Impacts of the soft electron precipitation on the neutral density during geomagnetic storms

Abstract:

Soft (<1 keV) electron precipitations are typically underestimated in general circulation models (GCMs), which may result in inaccurate neutral density estimations during geomagnetic storms and further cause challenges in the satellite tracking. To evaluate how soft electron precipitations can influence the storm-time neutral density estimation in GCMs, a recently developed electron precipitation model (ASHLEY-A) based on in-situ electron precipitation measurements from the Defense Meteorology Satellite Program (DMSP) F16-F18 satellites has been coupled into the global ionosphere thermosphere model (GITM). ASHLEY-A relaxes assumptions on the energy spectrum of incident electrons and directly provides the differential energy fluxes in 19 DMSP energy channels, so that the soft electron precipitation can be better specified in the ASHLEY-A. The simulation results are compared with those from default GITM simulations and Low-Earth-Orbit (LEO) satellites measurements at different altitudes to examine the effects on the ionosphere and thermosphere system associated with the improved soft electron precipitation specifications. Moreover, GITM simulations are carried out for different types of events associated with various geophysical conditions.