Dynamical components of northern hemispheric zonal mean total ozone changes during 1979–93

Abstract

In this work, we examine the influence of northern hemispheric large‐scale eddy fluxes on the zonal mean total ozone changes. For this purpose, zonal means of the eddy fluxes of the period 1979–93 were introduced into a dynamically‐chemically coupled two‐dimensional circulation model, based on a diffusivity approach for the quasi‐geostrophic potential vorticity, the potential temperature and the chemical tracers. The model calculations show that the eddy fluxes induce regular interannual ozone variations with a period of about 3–3.5 years in the northern midlatitudes, and, for the pre‐Pinatubo time period 1979–91, a decadal decline in the northern hemispheric total ozone that amounts to about 50% of the observed trend.