INVESTIGATION OF IONOSPHERIC OF REMOTE-SENSING USING THE 834-ANGSTROMAIRGLOW

We have studied the feasibility of ionospheric O+ remote sensing throu gh measurements of the 834-Angstrom airglow. Our approach uses discret e inverse theory (DIT) to retrieve O+ number density profiles from the airglow. Our tests of this method assume observations by a limb-scann ing system on an orbiting satellite at an altitude of 850 km. The scan s cover the range of 10 degrees-26.5 degrees below horizontal, consist ent with future multiyear missions. To provide a baseline assessment, we represent the synthetic ground truth (''true'') O+ distribution as a generalized Chapman-type profile with three or more parameters, base d on our recent analysis of topside incoherent scattering radar data a nd standard ionospheric models (International Reference Ionosphere 199 0 (IRI-90) and the parameterized ionospheric model (PIM)). The DIT met hod proves to be robust, converging to an accurate solution for a wide variation in ionospheric profiles. Using a detailed statistical error analysis of synthetic limb intensity data derived from the IRI-90 and PIM models, we work a difficult test case following from recent comme nts on the concept of 834-Angstrom remote sensing of ionospheric O+. W e find that the DIT method can correctly distinguish between distinctl y different F layers that produce nearly identical intensity profiles, consistent with instrument specifications for future missions.