Comment on "Sizes and relative geoeffectiveness of interplanetary   coronal mass ejections and the preceding shock sheaths during intense storms   in 1996-2005" by J. Zhang et al
  Recently Zhang et al. [2008] presented a statistical study of sizes and relative geoeffectiveness of ICMEs (bodies of magnetic clouds) and preceding sheaths for 46 events responsible for intense (Dst < -100 nT) geomagnetic storms in 1996-2005 in which only a single ICME was responsible for generating the storm. Here we would like to comment several results and conclusions of this paper. 
Yu. I. Yermolaev and M. Yu. Yermolaev