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High‐Latitude Westward Jets in the Earth's Outer Core Due to Small‐Scale Convection
Author(s) -
Afanasyev Y. D.
Publication year - 2018
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 - 10.1029/2018gl078550
Subject(s) - geology , buoyancy , equator , convection , geostrophic wind , geophysics , latitude , hydrostatic equilibrium , atmospheric sciences , climatology , mechanics , physics , geodesy , quantum mechanics
The general circulation of the Earth's outer core is driven by small‐scale convection. A model based on the dynamics of individual buoyant parcels is put forward to explain how the main features of the circulation are generated by the convection. The model predicts a distribution of buoyancy in the core such that the fluid is lighter/warmer at the poles and heavier/colder at the equator. Zonal velocity as a function of latitude is predicted by the model and compared with the previous observational data inferred from the variations of the Earth's magnetic field. The model demonstrates that the westward jets observed at the co‐latitude of approximately 21 0 are in a geostrophic balance with the dynamic pressure created by convecting parcels and with the excess hydrostatic pressure due to the redistribution of buoyancy in the meridional direction.