EGU25-9887, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-9887
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
A DGRF 2020 Candidate Model Only Based on Swarm ASM Experimental Vector Mode Data
Louis Chauvet1, Gauthier Hulot1, Robin Deborde1, Jean-Michel Léger2, and Thomas Jager2
Louis Chauvet et al.
  • 1Université Paris Cité, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France
  • 2CEA-Leti, Université Grenoble Alpes, MINATEC 17, rue des Martyrs, 38054, Grenoble Cedex 9 – France

ESA Swarm satellites carry a magnetometry payload consisting of an absolute scalar magnetometer (ASM), a relative flux gate vector magnetometer (VFM), and a set of star trackers (STR). The primary role of the ASM is to provide precise 1 Hz absolute field intensity measurements, while the VFM and STR provide the additional data needed to accurately reconstruct the attitude of the vector field to produce the official nominal Swarm L1b magnetic data. Each ASM instrument, however, can also produce its own self-calibrated 1 Hz experimental vector data, or, when requested, 250 Hz scalar burst data. Self-calibrated 1 Hz experimental vector data have routinely been produced ever since launch and are still run when the ASM instruments are not in burst mode. Such experimental data provide an interesting possibility of building alternative field models to those built from nominal Swarm L1b magnetic data. This possibility has been used to produce the only DGRF 2020 candidate model entirely and only relying on such data in the context of the recent IGRF 2025 call for candidate models. All other candidate models relied on either nominal Swarm L1b, or data from other satellites and ground observatories.

Here we will report on the way this unique DGRF candidate model was built, and on the post-calibration strategy that we used to further improve the quality of this model, only and entirely relying on a dedicated analysis of model residual signals. As will be discussed, our final candidate model turns out to be one of the DGRF 2020 candidate models closest to the final official DGRF model, which a posteriori provides encouraging evidence of both the quality of the Swarm ASM experimental vector mode data and the value of our post-calibration strategy.

How to cite: Chauvet, L., Hulot, G., Deborde, R., Léger, J.-M., and Jager, T.: A DGRF 2020 Candidate Model Only Based on Swarm ASM Experimental Vector Mode Data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9887, https://doi.org/10.5194/egusphere-egu25-9887, 2025.