Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

The unusual minimum of sunspot cycle 23 caused by meridional plasma flow variations

Nature volume 471, pages 80–82 (2011)Cite this article

Subjects

Abstract

Direct observations over the past four centuries1 show that the number of sunspots observed on the Sun’s surface varies periodically, going through successive maxima and minima. Following sunspot cycle 23, the Sun went into a prolonged minimum characterized by a very weak polar magnetic field2,3 and an unusually large number of days without sunspots4. Sunspots are strongly magnetized regions5 generated by a dynamo mechanism6 that recreates the solar polar field mediated through plasma flows7. Here we report results from kinematic dynamo simulations which demonstrate that a fast meridional flow in the first half of a cycle, followed by a slower flow in the second half, reproduces both characteristics of the minimum of sunspot cycle 23. Our model predicts that, in general, very deep minima are associated with weak polar fields. Sunspots govern the solar radiative energy8,9 and radio flux, and, in conjunction with the polar field, modulate the solar wind, the heliospheric open flux and, consequently, the cosmic ray flux at Earth3,10,11.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Simulated sunspot butterfly diagram with a variable meridional flow.
Figure 2: Cycle overlap and polar field strength at solar minimum in response to variable meridional flows.
Figure 3: Polar field strength versus cycle overlap at solar minimum.

Similar content being viewed by others

References

  1. Hoyt, D. V. & Schatten, K. H. Group sunspot numbers: a new solar activity reconstruction. Sol. Phys. 179, 189–219 (1998)

    Article  ADS  Google Scholar 

  2. Schrijver, C. J. & Liu, Y. The global solar magnetic field through a full sunspot cycle: observations and model results. Sol. Phys. 252, 19–31 (2008)

    Article  ADS  Google Scholar 

  3. Wang, Y.-M., Robbrecht, E. & Sheeley, N. R., Jr On the weakening of the polar magnetic fields during solar cycle 23. Astrophys. J. 707, 1372–1386 (2009)

    Article  ADS  Google Scholar 

  4. Solar Influences Data Analysis Center. Daily sunspot number 〈http://sidc.oma.be/sunspot-data/dailyssn.php〉 (2011)

  5. Solanki, S. K. Sunspots: an overview. Astron. Astrophys. Rev. 11, 153–286 (2003)

    Article  ADS  Google Scholar 

  6. Charbonneau, P. Dynamo models of the solar cycle. Living Rev. Solar Phys. 7, 3 〈http://solarphysics.livingreviews.org/Articles/lrsp-2010-3/〉 (2010)

  7. Muñoz-Jaramillo, A., Nandy, D., Martens, P. C. H. & Yeates, A. R. A double-ring algorithm for modeling solar active regions: unifying kinematic dynamo models and surface flux-transport simulations. Astrophys. J. 720, L20–L25 (2010)

    Article  ADS  Google Scholar 

  8. Krivova, N. A., Balmaceda, L. & Solanki, S. K. Reconstruction of the solar total irradiance since 1700 from the surface magnetic flux. Astron. Astrophys. 467, 335–346 (2007)

    Article  ADS  Google Scholar 

  9. Lean, J. The Sun’s variable radiation and its relevance for Earth. Annu. Rev. Astron. Astrophys. 35, 33–67 (1997)

    Article  ADS  CAS  Google Scholar 

  10. Solanki, S. K., Schüssler, M. & Fligge, M. Evolution of the Sun’s large-scale magnetic field since the Maunder minimum. Nature 408, 445–447 (2000)

    Article  ADS  CAS  Google Scholar 

  11. Lara, A. et al. Coronal mass ejections and galactic cosmic-ray modulation. Astrophys. J. 625, 441–450 (2005)

    Article  ADS  Google Scholar 

  12. Babcock, H. W. The topology of the Sun’s magnetic field and the 22-year cycle. Astrophys. J. 133, 572–587 (1961)

    Article  ADS  Google Scholar 

  13. Leighton, R. B. A magneto-kinematic model of the solar cycle. Astrophys. J. 156, 1–26 (1969)

    Article  ADS  Google Scholar 

  14. Choudhuri, A. R., Schussler, M. & Dikpati, M. The solar dynamo with meridional circulation. Astron. Astrophys. 303, L29–L32 (1995)

    ADS  Google Scholar 

  15. Dikpati, M., de Toma, G. & Gilman, P. A. Predicting the strength of solar cycle 24 using a flux-transport dynamo-based tool. Geophys. Res. Lett. 33, L05102 (2006)

    Article  ADS  Google Scholar 

  16. Choudhuri, A. R., Chatterjee, P. & Jiang, J. Predicting solar cycle 24 with a solar dynamo model. Phys. Rev. Lett. 98, 131103 (2007)

