Comment on A statistical comparison of solar wind sources of moderate and intense geomagnet.pdf

a r X i v : p h y s i c s / 0 6 0 3 2 5 1 v 1 [ p h y s i c s .s p a c e - p h ] 2 9 M a r 2 0 0 6 JOURNAL OF GEOPHYSICAL RESEARCH, VOL. ???, XXXX, DOI:10.1029/, Comment on ”A statistical comparison of solar wind sources of moderate and intense geomagnetic storms at solar minimum and maximum” by Zhang, J.-C., M. W. Liemohn, J. U. Kozyra, M. F. Thomsen, H. A. Elliott, and J. M. Weygand Yu. I. Yermolaev, M. Yu. Yermolaev and I. G. Lodkina Space Plasma Physics Department, Space Research Institute, Profsoyuznaya 84/32, Moscow 117997, Russia Yu. I. Yermolaev, M. Yu. Yermolaev, I. G. Lodkina, Space Plasma Physics Department, Space Research Institute, Profsoyuznaya 84/32, Moscow 117997, Russia. (yermol@iki.rssi.ru) D R A F T February 2, 2008, 7:13am D R A F T X - 2 YERMOLAEV ET AL.: COMMENT Abstract. (No abstract for Comment) D R A F T February 2, 2008, 7:13am D R A F T YERMOLAEV ET AL.: COMMENT X - 3 Conditions in the solar wind resulting in magnetic storms on the Earth are a subject of long and intensive investigations. Recently Zhang et al., 2006 [@] [Zh06 hereafter], published a paper, where they used superposed epoch analyses method to study solar wind features during 549 geomagnetic storms. Unfortunately, the used methodical approach has not allowed to improve essentially understanding of relation of magnetic storms with conditions in the solar wind, and first of all for the following reasons. 1. Authors of Zh06 selected data on 4 different categories: (1) moderate storm at solar minimum, (2) moderate storm at solar maximum, (3) strong storm at solar minimum, and (4) strong storm at solar maximum. In the strict sense, this selection approach has not sufficiently serious physical arguments. On the one side, authors of Zh06 correctly noted that the storms are generated by different types of solar wind: ICME (MC) including Sheath and body of ICME and CIR (see, for instance, Vieira et al., 2004 [@]; Huttunen and Koskinen 2004 [@]; Yermolaev et al., 2005 [@]; Yerm