Regime Transitions and Heteroclinic Connections in a Barotropic Atmosphere

Abstract

By interpreting transitions between atmospheric flow regimes as a deterministic rather than a stochastic phenomenon, new insight is gained into the phase-space characteristics of these transitions. The identification of regimes with steady states should be extended with the association of transitions with nearby heteroclinic connections between steady states, as known from the theory of dynamical systems. In the context of a moderately complex barotropic model of the Northern Hemisphere, which possesses regime behavior, steady states are found that correspond with regimes, and heteroclinic connections are approximated using a new algorithm based on adjoint modeling techniques. A 200-yr dataset generated by the model is shown to possess spatial preferences in its transitional behavior that match well with the approximated heteroclinic connections.