Total ozone and synoptic weather relationships over southern Africa and surrounding oceans

Relationships between Total Ozone Mapping Spectrometer (TOMS) total ozone and synoptic weather systems for a region bounded by longitudes 10°W–50°E and latitudes 0°–50°S are presented. Least squares regression analysis revealed a generally poor but negative relationship between total ozone and the heights of the 500, 300, and 100 hPa geopotential surfaces at nine selected stations for the period 1987 to 1988. The relationship strengthens with increasing latitude and suggests a physical link with the midlatitude cyclone which facilitates the injection of stratospheric ozone rich air into the troposphere. In the tropics the link with middle to upper tropospheric meteorological parameters is weak. Analysis of daily relationships between gridded TOMS ozone and gridded European Centre for Medium‐Range Weather Forecasts (ECMWF) geopotential height data over the study area showed considerable variations, indicative of varying synoptic weather situations. Case studies of a cutoff low sequence and a subtropical anticyclone system were selected as examples of synoptic situations which accounted for the highest and lowest correlations, respectively. The contrasting dynamics operating in these systems are highlighted.