Temporal resolution of internal magnetic field modes from satellite data
| Autor: | Dominique Jault, João Domingos, Maria Alexandra Pais, Mioara Mandea |
|---|---|
| Přispěvatelé: | Centro de Física Computacional (CFC), Universidade de Coimbra [Coimbra], Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National d’Études Spatiales [Paris] (CNES) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
010504 meteorology & atmospheric sciences
Field (physics) [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] lcsh:Geodesy Principal component analysis 010502 geochemistry & geophysics 01 natural sciences Swarm constellation 0105 earth and related environmental sciences lcsh:QB275-343 CHAMP satellite lcsh:QE1-996.5 Mode (statistics) lcsh:Geography. Anthropology. Recreation Swarm behaviour Spherical harmonics Geology Computational physics lcsh:Geology Noise Earth's magnetic field lcsh:G Space and Planetary Science Temporal resolution Virtual observatories Geomagnetic field |
| Zdroj: | Earth, Planets and Space, Vol 71, Iss 1, Pp 1-17 (2019) Earth Planets and Space Earth Planets and Space, Springer/Terra Scientific Publishing Company, 2019, 71 (1), ⟨10.1186/s40623-018-0983-5⟩ Earth Planets and Space, 2019, 71 (1), ⟨10.1186/s40623-018-0983-5⟩ |
| ISSN: | 1880-5981 1343-8832 |
| Popis: | International audience; We aim to obtain a modal decomposition of the internal geomagnetic field. In order to do so, we perform a principal component analysis of two virtual observatory datasets, with 4-month sampling time, from the CHAMP (2001-2009) and Swarm (2014-2017) satellite records. The spatial patterns of well-resolved modes calculated from the three field components all have internal origin as expected for these datasets, except for one Swarm mode. For both datasets, we find that the modes with the shortest timescales have also the smallest length scales as expected from a physical standpoint. Also, the energy ordering of the modes is from the least to the most variable, in agreement with independent results on the main field data spectrum. This is not achieved in regularised inversions of geomagnetic field data into time-varying spherical harmonic decomposition, where the highest degree terms have also the poorest time resolution. The improved accuracy of Swarm data is reflected in the lower level of the noise variance. |
| Databáze: | OpenAIRE |
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