An empirical Kp-dependent global auroral model based on TIMED/GUVI FUV data

Abstract

In this paper, a new empirical formulation of the mean energy and energy flux of precipitating electrons in the auroral oval is presented. Global far ultraviolet (FUV) observations by Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/Global Ultraviolet Imager (GUVI) (N 2 Lyman–Birge–Hopfield small (LBHS) 140.0–150.0 nm and Lyman–Birge–Hopfield long (LBHL) 165.0–180.0 nm) are used to estimate the mean energy (Eo) and energy flux ( Q) of precipitating electrons based on an auroral model (Boltzman Three Constituent—B3C) and airglow model (Atmospheric Ultraviolet Radiance Integrated Code—AURIC). For the first time, a FUV-based and Kp-dependent model of global auroral products (Eo, Q) was developed using 4 years (2002–2005) of GUVI data and Epstein function fitting. This FUV-based model covers all Kp ranges (0–9). Due to the large spatial coverage of FUV auroral images, the FUV measurements lead to a more consistent estimation of the auroral hemispheric power. The model described here will be useful in a number of applications: global ionosphere/thermosphere simulations, space weather forecasting and nowcasting, and global ionospheric models.