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Article Dans Une Revue Solid Earth Année : 2023

Earth's core variability from magnetic and gravity field observations

Anita Thea Saraswati
  • Fonction : Auteur
Olivier de Viron
Mioara Mandea

Résumé

The motions of the liquid within the Earth's outer core lead to magnetic field variations together with mass distribution changes. As the core is not accessible for direct observation, our knowledge of the Earth’s liquid core dynamics only relies on indirect information sources. Mainly generated by the core dynamics, the surface geomagnetic field provides information about the variations of the fluid motion at the top of the core. The dynamic of the fluid core is also associated with mass distribution changes inside the core and produces gravitational field time fluctuations. By applying several statistical blind source separation methods to both the gravity and magnetic field time series, we investigate the common space–time variabilities. We report several robust interannual oscillations shared by the two observation sets. Among those, a common mode of around 7 years looks very significant. Whereas the nature of the driving mechanism of the coupled variability remains unclear, the spatial and temporal properties of the common signal are compatible with a core origin.
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Dates et versions

hal-04360917 , version 1 (22-12-2023)

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Anita Thea Saraswati, Olivier de Viron, Mioara Mandea. Earth's core variability from magnetic and gravity field observations. Solid Earth, 2023, 14 (12), pp.1267-1287. ⟨10.5194/se-14-1267-2023⟩. ⟨hal-04360917⟩

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