Extreme value theory applied to the millennial sunspot number series
Acero, F. J.; Gallego, M. C.; Usoskin, I. G.; Vaquero, J. M. (2018-01-24)
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
© 2018. The American Astronomical Society. All rights reserved. Published in this repository with the kind permission of the publisher.
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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