Response to Increasing Southern Hemisphere Winds in CCSM4

AbstractResults from two perturbation experiments using the Community Climate System Model version 4 where the Southern Hemisphere zonal wind stress is increased are described. It is shown that the ocean response is in accord with experiments using much-higher-resolution ocean models that do not use an eddy parameterization. The key to obtaining an appropriate response in the coarse-resolution climate model is to specify a variable coefficient in the Gent and McWilliams eddy parameterization, rather than a constant value. This result contrasts with several recent papers that have suggested that coarse-resolution climate models cannot obtain an appropriate response.

[1]  P. Gent,et al.  Isopycnal mixing in ocean circulation models , 1990 .

[2]  M. Spall,et al.  Specification of eddy transfer coefficients in coarse resolution ocean circulation models , 1997 .

[3]  Robert Hallberg,et al.  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 , 2006 .

[4]  J. Fyfe.  Southern Ocean warming due to human influence , 2006 .

[5]  Michael P. Meredith,et al.  Circumpolar response of Southern Ocean eddy activity to a change in the Southern Annular Mode , 2006 .

[6]  A. Weaver,et al.  The Role of Poleward-Intensifying Winds on Southern Ocean Warming , 2007 .

[7]  G. Danabasoglu,et al.  Effects of vertical variations of thickness diffusivity in an ocean general circulation model , 2007 .

[8]  S. Rintoul,et al.  The response of the Antarctic Circumpolar Current to recent climate change , 2008 .

[9]  James C. McWilliams,et al.  Sensitivity of an Ocean General Circulation Model to a Parameterization of Near-Surface Eddy Fluxes , 2008 .

[10]  M. Meredith,et al.  Eddy Heat Flux in the Southern Ocean: Response to Variable Wind Forcing , 2008 .

[11]  N. Gillett,et al.  The role of eddies in the southern ocean temperature response to the southern annular mode. , 2009 .

[12]  Stephen M. Griffies,et al.  The Role of Mesoscale Eddies in the Rectification of the Southern Ocean Response to Climate Change , 2010 .

[13]  A. Weaver,et al.  Southern Ocean Response to Strengthening Winds in an Eddy-Permitting Global Climate Model , 2010 .

[14]  M. A. Morales Maqueda,et al.  The response of Southern Ocean eddies to increased midlatitude westerlies: A non‐eddy resolving model study , 2011 .

[15]  Peter R. Gent,et al.  The effects of the eddy-induced advection coefficient in a coarse-resolution coupled climate model , 2011 .

[16]  G. Danabasoglu,et al.  The Community Climate System Model Version 4 , 2011 .

[17]  S. Bates,et al.  The CCSM4 Ocean Component , 2012 .