Reconstruction of the annual variation in solar radio flux and the Catania sunspot area from tree ring-index time series

Four tree ring-index site chronologies, representing standardized annual growth rates for spruce trees growing at high altitude sites in Colorado, have been employed as proxy data in a regression model for the annual variation of solar radio flux at 2800 MHz (F_{10 x 7}) and the Catania sunspot area (A_C). These dendrochronological time series all exhibit significant power spectrum peaks at about 11 years and separately correlate with the annual values of R_z, F_{10 x 7} and A_C, as solar activity indicators. The two models constructed give the cyclic variation of F_{10 x 7} and A_C back to AD1673.