Modeling the Global Interannual Variability of Ozone Due to the Equatorial QBO and to Extratropical Planetary Wave Variability

Abstract

By forcing an interactive chemical?dynamical model of the stratosphere with the observed Singapore zonal winds and with the observed daily varying planetary wave heights just above the tropopause over the period from March 1980 to February 1993, much of the observed interannual variability (IAV) in the monthly mean ozone column from pole to pole was able to be reproduced. The best correlations were obtained equatorward of 50° during winter and autumn in both hemispheres. These correlations were due to the model?s interaction with the specified equatorial zonal wind. In the Southern Hemisphere, the observed high-latitude ozone anomaly in November (the month with the largest anomaly) is well anticorrelated with the 20-mb Singapore wind, and correlations suggest the anomaly propagates poleward from 45°S in August and possibly even from 15°S in June. The model reproduces this behavior well. In the Northern Hemisphere (NH), by contrast, the observed high-latitude ozone anomaly is not well correlated with the equatorial quasi-biennial oscillation nor does it propagate from lower latitudes. Model results demonstrate that the NH high-latitude ozone anomaly is influenced strongly by the IAV in the forcing of the planetary waves. Model results show a large IAV in the ozone column during polar night in the NH (where the Total Ozone Mapping Spectrometer is not able to observe) that is due to the IAV in the forcing of planetary waves.