Within a low-resolution primitive-equation model of the three-dimensional ocean circulation, audbifurcation analysis is performed of double-hemispheric basin flows. Main focus is on the connectionudbetween results for steady two-dimensional flows in a nonrotating basin and those for threedimensionaludflows in a rotating basin. With the use of continuation methods, branches of steady statesudare followed in parameter space and their linear stability is monitored. There is a close qualitativeudsimilarity between the bifurcation structure of steady-state solutions of the two- and three dimensionaludflows. In both cases, symmetry-breaking pitchfork bifurcations are central in generating audmultiple equilibria structure. The locations of these pitchfork bifurcations in parameter space can beudcharacterized through a zero of the tendency of a particular energy functional. Although balancesudcontrolling the steady-state flows are quantitatively very different, the zonally averaged patterns ofudthe perturbations associated with symmetry-breaking are remarkably similar for two-dimensionaludand three-dimensional flows, and the energetics of the symmetry-breaking mechanism is in essenceudthe same.
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