During July and August 1989 a number of ozone profiling instruments were intercompared at Table Mountain Observatory in California. During the intercomparison a Brewer ozone spectrophotometer made observations of the total ozone amount and the vertical distribution of ozone. It was demonstrated that the Umkehr technique produced estimates of the ozone profile which were accurate to better than 15% in the 20- to 40-km altitude range. Values determined for the 24- to 40-km region were most accurate, within about 5% of the mean of the other instruments involved. ¿ American Geophysical Union 1995