Separating climate‐induced mass transfers and instrumental effects from tectonic signal in repeated absolute gravity measurements. Issue 9 (7th May 2016)

• Record Type: Journal Article
• Authors: Van Camp, M.; de Viron, O.; Avouac, J. P.
• Is Part Of: Geophysical research letters. Volume 43:Issue 9(2016)
• Page Start: 4313
• Page End: 4320
• Publication Date: 2016-05-07
• Subjects: absolute gravity measurements -- hydrological effects on gravity -- time‐varying gravity; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL068648
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We estimate the signature of the climate‐induced mass transfers in repeated absolute gravity measurements based on satellite gravimetric measurements from the Gravity Recovery and Climate Experiment (GRACE) mission. We show results at the globe scale and compare them with repeated absolute gravity (AG) time behavior in three zones where AG surveys have been published: Northwestern Europe, Canada, and Tibet. For 10 yearly campaigns, the uncertainties affecting the determination of a linear gravity rate of change range 3–4 nm/s 2 /a in most cases, in the absence of instrumental artifacts. The results are consistent with what is observed for long‐term repeated campaigns. We also discuss the possible artifact that can result from using short AG survey to determine the tectonic effects in a zone of high hydrological variability. We call into question the tectonic interpretation of several gravity changes reported from stations in Tibet, in particular the variation observed prior to the 2015 Gorkha earthquake. Key Points: The signature of climate‐induced interannual mass transfers on repeated absolute gravity measurements is estimated everywhere in the world Instrumental artifacts should be taken into account and mitigated as much as possible In most cases, the uncertainty is estimated to ~5 nm/s²/a after 10 yearly campaigns