Medium-range oscillations of synoptic systems in summer

Using summer data of seven years (1973 to 1979), the authors investigated the medium-range oscillations of the parameters which represent the circulation and synoptic scale systems of tropical atmosphere in the area between 30�E and 130�W and the parameters in the area of the middle and high latitudes of the Northern Hemisphere, with more attention paid to the interannual steadiness of parameters with periodic oscillation. Though the parameters investigated are as many as 148, only a few have been found to have medium-range oscillations of which the interannual variability is relatively small. These oscillation systems are characterized by regional distribution. Relations among those parameters with annually steady oscillations have also been investigated.