Abstract:
Time-mean global general circulation data are employed to analyse the temperal and spatial variation of the meridional gradient of zonal mean poten-tial vorticity, the critical wave number nc for horizontal wave-propagation, and the critical wave number Kc for vertical wave-propagation. Thereby the kinematic characteristics for the propagation of atmospheric stationary waves and their annual variations are studied. Results show that in the troposphere nc and Kc usually decrease with the increase of either latitude or altitude. Synoptic and near-resonant Rossby waves could be trapped during their upward and meridional propagations. These characteristics possess prominent annual variations, especially in the Northern Hemisphere. It is found that the spatial and temperal variations of these kinematic characteristics are in good agreement with those of the atmospheric wave patterns.