Speaker
Description
The Sun is the primary energy source of the Earth system, and variations in solar activity can significantly influence climate. While direct observations of solar activity, such as sunspot records, extend back only about 400 years, cosmogenic radionuclides produced by cosmic rays and preserved in tree rings and ice cores provide valuable proxies for reconstructing solar variability over millennial timescales [1]. However, the limited temporal resolution of most long, precisely dated cosmogenic nuclide records constrains investigations of short-term solar variability, including the 11-year Schwabe cycle and solar energetic particle (SEP) events. Recent advances have yielded several new high-precision, annually resolved radiocarbon (14C) tree-ring records. Here, we present a continuous atmospheric 14C records spanning the past 4,000 years. These annually resolved datasets enable a detailed investigation of short- term solar variability. Spectral and time-series analyses reveal clear signatures of the 11-year solar cycle and provide constraints on potential SEP events. Our results indicate that the 11- year solar cycle has persisted over millennia, at least during periods of grand solar maxima.
[1] E. Bard, G. Raisbeck, F. Yiou,& J. Jouzel, Solar irradiance during the last 1200 years based on cosmogenic nuclides. Tellus B 52, 2000
Co-author list:
Marcus Christl (1), Charlotte Pearson (2), Alex Bayliss (3), Timothy Knowles (4), Kurt Nicolussi (5), Thomas Pichler (5), Rashit Hanterimov (6), Lukas Wacker (1)
1) Laboratory of Ion Beam Physics, ETH Zurich, Otto‑Stern‑Weg 5, Zurich, Switzerland
(2) Laboratory of Tree Ring Research, University of Arizona, Bryant Bannister Tree‑Ring Building, 1215 E. Lowell Street, Tucson, AZ 85721‑0045, USA
(3) Historic England, Cannon Bridge House, 25 Dowgate Hill, London EC4R 2YA, UK
(4) Bristol Radiocarbon Accelerator Mass Spectrometry Facility, University of Bristol, Bristol BS8 1TS, UK
(5) Department of Geography, Universität Innsbruck, Innrain 52, 6020 Innsbruck, Austria
(6) Laboratory of Dendrochronology, Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences, 8 Marta Street 202, Ekaterinburg 620144, Russia