Details of the Abstract
| Title of paper | Spectra of the geomagnetic field diurnal variations |
| List of authors | Author, I.I.Rokityansky , Co-author, A.V.Tereshyn |
| Affiliation(s) | Subbotin Institute of Geophysics of the National Academy of Sciences of Ukraine, Kiev, Ukraine |
| Summary | Spectral analysis of the 3 components of the geomagnetic field time series with the discreteness of 60 s (Intermagnet data) has been made by the Fast Fourier Transform and an average-annual and average-seasonal amplitude spectra have been obtained over periods from 300 s to 5 × 10^6 s. The spectrum consists of the continuous part and narrow lines at the diurnal period T1 = 86400 s and its harmonics with periods T = T1/n, where n = 2-7. The subject of this work is the diurnal line of the spectrum and its harmonics located in the interval of periods 10,000–100,000 s. The spectra were studied at 50 world-wide distributed observatories and the following results obtained. The representation of harmonics through spectral lines makes it possible to identify two phenomena. At the near-to-pole high geomagnetic latitudes ±79-90°, only the daily harmonic T1 is observed, harmonics of higher orders are absent. In this zone, the horizontal component is much larger than vertical one which is in good agreement with the quasi-uniform current layer in the polar cap ionosphere. An interesting new scientific result is the widening of the diurnal harmonic spectral line from September to February at all studied observatories. This is not a seasonal variation, since it is equally observed in both the northern and southern hemispheres, in which the seasons are in antiphase. We can assume that this phenomenon is associated with a certain orientation of the Earth in outer space relative to some factor that changes the daily spectral line to a wider one. The absolute motion of the Earth, formed by the hierarchy of cosmological rotations, is proposed as such a factor. |
| Session Keyword | 8.0 Global, planetary and source field studies |
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8.0_spectra_of_the_geomagneti_tereshyn.pdf
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