Antarctic Science



The dynamical balance, transport and circulation of the Antarctic Circumpolar Current


DIRK OLBERS a1c1, DANIEL BOROWSKI a1, CHRISTOPH VÖLKER a1 and JORG-OLAF WÖLFF a2
a1 Alfred Wegener Institute for Polar and Marine Research, D-27515 Bremerhaven, Germany
a2 ICBM, University of Oldenburg, D-26111 Oldenburg, Germany

Article author query
olbers d   [PubMed][Google Scholar] 
borowski d   [PubMed][Google Scholar] 
völker c   [PubMed][Google Scholar] 
wölff jo   [PubMed][Google Scholar] 

Abstract

The physical elements of the circulation of the Antarctic Circumpolar Current (ACC) are reviewed. A picture of the circulation is sketched by means of recent observations from the WOCE decade. We present and discuss the role of forcing functions (wind stress, surface buoyancy flux) in the dynamical balance of the flow and in the meridional circulation and study their relation to the ACC transport. The physics of form stress at tilted isopycnals and at the ocean bottom are elucidated as central mechanisms in the momentum balance. We explain the failure of the Sverdrup balance in the ACC circulation and highlight the role of geostrophic contours in the balance of vorticity. Emphasis is on the interrelation of the zonal momentum balance and the meridional circulation, the importance of diapycnal mixing and eddy processes. Finally, new model concepts are described: a model of the ACC transport dependence on wind stress and buoyancy flux, based on linear wave theory; and a model of the meridional overturning and the mean density structure of the Southern Ocean, based on zonally averaged dynamics and thermodynamics with eddy parametrization.

(Received December 22 2003)
(Accepted September 1 2004)


Key Words: ACC; Southern Ocean; form stress; meridional overturning; transient and standing eddies.

Correspondence:
c1 corresponding author: dolbers@awi-bremerhaven.de


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