Latitudinal variations of ionospheric-thermospheric responses to Geomagnetic Storms from Multi-Instruments

Abstract

Abstract. Scintillations of transionospheric satellite signals during geomagnetic storms can severely threaten navigation accuracy and the integrity of space assets. We analyze vertical Total Electron Content (vTEC) variations from the Global Navigation Satellite System (GNSS) at different latitudes around the world during the geomagnetic storms of June 2015 and August 2018. The resulting ionospheric perturbations at the low-and mid-latitudes are investigated in terms of the prompt penetration electric field (PPEF), the equatorial electrojet (EEJ), and the magnetic H component from INTERMAGNET stations near the equator. East and South-East Asia, Russia, and Oceania exhibited positive vTEC disturbances, while South American stations showed negative vTEC disturbances during both storms. We also analyzed the vTEC from the Swarm satellites and found similar results to the GNSS retrieved vTEC during different phases of both geomagnetic storms. Moreover, we observed that ionospheric plasma tended to increase rapidly during the afternoon in the main phase of the storms. At nighttime, the ionosphere depicted an opposite behavior under similar conditions. The equatorial ionization anomaly (EIA) crest expansion to mid and high latitudes is driven by PPEF during daytime at the main and recovery phases of the storms. The magnetic H component exhibits a longitudinal behavior along with the EEJ enhancement near the magnetic equator.