Modeling Equatorial Magnetic Perturbation Using the 3D Electrodynamo model: A case study in March 2009

Self-consistent modeling of magnetic perturbations at LEO altitudes and on the ground helps us better understand the causes of observed electrodynamical variability of the equatorial thermosphere and Ionosphere. In this study, magnetic perturbations associated with ionospheric currents simulated using a 3-D dynamo model of Maute and Richmond [2017] and the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) are being compared with space-based and ground-based magnetometer observations during March 2009. Magnetic perturbation observations from the Challenging Minisatellite Payload (CHAMP) satellite and ground-based magnetometer sites participating in the SuperMAG data service are used. TIEGCM is here driven with realistic magnetospheric and meteorological forcing specified by data assimilation data products. Specifically, troposphere and stratosphere wave forcing is specified using the Modern-Era Retrospective analysis for Research and Applications (MERRA) metrological reanalysis, and ionospheric convection and auroral particle precipitation patterns are obtained with the Assimilative Mapping of Geospace Observations (AMGeO). Roles of thermospheric wind and ionospheric conductivity changes due to tidal variability and induced electric current variation on the ground and over the ocean where conductivity characteristics are considerably different in causing observed day-to-day variability and longitudinal variation of equatorial ionospheric electrodynamics are being carefully investigated.

Maute, A., & Richmond, A. D. (2017). Examining the Magnetic Signal Due To Gravity and Plasma Pressure Gradient Current With the TIE-GCM. Journal of Geophysical Research: Space Physics, 122(12), 12486-12504. https://doi.org/10.1002/2017JA024841