J2: an evaluation of new estimates from GPS, GRACE and load models compared to SLR

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1029/2010GL045229.

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Authors

David Lavallee, Philip Moore, Peter John Clarke , Elizabeth J. Petrie, Tonie van Dam, Matt King

Abstract

Changes in J2, resulting from past and present changes in Earth’s climate, are traditionally observed by Satellite Laser ranging (SLR). Assuming an elastic Earth, it is possible to infer changes in J2 from changes in Earth’s shape observed by GPS. We compare estimates of non-secular J2 changes from GPS, SLR, GRACE and a load model. The GPS and SLR annual signals agree but are different (16%) to the load model. Subtraction of the load model removes the annual variation from GPS, SLR and GRACE, and the semi-annual variation in GPS. The GPS and SLR long-term signals are highly correlated, but GPS is better correlated with the loading model. Subtraction of the load model removes the 1998 anomaly from the GPS J2 series but not completely from the SLR J2 series, suggesting that the SLR anomaly may not be entirely due to mass redistribution as has been presumed.

DOI

https://doi.org/10.31223/osf.io/ebgms

Subjects

Earth Sciences, Environmental Monitoring, Environmental Sciences, Geophysics and Seismology, Other Earth Sciences, Other Environmental Sciences, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics

Keywords

climate, Global Positioning System (GPS), surface mass loading, Gravity Recovery and Climate Experiment (GRACE), J2, oblateness, Satellite Laser Ranging (SLR), seasonal

Dates

Published: 2017-11-13 16:39

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License

CC BY Attribution 4.0 International

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