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Astron. Astrophys. 332, 755-760 (1998)
Velocity structures from sunspot statistics in cycles 10 to 22
II. Latitudinal velocity and correlation functions
Pentti Pulkkinen 1, 2 and
Ilkka Tuominen 2
1 Department of Physics, Theory Division P.O. Box 9,
FIN-00014, University of Helsinki, Finland
2 Department of Geosciences and Astronomy, University of
Oulu, P.O. Box 333, FIN-90571 Oulu, Finland
Received 11 July 1996 / Accepted 11 December 1997
Abstract
From sunspot observations between 1853-1996 we calculate latitudinal velocities and correlation functions - the Reynolds stress and the helicity. Latitudinal motions exist, but their behaviour is not certain. The Reynolds stress is strongly present but the helicity is negligible.
Key words: Sun: activity; photosphere; sunspots
Send offprint requests to: Pentti Pulkkinen
Contents
- 1. Introduction
- 2. Correlation functions
- 2.1. Reynolds stress
- 2.2. Helicity
- 3. The data and methods
- 4. Results
- 4.1. Latitudinal velocity
- 4.2. The Reynolds stress
- 4.3. Helicity
- 5. Conclusions and discussion
- Acknowledgements
- References
© European Southern Observatory (ESO) 1998
Online publication: March 23, 1998
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