Describing and predicting the evolution of earth’s magnetic field : A long-term endeavor

In September 2024, the call for contributions for the 14th edition of the International Geomagnetic Reference Field (IGRF) took place. Updated every five years since 1965, the IGRF provides a global magnetic map along with five-year forecasts. It is essential for research on Earth’s core, space weather, and crustal magnetic anomalies, and it also supports practical applications such as navigation and guidance.



In this context, the ISTerre geodynamo team presented its candidate model, COV-SAT, covering the period 2000–2025 using continuous satellite data. Its key feature is the use of analytically derived temporal cross-covariance functions to better constrain the inversion of magnetic measurements. These functions reproduce the temporal spectrum of Earth’s dynamo and integrate satellite, observatory, paleomagnetic data, as well as advanced numerical simulations.

This approach represents an important methodological advance, helping to better separate the core-generated field from external sources (ionosphere and magnetosphere). By combining theory, observations, and simulations, the team contributes to more reliable models and forecasts, useful in both academic research and industrial applications.


The full study is published in Earth, Planets and Space

References :

Alken, P., Thébault, E., Beggan, C. D., Amit, H., Aubert, J., Baerenzung, J., Bondar, T., Brown, W., Califf, S., Chambodut, A., et al. (2021).
International geomagnetic reference field : the thirteenth generation
Earth, Planets and Space, 73, 1–25.

Claveau, F., Gillet, N., Amblard, P.-O., & Finlay, C. C. (2025).
Broadband a priori temporal cross-covariances for the geomagnetic inverse problem : application to the satellite era.

The COV-OBS.x2 geomagnetic field model

Scientific contacts :

  • Romain Claveau – Researcher, ISTerre – CNRS / Université Grenoble Alpes
  • Nicolas Gillet – Researcher, ISTerre – CNRS / Université Grenoble Alpes
  • Pierre-Olivier Amblard – Researcher, ISTerre – CNRS / Université Grenoble Alpes
  • Christopher C. Finlay – Researcher, DTU Space – Technical University of Denmark



Funding and Support

  • European Space Agency (ESA), within the EO Science for Society program, contract 4000127193/19/NL/IA (Swarm + 4D Deep Earth : Core)
  • French National Centre for Space Studies (CNES), financial support through the Core_Swarm mission
  • Labex OSUG@2020 (Investments for the Future – ANR10 LABX56), participation of R. Claveau and N. Gillet