The geomagnetic secular-variation timescale in observations and numerical dynamo models - Archive ouverte HAL Access content directly
Journal Articles Geophysical Research Letters Year : 2011

The geomagnetic secular-variation timescale in observations and numerical dynamo models

(1) , (1) , (1) , (1)
1

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.
Fichier principal
Vignette du fichier
Lhuillier_et_al-2011-Geophysical_Research_Letters.pdf (318.33 Ko) Télécharger le fichier
Origin : Publisher files allowed on an open archive
Loading...

Dates and versions

insu-01410184 , version 1 (06-12-2016)

Identifiers

Cite

Florian Lhuillier, Alexandre Fournier, Gauthier Hulot, Julien Aubert. The geomagnetic secular-variation timescale in observations and numerical dynamo models. Geophysical Research Letters, 2011, 38 (9), pp.L09306. ⟨10.1029/2011GL047356⟩. ⟨insu-01410184⟩
27 View
240 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More