The Royal Meteorological Institute at Uccle (Belgium, 50 48' N, 4 21' E, 100 m asl) has a long tradition of ozone observations. The ozone data on which the time series analysis described in this poster is based, are: total ozone column measurements with either a Dobson or Brewer spectrophotometers since mid 1971, vertical ozone pro les obtained with radiosondes (three times a week) since January 1969. 2 Aims to update the observed ozone trends above Uccle, to make a time series analysis of the vertical distribution of ozone layers relative to the tropopause. Abstract????