Solar excursion phases during the last 14 solar cycles

The 13.5-day periodicity in the Sun, solar wind, and geomagnetic activity: The last three solar cycles

We make a detailed analysis of the 13.5-day periodicity of the solar chromosphere, the nearEarth solar wind, interplanetary magnetic field and geomagnetic activity during the last three solar cycles. The 13.5-day periodicity is a real quasi-periodicity whose amplitude varies sizably with time, attaining occasionally values larger than, for example, the amplitude of the 27-day periodicity. In ca...

Total solar irradiance variability: What have we learned about its variability from the record of the last three solar cycles?

Since November 1978 a set of total solar irradiance (TSI) measurements from space is available, yielding a time series of almost 30 years. Presently, there are three TSI composites available, called PMOD, ACRIM and IRMB, which are all constructed from the same original data, but use different procedures to correct for sensitivity changes. The PMOD composite is the only one which also corrects t...

Solar Flare Cycles

We present a review of different solar flare periodicity intervals. Our analysis includes a statistical investigation of flare occurrence and N-S hemispheric distribution over the last three 11-yr solar cycles (SCs 21-23, corresponding to the period 1976-2001). Moreover, we try to estimate if there is any connection between the flare activity and the strength of solar cycles. For that purpose, ...

Solar Variability and Climate Cycles

Nonlinear analysis of solar cycles

In this paper, the recent improvement of the Wolf sunspot time–series by Hoyt and co-workers has been analysed with the Global Flow Reconstruction (GFR) method (Serre et al. 1996a and b). A nonlinear 4–dimensional chaotic model has been extracted from the data which captures the principal characteristic features of the sunspot group time–series. The hypothesis of interactions between magnetic m...