STRATOSPHERIC CLONO2 AND HNO3 PROFILES INSIDE THE ARCTIC VORTEX FROM MIPAS-B LIMB EMISSION-SPECTRA OBTAINED DURING EASOE

Vertical profiles of ClONO2 and HNO3 inside the Arctic vortex have bee n retrieved from infrared limb emission spectra recorded during balloo n flights on January 13 and in the night of March 14/15, 1992 from Esr ange, Sweden (68-degrees-N) as part of the European Arctic Stratospher ic Ozone Experiment (EASOE). The instrumentation used was the cryogeni c Michelson Interferometer for Passive Atmospheric Sounding, Balloon-b orne version (MIPAS-B). ClONO2 abundances in Mid-January indicate that a significant portion of ClONO2 had already been converted at that ti me. An unexpectedly high ClONO2 amount (1.8 to 3.1 ppvv between 16.1 a nd 21.5 km altitude) has been inferred from the March flight data. Thi s implies that obviously moat of the total available chlorine (ClO(y)) in the lower stratosphere was then in this reservoir molecule. The me asured HNO3 profiles give no hint of any significant layered removal o f gaseous HNO3 by condensation on particles or/and sedimentation.