Traveling planetary waves and their effect on the general circulation

Evidence of regularly propagating, large-scale waves was found in a 73 year record of Northern Hemisphere sea level pressure data and in a nine-year record of upper air data. Cross spectrum analyses indicated that south of 50 N, in all seasons, a zonal wave number one disturbance moves westward around the world in five days. In addition, north of 50 N, primarily in winter and spring, a zonal wave number one disturbance moves westward around the world in one to three weeks with an average period near 16 days. The structure of the 16-day wave during winter was studied, and it was shown to be consistent, in many respects, with that of a theoretically predicted free planetary wave of the second class. Further evidence is presented that demonstrates that the interaction of a transient, free, planetary wave and a quasi-stationary, forced wave can cause large fluctuations in vertical energy transport and in the total atmospheric energy cycle itself.