Fig. 1.
Sunspot and facular indices examined in this study. From top to bottom: total sunspot area (SA), international sunspot number (original; SN1, revision; SN2), group sunspot number (original; SG1, revision by Chatzistergos et al. 2017; SG2), 10.7 cm radio flux (F10.7), Ca II K 1 Å emission index (FCaIIK), Lyman α irradiance (FLα), Mg II index (FMgII), and the total magnetic flux enclosed in faculae and network (Fϕ). The SA, F10.7, FCaIIK, FLα and Fϕ are in units of ppm of the solar hemisphere, solar flux units, Ångström, Wm−2 and Weber, respectively. The grey segment of the FLα time series is excluded from the analysis. See Sect. 2 for details.
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