Shock Orientations, Magnitudes and Characteristics of ICMES

Forbush decrease (Fd) event in cosmic rays shows a sudden decrease in count rates of neutrons followed by gradual recovery, typically lasting for several days. In this study we have shorted out 54 events of Forbush decrease from the listings of hourly plots of cosmic ray intensity for the period of 1996 to 2007. The occurrence of forbush decrease is found to be higher during high solar activity period. The correlation between magnitudes of cosmic ray Forbush decreases and magnitude of geomagnetic storms are found positive and high for solar cycle 23.CME speed show normal correlation with Fd magnitudes. Large amount of Fds are associated with CMEs and M-Class solar flares.