Abstract
A study is made of the propagation of Rossby waves in a stably stratified
shear flows. The wave equation for the Rossby waves is derived in an isothermal
atmosphere on a beta plane in the presence of a latitudinally sheared zonal flow. It
is shown that the wave equation is singular at five critical levels, but the wave
absorption takes place only at the two levels where the local relative frequency
equals in magnitude to the Brunt Vaisala frequency. This analysis also reveals that
these two levels exhibit valve effect by allowing the waves to penetrate them from one
side only. The absorption coefficient exp