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Fig. 4

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. Variations of (a) annual mean of the Ap index and (b) the fraction of days in each year in the top 5% of Ap values, f[Ap > Apo]. The dots joined by the black lines are the observations. The green lines are fits from the power input to the magnetosphere Pα estimated from interplanetary data for years with data availability f > 0.5: these are generated using the linear regression fits shown in Figure 3a, b, for (a) an (b), respectively. The blue lines are generated using the same regression fits from the reconstructed Pα values generated in Paper 1 (Lockwood et al., 2017a, b) using the solar wind speed and number density and interplanetary magnetic field strength reconstructions by Owens et al. (2017) from sunspot numbers and models. The orange line in (b) shows f[Ap > Apo]′, which is generated from the reconstructed Ap values using the polynomial fit shown in Figure 2d, and tested in Figure 3c.

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