Global investigation of the ionospheric irregularities during the severe geomagnetic storm on September 7–8, 2017

Abstract

In this study, the global effects of the severe geomagnetic storm on the Earth's ionosphere on September 5–9, 2017 with Coronal Mass Ejections (CMEs) associated with X-9.3 flares on September 6, 2017 were investigated by the Rate of Total Electron Content (TEC) Index (ROTI). ROTI was used as a criterion of ionospheric irregularities that took place during the storm. This study was conducted with TEC values obtained from fifty stations connected to the International GNSS System (IGS)-GPS network for five different latitude regions. As a result, it was observed that the irregularities in the high latitude regions of the southern hemisphere were greater in number in comparison with those at the high latitude regions of the northern hemisphere during the storm. It was observed that these irregularities generally occurred during the main and recovery phases of the storm at all latitudes. The weak and moderate ionospheric irregularities that developed at high latitudes during the storm were more in the southern hemisphere. Especially, moderate ionospheric irregularities in high latitudes of both hemispheres took place in eastern longitudes (18oE-160oE). However, ionospheric irregularities in the mid-latitude regions were observed in more stations at the northern hemisphere than at the southern hemisphere. Generally, ionospheric irregularities during the storm developed at eastern longitudes in all sectors.