Comparative Hypothesis Testing of Auroral L-band Scintillation Layer

Ionospheric irregularities scintillate electromagnetic waves, such as Global Positioning System (GPS) signals, as the waves pass through the ionosphere, especially in auroral zones. Identification of the ionosphere scattering layer is an important factor in understanding the cause of scintillation. This work implements two techniques to determine whether the scattering might be in the E or F layer. The first technique is an updated process of Sreenivash et al. 2020 , in which the Poker Flat Incoherent Scatter Radar (PFISR) maximum electron densities and their uncertainties are used to hypothesize the layer in which scattering has occurred. The density based method predicts a majority of F region scintillation events for 2014, with a majority of E region events found for 2015 to 2019. The second technique consists of using optical all-sky images (ASI) from 2014 to 2018. The ratio of the 630 nm (red) to the 428 nm (blue) intensity is used to hypothesize the scattering layer with ASI. The decision threshold is set to 1.35 based on GLOW modeling. From 2014-2018 there are 185 events that have both PFISR data and ASIs with clear viewing conditions and alignment to within 25 degrees of magnetic zenith. There is an agreement between the two methods for 130 (70%) events. Most disagreements occur for events for which density hypothesizes scattering to occur in the F region, but the energy hypothesizes E layer scattering.