Disk Images of Neutral Temperature From the Global-Scale Observations of the Limb and Disk (GOLD) Mission

Observations of far-ultraviolet (FUV) dayglow by the Global-scale Observations of Limb and Disk (GOLD) mission provide an opportunity for quantifying the global-scale response of the thermosphere to solar extreme-ultraviolet variability and geomagnetic activity. Relative temperature changes can be measured by monitoring changes in the rotational structure observed in molecular nitrogen Lyman-Birge-Hopfield (LBH) band emissions. We present a new technique for deriving effective neutral temperatures from GOLD FUV observations using optimal estimation fits to spectra containing LBH band emissions. We provide an overview of the theoretical basis for the GOLD Level 2 TDISK algorithm. Effects on derived effective neutral temperatures from instrument artifacts and particle background are reviewed. We also discuss GOLD Level 1C DAY and Level 2 TDISK data products and present representative examples of each. We show that effective neutral temperatures vary with local time, exhibit a strong dependence on season and solar zenith angle, and correlate strongly with geomagnetic and solar activity. Finally, we present results from a preliminary data product validation that show good agreement with coincident GOLD exospheric temperatures and predictions from a global reference atmospheric model. Observations of the Earth's daytime ultraviolet emission by the Global-scale Observations of Limb and Disk (GOLD) mission provide an opportunity to determine how geomagnetic activity alters the temperature of Earth's upper atmosphere and enable us to quantify the global-scale response of the middle thermosphere to solar variability. We provide an overview of the GOLD upper atmosphere neutral temperature data product and present representative measurement examples. We show that derived temperatures vary with local time, exhibit a strong seasonal dependence, correlate strongly with geomagnetic and solar activity, and show good agreement with coincident GOLD exospheric temperatures and atmospheric model predictions. Neutral temperatures derived from binned spectra of far ultraviolet emission observed by the Global-scale Observations of the Limb and Disk (GOLD) instrument are presented Neutral temperatures vary with local time, show a strong seasonal dependence, and correlate strongly with geomagnetic and solar activity A preliminary validation shows good agreement with coincident GOLD exospheric temperatures and a global reference atmospheric model