Journal of Astronomy and Space Sciences

The Korean Space Science Society (한국우주과학회)
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Maximum Sunspot Numbers and Active Days

  • Chang, Heon-Young (Department of Astronomy and Atmospheric Sciences, Kyungpook National University)
  • Received : 2013.05.19
  • Accepted : 2013.06.19
  • Published : 2013.09.15
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Abstract

Parameters associated with solar minimum have been studied to relate them to solar activity at solar maximum so that one could possibly predict behaviors of an upcoming solar cycle. The number of active days has been known as a reliable indicator of solar activity around solar minimum. Active days are days with sunspots reported on the solar disk. In this work, we have explored the relationship between the sunspot numbers at solar maximum and the characteristics of the monthly number of active days. Specifically, we have statistically examined how the maximum monthly sunspot number of a given solar cycle is correlated with the slope of the linear relationship between monthly sunspot numbers and the monthly number of active days for the corresponding solar cycle. We have calculated the linear correlation coefficient r and the Spearman rank-order correlation coefficient $r_s$ for data sets prepared under various conditions. Even though marginal correlations are found, they turn out to be insufficiently significant (r ~ 0.3). Nonetheless, we have confirmed that the slope of the linear relationship between monthly sunspot numbers and the monthly number of active days is less steep when solar cycles belonging to the "Modern Maximum" are considered compared with rests of solar cycles. We conclude, therefore, that the slope of the linear relationship between monthly sunspot numbers and the monthly number of active days is indeed dependent on the solar activity at its maxima, but that this simple relationship should be insufficient as a valid method to predict the following solar activity amplitude.

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References

  1. Berghmans D, van der Linden RAM, Vanlommel P, Warnant R, Zhukov A, et al., Solar Activity: Nowcasting and Forecasting at the SIDC, AnGeo, 23, 3115-3128 (2005).
  2. Brown GM, What Determines Sunspot Maximum, MNRAS, 174, 185-189 (1976). https://doi.org/10.1093/mnras/174.1.185
  3. Chang HY, Oh SJ, Does Correction Factor Vary with Solar Cycle?, JASS, 29, 97-101 (2012). http://dx.doi.org/10.5140/JASS.2012.29.2.097
  4. Cho IH, Chang HY, Latitudinal Distribution of Sunspots Revisited, JASS, 28, 1-7 (2011). http://dx.doi.org/10.5140/JASS.2011.28.1.001
  5. Dikpati M, Gilman PA, de Toma G, The Waldmeier Effect: An Artifact of the Definition of Wolf Sunspot Number?, ApJ, 673, L99-L101 (2008). http://dx.doi.org/10.1086/527360
  6. Du ZL, Relationship Between Solar Maximum Amplitude and Max-Max Cycle Length, AJ, 132, 1485-1489 (2006). https://doi.org/10.1086/506474
  7. Hamid R, Galal A, Preliminary Prediction of the Strength of the 24th 11-year Solar Cycle. In: Bothmer, V, Hady, AA (eds.) Solar Activity and Its Magnetic Origin, Proc. IAU Symp. 233, Cambridge Univ. Press, Cambridge, 413-416 (2006).
  8. Harvey KL, White OR, What is Solar Cycle Minimum?, JGR, 104, 19759-19764 (1999). http://dx.doi.org/10.1029/1999JA900211
  9. Hathaway DH, Wilson RM, Reichmann, EJ, The Shape of the Sunspot Cycle, Sol. Phys., 151, 177-190 (1994). https://doi.org/10.1007/BF00654090
  10. Hoyt DV, Schatten KH, Group Sunspot Numbers: A New Solar Activity Reconstruction, Sol. Phys., 179, 189-219 (1998). https://doi.org/10.1023/A:1005007527816
  11. Javaraiah, J, Predicting the Amplitude of a Solar Cycle Using the North-South Asymmetry in the Previous Cycle: II. An improved Prediction for Solar Cycle 24, Sol. Phys., 252, 419-439 (2008). https://doi.org/10.1007/s11207-008-9269-6
  12. Kane RP, Solar Cycle Predictions Based on Extrapolation of Spectral Components: An update, Sol. Phys., 243, 205-217 (2007). https://doi.org/10.1007/s11207-007-0475-4
  13. Kim BY, Chang HY, Alternating Sunspot Area and Hilbert Transform Analysis, JASS, 28, 261-265 (2011). http://dx.doi.org/10.5140/JASS.2011.28.4.261
  14. Mursula K, Ulich Th, A New Method to Determine the Solar Cycle Length, Geophys. Res. Lett., 25, 1837-1840 (1998). https://doi.org/10.1029/98GL51317
  15. Oh SJ, Chang HY, Change of Sunspot Groups Observed from 2002 to 2011 at ButterStar Observatory, JASS, 29, 245-251 (2012). http://dx.doi.org/10.5140/JASS.2012.29.3.245
  16. Pesnell WD, Solar Cycle Predictions, Sol. Phys., 281, 507-532 (2012).
  17. Petrovay K, Solar Cycle Prediction, LRSP, 7, 6-64 (2010).
  18. Solanki SK, Krivova NA, Schussler M, Fligge M, Search for a Relationship between Solar Cycle Amplitude and Length, A&A, 396, 1029-1035 (2002). https://doi.org/10.1051/0004-6361:20021436
  19. Tlatov AG, The Minimum Activity Epoch as a Precursor of the Solar Activity, Sol. Phys., 260, 465-477 (2009). https://doi.org/10.1007/s11207-009-9451-5
  20. Usoskin IG, Mursula K, Kovaltsov GA, Cyclic Behaviour of Sunspot Activity during the Maunder Minimum, A&A, 354, L33-L36 (2000).
  21. Usoskin IG, Mursula K, Kovaltsov GA, Heliospheric modulation of cosmic rays and solar activity during the Maunder minimum, JGR, 106, 16039-16046 (2001). http://dx.doi.org/10.1029/2000JA000105
  22. Usoskin IG, Mursula K, Kovaltsov GA, An Upper Limit on Sunspot Activity During the Maunder Minimum, Sol. Phys., 224, 95-101 (2004). https://doi.org/10.1007/s11207-005-4281-6
  23. Vaquero JM, Historical Sunspot Observations: A Review, AdSpR, 40, 929-941 (2007).
  24. Vaquero JM, Trigo RM, Can the Solar Cycle Amplitude Be Predicted Using the Preceding Solar Cycle Length?, Sol. Phys., 250, 199-206 (2008). https://doi.org/10.1007/s11207-008-9211-y
  25. Vaquero JM, Trigo RM, Gallego MC, A Simple Method to Check the Reliability of Annual Sunspot Number in the Historical Period 1610- 847, Sol. Phys., 277, 389-395 (2012). https://doi.org/10.1007/s11207-011-9901-8

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