Estimating Auroral Characteristics using GOLD Disk Images

Global-scale Observations of the Limb and Disk (GOLD) is an ultraviolet (UV) imaging spectrograph on a geostationary satellite over Brazil. The GOLD images include a good portion of the northern hemisphere auroral oval, which allows for observations of the dayside (and some nightside) aurora in the UV emission bands. This work utilizes the emission lines of atomic oxygen, 136.5 nm, and atomic nitrogen, 149.3 nm, as well as the molecular nitrogen emission bands between ~140 and 160 nm, in order to estimate the energy and flux of the electrons causing the aurora. This is made possible by comparing the absolute intensities and flux ratios of these emission bands to the output of the Global Airglow (GLOW) model, with known inputs of electron energy and flux. This work specifically focuses on the large geomagnetic storms of February, March, and April of 2023 that resulted in enhanced auroral activity. Quantifying these auroral emissions allows us to better understand the energy input into the ionosphere. This is especially valuable on the large, Earth-sized scale that GOLD offers, and it provides a useful addition to ground-based observations and small-scale in-situ measurements.