45)

10:45 AM - 12:15 PM

[ACG43-P01] Sea level variability along the Japanese coast forced by the Kuroshio and its extension

★Invited Papers

*Norihisa Usui1, Koji Ogawa2 (1.Meteorological Research Institute, 2.Oita Meteorological Office)

Keywords:sea level, Kuroshio Extension, Kuroshio large meander

Sea level variability along the Japanese coast and its relation to the Kuroshio-Kuroshio Extension (KE) are investigated using ocean reanalysis data. The first mode of an empirical-orthogonal-function for the coastal sea-level represents a simultaneous sea-level change along the whole Japanese coast, which is synchronized with sea levels in the KE region , the Japan Sea and the East China Sea. The second mode is characterized by an east–west dipole pattern at the south coast. The first mode is correlated with the Kuroshio variations around the Izu–Ogasawara Ridge (IOR) and tends to be in a positive phase when the Kuroshio takes a nearshore path around IOR. The Kuroshio’s position around IOR is closely related to the KE dynamic state. When the KE jet is in a stable (unstable) state, a nearshore (meandering) Kuroshio path is formed around IOR. A composite analysis suggests that the sea level along the Japanese coast becomes high due to propagation of coastal trapped waves when the Kuroshio takes a nearshore path around IOR. That is why the first mode is synchronized with the KE decadal variability. The second mode has a close relation with the Kuroshio Large Meander (LM). The eastern positive anomaly at the coast between the Izu and Kii Peninsulas is formed by warm Kuroshio water brought by a westward branch flow along the coast. The western negative anomaly is attributed to a southward shift in the Kuroshio south of the Kii Peninsula associated with the LM.