On the available energy of symmetric circulations

A theory of available energy for cross-stream symmetric circulations is presented. While the theory is based on the Hamiltonian structure of the underlying conservative dynamics, it incorporates forcing and dissipation. Moreover, it has a local form and is exact at finite amplitude.

Both thermal and dynamical constraints on the reference state flow can be accounted for. The dynamical (momentum) constraints prove to be important in diagnosing mechanically driven, thermally damped cross-stream circulations.

Applications of the theory to symmetric and axisymmetric Boussinesq flows on an f-plane, and for the zonally averaged meridional circulation of the middle atmosphere are discussed.