Transfer coefficient eddy flux parametrizations in a simple model of the zonal average atmospheric circulation

Baroclinic eddy parametrizations of the type proposed by Green in 1970 are applied in a simple climate model which is the zonal average counterpart of the long wave model used by the authors in a recent paper. Three parametrization schemes, each with different specifications of transfer coefficients, are examined. Diabatic forcing is represented by a sinusoidal function of latitude, and the performance of each scheme is gauged by the realism of the eddy flux and zonal mean fields which it produces in the steady state. In broad agreement with numerical simulations of baroclinic eddy life cycles, the best results are obtained when a certain condition of maximum available potential energy release is relaxed. The main feature of the study is the systematic application of fundamental constraints on the eddy vorticity fluxes: these are used to determine free parameters in the functional specification of the transfer coefficients.