CARBONYL SULFIDE (COS) MEASUREMENTS IN THE ARCTIC POLAR VORTEX

One stratospheric carbonyl sulfide (COS) vertical profile in the Arcti c polar vortex has been retrieved from air samples collected by the MP AE balloon-borne cryogenic sampler on January 18, 1992, at Kiruna, Swe den. The measurements were made in the altitude range 7.5-28.5 km. The upper tropospheric volume mixing ratios of COS were 355 +/- 60 pptv. The stratospheric profile shows that COS is subject to considerable su bsidence this time of the year. The lowest VMRs were encountered at ar ound 20 km altitude, while above that height a COS increase was observ ed. A possible explanation could be reversible uptake of COS by frozen sulfuric acid aerosols.