Thermospheric Density, Composition, and Temperature From GOES‐R/SUVI Solar Occultations
Journal Article
Overview
abstract
AbstractA new data set of atomic oxygen (O) and molecular nitrogen () number density profiles, along with thermospheric temperature profiles between 180 and 500 km, has been developed. These profiles are derived from solar occultation measurements made by the Solar Ultraviolet Imager (SUVI) on the GOES‐R satellites, using the 17.1, 19.5, and 30.4 nm channels. Discussed is the novel approach and methods for using EUV solar occultation images for measuring the thermospheric state. Measurement uncertainties are presented as a function of tangent altitude. At 250 km, number density random uncertainties are found to be 8% and 17% for O and , respectively, and the random uncertainty for neutral temperature is 3%. The impact of effective cross section uncertainty on retrieval bias was assessed, revealing that the largest effects occur where O and are, respectively, the minor absorber. In contrast, total mass density and O/ ratios show substantially lower sensitivity, with biases that remain small or nearly constant with altitude. Total mass density comparisons with the NRLMSIS 2.0 model show good agreement at the dusk terminator (average difference −2%), but larger discrepancies at dawn (−26%), particularly during low solar activity. Density comparisons with the IDEA‐GRACE‐FO and Dragster models show dawn/dusk differences of −24%/−2% and +2%/+13%, respectively. As this measurement relies only on real‐time NOAA space weather SUVI images, these density and temperature profiles could be produced in real‐time, supporting critical space weather monitoring and prediction, and helping fill a long‐standing observational gap in thermospheric temperature and density.
