Quasi-Biennial and Long-Term Fluctuations In Total Ozone

Quasi-biennial and long-term fluctuations in total ozone are estimated from stations with more than 4 yr of record in north polar, tropical, south temperate, and south polar latitudes and more than 8 yr of record in north temperate latitudes. The quasi-biennial total-ozone fluctuations tend to be out of phase in tropical and extratropical latitudes, with the extratropical fluctuations better organized in the Southern than Northern Hemisphere. In the Tropics, the quasi-biennial total-ozone and zonal wind oscillations are significantly in phase, but, in extratropical latitudes, the total-ozone fluctuations are alternately in phase and out of phase with the tropical zonal wind oscillation, the out-of-phase relation being the dominant one. There is the suggestion that the Mt. Agung volcanic eruption in 1963 caused a breakdown of the quasi-biennial, total-ozone oscillation in the Southern Hemisphere subtropics, with anomalously high ozone values a few months after the eruption. We derive, for the past 15–20 yr, an increase in total ozone of 3.9 percent per decade in the Northern Hemisphere, a decrease of 1.2 percent per decade in the Southern Hemisphere, and a world-wide increase of 1.5 percent per decade. An increase in total ozone in north temperate latitudes seems quite certain, the four regional areas all showing increases varying from 1.9 percent per decade in North America to 10.7 percent per decade in the Soviet Union. There is considerable evidence that total-ozone maxima occur 1–3 yr after sunspot maxima, with the relation most pronounced in the Southern Hemisphere, but we find little evidence of a reduction in total ozone due to nuclear testing (production of nitric oxide).