J/A+A/649/A141ivo://CDS.VizieR/J/A+A/649/A141doi:10.26093/cds/vizier.36490141CDSUsoskinI.G.Solanki S.K.Krivova N.Hofer B.Kovaltsov G.A.,Wacker L.Brehm N.Kromer B.2022-07-28T08:53:13Z2021-05-28T08:45:54ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frthe-sunThe 11-year solar cycle (Schwabe cycle) is the dominant pattern of solar magnetic activity reflecting the oscillatory dynamo mechanism in the Sun's convection zone. Solar cycles have been directly observed since 1700, while indirect proxy data suggest their existence over a much longer period of time but generally without resolving individual cycles and their continuity. Here we reconstruct individual solar cycles for the last millennium using recently obtained 14C data and state-of-the-art models. Starting with the ^14^C production rate determined from the so far most precise measurements of radiocarbon content in tree rings, solar activity is reconstructed in three physics-based steps: (1) Correction of the ^14^C production rate for the changing geomagnetic field; (2) Computation of the open solar magnetic flux; and (3) Conversion into sunspot numbers outside of grand minima. All known uncertainties, including both measurement and model uncertainties are straightforwardly accounted for by a Monte-Carlo method. Results: Cyclic solar activity is reconstructed for the period 971-1900 (85 individual cycles) along with its uncertainties. This more than doubles the number of solar cycles known from direct solar observations. We found that lengths and strengths of well-defined cycles outside grand minima are consistent with those obtained from the direct sunspot observations after 1750. The validity of the Waldmeier rule (cycles with fast rising phase tend to be stronger) is confirmed at a highly significant level. Solar activity is found to be in a deep grand minimum when the activity is mostly below the sunspot formation threshold, during about 250 years. Therefore, although considerable cyclic variability in ^14^C is seen even during grand minima, individual solar cycles can hardly be reliably resolved therein. Three potential solar particle events, ca. 994, 1052 and 1279 AD, are shown to occur around the maximum phases of solar cycles. A new about 1000-year long solar activity reconstruction, in the form of annual (pseudo) sunspot numbers with full assessment of all known uncertainties, is presented based on new high-precision D14C measurements and state-of-the-art models, more than doubling the number of individually resolved solar cycles. This forms a solid basis for new, more detailed studies of solar variability.2021A&A...649A.141Uhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/649/A141CatalogResearchIsServedByTAP VizieR generic servicerelated-toVI/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/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)J/A+A/615/A93 : Reconstructed decadal sunspot numbers (Wu+, 2018)J/A+A/627/A46 : Sunspot penumbra and umbral flashes models (Bose+, 2019)J/A+A/628/A103 : Mt Wilson sunspot magnetic field measurements (Pevtsov+, 2019J/A+A/640/A78 : Sunspot area catalogue revisited (1874-2019) (Mandal+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/649/A141https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/649/A141http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/649/A141https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/649/A141https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/649/A141http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/649/A141GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/649/A141/osfData for annual opens solar flux (OSF) (fig. 8)Year[971/1899] YearyrtimeintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFoAnnual value of the reconstructed opens solar flux (OSF)1e+14Wbphot.fluxfloate_Fo1-sigma uncertainty of Fo1e+14Wbstat.errorfloat<Fo>Smoothed Fo value1e+14Wbphot.fluxfloatJ/A+A/649/A141/osnData for annual sunspot number (SN) (fig. 11)Year[971/1899] YearyrtimeintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSNAnnual value of the reconstructed sunspot numbermeta.numberfloate_SN1-sigma uncertainty of sunspot numberstat.errorfloat<SN>Smoothed sunspot number valuemeta.numberfloatJ/A+A/649/A141/table1Solar activity cycles as reconstructed here from annually resolved ^14^C; updated version of the table<SN>Cycle-averaged sunspot number (SN)meta.numberinte_<SN>1-sigma uncertainty of <SN>stat.errorintTSolar cycle length (min-to-min)yrtime;arith.diffintq[012345] Quality flag (1)meta.code.qualcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintn[1/85] Internal cycle numbermeta.idintYminYear of solar cycle minimumyrtime.epochintYmaxYear of solar cycle maximumyrtime.epochint