Geoeffectiveness of Interplanetary Coronal Mass Ejections as Drivers of Ground Based Magnetic Field Fluctuations

Global geomagnetic indices have proven to be invaluable tools for the investigation of the interplanetary drivers of geomagnetic disturbances. Mature global geomagnetic indices, such as Dst, yield multi-decadal time-series of geomagnetic activity levels. The geoeffectiveness of space weather drivers is commonly assessed using these global indices, yet they are not designed to capture the rapid and possibly localised geomagnetic disturbances thought to be responsible for unwanted effects on ground-based technologies (e.g. geomagnetically induced currents in power grids). Using data from the SuperMAG project (a collaboration of organisations and agencies operating over 300 ground-based magnetometers) we have explored indices that capture geomagnetic variations over spatially limited regions and derived from parameters not used in traditional indices (e.g. dB/dt). The geoeffectiveness of ICMEs is investigated, particularly in relation to the disturbances likely to result in geomagnetically induced currents.