Abstract
Earth gravity change is caused by mass redistribution within the Earth system, including air and water redistribution in the atmosphere, ocean, land, and cryosphere, and mass variation of the solid Earth (in the core, mantle, and crust). Gravity change can be quantified by geodetic measurements and numerical climate models. We estimate time series of low-degree gravitational variations, ΔC21, ΔS21, and ΔC20 using four different techniques, from the Gravity Recovery and Climate Experiment (GRACE), Earth Orientation Parameters (length of day and polar motion), advanced climate models (including atmospheric, oceanic, and hydrologic models), and satellite laser ranging. We compare these independent estimates at different time scales, and discuss major uncertainties for the various techniques. Independent estimates of ΔC21, ΔS21, and ΔC20 are important for validating the geodetic techniques and for improving understanding of large scale and low frequency mass redistribution within the Earth system.
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Acknowledgments
The authors would like to thank the two anonymous reviewers for their insightful comments, which led to improved presentation of the results. This research was supported by a NASA PECASE Award (NNG04G060G), NSF IPY Program (ANT-0632195), and NGA grants (HM1582-09-1-0001, HM1582-07-1-2032).
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Chen, J.L., Wilson, C.R. (2012). Multi-Sensor Monitoring of Low-Degree Gravitational Changes. In: Sneeuw, N., Novák, P., Crespi, M., Sansò, F. (eds) VII Hotine-Marussi Symposium on Mathematical Geodesy. International Association of Geodesy Symposia, vol 137. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-22078-4_44
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DOI: https://doi.org/10.1007/978-3-642-22078-4_44
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