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| Titel |
On the evolution of high-frequency ingredients of the secular variation and of their expression at core surface, as inferred from observatory data and main field models |
| VerfasserIn |
C. Demetrescu, V. Dobrica, C. Stefan |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250065605
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| Zusammenfassung |
| The analysis of the first time derivative, with the residual external contribution removed, of H, Z, and D for 24 observatories world-wide with 100-150 years long time series, shows the presence in data of a so-called ~80-year variation. The geographical distribution and its temporal evolution as revealed by 400 years time span of the gufm1 field model is derived and discussed. Time-longitude, time-latitude plots and spectral analysis have been used to derive quantitative information on the ~80-year variation features. The analysis has been extended to the radial component of the geomagnetic field at the core surface. The results indicate that the ~80-year variation entirely accounts for the field with time-averaged axisymmetric component subtracted and high-pass-filtered with cutoff period 400 years of Finlay and Jackson (2003). |
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