Planetary Variations of Stratospheric Temperatures

Abstract

Radiances emitted from the atmosphere near 669.3 cm?1 in the center of the 15-µm CO2 band were measured from the Nimbus 3 satellite. Changes in observed radiance correspond to weighted temperature changes of the upper 100 mb of air. The seasonal march of latitudinally averaged radiances is presented from 80°N to 80°S. The latitudinal and seasonal variations of radiance are removed from the data. The residuals emphasize the fact that winter polar stratospheric warmings are accompanied by stratospheric coolings in the Tropics and summer hemisphere. A warming of about 7°K near latitude 50° is accompanied by a cooling of about 1°K at the Equator. However, much larger warmings at latitudes near the poles do not produce correspondingly large coolings at the Equator. The synoptic distributions of radiances on 2 days are discussed: (1) the day when the average latitudinal radiance was a minimum in polar latitudes and (2) the day when the polar warming reached its maximum. The wave number 1 pattern in middle and high latitudes of the Northern (winter) Hemisphere is evident. In the Southern (summer) Hemisphere, wave numbers 2 and 3 dominate. The large latitudinal difference of the radiances, on the day before the warming begins, reaches a value corresponding to about 15°K between 30° and 50°N at about 20°W longitude.