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Sunspots as tracers of meridional circulation
Author(s) -
Wöhl H.
Publication year - 2002
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/1521-3994(200208)323:3/4<329::aid-asna329>3.0.co;2-m
Subject(s) - sunspot , zonal and meridional , meridional flow , circulation (fluid dynamics) , climatology , physics , atmospheric sciences , geology , astronomy , astrophysics , magnetic field , mechanics , quantum mechanics
Many sunspots and sunspot groups exhibit only a small amount of change of their heliographical latitude during their lifetime. This is called meridional motion and measured in fractions of degrees per day or meters per second. The fact is demonstrated for sunspots and sunspot groups selected from several sources and especially for recurrent sunspots from Debrecen data. There is a tendency of the sunspots and sunspot groups to move away from the activity belt, which is defined by all sunspots. The meridional velocities increase with distance to the activity belt. Since the braking of sunspot rotation velocities by aging is well known, it is suggested again that the meridional motion of the solar plasma is comparable to that of the sunspot groups.