Abstract
The 3-component McIntosh classification of sunspots was introduced in 1966, adopted for interchange and publication of data in 1969, and has been used increasingly in recent years. The McIntosh classification uses a modified Zurich evolutionary sequence as its first component, class, where two of the Zurich classes are omitted and more quantitative definitions are used. It then adds descriptions of the largest spot (second component) and the degree of spottedness in the group interior (third component) to define 60 distinct types of sunspot groups. Definitions of the McIntosh classification system and their rationale are presented herein. Correlations with solar flares excel those with the earlier Zurich classification, prompting the use of the McIntosh classification in an expert system (Theo) for predicting X-ray solar flares.
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References
Baker, 1970, AIAA Paper 70-1370.
Beck, R.: 1987, in G. D. Roth (ed.), Handbuch für Sternfreunde (4h ed.), Springer-Verlag, Berlin.
Bray, R. J. and Loughhead, R. E.: 1964, Sunspots, John Wiley and Sons, New York.
Chinese Solar-Geophysical Data: 1988 (and thereafter), Descriptive Text, Academia Sinica, Beijing.
Cortie, A. L.: 1901, Astrophys. J. 13, 260.
Gaizauskas, V.: 1989, Solar Phys. 121, 135.
Gaizauskas, V. and McIntosh, P. S.: 1986, in P. Simon, G. Heckman, and M. A. Shea (eds.), Solar-Terrestrial Predictions Workshop 1984, U.S. Dept. Commerce, Boulder, Colorado, p. 126.
Gaizauskas, V., Harvey, K. L., Harvey, J. W., and Zwaan, C: 1983, Astrophys. J. 265, 1056.
Giovanelli, R. G.: 1939, Astrophys. J. 89, 555.
Hill, R. E.: 1989, J. Assoc. Lunar Planetary Obs. 33, 10.
I.U.W.D.S. (International Ursigram and World Day Service): 1969, Synoptic Codes for Solar and Geophysical Data, 2nd revised edition, NOAA Space Environment Services Center and Observatoire de Paris.
Kiepenheuer, K. O.: 1953, in G. P. Kuiper (ed.), The Sun, Univ. of Chicago Press, Chicago, p. 322.
Kildahl, K.: 1980, in R. F. Donnelly (ed.), Proc. Solar-Terrestrial Predictions, U.S. Dept. Commerce, Boulder, Colorado 3, p. C166.
Krivsky, L.: 1972, in P. S. McIntosh and M. Dryer (eds.), Solar Activity Observations and Predictions, MIT Press, Cambridge, p. 398.
Kunzel, H.: 1960, Astron. Nachr. 285, 271.
Lewis, C. and Dennett, J.: 1986, CU Engineering, University of Colorado, p. 15.
McIntosh, P. S.: 1969, in Upper Atmosphere Geophysics Report, UAG 5, NOAA World Data Center A for Solar-Terrestrial Physics, Boulder, Colorado, p. 30.
McIntosh, P. S.: 1979, in Upper Atmosphere Geophysics Report, UAG 70, NOAA World Data Center A for Solar-Terrestrial Physics, Boulder, Colorado.
McIntosh, P. S.: 1981, in L. E. Cram and J. H. Thomas (eds.), The Physics of Sunspots, Sacramento Peak National Observatory, Sunspot, New Mexico, p. 7.
McIntosh, P. S.: 1986, in P. Simon, G. Heckman, and M. A. Shea (eds.), Solar-Terrestrial Predictions Workshop 1984, U.S. Dept. Commerce, Boulder, Colorado, p. 357.
McIntosh, P. S. and Dryer, M. (eds.): 1972, Solar Activity Observations and Predictions, MIT Press, Cambridge, 442 pp.
McIntosh, P. S. and Wilson, P. R.: 1985, Solar Phys. 97, 59.
Miller, R. W.: 1988, J. Roy. Astron. Soc. Can. 82, 191.
Newton, H. W.: 1958, The Face of the Sun, Penquin Books, London, p. 86.
Simon, P. and McIntosh, P. S.: 1972, in P. S. McIntosh and M. Dryer (eds.), Solar Activity Observations and Predictions, MIT Press, Cambridge, p. 346.
Smith, H. J. and Smith, E. v. P.: 1963, Solar Flares, McMillan, New York, 322 pp.
Solar-Geophysical Data Descriptive Text: 1972 (and thereafter), NOAA World Data Center A, Boulder, Colorado, p. 25.
Walmeier, M.: 1938, Z. Astrophys. 16, 276.
Walmeier, M.: 1947, Publ. Zürich Obs. 9, 1.
Walmeier, M.: 1973, Solar Phys. 28, 389.
Warwick, C. S.: 1966, Astrophys. J. 145, 215.
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McIntosh, P.S. The classification of sunspot groups. Sol Phys 125, 251–267 (1990). https://doi.org/10.1007/BF00158405
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DOI: https://doi.org/10.1007/BF00158405