  The sunspot activity is the end result of the cyclic destruction and
regeneration of magnetic fields by the dynamo action. We propose a new method
to analyze the daily sunspot areas data recorded since 1874. By computing the
power spectral density of daily data series using the Mexican hat wavelet, we
found a power spectrum with a well-defined shape, characterized by three
features. The first term is the 22 yr solar magnetic cycle, estimated in our
work to be of 18.43 yr. The second term is related to the daily volatility of
sunspots. This term is most likely produced by the turbulent motions linked to
the solar granulation. The last term corresponds to a periodic source
associated with the solar magnetic activity, for which the maximum of power
spectral density occurs at 22.67 days. This value is part of the 22-27 day
periodicity region that shows an above-average intensity in the power spectra.
The origin of this 22.67 day periodic process is not clearly identified, and
there is a possibility that it can be produced by convective flows inside the
star. The study clearly shows a north-south asymmetry. The 18.43 yr periodical
source is correlated between the two hemispheres, but the 22.67 day one is not
correlated. It is shown that towards the large timescales an excess occurs in
the northern hemisphere, especially near the previous two periodic sources. To
further investigate the 22.67 day periodicity we made a Lomb-Scargle spectral
analysis. The study suggests that this periodicity is distinct from others
found nearby.
