ABSTRACT
There is increasing interest in the relation between the solar activity and climate
change. Regarding the solar activity, the fractal property of the sunspot
number (SSN) has been studied by many previous works. In general, fractal
properties have been observed in the time series of the dynamics of complex
systems. The purpose of this research is to investigate the relationship between
the solar activity, total ozone, and the North Atlantic Oscillation
(NAO) from a viewpoint of multi-fractality. To detect the changes of multifractality,
we performed the wavelets analysis, and plotted the τ-function derived
from the wavelets of these time series. We showed that the solar activity
relate to the NAO, by observing the matching in monofractality or multifractality
of these indices. When the SSN increased and the solar activity was stable,
the NAO also became stable. When the SSN became maximum, the fractality
of the SSN, F10.7 flux, geomagnetic aa, and NAO indices changed from
multifractality to monofractality and those states became stable for most of
the solar cycles. When the SSN became maximum, the fluctuations became
large and multifractality became strong, and a change from multifractal to
monofractal behavior was observed in the SSN, F10.7 flux, geomagnetic aa,
and NAO indices. The strong interactions of the solar flux, geomagnetic activity,
total ozone, and NAO occur in the SSN maximum. The strong interactions
were inferred from the similarity of fractality changes and the wavelet
coherence. The influence of the solar activity on the NAO was shown from a
viewpoint of multi-fractality. These findings will contribute to the research on
the effects of the solar activity on climate change.