Barotropic dynamics of interactions between synoptic and low- frequency eddies

Abstract

The interaction is studied by diagnosing the time-averaged transport of vorticity by linear, transient eddies propagating on a basic state that includes a stationary wave. An analytic calculation assuming a weak stationary wave in a channel yields vorticity flux divergences that are in quadrature with the stationary wave, in the sense to shift it upstream. This effect is reproduced in numerical calculations with a linear barotropic model on a sphere. The numerical model, however, also produces an "in-phase' feedback generated primarily by meridional vorticity fluxes. The in-phase feedback is dominant for stationary waves with the smallest zonal wavenumbers, while the quadrature feedback is more important for zonally shorter waves. -from Authors