Journal of geomagnetism and geoelectricity
Online ISSN : 2185-5765
Print ISSN : 0022-1392
ISSN-L : 0022-1392
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Volume 33, Issue 12
Displaying 1-3 of 3 articles from this issue
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  • Long-Period Oscillations in Mesospheric and Lower Thermospheric Winds (60-110km) at Saskatoon (52°N, 107°W, L=4.3)
    A. H. MANSON, C. E. MEEK, J. B. GREGORY
    1981 Volume 33 Issue 12 Pages 613-621
    Published: 1981
    Released on J-STAGE: March 12, 2010
    DOIhttps://doi.org/10.5636/jgg.33.613
    JOURNAL FREE ACCESS
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    Winds from a medium-frequency radar (2.2MHz) are available in tidally corrected form, on a daily basis, for 28 months from September 1978-December 1980. These data have excellent temporal resolution, and there are few gaps in the sequence. The amplitudes and phase progressions with height (60-110km) are shown for the QBO, annual, semiannual, terannual, 3-mth, and 27-d waves. The results for the first three oscillations are consistent with those from CIRA (1972) model data to near 100km; above there are disagreements which are likely due to tidal contamination in that model.
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  • The Annual Wave in Geomagnetic Activity as a Magnetospheric Modulation Effect
    Detlef DAMASKE
    1981 Volume 33 Issue 12 Pages 623-633
    Published: 1981
    Released on J-STAGE: March 12, 2010
    DOIhttps://doi.org/10.5636/jgg.33.623
    JOURNAL FREE ACCESS
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    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.
    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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  • A Search for Correlation between Time Change in Transfer Functions and Seismic Activity in North Taiwan
    Po-Fang CHEN
    1981 Volume 33 Issue 12 Pages 635-643
    Published: 1981
    Released on J-STAGE: March 12, 2010
    DOIhttps://doi.org/10.5636/jgg.33.635
    JOURNAL FREE ACCESS
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    Time change of the transfer functions for short-period geomagnetic variations at Lunping, Taiwan, Geomagnetic Observatory is examined in association with earthquake occurrences near Lunping from 1972 to 1976. A remarkable change of transfer function A, possibly related to the earthquakes which occurred in 1975 and 1976, is found. In addition, it is evident that a seasonal change in both transfer functions exists.
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