Characteristic features of large geomagnetic storms observed during solar cycle 23

305-312 A set of 90 large geomagnetic storms, associated with disturbance storm time (Dst) (decreases of more than 100 nT) observed during 1997-2007, have been analysed. The analysis included various characteristics features as well as seasonal and solar cycle dependence of these storm events. It has been found that all severe geomagnetic storms are associated with coronal mass ejections (CMEs) during the solar cycle 23. A comparative study of 11 severe geomagnetic storms (Dst ≤ -250 nT) and their associative solar driver have also been discussed.