Thickness diffusitivityin the Southern Ocean

• Published in: Geophysical Research Letters
• Main Author: Eden, Carsten
• Format: Article in Journal/Newspaper
• Language: English
• Published: AGU (American Geophysical Union) 2006
• Subjects: Southern Ocean
• Online Access: https://oceanrep.geomar.de/id/eprint/6456/; https://oceanrep.geomar.de/id/eprint/6456/1/Eden-2006-Geophysical_Research_Letters.pdf; https://doi.org/10.1029/2006GL026157

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 m2/s poleward of the polar front, increases between 60–45°S to about 600 m2/s and peak between 45–35° S at almost 3000 m2/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.