Joint inversion estimate of regional glacial isostatic adjustment in Antarctica considering a lateral varying Earth structure (ESA STSE Project REGINA)

Sasgen, I. et al. (2017) Joint inversion estimate of regional glacial isostatic adjustment in Antarctica considering a lateral varying Earth structure (ESA STSE Project REGINA). Geophysical Journal International, 211(3), pp. 1534-1553. (doi:10.1093/gji/ggx368)

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Abstract

A major uncertainty in determining the mass balance of the Antarctic ice sheet from measurements of satellite gravimetry, and to a lesser extent satellite altimetry, is the poorly known correction for the ongoing deformation of the solid Earth caused by glacial isostatic adjustment (GIA). Although much progress has been made in consistently modelling the ice-sheet evolution throughout the last glacial cycle, as well as the induced bedrock deformation caused by these load changes, forward models of GIA remain ambiguous due to the lack of observational constraints on the ice sheet's past extent and thickness and mantle rheology beneath the continent. As an alternative to forward modelling GIA, we estimate GIA from multiple space-geodetic observations: GRACE, Envisat/ICESat and GPS. Making use of the different sensitivities of the respective satellite observations to current and past surface mass (ice mass) change and solid Earth processes, we estimate GIA based on viscoelastic response functions to disc load forcing. We calculate and distribute the viscoelastic response functions according to estimates of the variability of lithosphere thickness and mantle viscosity in Antarctica. We compare our GIA estimate with published GIA corrections and evaluate its impact in determining the ice mass balance in Antarctica from GRACE and satellite altimetry. Particular focus is applied to the Amundsen Sea Sector in West Antarctica, where uplift rates of several cm/yr have been measured by GPS. We show that most of this uplift is caused by the rapid viscoelastic response to recent ice-load changes, enabled by the presence of a low-viscosity upper mantle in West Antarctica. This paper presents the second and final contribution summarizing the work carried out within a European Space Agency funded study, REGINA, (www.regina-science.eu).

Item Type:Articles
Additional Information:The www.regina-science.eu work was enabled through CryoSat+ Cryosphere study funding from the Support To Science Element (STSE) of the European Space Agency (ESA) Earth Observation Envelope Programme. I. S. acknowledges additional funding through the German Academic Exchange Services (DAAD) and DFG grant SA1734/4-1. JLB and AME acknowledge additional support from UK NERC grant NE/I027401/1, and PJC and EJP from NE/I027681/1.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Petrie, Dr Elizabeth
Authors: Sasgen, I., Martín-Español, A., Horvath, A., Klemann, V., Petrie, E. J., Wouters, B., Horwath, M., Pail, R., Bamber, J. L., Clarke, P. J., Konrad, H., and Drinkwater, M. R.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Geophysical Journal International
Publisher:Oxford University Press
ISSN:0956-540X
ISSN (Online):1365-246X
Published Online:29 August 2017
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in Geophysical Journal International 211(3):1534-1553
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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