Disc-integrated facular and network magnetic flux, ΣΦ_FN, as indicated by the CJSS-YEA run (black crosses) and by the YSK model (red crosses), as a function of the disc-integrated sunspot magnetic flux, ΣΦ_S. The first solar cycle in the CJSS-YEA run (cycle 15, 1913 to 1923) has been excluded as the simulation is sensitive to the arbitrary initial condition here. The annual mean over the period of 1924 to 1986, where there is data from both models, is shown. The black line and the grey region represents the quadratic polynomial fit to the CJSS-YEA run values and the corresponding 95% confidence interval, while the red line represents the fit to the YSK model values. See Sect. 4 for details.