Summary
In order to improve our understanding of the January losses of ozone in the Arctic vortex two ozonesondes Match campaigns are scheduled within the project "Quantitative Understanding of Ozone losses by Bipolar Investigations" (QUOBI). The first one was successfully carried out within the first phase of VINTERSOL in the Arctic winter 2002/03. About 450 co-ordinated ozonesondes were launched from late November 2002 to March 2003 in the polar vortex. Temperatures low enough for the formation of polar stratospheric clouds (T_PSC) occurred already in the second half of November. The area covered by temperatures lower than T_PSC (A_PSC) at the 550 K potential temperature level showed record sizes in early and mid December with respect to the record started at the FU Berlin in 1964/65. The lower stratosphere remained cold until mid January when a major warming influenced the whole stratosphere. During late March temperature dropped below T_PSC only for short periods of time. The Match analysis shows increasing ozone loss rates at 475 K during the first days of December. They reached about 5 ppbv/sunlit hour by early January and stayed on that level until the end of the month. From then on the depletion rates slowly decreased until the end of March. At 475 K potential temperature we find an overall ozone loss of about 1.5 ppmv.The first Antarctic Match campaign has started in June 2003 as part of the second phase of VINTERSOL. 9 Antarctic stations will launch approx. 450 -500 ozonesondes until October. Temperatures dropped below T_PSC already in early June which is exceptional early. We will show the complete Match analysis for the Arctic campaign 2002/03 in the vertical range from 410 - 510 K potential temperature and preliminary results of the Antarctic Match campaign.