Mechanical core-mantle coupling and dynamo modelling
Abstract
Mechanical core-mantle coupling is first investigated in the absence of magnetic forces. Two different expressions for the pressure at the core surface are derived for the two symmetries with respect to the equator. It is shown that the modified Taylor's condition (for a non-spherical volume in the absence of magnetic forces) can be read as a condition on the surface pressure, which had been previously derived in a study of the topographic torque. The equation governing the time evolution of the geostrophic velocity in dynamo models is modified to take into account the distortion of geostrophic contours by small bumps. Finally, study of the time changes in the zonal velocity at the core surface seems to indicate that the observed core-mantle coupling is a by-product of torsional oscillations riding inside the Earth's fluid core.
- Publication:
-
Physics of the Earth and Planetary Interiors
- Pub Date:
- December 1996
- DOI:
- 10.1016/S0031-9201(96)03186-X
- Bibcode:
- 1996PEPI...98..187J