Possible source of advected water mass and residence times in the multi-structured Sea of Japan using rare earth elements

The Sea of Japan is a small, fast-acting model of global oceanic circulation. Observations from 1998 and 2001 are analyzed to clarify its circulation. New bottom water formed in early 2001 off Vladivostok was observed later that year near the southeastern edge of the Japan Basin, implying a velocity of 2.3-3.9 cm s^-1. Tb-Yb patterns of rare earth elements distinguish two classes of water volume: inactive old/well-mixed water and active relatively young water, frequently affected by the subduction of the surface water originating from Tsushima Warm Current (TWC). The proportion of TWC to old water and each residence time are: 50-75% and ∼15 years (200-400 m), and 35-80% and ∼38 years (600-1500 m). Using six strata, an improved estimate of the average residence time of Japan Sea Proper Water is >86 years; this includes the contributions from active and inactive strata.