How Eddies Gain, Retain, and Release Water: A Case Study of a Hokkaido Anticyclone

Abstract

AbstractA Lagrangian methodology is elaborated to identify the origin of water masses in the Kuroshio‐Oyashio frontal zone where waters of the Kuroshio Extension and Oyashio Current and of the Japan and Okhotsk Seas converge. It allows one to track the evolution of mesoscale eddies during the satellite‐altimetry era and to document how they gain, retain, and release water masses of different origin. The methodology is applied to study warm‐core mesoscale anticyclones propagating along the Japan and Kuril Trenches near the eastern coast of Hokkaido Island that have been observed from 1 January 1993 to 10 December 2016 in an altimetry‐based velocity field. The Hokkaido eddy, sampled by profiling floats and a few cruises in 2003 and 2004, is analyzed in detail in order to compare Lagrangian simulation results to observations.