Spatial And Temporal Changes Of The Geomagnetic Field: Insights From Forward And Inverse Core Field Models - Archive ouverte HAL Access content directly
Book Sections Year : 2019

Spatial And Temporal Changes Of The Geomagnetic Field: Insights From Forward And Inverse Core Field Models

Abstract

Observational constraints on geomagnetic field changes from interannual to millenial periods are reviewed, and the current resolution of field models (covering archeological to satellite eras) is discussed. With the perspective of data assimilation, emphasis is put on uncertainties entaching Gauss coefficients, and on the statistical properties of ground-based records. These latter potentially call for leaving behind the notion of geomagnetic jerks. The accuracy at which we recover interannual changes also requires considering with caution the apparent periodicity seen in the secular acceleration from satellite data. I then address the interpretation of recorded magnetic fluctuations in terms of core dynamics, highlighting the need for models that allow (or pre-suppose) a magnetic energy orders of magnitudes larger than the kinetic energy at large length-scales, a target for future numerical simulations of the geodynamo. I finally recall the first attempts at implementing geomagnetic data assimilation algorithms.
Fichier principal
Vignette du fichier
gillet_chapter9.pdf (2.94 Mo) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

hal-02042703 , version 1 (20-02-2019)

Identifiers

Cite

Nicolas Gillet. Spatial And Temporal Changes Of The Geomagnetic Field: Insights From Forward And Inverse Core Field Models. Geomagnetism, aeronomy and space weather: a journey from the Earth's core to the sun, In press. ⟨hal-02042703⟩
80 View
178 Download

Altmetric

Share

Gmail Facebook X LinkedIn More