Using GRACE to Explain Variations in the Earth's Oblateness

Journal article (2019)

Authors

Y. Sun Fuzhou University, Physical and Space Geodesy - CEG
R.E.M. Riva Physical and Space Geodesy - CEG
P.G. Ditmar Physical and Space Geodesy - CEG
Roelof Rietbroek Universität Bonn
Research Group
Physical and Space Geodesy (CEG) (TU Delft)
Copyright: © 2019 Y. Sun, R.E.M. Riva, P.G. Ditmar, Roelof Rietbroek
DOI: https://doi.org/10.1029/2018GL080607
More Info
expand_more

Published Date

2019

Language

English

Faculty

Civil Engineering & Geosciences

Department

Geoscience and Remote Sensing

Research Group

Physical and Space Geodesy

Abstract

We present a new approach to estimate time variations in J2. 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 J2. 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).