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The response of Southern Ocean eddies to increased midlatitude westerlies: a non-eddy resolving model study

By M. Hofmann and M. A. Morales Maqueda


The midlatitude westerlies of the southern hemisphere have intensified since the 1970s. Non-eddy resolving general circulation models respond to such wind intensification with steeper isopycnals, a faster Antarctic Circumpolar Current (ACC), and a stronger Atlantic Meridional Overturning Circulation (AMOC). However, hydrographic observations show little change in the slope of the Southern Ocean isopycnals over the past 40 years. This insensitivity seems to result from a compensating mechanism whereby an initial increase in the slope of the isopycnals causes eddy activity to intensify and forces the isopycnal slopes down. Climate models do not yet resolve ocean eddies, and the eddy parameterizations included in them do not capture well the compensation mechanism mentioned above. We present simulations with a non-eddy resolving model incorporating an eddy parameterization in which eddy compensation is greatly enhanced by the use of a non-constant, spatially varying thickness diffusivity. The sensitivity of the simulated ACC and AMOC to increased southern hemisphere westerlies is greatly reduced compared to simulations using constant and uniform diffusivitie

Topics: Marine Sciences
Publisher: American Geophysical Union
Year: 2011
DOI identifier: 10.1029/2010GL045972
OAI identifier: oai:nora.nerc.ac.uk:14333

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  20. (1993). On the transport and angular momentum balance of channel models of the Antarctic circumpolar current,
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  23. (2006). Simulated changes in extratropical Southern Hemisphere winds and currents, doi
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  26. (1997). Specification of eddy transfer coefficients in coarse‐resolution ocean circulation models, doi
  27. (2008). The atmospheric ocean: Eddies and jets in the Antarctic Circumpolar Current,
  28. (1991). The influence of numerical advection schemes on the results of ocean general circulation models,
  29. (1996). The NCEP/NCAR 40‐years reanalysis project,
  30. (2008). The response of the Antarctic Circumpolar Current to recent climate change,
  31. (2006). The role of eddies in determining the structure and response of the wind‐driven Southern Hemisphere overturning: Results from the modeling eddies in the Southern Ocean (meso) project,
  32. (2010). The role of mesoscale eddies in the rectification of the Southern Ocean response to climate change, doi
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