HO₂ measurements in the stratosphere and the mesosphere from the sub-millimetre limb sounder Odin/SMR

Abstract

This paper presents observations of the hydroperoxy radical (HO₂) performed by the Odin/SMR instrument from the middle stratosphere to the upper mesosphere (35–90 km). The data set covers the period from October 2003 to December 2005 on a basis of one observation period of 24 hours each month. Odin/SMR can provide two zonal maps of HO₂ per day, with a vertical resolution of 10 km. The non-standard processing applied to the retrievals is described. The consistency between HO₂ observations from three periods in August 2004 demonstrates the robustness of the retrieval method. It also shows that the measurements are sensitive enough to detect changes in the middle and upper mesosphere. The retrieval needs further improvements for studying stratospheric variations.

Acknowledgements

P. Baron thanks the Japanese Society for the Promotion of Science (JSPS) for financial support during two years. Thanks are extended to J. Stegman and S. Lossow for useful discussions and hosting in Stockholm University. The authors thank the International Meteorological Institute in Stockholm (IMI) for funding a visit to the Department of Meteorology at Stockholm University and the Chalmers Technological Institute in Sweden for work on the SMR L1b and L2 data. The Odin satellite is funded jointly by the Swedish National Space Board (SNSB), the Canadian Space Agency (CSA), the Centre National d'Études Spatiales (CNES) in France and the National Technology Agency of Finland (Tekes). Since April 2007, Odin has been a third-party mission of the European Space Agency (ESA). Initial funding for development of the MOLIERE code was provided by CNES.