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Surface deformation caused by pressure changes in the fluid core
Author(s) -
Fang Ming,
Hager Bradford H.,
Herring Thomas A.
Publication year - 1996
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 - 10.1029/96gl00743
Subject(s) - geology , equator , mantle (geology) , geostrophic wind , geodesy , geophysics , core–mantle boundary , secular variation , magnetic dip , deformation (meteorology) , outer core , cosmic microwave background , inner core , anisotropy , physics , latitude , climatology , optics , oceanography
Pressure load Love numbers are presented for calculating the mantle deformation induced by the variation of the pressure field at the core mantle boundary (CMB). We find that the CMB geostrophic pressure fields, derived from “frozen‐flux” core surface flow estimates at epochs 1965 and 1975, produce a relative radial velocity (RRV) field in the range of 3 mm/decade with uplift near the equator and subsidence near the poles. The contribution of this mechanism to the change in the length of day (l.o.d) is small—about 2.3×10 −2 ms/decade. The contribution to the time variation of the ellipticity coefficientJ . 2is more important—about −1.3×10 −11 /yr.