Peculiar nighttime ionospheric enhancements over the Asian sector during
the May 2024 Superstorm
Abstract
This study reports a peculiar nighttime ionospheric enhancement in the
total electron content (TEC) from the geostationary (GEO) satellites in
response to the geomagnetic superstorm of May 2024. The enhancements
occurred at low to mid-latitudes during the storm’s recovery phase on
11-12 May, with the TEC values almost twice as high as the quiet ones.
Surprisingly, the nighttime ionospheric enhancements sub-rotated
westward with a speed of ~130.5 m/s. The nighttime TEC
enhancements lasted ~5-7 hours for a given location;
however, they persisted over half a day over wide longitude ranges.
Meanwhile, ionosonde data from two equatorial ionization anomaly (EIA)
stations showed a higher peak height of the F2 layer, and a significant
double-crest EIA structure was observed by both GEO TECs and in situ
electron densities from China Seismo-Electromagnetic Satellite during
this period of interest, indicating a possible contribution from
disturbance electric fields producing nighttime eastward equatorial
electric fields. Nevertheless, it remains a mystery whether the
nighttime TEC enhancement and its movement were associated with the wind
disturbance dynamo.