Ozone Variations associated with the Equatorial Stratospheric Wind Oscillations

Abstract

With a view to elucidate the bi-annual Or possibly 26-monthly oscillation in the ozone content of the atmosphere corresponding to the recently discovered equatorial stratospheric wind oscillation, an analysis was made of the monthly mean total ozone values of five stations, three in India and two in Australia covering the years 1958-1962. When the effects of the annual oscillation are suitably eliminated, it has been found that the long-period variations show a 26-month cycle in the case of four out of the five stations studied. The oscillation seems to extended as far south as 38° Latitude in the southern hemisphere but only as far as 20oN in the northern hemisphere. The amplitude of the 26-month oscillation is greater in the southern hemisphere. Further, the phase of the oscillation is mutually opposite in the two hemispheres. During epochs when the easterly stratospheric winds over the equator at the 25-km level weaken and change over to westerlies, the ozone content increases in the northern hemisphere and decreases in the southern hemisphere. The opposite effect is produced when the westerly stratospheric winds weaken and change over to easterlies.