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Deep intense vertical mixing in the Bussol' Strait
Author(s) -
Yagi Masahiro,
Yasuda Ichiro
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl050349
Subject(s) - geology , amplitude , turbulence , mixing (physics) , thermohaline circulation , atmospheric sciences , vertical mixing , eddy diffusion , current (fluid) , internal tide , oceanography , internal wave , climatology , meteorology , physics , quantum mechanics
To reveal the intensity of deep mixing in the Bussol' Strait, we performed the direct observations of turbulence for the first time. Vigorous vertical mixing with a turbulent energy dissipation rate ε above 10 −6 W/kg and diapycnal diffusivity K ρ above 10 3 cm 2 /s were observed at depths of 600–1300 m (potential densities of 27.0–27.5 σ θ ) at the western gap of the Bussol' Strait, possibly affecting water‐mass transformation and thermohaline circulation. The strong vertical mixing with a diurnal period occurred when the diurnal tidal current flowed toward the Okhotsk Sea, corresponding to a period of enhanced shear consisting of the mean flow with a two‐layered structure and the large‐amplitude diurnal tidal current with a vertical structure explained by a low‐vertical mode topographically trapped wave. The empirical relationship of ε = 10 −1.46±1.91 × S 2.16±0.72 is obtained between ε and the shear S reconstructed from the 50‐m‐scale mean, diurnal, and semi‐diurnal tidal currents.