Long-term evolution of high-frequency ingredients of the core surface radial geomagnetic field
Abstract
Our previous research, based on observatory and main field models data, revealed the presence of high-frequency ingredients, at time scales of 22 and ~80 years, both in the Earth's surface field and in the core surface radial field. 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). The long-term evolution of the ~80-year variation of the core surface field, covering a time-span of about 320 years as given by gufm1 main field model, is illustrated and discussed in terms of displacements on the core surface of the field patterns and of their first two time-derivatives.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMGP31B1072D
- Keywords:
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- 1507 GEOMAGNETISM AND PALEOMAGNETISM / Core processes;
- 1560 GEOMAGNETISM AND PALEOMAGNETISM / Time variations: secular and longer