Global Circulation Regimes in the Presence of Stationary Planetary Wave Forcing

The three way interaction of the Hadley circulation, zonal jet streams and baroclinically unstable eddies gives rise to different circulation regimes, characterized by the type of jet stream. Idealized models which resolves the interactions between these three components show three main kinds of equilibrated jet streams- a thermally driven subtropical jet, an eddy driven jet, and a merged thermally-eddy driven jet. These regimes differ in the location and variability of the jet stream, as well as in the structure and zonal wavenumber and phase speed of the dominant modes. A main component missing from these models is the presence of stationary planetary waves. These waves influence the zonal jet stream and the Hadley circulation through their momentum fluxes, while the wave response to stationary forcing depends on the structure and position of the jet relative to the mountain. We will examine how the global circulation regime morphology varies in the presence of idealized stationary forcing at subtropical, mid- and high latitudes.