Astron. Astrophys. 321, 323-329 (1997)

Solar dynamics over cycle 19 using sunspots as tracers

E. Nesme-Ribes ^{* 1}, N. Meunier ¹ and I. Vince <sup>2

1</sup> URA 2080 CNRS, Département d'Astronomie Solaire et Planétaire, Observatoire de Paris, 5 Place Janssen, F-92195 Meudon, France
² Astronomical Observatory, Volgina 7, YU 11050 Beograd, Yugoslavia

Received 17 May 1996 / Accepted 1 October 1996

Abstract

The angular velocities and meridional motions of cycle 19 sunspots observed at Meudon were investigated. We compare our results with cycle 21 sunspot rotation properties (Nesme-Ribes et al. 1993a). We found also a complex latitudinal meridional circulation pattern similar to what was observed on cycle 21 sunspots (Nesme-Ribes et al. 1993b). We also corroborated the very small sunspot covariance (i.e. angular momentum transport via Reynolds stresses), which imposes a strong constraint on the source term of the differential rotation modeling.

Key words: sunspots Sun: rotation Sun: magnetic fields Sun: activity

* Deceased on November the 25th, 1996

Send offprint requests to: N. Meunier

Contents

• 1. Introduction
• 2. Observational data
• 3. Angular rotation rate
  • 3.1. Global rotation
  • 3.2. Cycle variability
  • 3.3. North-south asymmetry
  • 3.4. Age and magnetic polarity dependence
• 4. Meridional circulation
  • 4.1. Net meridional circulation
• 5. Reynolds stresses
  • 5.1. Covariance of cycle 19 sunspots
  • 5.2. Leading and following sunspot covariance
  • 5.3. Old/young sunspot covariance
• 6. Conclusion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: June 30, 1998
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