Correlation coefficient between the maxima of the unsigned toroidal field corresponding to each cycle at the base of convection zone (r = 0.7  R_⊙) and the observed maxima of the sunspot number for simulations with different values of the pumping (left panel), and the turbulent diffusivity (right panel) in the convection zone. The asterisk represents the actual numerical experiments which were performed. The square indicates the result for the reference case.