Ionospheric variations following the geomagnetic storm from BeiDou GEO satellite observations: A case study

As we known the geomagnetic variation is one of significant factors influencing the Earth´s ionosphere. Global Navigation Satellite System (GNSS) has been widely used in studying the ionospheric effect following the geomagnetic storm. However, it is difficult to detect the ionospheric effect during a moderate geomagnetic storm using one GPS observation arc. The BeiDou navigation satellite system (BDS) provides us a new potential means to investigate the ionospheric effect during a moderate geomagnetic storm with its Geosynchronous Earth Orbit (GEO) satellites´ observations. In this paper, the ionospheric behaviors of the geomagnetic storm with the Dst index up to -136 nT during in March 2013 are investigated using the BDS-GEO observations provided by the multi-GNSS experiments (MGEX). Total electron content (TEC) decrease is found following the Strom Sudden Commencements (SSC) and recovers to the normal gradually during the recovery phase of the geomagnetic storm, especially in the South Hemisphere. Furthermore, the ionospheric scintillation enhancement is detected by three BDS stations observations just several hours after the SSC.