Investigating Possible Causes of the Nighttime Ionospheric Localized Enhancement (NILE) via Data Assimilation

Jiahui Hu, Sarah E. McDonald, Aurora López Rubio, Alex Chartier, Gary S. Bust, Seebany Datta-Barua

Abstract:	The Nighttime Ionospheric Localized Enhancement (NILE) is a plasma enhancement sometimes observed in the local nighttime during significant geomagnetic storms, often over Florida. To investigate the physical mechanisms that might contribute to this phenomenon, we use the Estimating Model Parameters from Ionospheric Reverse Engineering (EMPIRE) algorithm, assimilating ion drift measurements in addition to plasma density rates, to estimate the mid-latitude electric potential and the ion drifts associated with it during the NILE. For this study, the 17 March 2015 storm is investigated because it has ion velocity measurements from various locations available for ingestion and for validation. The Super Dual Auroral Radar Network (SuperDARN) data are assimilated in EMPIRE, and Millstone Hill incoherent scatter radar (ISR) measurements are used to be the validation data set. Furthermore, we investigate the geographic east-north-up components of the ion velocity from the EMPIRE outputs in the F region above Miami, Florida, to examine whether the proposed theories of the pre-reversal and enhancement and polarization terminator might be contributing factors to the NILE.
Published in:	Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022) September 19 - 23, 2022 Hyatt Regency Denver Denver, Colorado
Pages:	2989 - 3001
Cite this article:	Hu, Jiahui, McDonald, Sarah E., Rubio, Aurora López, Chartier, Alex, Bust, Gary S., Datta-Barua, Seebany, "Investigating Possible Causes of the Nighttime Ionospheric Localized Enhancement (NILE) via Data Assimilation," Proceedings of the 35th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2022), Denver, Colorado, September 2022, pp. 2989-3001. https://doi.org/10.33012/2022.18342
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