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Thickness diffusivity in the Southern Ocean
Author(s) -
Eden Carsten
Publication year - 2006
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 - 10.1029/2006gl026157
Subject(s) - isopycnal , eddy diffusion , advection , geology , front (military) , thermal diffusivity , anisotropy , climatology , geophysics , atmospheric sciences , meteorology , oceanography , turbulence , physics , thermodynamics , quantum mechanics
Thickness diffusivity (κ) according to the Gent and McWilliams parameterisation which accounts for eddy‐driven advection in the ocean, is estimated using output from an eddy‐resolving model of the Southern Ocean. A physically meaningful definition of rotational eddy fluxes leads almost everywhere to positive κ. Zonally averaged near surface values of κ remain smaller than 200 m 2 /s poleward of the polar front, increases between 60–45°S to about 600 m 2 /s and peak between 45–35° S at almost 3000 m 2 /s. κ stays high in the upper 500 m but decreases with depth and is essentially zero below 2500 m. In addition to the thickness diffusion (κ) there is eddy‐induced eastward (westward) advection of isopycnal thickness at the poleward (equatorward) flank of the ACC pointing toward strong anisotropic lateral mixing.