J/A+A/562/L10 Solar activity reconstructed for 3 millennia (Usoskin+, 2014)
Evidence for distinct modes of solar activity.
Usoskin I.G., Hulot G., Gallet Y., Roth R., Licht A., Joos F.,
Kovaltsov G.A., Thebault E., Khokhlov A.
<Astron. Astrophys. 562, L10 (2014)>
=2014A&A...562L..10U 2014A&A...562L..10U
ADC_Keywords: Sun
Keywords: Sun: activity - Sun: dynamo - sunspots
Abstract:
The Sun shows a large variability in its magnetic activity, from Grand
minima to Grand maxima, but the nature of the variability is not fully
understood, mostly because of an insufficient length of the directly
observed solar activity records and of uncertainties related to
long-term reconstructions. Here we present a new adjustment-free
reconstruction of solar activity over three millennia and study its
different modes.
We present a new adjustment-free, physical reconstruction of solar
activity over the past three millennia, using the latest verified
carbon cycle, 14C production and archeomagnetic field models. This
great improvement allows us to study different modes of solar activity
at unprecedented level of details.
The distribution of solar activity is clearly bi-modal implying the
existence of distinct modes of activity. The main regular activity
mode corresponds to moderate activity varying in a relatively narrow
band between sunspot number 20 and 67. The existence of a separate
Grand minimum mode with reduced solar activity, which cannot be
explained by random fluctuations of the regular mode, is confirmed at
a high confidence level. The possible existence of a separate Grand
maximum mode is also suggested, but the statistics is too low for a
confident conclusion to be reached.
The Sun is shown to operate in distinct modes - a main general mode, a
Grand minimum mode corresponding to an inactive Sun, and a possible
Grand maximum mode corresponding to an unusually active Sun. These
results provide important constraints for both dynamo models of
Sun-like stars and investigations of possible solar influence on
Earth's climate.
Description:
Indices of solar activity reconstructed from 14C using the method
used in the paper. Two indices are provided - the sunspot number and
the cosmic ray modulation potential, both with the 95% confidence
intervals. The data sets are provided with decadal resolution, thus
the individual solar cycles are not resolved.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
sn.dat 21 310 Decadal sunspot number reconstruction
phi.dat 17 310 Decadal heliospheric modulation parameter
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See also:
VI/138 : Sunspots catalogues, 1853-1870 (Casas+, 2013)
J/A+A/531/A6 : Evolution of solar irradiance during Holocene (Vieira+, 2011)
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+AS/110/351 : Sun observations in 1992 (Sanchez+, 1995)
J/A+AS/106/327 : Observations of the Sun during 1993 at Santiago (Noel 1994)
J/A+AS/113/131 : Observations of the Sun during 1994 (Noel, 1995)
J/A+AS/132/195 : Astrolabe observations of the Sun in 1995-1997 (Noel 1998)
J/A+AS/102/11 : Astrolabe observations of the Sun in 1990-1992 (Noel 1993)
J/A+A/375/614 : Astrolabe observations of the Sun in 1990-2000 (Noel, 2001)
J/A+A/309/655 : Solar chromospheric activity (HeI 10830A) (Shcherbakov+, 1996)
J/A+A/313/949 : Solar chromospheric structures. II. (Bocchialini+, 1996)
J/A+A/375/591 : SUMER Spectral Atlas of Solar Disk Features (Curdt+, 2001)
J/A+A/422/337 : Solar EUV Post-Eruptive Arcades (Tripathi+, 2004)
J/A+A/423/1109 : Center-to-limb variation of quiet Sun (Allende+, 2004)
J/ApJ/709/1238 : Solar Coronal Mass Ejection (Yeates+, 2010)
J/A+A/539/A13 : Solar bipolar magnetic fields (Yamamoto, 2012)
J/A+A/552/A114 : Sun chromospheric CaII-HK emission (Shapiro+, 2013)
J/A+A/555/A123 : 3D-MHD model of a solar active region corona (Bourdin+, 2013)
J/A+AS/119/489 : Solar Type II Radio Bursts, 1990.09 - 1993.12 (Mann+ 1996)
J/A+AS/130/233 : WATCH Solar X-Ray Burst Catalogue (Crosby+ 1998)
J/ApJ/710/L58 : Coronal type II radio bursts in 2002 (Lobzin+, 2010)
J/ApJ/747/L41 : Solar flares probabilities (Bloomfield+, 2012)
Byte-by-byte Description of file: sn.dat
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Bytes Format Units Label Explanations
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1- 5 I5 yr Year [-1145/1945] Central year of the decadal
interval (-BC/AD)
7- 10 F4.1 -- SN Decadal sunspot number (mean)
12- 16 F5.1 -- b_SN Decadal sunspot number (lower c.i. 95% bound)
18- 21 F4.1 -- B_SN Decadal sunspot number (upper c.i. 95% bound)
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Byte-by-byte Description of file: phi.dat
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Bytes Format Units Label Explanations
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1- 5 I5 yr Year [-1145/1945] Central year of the decadal
interval (-BC/AD)
7- 9 I3 MV phi Decadal modulation potential (mean)
11- 13 I3 MV b_phi Decadal mod. potential (lower c.i. 95% bound)
15- 17 I3 MV B_phi Decadal mod. potential (upper c.i. 95% bound)
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Acknowledgements:
Ilya Usoskin, ilya.usoskin(at)oulu.fi
(End) Ilya Usoskin [Univ.Oulu, Finland], Patricia Vannier [CDS] 07-Feb-2014