Abstract
A model of wave-mean-field interaction in a baroclinic flow is formulated for the case where the ratio of the current width L to the Rossby deformation radius R is large for waves whose zonal wavelength is O(R). In this limit sufficient simplifications occur in the dynamical problem for the wave evolution to allow the examination of the wave amplitude behavior at larger effective supercritically than in previous weakly nonlinear theories. The model is shown, however, to contain within it the earlier theories.
Detailed numerical calculations with the model predict amplitude vacillation for fairly large values of the ratio E½/Ro, where E is the Ekman number and Ro the Possby number. Examination of the wave amplitude as a function of L/R shows that the velocity of the perturbations remains of the same order as the mean, although the total available potential energy of the mean exceeds its kinetic energy by a factor of L2/R2.
