Global Ionospheric Responses in Both Hemispheres during the 2015 St. Patrick's Day Storm

On St. Patrick's Day, March 17, 2015, the first historical intense geomagnetic storm (Dst < −200 nT) of the 24^th solar cycle occurred. This storm caused complex effects around the globe. Geomagnetic storms are a concern for society, especially the strongest storms and how they affect satellite communications, navigations and power grids. Using Global Positioning System (GPS) data to compute the Total Electron Content (TEC) of the Earth's ionosphere is one of the most common methods used to investigate perturbations in the ionosphere. GPS TEC variations may reveal ionospheric anomalies, which might endanger the continuity and availability of GPS performance metrics. Thus, the ionospheric consequences of geomagnetic storms have been researched intensively for decades but are still not fully understood. This study investigates the ionospheric behaviour during an intense geomagnetic storm that occurred from 14 - 24 March 2015. In particular, we used geomagnetic indices and GPS TEC data from various IGS stations all over the world to give a comprehensive analysis of how the ionospheric total electron content changes in both the northern and southern hemispheres at different latitude and longitude stations.