J/A+A/587/A150 Solar activity during the Holocene (Usoskin+, 2016)
Solar activity during the Holocene: the Hallstatt cycle and its consequence for
grand minima and maxima.
Usoskin I.G., Gallet Y., Lopes F., Kovaltsov G.A., Hulot G.
<Astron. Astrophys. 587, A150 (2016)>
=2016A&A...587A.150U 2016A&A...587A.150U (SIMBAD/NED BibCode)
ADC_Keywords: Sun
Keywords: Sun: activity - solar-terrestrial relations
Abstract:
Cosmogenic isotopes provide the only quantitative proxy to analyze the
long-term solar variability over the centennial time scale. While an
essential progress has been achieved in both measurements and
modelling of the cosmogenic proxy, uncertainties still remain in the
determination of the geomagnetic dipole moment evolution. Here we aim
at improving the reconstruction of solar activity over the past nine
millennia using a multi-proxy approach. We use records of the 14C
and 10Be cosmogenic isotopes, up-to-date numerical models of the
isotope production and transport in the Earth's atmosphere, and
available geomagnetic field reconstructions, including a new
reconstruction relying on an updated archeo/paleointensity database.
The obtained series were analyzed using the SSA (Singular Spectrum
Analysis) method to study the millennial-scale trends. A new
reconstruction of the geomagnetic dipole field moment, referred to as
GMAG.9k, is built for the last nine millennia. New reconstructions of
solar activity covering the last nine millennia, quantified in terms
of sunspot numbers, are presented and analyzed. A conservative list of
Grand minima and maxima is also provided. The primary components of
the reconstructed solar activity, as determined using the SSA method,
are different for the 14C and 10Be based series. This shows
that these primary components can only be ascribed to long-term
changes in the terrestrial system, and not to the Sun. These
components have therefore been removed from the reconstructed series.
In contrast, the secondary SSA components of the reconstructed solar
activity are found to be dominated by a common ∼2400-year
quasi-periodicity, the so-called Hallstatt cycle, in both the 14C
and 10Be based series. This Hallstatt cycle thus appears to be
related to solar activity. Finally, it is shown that the Grand minima
and Grand maxima occurred intermittently over the studied period, with
clustering near highs and lows of the Hallstatt cycle, respectively.
Description:
tables1.dat contains axial dipole evolution between 1500 BC and 1900
AD as constrained by Virtual Axial Dipole Moments (VADM) averaged over
sliding windows of 200 years shifted every 10 years.
tables2.dat contains axial dipole evolution between 6750 BC and 1500
BC as constrained by Virtual Axial Dipole Moments (VADM) averaged over
sliding windows of 500 years shifted every 10 years.
Details on the computations are provided in Appendix A.
The columns report the epoch [yr], the mean VADM [Gmean] (in units of
1022 Am2), the standard deviation [SD] and the maximum [Gmax] and
minimum [Gmin] values defining the envelope of possible VADM results.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tables1.dat 41 341 Virtual Dipole Moment (VDM) for 1500 BC - 1900 AD
tables2.dat 41 526 Virtual Dipole Moment (VDM) for 6750 BC - 1500 BC
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See also:
J/A+A/531/A6 : Evolution of solar irradiance during Holocene (Vieira+, 2011)
Byte-by-byte Description of file: tables1.dat tables2.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 yr Year Year AD ("-" denotes years BC)
9- 15 F7.4 10+22A*m+2 Gmean Mean Virtual Axial Dipole Moment (VADM)
18- 25 F8.6 10+22A*m+2 SD Standard deviation of VADM
27- 33 F7.4 10+22A*m+2 Gmax Maximum Virtual Axial Dipole Moment
35- 41 F7.4 10+22A*m+2 Gmin Minimum Virtual Axial Dipole Moment
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Acknowledgements:
Ilya Usoskin, ilya.usoskin(at)oulu.fi
Yves Gallet, gallet(at)ipgp.fr
(End) Patricia Vannier [CDS] 18-Jan-2016