An assessment of the ozone loss during the 1999-2000 SOLVE/THESEO 2000 Arctic campaign

Ozone observations from ozonesondes, the lidars aboard the DC-8, in situ ozone measurements from the ER-2, and satellite ozone measurements from Polar Ozone and Aerosol Measurement III (POAM) were used to assess ozone loss during the Sage III Ozone Loss and Validation Experiment (SOLVE) and Third European Stratospheric Experiment on Ozone (THESEO) 1999-2000 Arctic campaign. Two methods of analysis were used. In the first method a simple regression analysis of the data time series is performed on the ozonesonde and POAM measurements within the vortex. In the second method the ozone measurements from all available ozone data were injected into a free-running diabatic trajectory model and were carried forward in time from 1 December to 15 March. Vortex ozone loss was then estimated by comparing the ozone values of those parcels initiated early in the campaign with those parcels injected later in the campaign. Despite the variety of observational techniques used during SOLVE, the measurements provide a fairly consistent picture. Over the whole vortex the largest ozone loss occurs between 550 and 400 K potential temperatures (similar to23-16 km) with over 1.5 ppmv (similar to55%) lost by 15 March, the end of the SOLVE mission period. An ozone loss rate of 0.04-0.05 ppmv/day was computed for 15 March. The total column loss was between 44 and 57 DU or 11-15%. Ozonesondes launched after 15 March suggest that an additional 0.5 ppmv or more ozone was lost between 15 March and 1 April.