Seminar on Physics and Chemistry of the Atmosphere (Abstract)

Retrieval of stratospheric ozone profiles from ODIN/OSIRIS limb spectra

Christian von Savigny
csavigny@stpl.cress.yorku.ca
University of Toronto

23.11.2001, 13.00 c.t.
Raum N3380 OSIRIS, the Optical Spectrograph and InfraRed Imager System is one of two instruments aboard the Swedish/Canadian/Finnish/French Odin satellite. Odin was launched in February 2001 from eastern Siberia into a sun-synchronous, near-terminator orbit with a descending node at 6:00 Local Solar Time. OSIRIS scans the atmosphere between tangent heights of 10 km and 70 km in steps of about 2 km, and takes limb-radiance spectra covering the spectral range from 280 nm to 800 nm with a spectral resolution of about 1 nm.

This talk describes a method to infer vertical profiles of stratospheric ozone density from limb-spectra, based on the application of optimal estimation on normalized limb-radiance profiles at selected wavelengths covering the Huggins- and Chappuis-bands of ozone. The weighting functions required for the recovery are calculated with the pseudo-spherical multiple scattering RT code LIMBTRAN. McPeters et al. [2000] (GRL 27, 17, 2601) successfully applied the method to infer ozone density profiles from limb radiance measurements carried out with the SOLSE/LORE instruments flown on the NASA's Space Shuttle.

Sample recoveries as well as a comprehensive sensitivity study to estimate the systematic uncertainties caused by inaccurate knowledge of ground albedo, stratospheric aerosols, clouds, etc. will be presented. The method is shown to be robust and comparisons of recovered ozone profiles with profiles obtained with ozonesondes and other satellite instruments indicate agreement within approximately 10% between 15 km and 45 km.