Patterns in solar activity over the first millennium CE

Wang, J. ORCID: https://orcid.org/0009-0004-7090-0028, Dee, M. W. ORCID: https://orcid.org/0000-0002-3116-453X, Pope, B. J. S., Owens, M. J. ORCID: https://orcid.org/0000-0003-2061-2453, Brown, D., Lindauer, S. ORCID: https://orcid.org/0000-0001-5363-2755, Schwabe, K., Knapp, H., Westphal, T. and Friedrich, R. ORCID: https://orcid.org/0000-0001-5199-1957 (2025) Patterns in solar activity over the first millennium CE. Communications Earth & Environment. ISSN 2662-4435 doi: 10.1038/s43247-025-03120-4 (In Press)

Abstract/Summary

Radiocarbon (14C) measurements are a powerful tool for reconstructing past solar activity and identifying extreme events caused by bursts of high-energy particles from the Sun. Such reconstructions improve understanding of long-term solar behaviour and the likelihood of hazardous particle events that are capable of disrupting modern technology. Here we present an annually resolved 14C record spanning 1 to 970 CE comprising five newly measured and three existing series from tree rings. The record is analysed with methods that combine statistical modelling of the carbon cycle, data-adaptive decomposition of solar cycles, and probabilistic detection of rapid 14C increases associated with energetic particle events. These analyses reveal four major intervals of reduced solar activity, two patterns in which the eleven-year cycle weakens then strengthens, and four candidate particle events in the years 14, 553, 675 and 954 CE.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/127817
Identification Number/DOI	10.1038/s43247-025-03120-4
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Springer Nature
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