Satellite Observations of Total Ozone Above South Africa

Abstract

TOMS (Total Ozone Mapping Spectrometer) satellite data for 1988 have provided the opportunity for an investigation of spatial and temporal variations in total ozone over South Africa. Data for five South African stations and one southern ocean station. Gough Island, have been extracted from the TOMS data base. The seasonal peak in ozone occurs in October. Day-to-day variability is shown to increase with increasing latitude from Pretoria in the north to Gough Island in the south. as the influence of the transient eddies in the midlatitude westerlies becomes more dominant A model explaining the link between total ozone and a midlatitude wave is proposed. With the passage of a baroclinic westerly wave. north-westerly advection of ozone-poor air of tropical origin occurs in conjunction with a surface pressure minimum and upper air ridge. This is followed by the south-westerly advection of ozone-rich air of midlatitude origin in association with a surface high and stratospheric injection of ozone-rich air in association with the concomitant upper air trough.