A method for recovering stratospheric minor species densities from the Odin/OSIRIS scattered-sunlight measurements

A method for recovering minor species density profiles in the stratosphere from observations made with the OSIRIS (optical spectrograph and infrared imager system) instrument on the Odin satellite is described. The OSIRIS instrument measures limb radiances of scattered sunlight over the spectral range 2800 to 8000 A, for tangent heights ranging from 10 to 100 km. We describe how the limb spectra may be processed using the DOAS (differential optical absorption spectroscopy) technique to derive apparent column densities for the minor atmospheric constituents O-3, NO2, OClO, and BrO. We also show how these column densities, measured over a range of tangent heights, may be inverted using an iterative least-squares technique to determine the local density profiles, The procedures are illustrated using simulated limb radiances generated with a realistic OSIRIS instrument model.