Equatorial Superrotation and Maintenance of the General Circulation in Two-Level Models Academic Article uri icon


  • Suarez and Duffy have noted an interesting bifurcation in a two-level gridpoint general circulation model when strong tropical heating is imposed. This bifurcation results in a model climatology with strong upper-level westerlies in the tropics. In this paper, it is argued that this bifurcation is essentially due to the dominant role played by extratropical baroclinic transients in the tropical angular momentum budget. A series of numerical experiments is analyzed with a global two-level primitive equation model, using spectral truncation in the horizontal. It is concluded that the conventional climatology is stable to weak perturbations, with the "restoring' force being provided primarily by extratropical baroclinic eddies. Strong perturbations completely change the propagation characteristics of these eddies, leading to a bifurcation of the general circulation. -from Author

author list (cited authors)

  • Saravanan, R.

citation count

  • 68

publication date

  • May 1993