Ice age effects on the satellite-derived J˙ 2 datum: Mapping the sensitivity to 3D variations in mantle viscosity
Studies 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,...
Main Authors: | , , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Elsevier BV
2022
|
Subjects: | |
Online Access: | https://www.repository.cam.ac.uk/handle/1810/332736 https://doi.org/10.17863/CAM.80177 |
id |
ftunivcam:oai:www.repository.cam.ac.uk:1810/332736 |
---|---|
record_format |
openpolar |
spelling |
ftunivcam:oai:www.repository.cam.ac.uk:1810/332736 2024-01-14T10:07:44+01:00 Ice age effects on the satellite-derived J˙ 2 datum: Mapping the sensitivity to 3D variations in mantle viscosity Kim, AJ Crawford, O Al-Attar, D Lau, HCP Mitrovica, JX Latychev, K 2022-01-14T12:56:17Z application/pdf https://www.repository.cam.ac.uk/handle/1810/332736 https://doi.org/10.17863/CAM.80177 eng eng Elsevier BV Department of Earth Sciences http://dx.doi.org/10.1016/j.epsl.2022.117372 Earth and Planetary Science Letters https://www.repository.cam.ac.uk/handle/1810/332736 doi:10.17863/CAM.80177 Attribution-NonCommercial-NoDerivatives 4.0 International https://creativecommons.org/licenses/by-nc-nd/4.0/ satellite geodesy glacial isostatic adjustment 3D mantle viscosity long wavelength geopotential adjoint method sensitivity kernels Article 2022 ftunivcam https://doi.org/10.17863/CAM.80177 2023-12-21T23:22:40Z Studies 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. Article in Journal/Newspaper Ice Sheet Apollo - University of Cambridge Repository Canada Peltier ENVELOPE(-63.495,-63.495,-64.854,-64.854) |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
satellite geodesy glacial isostatic adjustment 3D mantle viscosity long wavelength geopotential adjoint method sensitivity kernels |
spellingShingle |
satellite geodesy glacial isostatic adjustment 3D mantle viscosity long wavelength geopotential adjoint method sensitivity kernels Kim, AJ Crawford, O Al-Attar, D Lau, HCP Mitrovica, JX Latychev, K Ice age effects on the satellite-derived J˙ 2 datum: Mapping the sensitivity to 3D variations in mantle viscosity |
topic_facet |
satellite geodesy glacial isostatic adjustment 3D mantle viscosity long wavelength geopotential adjoint method sensitivity kernels |
description |
Studies 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. |
format |
Article in Journal/Newspaper |
author |
Kim, AJ Crawford, O Al-Attar, D Lau, HCP Mitrovica, JX Latychev, K |
author_facet |
Kim, AJ Crawford, O Al-Attar, D Lau, HCP Mitrovica, JX Latychev, K |
author_sort |
Kim, AJ |
title |
Ice age effects on the satellite-derived J˙ 2 datum: Mapping the sensitivity to 3D variations in mantle viscosity |
title_short |
Ice age effects on the satellite-derived J˙ 2 datum: Mapping the sensitivity to 3D variations in mantle viscosity |
title_full |
Ice age effects on the satellite-derived J˙ 2 datum: Mapping the sensitivity to 3D variations in mantle viscosity |
title_fullStr |
Ice age effects on the satellite-derived J˙ 2 datum: Mapping the sensitivity to 3D variations in mantle viscosity |
title_full_unstemmed |
Ice age effects on the satellite-derived J˙ 2 datum: Mapping the sensitivity to 3D variations in mantle viscosity |
title_sort |
ice age effects on the satellite-derived j˙ 2 datum: mapping the sensitivity to 3d variations in mantle viscosity |
publisher |
Elsevier BV |
publishDate |
2022 |
url |
https://www.repository.cam.ac.uk/handle/1810/332736 https://doi.org/10.17863/CAM.80177 |
long_lat |
ENVELOPE(-63.495,-63.495,-64.854,-64.854) |
geographic |
Canada Peltier |
geographic_facet |
Canada Peltier |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/332736 doi:10.17863/CAM.80177 |
op_rights |
Attribution-NonCommercial-NoDerivatives 4.0 International https://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.17863/CAM.80177 |
_version_ |
1788062124816203776 |