  In the present paper a systematic study is carried out to validate the
similarity or degree of relationship between daily terrestrial cosmic rays
intensity and three characteristics of about evolution of solar corona, like a
number of sunspots and flare index observed in the solar corona and to Ap index
for regular magnetic field variation caused by regular solar radiation changes.
The study is made in a range including three solar cycles starting with the
cycle 21 (year 1976) and ending on cycle 23 (year 2008). The technique used in
this case will be the use of the cross-correlation technique to establish
patterns and dependence on the behavior of both variables. This study focused
on the time lag calculation for these variables and found a maximum of negative
correlation over $CC_1\approx 0.85$, $CC_2\approx 0.75$ and $CC_3\approx 0.63$
with an estimation of 181, 156 and 2 days of deviation between maximum/minimum
of peaks for the intensity of cosmic rays related with sunspot number, flare
index and Ap index regression, respectively.
