Retrieving the vertical distribution of stratospheric OClO from Odin/OSIRIS limb-scattered sunlight measurements
1Department of Meteorology, Stockholm University, Stockholm, Sweden
2Centre for Research in Earth and Space Science, York University, Toronto, Canada
3Department of Radio and Space Science, Chalmers University of Technology, Güteborg, Sweden
4Service d’Aéronomie, Institut Pierre-Simon Laplace, Paris, France
*now at: Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
Abstract. The first vertical profiles of stratospheric OClO retrieved from Odin/OSIRIS limb-scattered sunlight radiances are presented. The retrieval method is based on a two-step approach, using differential optical absorption spectroscopy combined with the maximum a posteriori estimator. The details of the spectral window selection, spectral corrections and inversion technique are discussed. The results show that OClO can be detected inside the South polar vortex region between about 12 and 20 km altitude with a 2–5 km height resolution and an estimated retrieval error better than 60% at the peak. OClO concentrations are consistent with chemical transport model simulations and show the expected relation to the atmospheric conditions in the lower stratosphere in the austral spring 2002. This unique data set of OClO profiles is very promising to study the stratospheric chlorine activation in both polar regions.