Skip to main content
Log in

Long-Term Solar Activity: Direct and Indirect Study

  • Published:
Solar Physics Aims and scope Submit manuscript

Abstract

The series of directly observed sunspot numbers is nearly 400 years long. We stress that the recently compiled group sunspot number series is an upgrade of the old Wolf series and should always be used before 1850. The behavior of solar activity on longer time scales can be studied only using indirect proxies. Such proxies as aurorae occurrence or naked-eye sunspot observations are qualitative indicators of solar activity but can be hardly quantitatively interpreted. Cosmogenic isotope records provide a basis for quantitative estimate of the past solar activity. Here we overview the main methods of the long-term solar activity reconstruction on the centennial to multimillennia time scale. We discuss that regression-based reconstructions of solar activity lead to very uncertain results, while recently developed physics-based models raise solar activity reconstruction to a new level and allow studying its behavior on a multimillennia time scale. In particular, the reconstructions show that the recent episode of high solar activity is quite unusual in the multimillennia time scale.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
$34.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or eBook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to I. G. Usoskin.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Usoskin, I.G., Kovaltsov, G.A. Long-Term Solar Activity: Direct and Indirect Study. Sol Phys 224, 37–47 (2004). https://doi.org/10.1007/s11207-005-3997-7

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11207-005-3997-7

Keywords

Navigation