  We have used Simple Denoising Algorithm using Wavelet Transform on the daily
Forbush decrease data from the year 1967 to 2003. For this data we observe
periodicity around 5-6, 11, 13, 15 and 24 years. For all the obtained peaks
corresponding confidence levels are higher than 95%. We observe that the
periodicity of around 5-6 years is common to solar flare data, major proton
event data and solar neutrino flux data. Because of that common periodicity, it
is suggested that Forbush decrease with the solar flare data and major solar
proton event data together with solar neutrino flux variations, behave
similarly and may have a common origin.

Astrophysics