Investigation of the Severe Geomagnetic Storm Effects on Ionosphere at Nighttime through ROTI

In this study, the effect of the intense geomagnetic storm on the Earth's ionosphere during the period 07-08 September 2017 with the early arrival of coronal mass discharges associated with X-9 flares on the 6 September 2017 was investigated through ROTI, an index of Total Electron Content (TEC) ratio (ROT). The study was conducted with TEC values obtained from ten stations connected to the IGS-GPS network for five different latitude regions. As a result, it was observed that during the storm, the disturbances that occurred in the high latitude region of the southern hemisphere were more disturbed than the high latitude region of the northern hemisphere at nighttime. In addition, ROTI values were found to be higher than other days on disturbed days (07-08 September 2017)