TOTAL OZONE MEASUREMENTS MADE WITH THE BREWER OZONE SPECTROPHOTOMETERDURING STOIC 1989

The Canadian Atmospheric Environment Service participated in the Strat ospheric Ozone Intercomparison Campaign (STOIC) by operating a Brewer ozone spectrophotometer at the Table Mountain Observatory from July 19 to August 2, 1989. Frequent direct Sun measurements of total column o zone were made throughout most days during the 2 weeks of the intercom parison. Results of the Brewer instrument total ozone measurements are given. They show that there is a diurnal variation of total ozone wit h values increasing on average by 6.6 +/- 2.4 Dobson units between ear ly morning and late afternoon. Comparing the total ozone measurements with ozone concentration measurements made at ground level suggests th at the daytime increase is a result of a buildup of surface ozone duri ng the day. The total ozone measurements made by the Brewer instrument during STOIC are compared with total ozone measurements made by the N ational Oceanic and Atmospheric Administration (NOAA) Dobson instrumen t, the NASA/Wallops electrochemical concentration cell ozonesondes and the total ozone mapping spectrometer satellite instrument.