  The relationship between cosmic ray intensity decreases and solar events is
still an open field of space research. In this work a complete study of solar
events occurred from January 2003 to December 2005, is considered. This
three-years time period characterized by an unexpected activity of the Sun was
divided into 27-day intervals starting from BR 2313 (06.01.2003) to 2353
(21.12.2005), generating diagrams of the cosmic ray intensity data recorded at
the Athens Neutron Monitor Station. This station is working at an altitude of
260m and cut-off rigidity 8.53GV provided to the Internet high-resolution data
in real-time. A mapping of all available solar and interplanetary events, such
as solar flares with importance M and X, coronal mass ejections (Halo and
Partial) was done. As we are going down from the solar maximum to the declining
phase of the 23rd solar cycle, a statistical overview of the corresponding
relationship among these phenomena, the significant percentage of the
connection of Halo CMEs and solar flares and the respective connection to
Forbush decreases on yearly and monthly basis are discussed. The close
association, as well as a probable quantitative analysis, between solar events
is being denoted. The role of extreme solar events occurred in October /
November 2003 and January 2005 is also discussed. Obtained results may be
useful for predictions of transient solar events and space weather forecasting.
