Interannual variability in the spatial distribution of extratropical total ozone

Quasi‐stationary planetary waves induce zonal asymmetries in wintertime extratropical total ozone fields with typical magnitudes of 30 to 60 Dobson Units. Year‐to‐year changes in the zonally asymmetric component of monthly mean total ozone fields are examined using both the Nimbus 7 TOMS record (1979–1993) and the combined Nimbus 7, NOAA 11, and NOAA 9 SBUV(2) records (1979–1996), focusing on northern extratropical latitudes in February and southern extratropical latitudes in October. A simple model based on the linearized ozone mixing ratio continuity equation, in which the dynamics are specified from NCEP reanalysis geopotential height and temperature fields, is used to simulate the interannual variability in the spatial distribution of total ozone. Model estimates of the wave‐induced variability in total ozone fields agree well, both qualitatively and quantitatively, with the variability observed in lower‐resolution SBUV(2) and higher‐resolution TOMS records, with the exception of certain years at high southern latitudes in October. Disagreement during these years is related to the displacement of the springtime ozone minimum from over the pole by enhanced planetary wave activity.