Estimate of Global Temperature Variations in the 100–30 mb Layer between 1958 and 1977

Based on a network of 42 radiosonde stations distributed around the world, the (smoothed) global temperature within the 100-30-mb layer was colder in the spring of 1977 than at any time since initiation of the record in 1958, a result mainly of the cold temperatures in the Tropics (east wind phase of the quasi-biennial oscillation). This cold followed, by about six months, the record-cold global temperature observed for the surface-100-mb layer. The highest global temperature on record for the 100-30-mb layer was observed after the eruption of Mt. Agung in 1963, with the phase of the quasi-biennial oscillation in the Tropics augmenting any stratospheric warming induced by Agung. Since the Agung eruption, there has been slightly greater global cooling in the 100-30-mb layer than in the surface-100-mb layer. However, this result derives solely from uncertain Southern Hemisphere data and cannot be cited as evidence of a carbon dioxide influence on atmospheric temperature, because in the Northern Hemisphere, an opposite tendency has been observed. The quasi-biennial oscillation of temperature in the low tropical stratosphere extends, with much reduced amplitude, into the north temperate latitude stratosphere with a lag time of about two months. There is evidence of tropospheric temperature variations in north extratropics which follow the three-year oscillations in the Tropics by about six months (important for seasonal foreshadowing in northern latitudes), as well as evidence that temperature variations in the low tropical stratosphere follow the variations in the tropical troposphere by about nine months. A longer data record is needed to clarify the relation between El Nino occurrences, or the Southern Oscillation, and the quasi-biennial oscillation of the tropical stratosphere.