Thermospheric Composition and Solar EUV Flux from the Global-scale Observations of the Limb and Disk (GOLD) mission | CU Experts

Observations of far-ultraviolet (FUV) dayglow by the Global-scale; Observations of Limb and Disk (GOLD) mission provide a new opportunity; to monitor relative composition changes in the upper atmosphere as well; as solar extreme ultraviolet (EUV) variability. Relative composition; changes are quantified by ΣO/N2, the column density ratio of atomic; oxygen to molecular nitrogen, while QEUV provides a measure of the solar; EUV energy flux from 1 to 45 nm into the upper atmosphere. This spectral; range provides the ionizing radiation which ultimately results in FUV; airglow emission produced by photodissociation and photoelectron impact.; The quantities ΣO/N2 and QEUV are derived from GOLD FUV observations; through lookup tables that are constructed using a first-principles; photoelectron transport model. The two FUV emissions used are O I 135.6; nm and the N2 Lyman-Birge-Hopfield (LBH) bands. We present an overview; of the theoretical basis for the algorithms and practical considerations; for application to GOLD data. The effects of uncertainties in electron; impact cross sections, off-nadir viewing, and instrument artifacts are; reviewed. We also discuss GOLD Level 1C DAY, Level 2 data products ON2; and QEUV, and present representative samples of each.

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