Validation of Odin/OSIRIS stratospheric NO₂ profiles

Samuel M. Brohede (1) , Craig S. Haley (2) , Chris A. Mclinden (3) , Christopher E. Sioris (3, 4) , Donal P. Murtagh (1) , Svetlana V. Petelina (4) , Edward J. Llewellyn (4) , Ariane Bazureau (5) , Florence Goutail (5) , Cora E. Randall (6, 7) , Jerry D. Lumpe (8) , Ghassan Taha (9) , Larry W. Thomasson (10) , Larry L. Gordley (11)

1 Department of Radio and Space Science [Göteborg]
2 CRESS - Centre for Research in Earth and Space Science [Toronto]
3 ECCC - Environment and Climate Change Canada
4 Department of Physics and Engineering Physics [Saskatoon]
5 SA - Service d'aéronomie
6 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
7 ATOC - Department of Atmospheric and Oceanic Sciences [Boulder]
8 Computational Physics, Inc.
9 SSAI - Science Systems and Applications, Inc. [Lanham]
10 LaRC - NASA Langley Research Center [Hampton]
11 GATS Inc.

This paper presents the validation study of stratospheric NO₂ profiles retrieved from Odin/OSIRIS measurements of limb-scattered sunlight (version 2.4). The Optical Spectrograph and Infrared Imager System (OSIRIS) NO₂ data set is compared to coincident solar occultation measurements by the Halogen Occultation Experiment (HALOE), Stratospheric Aerosol and Gas Experiment (SAGE) II, SAGE III, and Polar Ozone and Aerosol Measurement (POAM) III during the 2002–2004 period. Comparisons with seven Systeme d'Analyse par Observation Zenithal (SAOZ) balloon measurements are also presented. All comparisons show good agreement, with differences, both random and systematic, of less than 20% between 25 km and 35 km. Inconsistencies with SAGE III below 25 km are found to be caused primarily by diurnal effects from varying NO₂ concentrations along the SAGE III line-of-sight. On the basis of the differences, the OSIRIS random uncertainty is estimated to be 16% between 15 km and 25 km, 6% between 25 km and 35 km, and 9% between 35 km and 40 km. The estimated systematic uncertainty is about 22% between 15 and 25 km, 11–21% between 25 km and 35 km, and 11–31% between 35 km and 40 km. The uncertainties for AM (sunrise) profiles are generally largest and systematic deviations are found to be larger at equatorial latitudes. The results of this validation study show that the OSIRIS NO₂ profiles are well behaved, with reasonable uncertainty estimates between 15 km and 40 km. This unique NO₂ data set, with more than hemispheric coverage and high vertical resolution will be of particular interest for studies of nitrogen chemistry in the middle atmosphere, which is closely linked to ozone depletion.

Mots clés: OSIRIS; validation; NO2

Domaines: Physique Atmosphérique et Océanique [physics.ao-ph]

Samuel M. Brohede, Craig S. Haley, Chris A. Mclinden, Christopher E. Sioris, Donal P. Murtagh, et al.. Validation of Odin/OSIRIS stratospheric NO₂ profiles. Journal of Geophysical Research: Atmospheres, 2007, 112, pp.D07310. ⟨10.1029/2006JD007586⟩. ⟨hal-00145004⟩