Severe Arctic ozone loss in the winter 2004/2005: observations from ACE-FTS

The severe Arctic ozone reduction in the winter 2004/ 2005 is analyzed using ACE-FTS observations and four different analysis techniques: correlations between ozone and long-lived tracers ( adjusted to account for mixing), an artificial tracer correlation method, a profile-descent technique, and the empirical relationship between ozone loss and potential PSC volume. The average maximum ozone loss was about 2.1 ppmv at 475 K - 500 K ( similar to 18 km 20 km). Over 60% of the ozone between 425 K - 475 K ( similar to 16 km - 18 km) was destroyed. The average total column ozone loss was 119 DU, similar to 20 - 30 DU larger than the largest previously observed Arctic ozone loss in the winter 1999/ 2000.