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Simultaneous measurements of OClO, NO2 and O3 in the Arctic polar vortex by the GOMOS instrument

Cédric Tétard(1), Didier Fussen(1), Filip Vanhellemont(1), Nina Mateshvili(1), Nicolas Loodts(1), Emmanuel Dekemper(1), Christine Bingen(1), Nadège Capouillez(1), Erkki Kyrölä(2), Viktoria Sofieva(2), Johanna Tamminen(2), Alain Hauchecorne(3), Francis Dalaudier(3), Jean-Loup Bertaux(3), Odile Fanton d'Andon(4), Gilbert Barrot(4), Marielle Guirlet(4), Thorsten Fehr(5) and Lidia Saavedra(6)

(1) BIRA-IASB, 3 avenue circulaire, B-1180 Brussels, Belgium
(2) FMI, Erik Palmenin aukio 1, 00101, Helsinki, Finland
(3) Service d'aéronomie du CNRS - LATMOS, Bois de Verrieres, 91371, Verrieres le buisson Cedex, France
(4) ACRI, route du pin montard, Sophia-antipolis, France
(5) ESA, Via Galileo Galilei, 00044 Frascati, Italy
(6) ESA/ESRIN, , Frascaty, Italy

Abstract

The GOMOS instrument onboard ENVISAT is a stellar occultation spectrometer dedicated to the remote sounding of the stratosphere. By co-adding transmittances from measurements selected in latitudinal bins, we increase the signal-to-noise ratio and then, we can detect the signature of small absorbing constituents. In particular, the retrieval of OClO (considered as a proxy of the halogen activation) is possible. We have developed a DOAS approach to retrieve simultaneously OClO, NO2 and O3 slant column densities (SCD) from the weighted median GOMOS transmittances. We present a study about the longitudinal distributions of OClO, NO2 and O3 SCD in the North polar region in January 2008. We focus on the correlation between cold temperature, strong OClO SCDs and weak NO2 SCDs inside the polar vortex. In a second part, we present the temporal evolutions of these species in the Arctic region during winters from 2002/2003 to 2007/2008. This study shows also that denoxification, halogen activation and low temperatures are correlated.