Statistical comparison of the ICME's geoeffectiveness of different types and different solar phases from 1995 to 2014

Abstract

AbstractThe geoeffectiveness of interplanetary coronal mass ejections (ICMEs) is an important issue in space weather research and forecasting. Based on the ICME catalog that we recently established and the Dst indices from the World Data Center, we study and compare the geoeffectiveness of ICMEs of different in situ signatures and different solar phases from 1995 to 2014. According to different in situ signatures, all ICMEs are divided into three types: isolated ICMEs (I‐ICMEs), multiple ICMEs (M‐ICMEs), and shock‐embedded ICMEs (S‐ICMEs), resulting in a total of 363 group events. The main findings of this work are as follows: (1) Fifty‐eight percent of ICMEs caused geomagnetic storms with Dstmin≤−30 nT. Further, large fraction (87%) of intense geomagnetic storms are caused by ICME groups and their sheath regions. (2) Numbers of ICME groups and the probabilities of ICME groups in causing geomagnetic storms varied in pace with the solar cycle. Meanwhile, the ICME groups and the probabilities of them in causing geomagnetic storms in Solar Cycle 24 are much lower than those in Solar Cycle 23. (3) The maximum value of the intensity of the magnetic field (B), south component of the magnetic field (Bs), and dawn‐dusk electric field vBs are well correlated with the intensity of the magnetic storms. (4) Shock‐embedded ICMEs have a high probability in causing geomagnetic storms, especially intense geomagnetic storms. (5) The compression of shock on the south component of magnetic field is an important factor to enhance the geoeffectiveness of S‐ICMEs structures.