J/A+A/615/A93 Reconstructed decadal sunspot numbers (Wu+, 2018)
Solar activity over nine millennia: A consistent multi-proxy reconstruction.
Wu C.J, Usoskin I.G., Krivova N., Kovaltsov G.A., Baroni M., Bard E.,
Solanki S.K.
<Astron. Astrophys. 615, A93 (2018)>
=2018A&A...615A..93W 2018A&A...615A..93W (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Sun
Keywords: Sun: activity - solar-terrestrial relations - sunspots
Abstract:
The solar activity in the past millennia can only be reconstructed
from cosmogenic radionuclide proxy records in terrestrial archives.
However, because of the diversity of the proxy archives, it is
difficult to build a homogeneous reconstruction. All previous studies
were based on individual, sometimes statistically averaged, proxy
datasets. Here we aim to provide a new consistent multiproxy
reconstruction of the solar activity over the last 9000 years, using
all available long-span datasets of 10Be and 14C in terrestrial
archives.
A new method, based on a Bayesian approach, was applied for the first
time to solar activity reconstruction. A Monte Carlo search (using the
x2 statistic) for the most probable value of the modulation potential
was performed to match data from different datasets for a given time.
This provides a straightforward estimate of the related uncertainties.
We used six 10Be series of different lengths (from 500-10000
years) from Greenland and Antarctica, and the global 14C production
series. The 10Be series were resampled to match wiggles related to the
grand minima in the 14C reference dataset. The stability of the long
data series was tested. Results. The Greenland Ice-core Project (GRIP)
and the Antarctic EDML (EPICA Dronning Maud Land) 10Be series
diverge from each other during the second half of the Holocene, while
the 14C series lies in between them. A likely reason for the
discrepancy is the insufficiently precise beryllium transport and
deposition model for Greenland, which leads to an undercorrection of
the GRIP series for the geomagnetic shielding effect. A slow
6-7-millennia variability with lows at ca. 5500 BC and 1500 AD in
the longterm evolution of solar activity is found. Two components of
solar activity can be statistically distinguished: the main component,
corresponding to the 'normal' moderate level, and a component
corresponding to grand minima. A possible existence of a component
representing grand maxima is indicated, but it cannot be separated
from the main component in a statistically significant manner.
A new consistent reconstruction of solar activity over the last nine
millennia is presented with the most probable values of decadal
sunspot numbers and their realistic uncertainties. Independent
components of solar activity corresponding to the main moderate
activity and the grand-minimum state are identified; they may be
related to different operation modes of the dynamo.
Description:
The file contains the decadal numbers of sunspot groups including the
decade central year [Y], the low [S_l], the mean [S_M] and the upper
[S_u] 1-sigma (68% bounds).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 26 865 Sunspot numbers
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See also:
VI/138 : Sunspots catalogues, 1853-1870 (Casas+, 2013)
J/A+A/390/707 : Hemispheric Sunspot Numbers 1975-2000 (Temmer+, 2002)
J/A+A/447/735 : Hemispheric Sunspot Numbers 1945-2004 (Temmer+, 2006)
J/A+A/584/A73 : Sunspot areas and tilt angles (Senthamizh Pavai+, 2015)
J/A+A/595/A104 : Scheiner drawing sunspot areas and tilt angles (Arlt+, 2016)
J/A+A/599/A131 : Butterfly diagram wings (Leussu+, 2017)
J/A+A/601/A106 : Sunspot on 1921-2011 (Mandal+, 2017)
J/A+A/601/A109 : Monthly numbers of sunspot groups 1749-1996 (Willamo+, 2017)
J/A+A/602/A69 : Group sunspot number series since 1739 (Chatzistergos+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 yr Year [-6755/1885] Decade central year -BC/AD
8- 12 F5.2 --- b_S Low 68% bound of S-value (S_l)
15- 19 F5.2 --- S [-8.04/78] Mean number of sunspot groups
(S-value) (S_M)
22- 26 F5.2 --- B_S Upper 68% bound of S-value (S_u)
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Acknowledgements:
Ilya Usoskin, ilya.usoskin(at)oulu.fi
(End) Patricia Vannier [CDS] 08-Apr-2018