Waldmeier relations and the solar cycle dynamics by the mean-field   dynamos
  The long-term variability of the sunspot cycle, as recorded by the Wolf numbers, are imprinted in different kinds of statistical relations which relate the cycle amplitudes, duration and shapes. This subject always gets a special attention because it is important for the solar activity forecast. We discuss statistical properties of the mean-field dynamo model with the fluctuating \alpha-effect. Also, we estimate dynamical properties of the model for the long and short time-scale and compare it with the dynamics of the sunspot numbers data sets. 
V.V. Pipin, D.D. Sokoloff and I.G. Usoskin
astro-ph.SR