Modelling of geomagnetically induced currents during geomagnetic storms using geoelectric fields and auroral electrojet indices

The effects of space weather on ground based technology mostly occur due to the varying geomagnetic field during geomagnetic storms, producing geomagnetically induced current (GIC). Space weather storms involve intense and rapidly varying electric currents in the ionosphere, which create geoelectric and geomagnetic fields at the Earth's surface. In this study we have investigated some intense geomagnetic storms: September 18th, 2000; March 31th, 2001; October 21st, 2001; November 6th and 24th, 2001; October 29th and 31st, 2003 and November 9th, 2004. The electric field for each day has been computed using ground conductivity and geomagnetic recordings. The conductivity models are determined by least square fit between the observed and predicted GIC values. Our results show that GIC are strongly correlated with the geoelectric field, and also with eastward and westward auroral electrojet indices and time derivatives of the horizontal geomagnetic field. Root mean square error statistical test has been employed to evaluate the accuracy of the models used.