FORCED ROSSBY WAVE PACKET PROPAGATION AND TELECONNECTIONS IN THE ATMOSPHERE

By use of the concept of wave packet and WKB method,the all-round characteristics of the Rossby wave packet under the background of the basic current and the topography are obtained,and the equation and condition for the development of the wave packet are gained as well.Applying the condition obtained to the background basic current of southwest and southeast jet,we propose the concept on the wave packet splitting and the wave passage branching,i.e.according to the disposition of the wave packet with respect to the jet and the condition satisfied by the stationary wave packet,its trough(ridge)line must be deformed,bent,splitted and bifurcated,the wave passage hence bifurcates accordingly.Under the SW jet,one bifurcated wave packet propagates toward high latitudes and penetrates upward into the stratosphere,and the other propagates toward low latitudes,but it propagates a far less distance than the former,and only reaches the tropopause in the vertical.By means of the feature of the wave passage bifurcation of the Rossby wave packet in the SW jet,the PNA and EU patterns of teleconnections suggested by Wallace and Gutzler(1981)are investigated.