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Centennial to millennial geomagnetic field variations

Author:
  • Monika Korte
  • Raimund Muscheler
Publishing year: 2012
Language: English
Publication/Series: Journal of Space Weather and Space Climate
Volume: 2
Document type: Journal article
Publisher: EDP Sciences

Abstract english

Reconstructions of the geomagnetic field in the past represent a useful tool not only to investigate the geodynamo process, but also to estimate the effect of geomagnetic shielding for any studies on cosmogenic radionuclides and galactic cosmic rays. A number of new millennial-scale geomagnetic field reconstructions have been published over the last years, based on improved global archeo- and paleomagnetic data compilations. Here we review several spherical harmonic models and compare their dipole field predictions to reconstructions based on virtual axial dipole moments and virtual geomagnetic poles. Dipole intensity estimates from cosmogenic radionuclide production records, with suitable filtering to minimise the solar influence, have also been included in the comparison to provide independent information about variations in the strength of the geomagnetic field. However, due to differences among geomagnetic models and between C-14 and Be-10 production records this comparison is fairly inconclusive with respect to multi-centennial variations. Different geomagnetic dipole tilt reconstructions agree well for much of the Holocene, but dipole moment estimates still differ substantially. Recent spherical harmonic models for the past 3 and 10 kyrs have improved considerably compared to earlier versions. Nevertheless at present we recommend to test if any interpretation depends on the choice of model.

Keywords

  • Geology
  • magnetic field
  • geomagnetic dipole intensity
  • geomagnetic shielding
  • cosmogenic radionuclide production

Other

Published
  • ISSN: 2115-7251
Raimund Muscheler
E-mail: raimund.muscheler [at] geol.lu.se

Professor

Quaternary Sciences

+46 46 222 04 54

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