Uncertainties of Glacial Isostatic Adjustment Model Predictions in North America Associated With 3D Structure

We quantify GIA prediction uncertainties of 250 1D and 3D glacial isostatic adjustment (GIA) models through comparisons with deglacial relative sea‐level (RSL) data from North America and rate of vertical land motion ( U̇) and gravity rate of change ( Ġ) from GNSS and GRACE data, respectively. Spat...

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Bibliographic Details
Published in:Geophysical research letters 2020-05, Vol.47 (10), p.n/a
Main Authors: Li, Tanghua, Wu, Patrick, Wang, Hansheng, Steffen, Holger, Khan, Nicole S., Engelhart, Simon E., Vacchi, Matteo, Shaw, Timothy A., Peltier, W. Richard, Horton, Benjamin P.
Format: Article
Language:English
Subjects:
3D structure
Glacial Isostatic Adjustment
Gravity
Ice
Last Glacial Maximum
Lateral heterogeneity
Lower mantle
Mantle
North America
Sea level change
Three dimensional models
Uncertainties
Uncertainty
Viscosity
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Summary:We quantify GIA prediction uncertainties of 250 1D and 3D glacial isostatic adjustment (GIA) models through comparisons with deglacial relative sea‐level (RSL) data from North America and rate of vertical land motion ( U̇) and gravity rate of change ( Ġ) from GNSS and GRACE data, respectively. Spatially, the size of the RSL uncertainties varies across North America with the largest from Hudson Bay and near previous ice margins along the northern Atlantic and Pacific coasts, which suggests 3D viscosity structure in the lower mantle and laterally varying lithospheric thickness. Temporally, RSL uncertainties decrease from the Last Glacial Maximum to present except for west of Hudson Bay and the northeastern Pacific coast. The uncertainties of both these regions increase from 30 to 45 m between 15 and 11 ka BP, which may be due to the rapid decrease of surface loading at that time. Present‐day U̇ and Ġ uncertainties are largest in southwestern Hudson Bay with magnitudes of 2.4 mm/year and 0.4 μGal/year, mainly due to the 3D viscosity structure in the lower mantle. Key Points We predict the GIA signal with uncertainties of RSL and present‐day U̇ and Ġ in North America that are associated with 3D structures GIA‐predicted RSL uncertainties are largest around Hudson Bay and near former ice margins along northern Atlantic and Pacific coasts The maximum uncertainties of present‐day U̇ and Ġ are centered in southwestern Hudson Bay and near former ice margins
ISSN:0094-8276
1944-8007
DOI:10.1029/2020GL087944