Quantitative chemical ozone loss rates at the 475 K isentropic surface inside the Arctic polar vortex are evaluated for six winters (January through March) using a satellite-based Match technique. Satellite observational data are taken from the Polar Ozone and Aerosol Measurement (POAM) II for 1994-1996, the Improved Limb Atmospheric Spectrometer (ILAS) for 1997, and the POAM III for 1999-2000. The largest ozone loss rates were observed in the end of January 1995 (similar to 50 +/- 20 ppbv d(-1)), February 1996 (similar to 40-50 +/- 15 ppbv d(-1)), February 1997 (similar to 40 +/- 8 ppbv d(-1)), January 2000 (similar to 60 +/- 30 ppbv d(-1)), and early March 2000 (similar to 40 +/- 10 ppbv d(-1)). The probability of polar stratospheric cloud (PSC) existence is estimated using aerosol extinction coefficient data from POAM II/III and ILAS. Ozone loss and the PSC probability are strongly correlated and an absolute increase of 10% in the PSC probability is found to amplify the chemical ozone loss rate during Arctic winter by approximately 25 +/- 6 ppbv per day or 3.2 +/- 0.7 ppbv per sunlit hour. Relationships between average Arctic winter ozone loss rates and various PSC-and temperature-related indices are investigated, including the area of polar vortex that is colder than the threshold temperature for PSC existence (A(PSC)), the PSC formation potential (PFP), and the potential for activation of chlorine (PAC1). Of these three, PAC1 provides the best proxy representation of interannual variability in Arctic ozone loss at the 475 K level. Large ozone loss occurred primarily for air masses that experienced low temperatures between 187 K and 195 K within the previous 10 days and the ozone loss rates clearly increase with decreasing the minimum temperature. The particularly large ozone losses of similar to 9 +/- 3 ppbv per sunlit hour in February 1996 and January 2000 were associated with low minimum temperatures of 187-189 K, simultaneously with high PSC probabilities.
