Validation of retrieval techniques using Atmosphere Explorer data

A technique for retrieving key thermospheric atomic oxygen densities, molecular nitrogen densities and temperatures for the altitudes between 200 to 400 km from space-based remote thermospheric airglow emission measurements is presented. The accuracy of the retrievals has been determined by using remote airglow emission measurements and in situ measurements of densities and temperatures from the Atmosphere Explorer-C (AE-C) satellite mission. The retrieval technique uses remote-sensing measurements of O{dollar}sp+(sp2{dollar}P) ion at 7320-30 A airglow emission recorded by the AE-C Visible Airglow Experiment (VAE) instrument. The retrieved values were compared to in situ measurements of densities and temperatures made by AE-C Open Source Mass Spectrometer (OSS), and the Neutral Atmosphere Temperature Experiment (NATE), respectively.; The technique was shown to retrieve the thermospheric atomic oxygen densities within 19% of the known values. which is well within the accuracy of the measurements. The retrieved temperatures agreed to within 10% of the measured temperatures. It was found that the viewing geometry of the VAE instrument was such that the airglow measurements did not contain enough information to be able to retrieve the molecular nitrogen densities. Also, it was shown that the retrieval technique was robust and that it could be used under operational conditions to retrieve atomic oxygen densities and temperatures between 200 and 400 km above the Earth's surface on a continuous basis with a high degree of confidence.