INTERCOMPARISON OF TOTAL OZONE MEASURED AT LOW SUN ANGLES BY THE BREWER AND DOBSON SPECTROPHOTOMETERS AT SCOTT-BASE, ANTARCTICA

The total ozone measurements made at Scott Base (78-degrees-S, 167-deg rees-E) with Dobson spectrophotometer #17 and Brewer spectrophotometer #50 during the 1991 Antarctic ozone hole season are compared. Due to the high latitude of Scott Base, these measurements have been made usi ng low-sun measurement techniques, which are considered to be less rel iable and less accurate. The differences between the quasi-simultaneou s total ozone measurements, and the mean daily total ozone values, fro m Dobson instrument 17 and Brewer instrument 50 are generally between +/-5%. The Dobson-Brewer differences can, on occasions, be as great as 10% for measurements made at airmass values between 5 and 6. The Dobs on and Brewer ozone data are generally within +/-5% of the Total Ozone Mapping Spectrometer (TOMS) value.