Long-term solar variability deduced from changes in the atmospheric 14C production rate

Abstract

A power spectral analysis of the atmospheric ¹⁴C production rate (300-1900 AD) has yielded evidence of the existence of supersecular oscillations in solar actlvity. The significance and stability of these oscillations is tested by reproducing the historical record. The results of a projection into a future period show that a new Sporer type oscillation, similar to that occurred in the 15th century, will probably occur again around the year A.D. 2300.