Skip to main content
SpringerLink
Log in

Modelling solar irradiance variations: Comparison with observations, including line-ratio variations

  • Published:
Space Science Reviews Aims and scope Submit manuscript

Abstract

Solar irradiance variations show a strong temporal and spectral dependence. The progression of the Sun through its activity cycle as well as solar rotation are mirrored in the irradiance variations. The spectral dependence is such that the variations are several magnitudes larger in the EUV than in the visible or infrared.

We present a simple 3-component model that is based on the assumption that changes in the solar flux are exclusively due to changes in spot and facular coverage. We compare our model to observations of the spectral solar irradiance variations.

Despite its simplicity, we find that the agreement between our model and the observations is surprisingly good. We also explore the reliability and the limitations of our approach by comparing observations of the solar facular contrast and of the changes in spectral line depths with our calculations.

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

Access this article

Log in via an institution

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

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Auffret, H. and Muller, R.: 1991, A&A 246, 264.

    Google Scholar 

  • Chapman, G. A. and McGuire, T. E.: 1977, ApJ 217, 657.

    Google Scholar 

  • Chapman, G. A., Cookson, A. M. and Dobias, J. J.: 1997, ApJ 482, 541.

    Google Scholar 

  • Fligge, M., Solanki, S. K., Unruh, Y. C., Fröhlich, C. and Wehrli, C.: 1998, A&A 335, 709.

    Google Scholar 

  • Fligge, M., Solanki, S. K. and Unruh, Y. C.: 2000a, A&A 353, 380.

    Google Scholar 

  • Fligge, M., Solanki, S. K. and Unruh, Y. C.: 2000b, Space Sci. Rev., this volume.

  • Fontenla, J. M., Avrett, E. H. and Loeser, R.: 1993, ApJ 406, 319.

    Google Scholar 

  • Fontenla, J. M., White, O.R., Fox, P.A., Avrett, E. H. and Kurucz, R.L.: 1999, ApJ 518, 480.

    Google Scholar 

  • Frazier, E. N.: 1971, Solar Phys. 21, 42.

    Google Scholar 

  • Fröhlich, C. and Lean, J.: 1998, GRL 25, 4377.

    Google Scholar 

  • Fröhlich, C. et al.: 1997, Solar Phys. 170, 1.

    Google Scholar 

  • Gray, D. F. and Livingston, W. C.: 1997a, ApJ 474, 802.

    Google Scholar 

  • Gray, D. F. and Livingston, W. C.: 1997b, ApJ 474, 798.

    Google Scholar 

  • Kurucz, R. L.: 1991, in Stellar Atmospheres: Beyond Classical Models, L. Crivellari, I. Hubeny, D. G. Hummer (Eds), Kluwer, Dordrecht, p. 441.

    Google Scholar 

  • Lawrence, J. K. and Chapman, G. A.: 1988, ApJ 335, 996.

    Google Scholar 

  • Lean, J.: 1997, ARA&A 35, 33.

    Google Scholar 

  • Libbrecht, K. G. and Kuhn, J. R.: 1985, ApJ 299, 1047.

    Google Scholar 

  • Mitchell, W. E. Jr. and Livingston, W. C.: 1991, ApJ 372, 336.

    Google Scholar 

  • Solanki, S. K. and Unruh, Y. C.: 1998, A&A 329, 747.

    Google Scholar 

  • Taylor, S. F., Varsik, J. R., Woodard, M. F. and Libbrecht, K. G.: 1998, Solar Phys. 178, 1.

    Google Scholar 

  • Unruh, Y. C., Solanki, S. K. and Fligge, M.: 1999, A&A 345, 635.

    Google Scholar 

  • Wang, H. and Zirin, H.: 1987, Solar Phys. 110, 281.

    Google Scholar 

  • White, O.R., Fontenla, J. M. and Fox, P.A.: 2000, Space Sci. Rev., this volume.

  • Willson, R. C. and Hudson, H. S.: 1991, Nat 351, 42.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Institute of Astronomy, University of Vienna, Türkenschanzstr. 17, 1180, Wien, Austria

    Y.C. Unruh

  2. Max-Planck-Institut für Aeronomie, D-37191, Katlenburg-Lindau, Germany

    S.K. Solanki

  3. Institute of Astronomy, ETH Zentrum, CH-8092, Zürich, Switzerland

    M. Fligge

Authors
  1. Y.C. Unruh
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. S.K. Solanki
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. M. Fligge
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Unruh, Y., Solanki, S. & Fligge, M. Modelling solar irradiance variations: Comparison with observations, including line-ratio variations. Space Science Reviews 94, 145–152 (2000). https://doi.org/10.1023/A:1026758904332

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1023/A:1026758904332

Keywords

Search

Navigation