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Steady surficial core motions: An alternate method
Author(s) -
Voorhies Coerte V.
Publication year - 1986
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/gl013i013p01537
Subject(s) - earth's magnetic field , geology , core–mantle boundary , geophysics , outer core , geomagnetic secular variation , secular variation , mantle (geology) , geodesy , flux (metallurgy) , inner core , magnetic field , physics , geomagnetic storm , materials science , quantum mechanics , metallurgy
A new method for deriving steady surficial core motions from geomagnetic field models is presented and applied. The original method determines the steady velocity field at the top of a frozen‐flux core which best fits, in both the spatial and temporal linear least squares sense, a model of the large scale geomagnetic secular variation (SV) at the base of a source‐free mantle [Voorhies, 1986]. The new method is based upon the same physical assumptions, but fits SV at earth's surface instead of the core‐mantle boundary (CMB). The newly derived flow differs somewhat from prior solutions, and shows but slight westward drift; however, other key global properties are virtually unchanged. Over a 15 year interval the new method provides a better fit to the time‐varying geomagnetic field at earth's surface than does the old.