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The ozone distribution and its variability is simulated with a general circulation model (GCM), which includes self‐consistent representation of the physical processes and an accurate parameterization of the ozone photochemical sources and sinks. Emphasis is placed on analysis of the action of atmospheric waves on the O3 distribution. In particular, the model generates the medium‐scale waves which are often observed in the southern hemisphere. These waves tend to form quasi‐regular O3 patterns with zonal wave numbers 4, 5, and 6, in fairly good agreement with the observations. Baroclinic instability generates the waves in the lower troposphere, but it is their equivalent barotropic structure in the upper troposphere‐lower stratosphere which produces the signal on the total ozone column, since O3 disturbances are nearly in phase in this altitude range. Episodes of large amplitude of the medium‐scale waves occur when the transient waves interact with a stationary wave. This standing wave has a zonal wave number close to 4 and appears to result from the large convective activity within the South Pacific Convergence Zone and its southward extension at mid‐latitudes. This study gives a good illustration of the important role played by GCMs in understanding the interactions between dynamical and physical processes in the troposphere and wave activity and O3 distribution in the lower stratosphere.

Abstract. This article describes the validation of a linear parameterization of the ozone photochemistry for use in upper tropospheric and stratospheric studies. The present work extends a previously developed scheme by improving the 2-D model used to derive the coefficients of the parameterization. The chemical reaction rates are updated from a compilation that includes recent laboratory work. Furthermore, the polar ozone destruction due to heterogeneous reactions at the surface of the polar stratospheric clouds is taken into account as a function of the stratospheric temperature and the total chlorine content.Two versions of the parameterization are tested. The first one only requires the solution of a continuity equation for the time evolution of the ozone mixing ratio, the second one uses one additional equation for a cold tracer. The parameterization has been introduced into the chemical transport model MOCAGE. The model is integrated with wind and temperature fields from the ECMWF operational analyses over the period [2000][2001][2002][2003][2004]. Overall, the results from the two versions show a very good agreement between the modelled ozone distribution and the Total Ozone Mapping Spectrometer (TOMS) satellite data and the "in-situ" vertical soundings. During the course of the integration the model does not show any drift and the biases are generally small, of the order of 10%. The model also reproduces fairly well the polar ozone variability, notably the formation of "ozone holes" in the Southern Hemisphere with amplitudes and a seasonal evolution that follow the dynamics and time evolution of the polar vortex.