Access to Astronomical Catalogues

← Click to display the menu
J/A+A/602/A69      Group sunspot number series since 1739 (Chatzistergos+, 2017)

New reconstruction of the sunspot group numbers since 1739 using direct calibration and 'backbone' methods. Chatzistergos T., Usoskin I.G., Kovaltsov G.A., Krivova N.A., Solanki S.K <Astron. Astrophys. 602, A69 (2017)> =2017A&A...602A..69C (SIMBAD/NED BibCode)
ADC_Keywords: Sun Keywords: Sun: activity - Sun: sunspots - methods: statistical Abstract: The group sunspot number (GSN) series constitute the longest instrumental astronomical database providing information on solar activity. This database is a compilation of observations by many individual observers, and their inter-calibration has usually been performed using linear rescaling. There are multiple published series that show different long-term trends for solar activity. We aim at producing a GSN series, with a non-linear non-parametric calibration. The only underlying assumptions are that the differences between the various series are due to different acuity thresholds of the observers, and that the threshold of each observer remains constant throughout the observing period. We used a daisy chain process with backbone (BB) observers and calibrated all overlapping observers to them. We performed the calibration of each individual observer with a probability distribution function (PDF) matrix constructed considering all daily values for the overlapping period with the BB. The calibration of the BBs was carried out in a similar manner. The final series was constructed by merging different BB series. We modelled the propagation of errors straightforwardly with Monte Carlo simulations. A potential bias due to the selection of BBs was investigated and the effect was shown to lie within the 1σ interval of the produced series. The exact selection of the reference period was shown to have a rather small effect on our calibration as well. The final series extends back to 1739 and includes data from 314 observers. This series suggests moderate activity during the 18th and 19th century, which is significantly lower than the high level of solar activity predicted by other recent reconstructions applying linear regressions. The new series provides a robust reconstruction, based on modern and non-parametric methods, of sunspot group numbers since 1739, and it confirms the existence of the modern grand maximum of solar activity in the second half of the 20th century. Description: Annual, monthly, and daily values of the Group sunspot number series produced in the paper. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file ch_gsn_y.dat 27 272 GSN series, annual values ch_gsn_m.dat 29 3264 GSN series, monthly values ch_gsn_d.dat 31 101184 GSN series, daily values
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) Byte-by-byte Description of file: ch_gsn_y.dat
Bytes Format Units Label Explanations
1- 6 F6.1 yr Date Observation date 8- 13 F6.2 --- Rg ?=-99 Group sunspot number 15- 20 F6.2 --- sigmaU ?=-99 Upper limit of standard deviation 22- 27 F6.2 --- sigmaL ?=-99 Lower limit of standard deviation
Byte-by-byte Description of file: ch_gsn_m.dat
Bytes Format Units Label Explanations
1- 4 I4 yr Obs.year Year of observation 6- 7 I2 --- Obs.month Month of observation 10- 15 F6.2 --- Rg ?=-99 Group sunspot number 17- 22 F6.2 --- sigmaU ?=-99 Upper limit of standard deviation 24- 29 F6.2 --- sigmaL ?=-99 Lower limit of standard deviation
Byte-by-byte Description of file: ch_gsn_d.dat
Bytes Format Units Label Explanations
1- 4 I4 yr Obs.year Year of observation 6- 7 I2 --- Obs.month Month of observation 9- 10 I2 d Obs.day Day of observation 12- 17 F6.2 --- Rg ?=-99 Group sunspot number 19- 24 F6.2 --- sigmaU ?=-99 Upper limit of standard deviation 26- 31 F6.2 --- sigmaL ?=-99 Lower limit of standard deviation
Acknowledgements: Theodosios Chatzistergos, chatzistergos(at)mps.mpg.de
(End) Theodosios Chatzistergos [MPS], Patricia Vannier [CDS] 27-Feb-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© Université de Strasbourg/CNRS

    • Contact