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| Titel |
The along-track spectral-spatial approach for estimating the ocean-induced magnetic field from Swarm vector magnetic data |
| VerfasserIn |
Zdeněk Martinec, David Einšpigl, Libor Šachl, Jakub Velimsky |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123153
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| Publikation (Nr.) |
 EGU/EGU2016-2353.pdf |
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| Zusammenfassung |
| This study deals with the analysis of Swarm vector magnetic field measurements for
estimating the poloidal part of the ocean-induced magnetic field. For a single Swarm satellite,
the magnetic measurements from magnetically quiet nights are processed by the along-track
spectral-spatial approach on track-by-track basis with careful treatment of four unwanted
magnetic fields, the main magnetic field, the magnetospheric magnetic field, the polar
electrojet and field-aligned current magnetic fields. The respective magnetic fields are
modelled by the CHAOS-5 field model, the spectral approach and simplified spatial
representations of electric currents flowing in the polar regions. One by one the modelled
magnetic fields are subtracted from the along-track Swarm magnetic measurements. The
remaining residual magnetic field is expected to contain the magnetic field induced by ocean
currents. The X and Z components of the residual magnetic field are spectrally
analyzed and tested whether the field has an internal origin only and whether the
components are physically consistent. If the test is positive, the modelled residual
magnetic field is interpreted as the magnetic field induced by ocean currents. A few
examples of the along-track, spectral-spatial analysis of Swarm vector magnetic
data are presented. The Swarm-based estimates of the ocean-induced magnetic
field are then compared with the simulated magnetic signals. The simulations are
done for the global barotropic ocean circulation under lunisolar tidal forcing by the
data-assimilated DEBOT model. The Swarm-based estimates and the simulations of the
ocean-induced magnetic field are in satisfactory agreement along chosen Swarm tracks. |
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