The Propagation of the Winter Monsoon During Clod Air Outbreaks in East Asia and the Associated Planetary-scale Effect

The present paper has delt with the characteristics of propagation of the winter monsoon during cold air outbreaks for 19 cases of 1980—1984 in East Asia as well as the associated planetary-scale effect. It has been revealed that the propagation of cold air mainly shows a mode of 10—20 day period oscillation. Furthermore, the Siberian cold high associated with outbreaks of cold air may lead to the response of a chain of planetary-scale events. This mainly shows up in the fact that the branch of upward motion of the divergent circulation rapidly shifts from the Indonesia-Malaysian region eastward to the eastern Pacific, thus causing the normal-type Walker circulation to reverse its sense. This condition is very similar to the movement of divergent circulation from non-El Nino year to El Nino year. From the dynamic viewpoint, this kind of divergent circulation is favorable to the synoptic development over the eastern Pacific and the western coast of North America.