ROSSBY-WAVE PROPAGATION ON A REALISTIC LONGITUDINALLY VARYING FLOW

The response of a barotropic model, linearized about a climatological 300-mb December-February time-mean flow to localized forcing, is consi dered. In order to aid the design of the experiments and interpretatio n of the results, a simplified analysis is made of the basic flow in t erms of zonal wind, meridional vorticity gradient, and stationary wave number. From the analysis the possible existence of a strong waveguide in the Asian jet and weaker waveguides in the North Atlantic and Sout hern Hemisphere jets is deduced. The possibility of propagation into t he equatorial east Pacific and Atlantic oceans and even across these r egions is also suggested. These features are confirmed by barotropic m odel integrations for a variety of perturbation vorticity source posit ions and shapes. These integrations also show preferred propagation re gions arching across North America, from Europe to the Arabian Gulf an d, in the Southern Hemisphere, into the equatorial Indian Ocean and In donesian regions. They also show a tendency to produce a low-wavenumbe r, fast westward-moving ''tail'' along the Asian jet. Many of the feat ures found in this study are remarkably consistent with observational teleconnection studies.