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| Titel |
An accelerating high-latitude jet in Earth's core |
| VerfasserIn |
Phil Livermore, Rainer Hollerbach, Chris Finlay |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250144283
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| Publikation (Nr.) |
 EGU/EGU2017-8092.pdf |
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| Zusammenfassung |
| Observations of the change in Earth’s magnetic field, the secular variation, provide
information on the motion of liquid metal within the core that is responsible for its
generation. The very latest high-resolution observations from ESA’s Swarm satellite mission
show intense field change at high-latitude localised in a distinctive circular daisy-chain
configuration centred on the north geographic pole. Here we explain this feature with a
localised, non-axisymmetric, westwards jet of 420 km width on the tangent cylinder, the
cylinder of fluid within the core that is aligned with the rotation axis and tangent to
the solid inner core. We find that the jet has increased in magnitude by a factor
of three over the period 2000–2016 to about 40 km/yr, and is now much stronger
than typical large-scale flows inferred for the core. The current accelerating phase
may be a part of a longer term fluctuation of the jet causing both eastwards and
westwards movement of magnetic features over historical periods, and may contribute to
recent changes in torsional wave activity and the rotation direction of the inner core. |
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