Two-Satellite Comparison of Molecular Oxygen Singlet Delta in the Mesosphere

Optical Spectrograph and InfraRed Imager System (OSIRIS) on the Odin satellite has been in full operation since November, 2001. OSIRIS routinely produces, among other parameters, 2-D maps of the Oxygen Infrared Atmospheric band airglow, O2(a1Δg), with the vertical and horizontal (along the satellite track) resolution of 1 km and 27 km respectively. The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite has been operational since January, 2002. SABER measures different atmospheric constituents, including the vertical profiles of O2(a1Δg), with the 0.3-0.4 km spacing. As OSIRIS and SABER have different line-of-sight directions, it is valuable to compare the two datasets for various coincidence criteria and analyze the results for the steady state and non-steady state conditions. Apart from direct validation and improving the OSIRIS and SABER O2(a1Δg) retrieval algorithms, such comparisons also provide important information for chemical models as the different viewing geometries and certain local solar time variations at the instrument tangent points may help to improve our understanding of the chemical processes in the mesosphere. In this paper we discuss the systematic and random differences in the OSIRIS and SABER O2(a1Δg) climatology, as well as the individual coincidences for steady state and non-steady state conditions.