Cancellation of the Deacon Cell by Vertical Eddy Fluxes

• Main Author: Zika, Jan D.
• Other Authors: Laboratoire des Écoulements Géophysiques et Industriels Grenoble (LEGI), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
• Format: Report
• Language: English
• Published: HAL CCSD 2011
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Antarctic; Deacon; Southern Ocean; The Antarctic; Antarc*; Sea ice
• Online Access: https://hal.science/hal-00592075; https://hal.science/hal-00592075/document; https://hal.science/hal-00592075/file/Zika_Deacon_Cancel_GRL_subm_2col_y11m04d13.pdf

The Overturning Circulation of the Southern Ocean has been investigated using a state of the art, eddy resolving ocean-sea ice model. The overturning circulation at constant depth and latitude reveals a 'Deacon Cell', a wind-driven meridional cell which acts to flux light surface waters Northward and downward and dense deep waters Southward and upward. The overturning has been further analysed in density-latitude space. Northward transport of light water and Southward transport of dense water by the Deacon Cell are compensated by the standing meanders of the Antarctic Circumpolar Current and other stationary features. The overturning has been finally analysed in depth-density space. Here, the Deacon Cell is compensated by transient eddy fluxes. We thus propose a new paradigm to conceptualize the Southern Ocean Overturning Circulation: the ACC's standing meanders transport light water Southward and dense water Northward with little vertical excursion; transient eddies then act on the resulting zonal gradients of isopycnals, transporting light water upward and dense water downward. Although transient eddies have previously been shown to play a minor role in meridional exchanges in the Southern Ocean, here they are found to play a crucial role in vertical exchanges.