Q; EUV; vs. Other EUV Proxies: A Re‐Evaluation of Solar EUV Proxies for Thermospheric and Space Weather Investigations
Journal Article
Overview
abstract
Abstract; ; F; 10.7; , Mg II, and F; 30; are widely used proxies for variability in solar Extreme UltraViolet (EUV, 5–120 nm) irradiance. An alternative proxy for solar EUV variability is Q; EUV; , an indirect measure of total solar EUV irradiance, retrieved from observations of Earth's Far UltraViolet (FUV, 120–300 nm) airglow and from empirically modeled solar EUV spectra. Daily Q; EUV; derived from FUV airglow is available from the Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) Global Ultraviolet Imager (GUVI) and Global‐scale Observations of the Limb and Disk (GOLD) missions, as is Q; EUV; from empirical solar EUV spectrum. Spectral measurements from GOLD are also used to retrieve lower‐middle thermospheric temperature, termed as T; disk; . The availability of GOLD T; disk; and Q; EUV; provides a new opportunity to reassess the effectiveness of various solar EUV proxies for thermospheric use. This investigation showed that Q; EUV; has the best correlation with GOLD T; disk; compared to all the other EUV proxies. Therefore, it can be used as an alternate proxy for total solar EUV variability, on day‐to‐day to solar cycle time scales.;
