FTA: A Feature Tracking Empirical Model of Auroral Precipitation

• Published in: Space Weather
• Main Authors: Wu, Chen, Ridley, Aaron J., DeJong, Anna D., Paxton, Larry J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union (AGU) 2021
• Subjects: M‐I coupling; data‐model comparisons; cumulative energy bins; auroral precipitation model; statistical analyses; Electrical Engineering; Engineering; Fuller; Advances in Polar Science; Arctic; Polar Science
• Online Access: https://hdl.handle.net/2027.42/167826; https://doi.org/10.1029/2020SW002629

The Feature Tracking of Aurora (FTA) model was constructed using 1.5 years of Polar Ultraviolet Imager data and is based on tracking a cumulative energy grid in 96 magnetic local time (MLT) sectors. The equatorward boundary, poleward boundary, and 19 cumulative energy bins are tracked with the energy flux and the latitudinal position. With AE increasing, the equatorward boundary moves to lower latitudes everywhere, while the poleward boundary moves poleward in the 2300–0300 MLT region and equatorward in other MLT sectors. This results in the aurora getting wider on the nightside and becoming narrower on the dayside. The peak intensity of the aurora in each MLT sector is almost linearly related to AE, with the global peak moving from pre‐midnight to post‐midnight as geomagnetic activity increases. Ratios between the Lyman‐Birge‐Hopfield‐long and ‐short models allow the average energy to be calculated. Predictions from the FTA and two other auroral models were compared to the measurements by the Defense Meteorological Satellite Program Special Sensor Ultraviolet Spectrographic Imagers (SSUSI) on March 17, 2013. Among the three models, the FTA model specified the most confined patterns with the highest energy flux, agreeing with the spatial and temporal evolution of SSUSI measurements better and predicted auroral power (AP) better during higher activity levels (SSUSI AP > 20 GW). The Fuller‐Rowell and Evans (1987) and FTA models specified very similar average energy compared with SSUSI measurements, doing slightly better by ∼1 keV than the OVATION Prime model.Key PointsThe AE‐based Feature Tracking of Aurora (FTA) model provides the energy flux and the average energy using 1.5 years of Polar Ultraviolet Imager dataThe FTA model’s grid is tied to auroral boundaries and spatial distribution: tracking a cumulative energy grid in each magnetic local time sectorFor the March 17, 2013 event, the FTA model had the most confined patterns and agreed best with Special Sensor Ultraviolet Spectrographic Imagers observations ...