Journal articles
The geomagnetic secular-variation timescale in observations and numerical dynamo models
Abstract : The knowledge of the spatial power spectra of the main geomagnetic field and of its secular variation makes it possible to define typical timescales t n for each spherical harmonic degree n. Investigating both observations and numerical dynamos, we show that a one‐parameter law of the form t n = t SV/n is satisfied for the non‐dipole field, given the statistical way the observed t n are expected to fluctuate. Consequently, we determine the corresponding secular‐ variation timescale t SV from either instantaneous or time‐ averaged spectra, leading to a value of 415 ± 45 55 yr for recent satellite field models. In the broader context of geomagnetic data assimilation, t SV could provide a sensible and convenient means to rescale the time axis of dynamo simulations.
Cited literature [23 references]
https://hal-insu.archives-ouvertes.fr/insu-01410184
Contributor : Eva Fareau <>
Submitted on : Tuesday, December 6, 2016 - 3:00:08 PM
Last modification on : Wednesday, June 30, 2021 - 9:40:13 PM
Long-term archiving on: : Tuesday, March 21, 2017 - 12:23:35 AM
Contributor : Eva Fareau <>
Submitted on : Tuesday, December 6, 2016 - 3:00:08 PM
Last modification on : Wednesday, June 30, 2021 - 9:40:13 PM
Long-term archiving on: : Tuesday, March 21, 2017 - 12:23:35 AM
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