University of Oulu

Acero, F., Gallego, M., García, J., Usoskin, I., Vaquero, J. (2018) Extreme Value Theory Applied to the Millennial Sunspot Number Series. Astrophysical Journal, 853 (1), 80. doi:10.3847/1538-4357/aaa406

Extreme value theory applied to the millennial sunspot number series

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Author: Acero, F. J.1,2; Gallego, M. C.1,2; Usoskin, I. G.3;
Organizations: 1Departamento de Física, Universidad de Extremadura, E-06071 Badajoz, Spain
2Instituto Universitario de Investigación del Agua, Cambio Climático y Sostenibilidad (IACYS), Universidad de Extremadura, E-06006 Badajoz, Spain
3Space Climate Research Unit and Sodankylä Geophysical Observatory, University of Oulu, Finland
4Departamento de Física, Universidad de Extremadura, E-06800 Mérida, Spain
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.7 MB)
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Language: English
Published: IOP Publishing, 2018
Published for the American Astronomical Society, 2018
Publish Date: 2018-01-29


In this work, we use two decadal sunspot number series reconstructed from cosmogenic radionuclide data (¹⁴C in tree trunks, SN 14C, and ¹⁰Be in polar ice, SN 10Be) and the extreme value theory to study variability of solar activity during the last nine millennia. The peaks-over-threshold technique was used to compute, in particular, the shape parameter of the generalized Pareto distribution for different thresholds. Its negative value implies an upper bound of the extreme SN 10Be and SN 14C timeseries. The return level for 1000 and 10,000 years were estimated leading to values lower than the maximum observed values, expected for the 1000 year, but not for the 10,000 year return levels, for both series. A comparison of these results with those obtained using the observed sunspot numbers from telescopic observations during the last four centuries suggests that the main characteristics of solar activity have already been recorded in the telescopic period (from 1610 to nowadays) which covers the full range of solar variability from a Grand minimum to a Grand maximum.

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Series: Astrophysical journal
ISSN: 0004-637X
ISSN-E: 1538-4357
ISSN-L: 0004-637X
Volume: 853
Issue: 1
Article number: 80
DOI: 10.3847/1538-4357/aaa406
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: Support from the Junta de Extremadura (Research Group Grant GR15137) and from the Ministerio de Economía y Competitividad of the Spanish Government (AYA2014-57556-P) is gratefully acknowledged. I.U. acknowledges support by the Center of Excellence ReSoLVE (Academy of Finland Project No. 272157).
Academy of Finland Grant Number: 272157
Detailed Information: 272157 (Academy of Finland Funding decision)
Copyright information: © 2018. The American Astronomical Society. All rights reserved. Published in this repository with the kind permission of the publisher.