Premium
The dynamical regime of fluid flow at the core surface
Author(s) -
Bloxham Jeremy
Publication year - 1988
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl015i006p00585
Subject(s) - geostrophic wind , mechanics , toroid , flow (mathematics) , nonlinear system , physics , classical mechanics , fluid dynamics , core (optical fiber) , geology , optics , plasma , quantum mechanics
We present an alternative method for determining the fluid motion immediately beneath the core‐mantle boundary, based on solving the full nonlinear core motions problem. We use this method to examine three dynamical hypotheses about the flow: the steady motions hypothesis; the geostrophic hypothesis; and the toroidal flow hypothesis. We obtain better fits to the field with the toroidal flows than with geostrophic flows, casting considerable doubt on the validity of the geostrophic hypothesis. Additionally, we find some indication that failure of the frozen‐flux approximation, a concomitant assumption, may be a serious obstacle to obtaining reliable maps of the core fluid flow.