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| Titel |
Influence of geometrical settings like flattening and topography of the core-mantle and inner-core boundaries on the gravitational core-mantle coupling |
| VerfasserIn |
Jan M. Hagedoorn, Hans Greiner-Mai, Ludwig Ballani |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250047968
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| Zusammenfassung |
| Different processes influence the variation of the Earth’s rotation on decadal time scale.
The consideration of surface processes, like the exchange of angular momentum
of the fluid sub-systems of atmosphere and ocean, and coupling processes at the
core-mantle boundary like electromagnetic and topographic coupling torques, lead still to
significant differences between observed and modelled Earth rotation parameters
(ERP).
For the modelled ERP, we consider the electromagnetic (EM) and topographic (TOP)
core-mantle coupling torques and compute equivalent excitation functions, which
are combined with atmospheric (AAM) and oceanic (OAM) angular momentum
functions.
Our investigation is focused on an additional core-mantle coupling process, the gravitational
coupling, which should partly explain the remaining differences between modelled and
observed ERP. The influence of assumed geometrical settings, like flattening and topography
of the core-mantle (CMB) and inner-core (ICB) boundary on the gravitational coupling
torque are studied systematically. First, simplified geometrical settings are applied, where the
CMB and ICB are represented by two-axial ellipsoids. In a second step, published CMB
topographies based on seismic tomography are considered and the resulting torques are
compared with the simplified case. Results from this study will be used for the further
extension of our core-mantle coupling model by the gravitational core-mantle coupling. |
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