A STUDY ON THE EFFECTS OF GEOMAGNETIC STORMS ON IONOSPHERIC TOTAL ELECTRON CONTENT OVER NIGERIA USING THE GNSS

In order to study the effect of geomagnetic storms on ionospheric TEC (Total Electron Content) over Nigeria, the investigation is presented in this work. GNSS (Global Navigation Satellite System) data for year 2012 and from 3 Nigerian stations (Zaria, Abuja and Calabar) obtained from the NIGNET (Nigerian GNSS Reference Network) were used. An analysis of the diurnal TEC variations three days before and three days after the storms were done. DST (Disturbance Storm Time) indices, used for storm classification, were obtained from the World Data Centre, and only intense geomagnetic storms were considered in this work. Results from the work show that geomagnetic storms have both negative and positive effects on the ionospheric TEC, and there are occasions of both pre-storm and post-storm effects. For each of the 3 stations, varying degrees of TEC fluctuations were observed for the different geomagnetic storms. It was observed that the TEC fluctuations are dependent on peak DST value and its occurrence time depends on the storm day.