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Topographic core‐mantle coupling in geodynamo modeling
Author(s) -
Kuang Weijia,
Chao Benjamin Fong
Publication year - 2001
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 - 10.1029/2000gl012237
Subject(s) - geology , mantle (geology) , geophysics , amplitude , dynamo theory , coupling (piping) , cosmic microwave background , earth's magnetic field , hydrostatic equilibrium , dynamo , geodesy , physics , magnetic field , anisotropy , mechanical engineering , quantum mechanics , engineering
A 3‐dimensional, fully nonlinear numerical geodynamo model is used to study the core‐mantle coupling arising from a non‐hydrostatic pressure field acting on an aspherical core‐mantle boundary (CMB) based on a seismological model. The simulation results demonstrate that the topographic coupling torque is close to being proportional to the square of the amplitude of the CMB topography. We conclude that the contribution of the topographic coupling to the total torque that is responsible for the axial angular momentum transfer on decadal timescales (for the decadal length‐of‐day variation) is significant only if the amplitude of the CMB topography is considerably larger than 3km inferred from seismological evidence.