Reconstruction of grand minima of solar activity from Δ¹⁴C data: Linear and nonlinear signal analysis

Abstract

Using a special technique of data analysis, we have found 34 grand minima of solar activity in a 7700-year-long Δ¹⁴C record. The method used rests on a proper filtering of the Δ¹⁴C record and the extrapolation of verifiable results for the later history back in time. Additionally, we have applied a method of nonlinear dynamics, the recurrence rate, to back up the results. Our findings are not contradictory to the record of grand minima by Eddy [1977] but constitute a considerable extension. Hence it has become possible to look closer at the validity of models. This way, we have tested the model of Barnes et al. [1980]. There are hints for that the grand minima might solely be driven by the 209-year period found in the Δ¹⁴C record.