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Using GRACE to Explain Variations in the Earth's Oblateness
Author(s) -
Sun Yu,
Riva Riccardo,
Ditmar Pavel,
Rietbroek Roelof
Publication year - 2019
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 - 10.1029/2018gl080607
Subject(s) - post glacial rebound , geology , geoid , glacial period , solid earth , atmosphere (unit) , laser ranging , geodesy , climatology , satellite , ice sheet , geophysics , oceanography , meteorology , geomorphology , geography , laser , physics , astronomy , optics , measured depth
We present a new approach to estimate time variations in J 2 . Those variations are represented as the sum of contributions from individual sources. This approach uses solely Gravity Recovery And Climate Experiment (GRACE) data and the geoid fingerprints of mass redistributions that take place both at the surface and in the interior of the solid Earth. The results agree remarkably well with those based on satellite laser ranging, while estimates of the sources explain the observed variations in J 2 . Seasonal variations are dominated by terrestrial water storage and by mass redistribution in the atmosphere and ocean. Trends, however, are primarily controlled by the Greenland and Antarctic ice sheets and by glacial isostatic adjustment. The positive trend from surface mass variations is larger than the negative trend due to glacial isostatic adjustment and leads to an overall rising trend during the GRACE period (2002–2017).