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Polar and tropical auroræ: And the isoauroral diagram

  • Sydney Chapman
Article

Summary

  1. (1)

    After describing theisochasmic diagrams of Fritz and Vestine, which map the distribution of frequency of auroralvisibility from any point on the earth, it is pointed out that there is a need for a new type ofisoauroral diagram, showingisoaurores or lines of equal frequency ofoccurrence above any terrestrial point. The nature and “enumeration” of the isoaurores is discussed.

     
  2. (2)

    The few auroræ which have been reported as visible from India are discussed: namely (1) one reported from Benares on 1847 November 11, (2) one reported by J. D. Hooker as seen on 1848 Feb. 14, from a point on the Soane River at 24° 52′ N., 84° 22′ E.,—the validity of both these reports has been questioned—and (3) the undoubted case of the aurora of 1872 Feb. 4, seen as far south as Bombay, and from many more northerly points in India and elsewhere.

     
  3. (3)

    An appeal is made for a search by Indian scientists for material relating to Indian observations of these and possibly other auroræ.

     

Keywords

Magnetic Storm Geomagnetic Latitude Auroral Zone Geomagnetic Equator Auroral Visibility 
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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References

  1. 1.
    Fritz, H. “Verzeichniss beobachteter Polarlichter,”Akad. Wiss. Wien, 1873.Google Scholar
  2. 2.
    Fritz, H.Vierteljahrschrift der Naturforschenden Gesellschaft in Zürich, 1867,12.Google Scholar
  3. 3.
    Fritz, H.Petermann’s Geographische Mittheilungen, 1874, 20 (see also Heis.Wochenschrift für Astronomie, Meteorologie and Geographie, 1877, 161).Google Scholar
  4. 4.
    Das Polarlicht, Leipzig, F. A. Brockhaus, 1881.Google Scholar
  5. 5.
    Vestine, E. H.Terr. Mag., 1944,49, 77.CrossRefGoogle Scholar
  6. 6.
    — and Snyder, E. J.Ibid., 1945,50, 105.CrossRefGoogle Scholar
  7. 7.
    Davies, F. T.Ibid., 1931,36, 199.CrossRefGoogle Scholar
  8. 8.
    Geddes, M.Ibid., 1939,44, 189; White, F. W. G.Ibid., Terr. Mag., 1939,44, 367.CrossRefGoogle Scholar
  9. 9.
    Jahresbericht d. Vereines f. vaterländ. Naturkunde in Würtemburg, Stuttgart, 1849,4, 378.Google Scholar
  10. 10.
    Hooker, J. D.Himalayan Journals, London (Murray), 1854, see vol. 2, 384–86.Google Scholar

Copyright information

© Indian Academy of Sciences 1953

Authors and Affiliations

  • Sydney Chapman
    • 1
    • 2
  1. 1.The Queen’s CollegeOxford
  2. 2.The Geophysical InstituteCollege

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