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

Abstract Radiocarbon ( 14 C) 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 14 C 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 14 C 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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