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Solar Physics

, Volume 182, Issue 1, pp 217–230 | Cite as

A Comparison of Wolf's Reconstructed Record of Annual Sunspot Number with Schwabe's Observed Record of ‘Clusters of Spots’ for the Interval of 1826–1868

  • Robert M. Wilson
Article

Abstract

Samuel Heinrich Schwabe, the discoverer of the sunspot cycle, observed the Sun routinely from Dessau, Germany during the interval of 1826–1868, averaging about 290 observing days per year. His yearly counts of ‘clusters of spots’ (or, more correctly, the yearly number of newly appearing sunspot groups) provided a simple means for describing the overt features of the sunspot cycle (i.e., the timing and relative strengths of cycle minimum and maximum). In 1848, Rudolf Wolf, a Swiss astronomer, having become aware of Schwabe's discovery, introduced his now familiar ‘relative sunspot number’ and established an international cadre of observers for monitoring the future behavior of the sunspot cycle and for reconstructing its past behavior (backwards in time to 1818, based on daily sunspot number estimates). While Wolf's reconstruction is complete (without gaps) only from 1849 (hence, the beginning of the modern era), the immediately preceding interval of 1818–1848 is incomplete, being based on an average of 260 observing days per year. In this investigation, Wolf's reconstructed record of annual sunspot number is compared against Schwabe's actual observing record of yearly counts of clusters of spots. The comparison suggests that Wolf may have misplaced (by about 1–2 yr) and underestimated (by about 16 units of sunspot number) the maximum amplitude for cycle 7. If true, then, cycle 7's ascent and descent durations should measure about 5 years each instead of 7 and 3 years, respectively, the extremes of the distributions, and its maximum amplitude should measure about 86 instead of 70. This study also indicates that cycle 9's maximum amplitude is more reliably determined than cycle 8's and that both appear to be of comparable size (about 130 units of sunspot number) rather than being significantly different. Therefore, caution is urged against the indiscriminate use of the pre-modern era sunspot numbers in long-term studies of the sunspot cycle, since such use may lead to specious results.

Keywords

Maximum Amplitude Sunspot Number Sunspot Group Past Behavior Number Estimate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Bray, R. J. and Loughhead, R. E.: 1965, Sunspots, John Wiley and Sons, New York.Google Scholar
  2. Butler, C. J. and Johnston, D. J.: 1996, J. Atmospheric Terrest. Phys. 58(15), 1657.CrossRefADSGoogle Scholar
  3. Eddy, J. A.: 1977, in O. R. White (ed.), The Solar Output and Its Variation, Colorado Associated University Press, Boulder, Colorado, p. 51.Google Scholar
  4. Eddy, J. A.: 1980, in R. O. Pepin, J. A. Eddy, and R. B. Merrill (eds.), The Ancient Sun: Fossil Record in the Earth, Moon, and Meteorites, Pergamon Press, New York, p. 119.Google Scholar
  5. Hoyt, D. V. and Schatten, K. H.: 1995a, Solar Phys. 160, 371.CrossRefADSGoogle Scholar
  6. Hoyt, D. V. and Schatten, K. H.: 1995b, Solar Phys. 160, 379.CrossRefADSGoogle Scholar
  7. Hoyt, D. V. and Schatten, K. H.: 1995c, Solar Phys. 160, 387.CrossRefADSGoogle Scholar
  8. Hoyt, D. V. and Schatten, K. H.: 1995d, Solar Phys. 160, 393.CrossRefADSGoogle Scholar
  9. Hoyt, D. V. and Schatten, K. H.: 1997, The Role of the Sun in Climate Change, Oxford University Press, New York.Google Scholar
  10. Kiepenheuer, K. O.: 1953, in G. P. Kuiper (ed.), The Sun, University of Chicago Press, Chicago, Illinois, p. 322.Google Scholar
  11. McKinnon, J. A.: 1987, Report UAG-95, World Data Center A for Solar-Terrestrial Physics, Boulder, Colorado.Google Scholar
  12. McNish, A. G. and Lincoln, J. V.: 1949, Trans. AGU 30, 673.Google Scholar
  13. Schove, D. J.: 1983, Sunspot Cycles, Van Nostrand Reinhold, New York.Google Scholar
  14. Schröder, W.: 1997, Planetary Space Sci. 45, 395.CrossRefADSGoogle Scholar
  15. Schwabe, H.: 1844, Astron. Nachr. 21(495), 233.ADSGoogle Scholar
  16. Simkin, T. and Siebert, L.: 1994, Volcanoes of the World, 2nd ed., Geoscience Press, Tucson, Arizona.Google Scholar
  17. Sonett, C. P.: 1983, J. Geophys. Res. 88(A4), 3225.ADSCrossRefGoogle Scholar
  18. Waldmeier, M.: 1961, The Sunspot-Activity in the Years 1610–1960, Schulthess and Co., Zürich, Switzerland.Google Scholar
  19. Wilson, R. M.: 1992, Solar Phys. 140, 181.CrossRefADSGoogle Scholar
  20. Wilson, R. M.: 1998, J. Geophys. Res., submitted.Google Scholar
  21. Wilson, R. M., Hathaway, D. H., and Reichmann, E. J.: 1996, NASA Tech. Paper 3648, Huntsville, Alabama.Google Scholar

Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Robert M. Wilson
    • 1
  1. 1.Space Sciences LaboratoryNASA Marshall Space Flight CenterHuntsvilleU.S.A.

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