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Raimund Muscheler

Raimund Muscheler

Professor

Raimund Muscheler

Eleven-year solar cycles over the last millennium revealed by radiocarbon in tree rings

Author

  • Nicolas Brehm
  • Alex Bayliss
  • Marcus Christl
  • Hans Arno Synal
  • Florian Adolphi
  • Jürg Beer
  • Bernd Kromer
  • Raimund Muscheler
  • Sami K. Solanki
  • Ilya Usoskin
  • Niels Bleicher
  • Silvia Bollhalder
  • Cathy Tyers
  • Lukas Wacker
Show all

Summary, in English

The Sun provides the principal energy input into the Earth system and solar variability represents a significant external climate forcing. Although observations of solar activity (sunspots) cover only the last about 400 years, radionuclides produced by cosmic rays and stored in tree rings or ice cores serve as proxies for solar activity extending back thousands of years. However, the presence of weather-induced noise or low temporal resolution of long, precisely dated records hampers cosmogenic nuclide-based studies of short-term solar variability such as the 11-yr Schwabe cycle. Here we present a continuous, annually resolved atmospheric 14C concentration (fractionation-corrected ratio of 14CO2 to CO2) record reconstructed from absolutely dated tree rings covering nearly all of the last millennium (ad 969–1933). The high-resolution and precision 14C record reveals the presence of the Schwabe cycle over the entire time range. The record confirms the ad 993 solar energetic particle event and reveals two new candidates (ad 1052 and ad 1279), indicating that strong solar events that might be harmful to modern electronic systems probably occur more frequently than previously thought. In addition to showing decadal-scale solar variability over the last millennium, the high-temporal-resolution record of atmospheric radiocarbon also provides a useful benchmark for making radiocarbon dating more accurate over this interval.

Department/s

  • Quaternary Sciences
  • MERGE: ModElling the Regional and Global Earth system

Publishing year

2021

Language

English

Pages

10-15

Publication/Series

Nature Geoscience

Volume

14

Issue

1

Document type

Journal article

Publisher

Nature Publishing Group

Topic

  • Geology

Status

Published

ISBN/ISSN/Other

  • ISSN: 1752-0894