Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-25T18:58:38.130Z Has data issue: false hasContentIssue false
  • English
  • Français

How well do we know the sunspot number?

Published online by Cambridge University Press:  05 July 2012

Leif Svalgaard
Leif Svalgaard*
Affiliation:
Hansen Experimental Physics Laboratory, Stanford University, 650 Via Ortega, Stanford, CA 94304, USA email: leif@leif.org
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We show that only two adjustments are necessary to harmonize the Group Sunspot Number with the Zürich Sunspot Number. The latter has been increased from the 1940s on to the present by 20% due to weighting of sunspot counts according to size of the spots and can be corrected by increasing the earlier values as well. The Group Sunspot Number before ~1885 is too low by ~50%. With these adjustments a single sunspot number series results. Of note is that there is no longer a distinct Modern Grand Maximum.

Keywords

Sun: activitysunspots
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 7 , Symposium S286: Comparative Magnetic Minima: Characterizing quiet times in the Sun and Stars , October 2011 , pp. 27 - 33
Copyright
Copyright © International Astronomical Union 2012

References

Arlt, R. 2009 Sol. Phys., 255, 143CrossRefGoogle Scholar
Arlt, R. & Abdolvand, A. 2011 Proc. IAU Symposium 273, 6, 286CrossRefGoogle Scholar
Balmaceda, L. A., Solanki, S. K., Krivova, N. A., & Foster, S. 2009, J. Geophys. Res., 114, A07104CrossRefGoogle Scholar
Emmert, J. T. & Beig, G. 2011, J. Geophys. Res., 116, A00H01Google Scholar
Foukal, P. 1998, Geophys. Res. Lett., 25, 2909CrossRefGoogle Scholar
Hoyt, D. V., Schatten, K. H., & Nesmes-Ribes, E. 1994, Geophys. Res. Lett., 21, 2067CrossRefGoogle Scholar
Kopecký, M., Ružičková-Topolová, B., & Kuklin, G. V. 1980, Bull. Astron. Inst. Czech, 31, 267Google Scholar
Lean, J. L. & Rind, D. H. 2009, Geophys. Res. Lett., 36, L15708CrossRefGoogle Scholar
Ostrow, S. M. & PoKempner, M. 1952, J. Geophys. Res., 57, 473CrossRefGoogle Scholar
Waldmeier, M. 1948, Astron. Mitteil., Nr. 152CrossRefGoogle Scholar
Waldmeier, M. 1968, Astron. Mitteil., Nr. 285Google Scholar
Wolf, J. R. 1859, Mittheil. Sonnenfl., Nr. 9Google Scholar