Hostname: page-component-cb9f654ff-c75p9 Total loading time: 0 Render date: 2025-08-21T11:13:22.456Z Has data issue: false hasContentIssue false
  • English
  • Français

Sunspot and Group Number: Recent advances from historical data

Published online by Cambridge University Press:  03 March 2020

Frédéric Clette ,
José M. Vaquero ,
María Cruz Gallego  and
Laure Lefèvre
Frédéric Clette
Affiliation:
Royal Observatory of Belgium, 3, avenue Circulaire, 1180 Brussels, Belgium email: frederic.clette@oma.be
José M. Vaquero
Affiliation:
Departamento de Fsica, Universidad de Extremadura, 06071 Mérida, Spain
María Cruz Gallego
Affiliation:
Departamento de Fsica, Universidad de Extremadura, 06071 Badajoz, Spain
Laure Lefèvre
Affiliation:
Royal Observatory of Belgium, 3, avenue Circulaire, 1180 Brussels, Belgium email: frederic.clette@oma.be
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.

Due to its unique 400-year duration, the sunspot number is a central reference for understanding the long-term evolution of solar activity and its influence on the Earth environment and climate. Here, we outline current data recovery work. For the sunspot number, we find historical evidence of a disruption in the source observers occurring in 1947–48. For the sunpot group number, recent data confirm the clear southern predominance of sunspots during the Maunder Minimum, while the umbra-penumbra ratio is similar to other epochs. For the Dalton minimum, newly recovered historical observations confirm a higher activity level than in a true Grand Minimum.

Keywords

Sun: sunspotsSun: photosphereSun: activitymethods: data analysishistory of astronomy

References

Carrasco, V. M. S., Álvarez, J. V., & Vaquero, J. M. 2015, Sol. Phys., 290, 2719 CrossRefGoogle Scholar
Carrasco, V. M. S., & Vaquero, J. M. 2016, Sol. Phys., 291, 2493 CrossRefGoogle Scholar
Carrasco, V. M. S., Garca-Romero, J. M., Vaquero, J. M., et al. 2018a, Astrophys. J., 865, 88 CrossRefGoogle Scholar
Carrasco, V. M. S., Vaquero, J. M., Arlt, R., & Gallego, M. C. 2018b, Sol. Phys., 293, 102 Google Scholar
Chatzistergos, T., Usoskin, I., Kovaltsov, G., Krivova, N.A., & Solanki, S.K. 2017, Astron. & Astrophys., 602, A69 CrossRefGoogle Scholar
Clette, F., Svalgaard, L., Vaquero, J.M., & Cliver, E.W. 2014, Space Sci. Rev., 186, 35 CrossRefGoogle Scholar
Clette, F., & Lefèvre, L. 2016, Sol. Phys., 291, 2629 CrossRefGoogle Scholar
Clette, F., Cliver, E.W., Lefèvre, L., Svalgaard, L., Vaquero, J.M., & Leibacher, J.W. 2016a, Sol. Phys., 291, 2479 Google Scholar
Denig, W. F., & McVaugh, M. R. 2017, Space Weather, 15, 857 CrossRefGoogle Scholar
Friedli, T.K. 2016, Sol. Phys., 291, 2505 CrossRefGoogle Scholar
Hayakawa, H., Iwahashi, K., Tamazawa, H., Toriumi, S., & Shibata, K. 2018, Sol. Phys., 293, 8 CrossRefGoogle Scholar
Hoyt, D.V., & Schatten, K.H. 1998, Sol. Phys., 181, 491 CrossRefGoogle Scholar
Lockwood, M., Owens, M.J., & Barnard, L. 2014 J. Geophys. Res., 119(A7), 5193 Google Scholar
Neuhäuser, R., Arlt, R., & Richter, S. 2018, Astronomische Nachrichten, 339, 219 Google Scholar
Ogurtsov, M. G. 2018, Astronomy Letters, 44, 278 CrossRefGoogle Scholar
Svalgaard, L., Cagnotti, M., & Cortesi, S. 2017, Sol. Phys., 292, 34 CrossRefGoogle Scholar
Usoskin, I. G., Arlt, R., Asvestari, E., et al. 2015, Astron.& Astrophys., 581, A95 CrossRefGoogle Scholar
Vaquero, J. M., Nogales, J. M., & Sánchez-Bajo, F. 2015a, Advances in Space Res., 55, 1546 CrossRefGoogle Scholar
Vaquero, J. M., Kovaltsov, G. A., Usoskin, I. G., Carrasco, V. M. S., & Gallego, M. C. 2015b, Astron.& Astrophys., 577, A71 Google Scholar
Vaquero, J.M., Svalgaard, L., Carrasco, V.M.S., Clette, F., Lefèvre, L., Gallego, M.C., Arlt, R., Aparicio, A.J.P., Richard, J.-G., & Howe, R. 2016 Sol. Phys., 291, 3061 Google Scholar
Wolf, R. 1859, Astron. Mitt. Eidgnöss. Sternwarte Zürich, I (VIII), 66Google Scholar
Zolotova, N. V., & Ponyavin, D. I. 2015, Astrophys. J., 800, 42 CrossRefGoogle Scholar