Oscillations in the Winter Stratosphere: Part 1. Description

Abstract

Two patterns dominate changes of monthly mean temperature and pressure-height in the stratosphere. In the one, the middle latitudes vary oppositely to low and high latitudes, and in the other the changes at higher latitudes are out of phase with those at lower latitudes. A shorter trend consisting of opposite changes at middle and high latitudes is superposed on the above variations which a cross-spectrum analysis shows has a preferred time scale of one to three weeks. The contrast between middle and high latitudes thus undergoes a series of corresponding fluctuations and we show that these are associated with amplitude changes in waves 1 and 2 in that the meridional contrast decreases when the amplitude of one or both waves is large, and vice versa.