Testing for nonlinearity in radiocarbon data

Abstract. The radiocarbon record that has been extended from 7199 BC to 1891 AD is of fundamental importance to understand century-scale variations of solar activity. We have, therefore, studied how to extract information from dynamic reconstructions of this observational record.
Using some rather unusual methods of nonlinear dynamics, we have found that the data are significantly different from linear coloured noise and that there is some evidence of nonlinear behaviour. The method of recurrence plots exhibits that the grand minima of solar activity are quite different in their recurrence. Most remarkably, it suggests that the recent epoch seems to be similar to the Medieval maximum.