Statistical studies of geomagnetic storms with peak Dst≤−50 nT from 1957 to 2008

A catalog of 1377 geomagnetic storms with peak Dst (Dstp)≤−50 nT for the period 1957–2008 has been compiled. The dependence of Dstp on the solar cycle and annual variation are studied in this paper. It is found that geomagnetic storm peak intensity distribution can be described by an exponential form, P(Dstp)≈1.2e−Dstp/34, where P is the probability of geomagnetic storm occurrence with a given value Dstp. The updated solar cycle and annual distribution of geomagnetic storms have confirmed the expected behavior. For the solar cycle variation, geomagnetic storms display a two-peak distribution, with one peak close to solar maximum and the other a few years later in the beginning of the declining phase. Geomagnetic storms follow the well-known seasonal variation of geomagnetic activity. More intense storms show a peak in probability occurrence in July, confirming previous observations. These results are of practical importance for space weather applications.

► A catalog of 1377 geomagnetic storms (Dst ≤−50 nT) for the period 1957–2008 was compiled.
► It is found that geomagnetic storm distribution can be described by an exponential form.
► Geomagnetic storms display a two-peak distribution with the solar cycle.
► Geomagnetic storms follow the well-known seasonal variation of geomagnetic activity.
► More intense storms show a peak in probability occurrence in July.