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Ice age effects on the satellite-derived J˙2 datum: Mapping the sensitivity to 3D variations in mantle viscosity

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cam.depositDate2022-01-14
cam.orpheus.counter2
cam.orpheus.successWed Mar 23 10:26:24 GMT 2022 - Embargo updated
dc.contributor.authorKim, AJ
dc.contributor.authorCrawford, O
dc.contributor.authorAl-Attar, D
dc.contributor.authorLau, HCP
dc.contributor.authorMitrovica, JX
dc.contributor.authorLatychev, K
dc.contributor.orcidKim, AJ [0000-0003-2666-7914]
dc.contributor.orcidLau, HCP [0000-0003-0311-695X]
dc.contributor.orcidMitrovica, JX [0000-0002-3920-1331]
dc.date.accessioned2022-01-15T00:31:01Z
dc.date.available2022-01-15T00:31:01Z
dc.date.issued2022
dc.date.updated2022-01-14T12:56:17Z
dc.description.abstractStudies of glacial isostatic adjustment (GIA) based on spherically symmetric viscoelastic Earth models have argued that the rate of change of the degree 2 zonal harmonic of the Earth’s geopotential, or J˙2, provides an important constraint on mean viscosity in the deep mantle (Mitrovica and Peltier, 1993; Nakada et al., 2015; Lau et al., 2016). To refine this constraint, we compute Fr´echet kernels using an adjoint methodology that reveal the sensitivity of the datum to 3D variations in mantle viscosity. We demonstrate that the mantle sensitivity of the datum is largely limited to the region below the ancient Laurentide ice sheet that covered Canada and significant portions of the northeastern United States at Last Glacial Maximum (LGM). In the bottom half of the lower mantle, this region of maximum sensitivity lies outside the location of Large Low Shear Velocity Provinces (LLSVPs) imaged from seismic tomographic studies. Thus, if the low shear velocity of these provinces originates from thermal effects, previous inferences of viscosity based upon the J˙ 2 datum are likely higher than the actual mean viscosity of the lower mantle.
dc.identifier.doi10.17863/CAM.80177
dc.identifier.eissn1385-013X
dc.identifier.issn0012-821X
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/332736
dc.language.isoeng
dc.publisherElsevier BV
dc.publisher.departmentDepartment of Earth Sciences
dc.publisher.urlhttp://dx.doi.org/10.1016/j.epsl.2022.117372
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 International
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subjectsatellite geodesy
dc.subjectglacial isostatic adjustment
dc.subject3D mantle viscosity
dc.subjectlong wavelength geopotential
dc.subjectadjoint method
dc.subjectsensitivity kernels
dc.titleIce age effects on the satellite-derived J˙<inf>2</inf> datum: Mapping the sensitivity to 3D variations in mantle viscosity
dc.typeArticle
dcterms.dateAccepted2022-01-09
prism.publicationNameEarth and Planetary Science Letters
pubs.funder-project-idNERC (NE/V010433/1)
pubs.licence-display-nameApollo Repository Deposit Licence Agreement
pubs.licence-identifierapollo-deposit-licence-2-1
rioxxterms.typeJournal Article/Review
rioxxterms.versionAM
rioxxterms.versionofrecord10.1016/j.epsl.2022.117372

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