Dynamic Mean Flow and Small-Scale Interaction through Topographic Stress

Abstract

The equations describing the mean flow and small-scale interaction of a barotropic flow via topographic stress with layered topography are studied here through the interplay of theory and numerical experiments. Both a viewpoint toward atmosphere—ocean science and one toward chaotic nonlinear dynamics are emphasized. As regards atmosphere—ocean science, we produce prototype topographic blocking patterns without damping or driving, with topographic stress as the only transfer mechanism; these patterns and their chaos bear some qualitative resemblance to those observed in recent laboratory experiments on topographic blocking. As regards nonlinear dynamics, it is established that the equations for mean flow and small-scale interaction with layered anisotropic topography form a novel Hamiltonian system with rich regimes of intrinsic conservative chaos, which include both global and weak homoclinic stochasticity, as well as other regimes with complete integrability involving complex heteroclinic structure.