    Article  ADS  Google Scholar 

  17. Yeates, A. R., Nandy, D. & Mackay, D. H. Exploring the physical basis of solar cycle predictions: flux transport dynamics and persistence of memory in advection- versus diffusion-dominated solar convection zones. Astrophys. J. 673, 544–556 (2008)

    Article  ADS  Google Scholar 

  18. Giles, P. M., Duvall, T. L., Scherrer, P. H. & Bogart, R. S. A subsurface flow of material from the Sun’s equator to its poles. Nature 390, 52–54 (1997)

    Article  ADS  CAS  Google Scholar 

  19. Zhao, J. & Kosovichev, A. G. Torsional oscillation, meridional flows, and vorticity inferred in the upper convection zone of the Sun by time-distance helioseismology. Astrophys. J. 603, 776–784 (2004)

    Article  ADS  Google Scholar 

  20. González Hernández, I. et al. Meridional circulation variability from large-aperture ring-diagram analysis of global oscillation network group and Michelson Doppler imager data. Astrophys. J. 638, 576–583 (2006)

    Article  ADS  Google Scholar 

  21. Švanda, M., Kosovichev, A. G. & Zhao, J. Speed of meridional flows and magnetic flux transport on the Sun. Astrophys. J. 670, L69–L72 (2007)

    Article  ADS  Google Scholar 

  22. Hathaway, D. H., Nandy, D., Wilson, R. M. & Reichmann, E. J. Evidence that a deep meridional flow sets the sunspot cycle period. Astrophys. J. 589, 665–670 (2003)

    Article  ADS  Google Scholar 

  23. Nandy, D. & Choudhuri, A. R. Explaining the latitudinal distribution of sunspots with deep meridional flow. Science 296, 1671–1673 (2002)

    Article  ADS  CAS  Google Scholar 

  24. Muñoz-Jaramillo, A., Nandy, D. & Martens, P. C. H. Helioseismic data inclusion in solar dynamo models. Astrophys. J. 698, 461–478 (2009)

    Article  ADS  Google Scholar 

  25. Durney, B. R. On a Babcock-Leighton solar dynamo model with a deep-seated generating layer for the toroidal magnetic field. IV. Astrophys. J. 486, 1065–1077 (1997)

    Article  ADS  Google Scholar 

  26. Nandy, D. & Choudhuri, A. R. Toward a mean field formulation of the Babcock-Leighton type solar dynamo. I. α-coefficient versus Durney’s double-ring approach. Astrophys. J. 551, 576–585 (2001)

    Article  ADS  Google Scholar 

  27. Rempel, M. Origin of solar torsional oscillations. Astrophys. J. 655, 651–659 (2007)

    Article  ADS  Google Scholar 

  28. Jiang, J., Işik, E., Cameron, R. H., Schmitt, D. & Schüssler, M. The effect of activity-related meridional flow modulation on the strength of the solar polar magnetic field. Astrophys. J. 717, 597–602 (2010)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

This work was supported through the Ramanujan Fellowship of the Government of India at the Indian Institute of Science Education and Research, Kolkata, and by a NASA Living With a Star grant to the Smithsonian Astrophysical Observatory and Montana State University. We are grateful to D. Hathaway for providing the observational data on days without sunspots; the analysis of these data is reported in Supplementary Fig. 1.

Author information

Authors and Affiliations

  1. Department of Physical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741252, West Bengal, India,

    Dibyendu Nandy

  2. Department of Physics, Montana State University, Bozeman, Montana 59717, USA,

    Andrés Muñoz-Jaramillo & Petrus C. H. Martens

  3. Harvard-Smithsonian Center for Astrophysics, Cambridge, 02138, Massachusetts, USA

    Andrés Muñoz-Jaramillo & Petrus C. H. Martens

Authors
  1. Dibyendu Nandy
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Andrés Muñoz-Jaramillo
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Petrus C. H. Martens
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

D.N. conceived the principal idea and, in conjunction with P.C.H.M. and A.M.-J., planned the simulations, which were performed by A.M.J. under the guidance of D.N. and P.C.H.M. D.N. led the interpretation of the results and all authors contributed to writing the paper.

Corresponding author

Correspondence to Dibyendu Nandy.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Text and Data comprising a description of the observed characteristics of the minimum of solar cycle 23, details of the dynamo model used for the simulations, an analysis of sensitivity of results to parameter changes and a note on solar plasma flow observations, Supplementary Figures 1-4 with legends, Supplementary Tables 1-3 and additional references. (PDF 311 kb)

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Nandy, D., Muñoz-Jaramillo, A. & Martens, P. The unusual minimum of sunspot cycle 23 caused by meridional plasma flow variations. Nature 471, 80–82 (2011). https://doi.org/10.1038/nature09786

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature09786

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing