pure and applied geophysics

, Volume 63, Issue 1, pp 196–204 | Cite as

The longitudinal proper motion of sunspots and the solar rotation rate

  • Fred Ward


The longitudinal proper motion of sunspot groups has been shown to be a function of their size and relative extension in longitude. Two theories are proposed to explain these effects, which theories assume that the wind circulation of the spots and the wind field surrounding the spots are intimately connected, and dynamically interact. The retardation in the motion of large spot groups is hypothesized to be due to the effect of the latitudinal variation of the Coriolis parameter (on a rotating spherical body) and an assumed vortical circulation around the spots. The more rapid longitudinal motion of extended spot groups is suggested to be the result of the preferential occurrence and development of such groups in regions of above-average horizontal wind and wind shear. If these theories are essentially correct, the real solar rotation rate—i.e., the longitude- and time-averaged fluid motion field—should be derived from the motions of small spot groups, and is 1% to 11/2% higher than the usually accepted rate whichNewton andNunn derived.


Wind Field Wind Shear Fluid Motion Horizontal Wind Sunspot Group 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. [1]
    M. G. Adam,A New Determination of the Centre to Limb Change in Solar Wave-Lengths, MNRAS119 (1959), 460.Google Scholar
  2. [2]
    R. J. Boucher andR. J. Newcomb,Synoptic Interpretation of Some TIROS Vortex Patterns: A Preliminary Cyclone Model, J. App. Meteorology1 (1962), 127.Google Scholar
  3. [3]
    R. E. De Lury,The Law of the Solar Rotation, JRASCXXXIII (1939), 345.Google Scholar
  4. [4]
    G. E. Hale,Solar Vortices, Astrophysical J.28 (1908), 100.Google Scholar
  5. [5]
    A. B. Hart,Motions in the Sun at the Photospheric Level. IV.The Equatorial Rotation and Possible Velocity Fields in the Photosphere, MNRAS114 (1954), 17.Google Scholar
  6. [6]
    A. B. Hart,Motions in the Sun at the Photospheric Level. VI.Large Scale Motions in the Equatorial Region, MNRAS116 (1956), 38.Google Scholar
  7. [7]
    L. F. Hubert andO. Berg,A Rocket Portrait of a Tropical Storm, Mon. Weather Rev.83 (1955), 119.Google Scholar
  8. [8]
    A. Kasahara,The Numerical Prediction of Hurricane Movement with the Baratropic Model, J. Meteor.14 (1957), 386.Google Scholar
  9. [9]
    K. O. Kiepenheuer,Solar Activity, The Sun, edited by G. P. Kuiper, University of Chicago Press (1953), 322.Google Scholar
  10. [10]
    N. J. Macdonald,Methods of Measuring Solar and Terrestrial Atmospheric Circulations, Tellus18 (1966), 13.Google Scholar
  11. [11]
    P. Maltey,On the Velocity Field in Sunspots, Astrophysica NorvegicaVIII (1964), 205.Google Scholar
  12. [12]
    F. R. Miller,An Application of TIROS Cloud Observations in Sparse Data Regions, Mon. Weather Rev.91 (1963), 433.Google Scholar
  13. [13]
    H. W. Newton andM. L. Nunn,The Sun's Rotation Derived from Sunspots and Additional Results, 1934 to 1944, MNRAS111 (1951), 413.Google Scholar
  14. [14]
    H. H. Plaskett,Motions in the Sun at the Photospheric Level. I.Methods, MNRAS112 (1952), 414.Google Scholar
  15. [15]
    H. H. Plaskett,Motions in the Sun at the Photospheric Level. V.Velocities of Granules and of Other Localized Regions, MNRAS114 (1954), 251.Google Scholar
  16. [16]
    H. H. Plaskett,Motions in the Sun at the Photospheric Level. VIII.Solar Rotation and Photospheric Circulation, MNRAS119 (1959), 197.Google Scholar
  17. [17]
    H. H. Plaskett,Limb Darkening and Solar Rotation, MNRAS123 (1962), 541.Google Scholar
  18. [18]
    V. P. Starr andP. A. Gilman,Energetics of the Solar Rotation, Astrophysical J.141 (1965), 1119.Google Scholar
  19. [19]
    F. Ward,General Circulation of the Solar Atmosphere from Observational Evidence, Pure and Appl. Geophys.58 (1964/II), 157.Google Scholar
  20. [20]
    F. Ward,The General Circulation of the Solar Atmosphere and the Maintenance of the Equatorial Acceleration, Astrophysical. J.141 (1965), 534.Google Scholar
  21. [21]
    F. Ward,The Determination of the Solar Rotation Rate from the Motion of Identifiable Features, Astrophysical J.145 (1966), in press.Google Scholar
  22. [22]
    H. Wexler,Structure of Hurricanes as Determined by Radar, Annals, NYASXLVIII (1947), 821.Google Scholar
  23. [23]
    W. K. Widger, Jr.,A Synthesis of Interpretations of Extratropical Vortex Patterns as Seen by TIROS, Mon. Weather Rev.92 (1964), 263.Google Scholar

Copyright information

© Birkhäuser Verlag 1966

Authors and Affiliations

  • Fred Ward
    • 1
  1. 1.Air Force Cambridge Research LaboratoriesBedfordUSA

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