The annual wave in geomagnetic activity as a magnetospheric modulation effect.

DOI BIBCODE
  • DAMASKE Detlef
    Institut für Geophysikalische Wissenschaften, Freie Universität Berlin Present address: Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg, Hannover, West Germany

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Description

A harmonic analysis of a 20-year series of geomagnetic daily character figures C9n and C9s, derived from means of the linear 3-hour indices an and as, yields an annual wave in hemispheric activity with a maximum near the June solstice (northern hemisphere) or December solstice (southern hemisphere). Examination of the results for every two consecutive years separately in a harmonic dial, however, shows systematic deviations of the dial vectors for both hemispheres towards either spring or fall. This indicates the residual effect of a superimposed planetary wave which can be attributed to the well known 12-month wave in activity sequences.<br>Elimination of this sequential wave yields the hemispheric annual wave with considerably increased accuracy, the wave maximum occurring 6 days after either one of the solstices. The results are in accordance with those expected from a modified modulation function which comprises all significant harmonic constituents of hemispheric geomagnetic activity, with regard to both seasonal and daily (UT) variations.

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Details 詳細情報について

  • CRID
    1390001206510947328
  • NII Article ID
    130003422862
  • DOI
    10.5636/jgg.33.623
  • BIBCODE
    1981JGG....33..623D
  • ISSN
    21855765
    00221392
  • Text Lang
    en
  • Data Source
    • JaLC
    • Crossref
    • CiNii Articles
  • Abstract License Flag
    Disallowed

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