Influences of Vorticity Source and Momentum Source on Atmospheric Circulation

A simplified one-dimensional barotropic vorticity equation is used to study the influences of the vorticity and the momentum source on the large scale wave. Both vorticity source and momentum source can cause the formation of the large scale wave, but the former can produce large scale wave only under the condition that there is apparent basic flow acting on it, while the latter can produce the large scale wave even when ū tends to be zero. Furthermore, the amplitude of steady wave caused by the former is proportional to √ū, while the amplitude caused by the latter has no relation to ū, instead it depends only on the magnitude of the perturbation of momentum.