Abstract
A quasi-geostrophic, barotropic, low-order model with bottom topography is constructed to investigate the bifurcation properties of steady solutions and time-dependent solutions in a numerical model of geophysical fluid system. The low-order model with six dependent variables is a direct extension of that in the pioneering work by Charney and DeVore (1979). This is the most simplified system in which spectral components consist of two symmetry groups.
Compared with the three-variables model in Charney and DeVore (1979) and some other studies, new bifurcation properties are obtained such as (1) bifurcation of steady solutions with symmetry breaking, (2) appearance of periodic solutions due to Hopf bifurcation, (3) symmetric saddle-node bifurcation, period doubling bifurcation and intermittent chaos. As for the multiplicity of stable solutions, there exist stable periodic solutions in addition to stable steady solutions for some given external parameters.
