INTERANNUAL VARIABILITY IN THE SPATIAL-DISTRIBUTION OF EXTRATROPICAL TOTAL OZONE

Quasi-stationary planetary waves induce zonal asymmetries in wintertim e extratropical total ozone fields with typical magnitudes of 30 to 60 Dobson Units. Year-to-year changes in the zonally asymmetric componen t of monthly mean total ozone fields are examined using both the Nimbu s 7 TOMS record (1979 - 1993) and the combined Nimbus 7, NOAA 11, and NOAA 9 SBUV(2) records (1979 - 1996), focusing on northern extratropic al latitudes in February and southern extratropical latitudes in Octob er. A simple model based on the linearized ozone mixing ratio continui ty equation, in which the dynamics are specified from NCEP reanalysis geopotential height and temperature fields, is used to simulate the in terannual variability in the spatial distribution of total ozone. Mode l estimates of the wave-induced variability in total ozone fields agre e well, both qualitatively and quantitatively, with the variability ob served in lower-resolution SBUV(2) and higher-resolution TOMS records, with the exception of certain years at high southern latitudes in Oct ober. Disagreement during these years is related to the displacement o f the springtime ozone minimum from over the pole by enhanced planetar y wave activity.