Abstract
The evolution and interaction of quasi-geostrophic disturbances and zon barotropic atmosphere on a rotating sphere are investigated by integral properties as well as by the WKB method. The results obtained by these two methods are in full agreement and supplement with each other. Two concepts, the available zonal energy and rotational adaptation, are introduced. It is indicated that the atmospheric motion on a rotating sphere always keeps some anisotropy, and can become a completely zonal flow under favorable conditions. Developing (decaying) disturbance superimposed on zonal flow or ultra-long wave enlarges (shortens) its size, i.e., local wave length, provided the jet is moderate and satisfies the stable condition. Developing (decaying) disturbances transfer angular momentum out from (into) the jet region; and weaken (strengthen) both the jet and its shear. At the same time, the propagation of developing (decaying) disturbance decelerates (accelerates).
