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| Titel |
A new model of Earth's radial conductivity structure derived from over 10 years of satellite and observatory magnetic data |
| VerfasserIn |
Christoph Püthe, Alexey Kuvshinov, Nils Olsen, Amir Khan |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250102256
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| Publikation (Nr.) |
 EGU/EGU2015-1565.pdf |
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| Zusammenfassung |
| We present a new model of the radial (1-D) conductivity structure of Earth’s mantle. This
model was derived from more than ten years of magnetic measurements taken by
the satellites Ørsted, CHAMP, SAC-C and the Swarm trio as well as the global
network of geomagnetic observatories. After removal of core and crustal field as
predicted by a recent field model we fit the data with spherical harmonic coefficients
describing ring current activity and associated induction effects, and estimate global
C-responses at periods between 1.5Âdays and 150Âdays. An iterative approach is used
to correct the estimated C-responses for 3-D effects arising from induction in a
heterogeneous surface shell that takes into account the distribution of oceans and
continents.
We invert the corrected C-responses for a 1-D model of mantle conductivity using both
probabilistic and deterministic methods. The different methods yield very similar results,
consisting of a highly resistive upper mantle, a conductive lower mantle, and an increase in
conductivity in and beneath the transition zone. Analysis of the Hessian of the cost
function reveals that the data are most sensitive to structures at depths between
700 km and 1200 km, in agreement with the results obtained from the probabilistic
approach. The recovered models feature a marked kink in this well-resolved depth
range. |
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