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Clearing observed PGR in GRACE data aimed at global viscosity inversion: Weighted Mass Trends technique
Author(s) -
Barletta V. R.,
Bordoni A.
Publication year - 2009
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 - 10.1029/2008gl036429
Subject(s) - deglaciation , post glacial rebound , geology , inversion (geology) , geophysics , geodesy , glacial period , climatology , geomorphology , seismology , tectonics
The time‐variable gravity field shows the effects of large present‐day mass variations associated with hydrological phenomena and melting ice‐sheets, resulting in a shaded Post Glacial Rebound (PGR) signal. A meaningful viscosity inversion based on a global scale comparison of GRACE data and PGR predictions is thus hard to obtain. We derive a weighted surface mass distribution in water equivalent, starting from an initial guess, which portrays the secular effects of present‐day phenomena. The gravity field it generates is then carefully removed from GRACE data, resulting in a gravity pattern where the effects of PGR are clearer and ready to be compared with the predictions. On the basis of viscoelastic stratified Earth models and different Pleistocene deglaciation models, we show that the quality of a global preliminary viscosity inversion greatly improves.