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Uplift rates from a new high-density GPS network in Palmer Land indicate significant late Holocene ice loss in the southwestern Weddell Sea

Wolstencroft, M.; King, M.A.; Whitehouse, P.L.; Bentley, M.J.; Nield, G.A.; King, E.C.; McMillan, M.; Shepherd, A.; Barletta, V.; Bordoni, A.; Riva, R.E.M.; Didova, O.; Gunter, B.C.

Uplift rates from a new high-density GPS network in Palmer Land indicate significant late Holocene ice loss in the southwestern Weddell Sea Thumbnail


Authors

M. Wolstencroft

M.A. King

E.C. King

M. McMillan

A. Shepherd

V. Barletta

A. Bordoni

R.E.M. Riva

O. Didova

B.C. Gunter



Abstract

The measurement of ongoing ice-mass loss and associated melt water contribution to sea-level change from regions such as West Antarctica is dependent on a combination of remote sensing methods. A key method, the measurement of changes in Earth's gravity via the GRACE satellite mission, requires a potentially large correction to account for the isostatic response of the solid Earth to ice-load changes since the Last Glacial Maximum. In this study, we combine glacial isostatic adjustment modelling with a new GPS dataset of solid Earth deformation for the southern Antarctic Peninsula to test the current understanding of ice history in this region. A sufficiently complete history of past ice-load change is required for glacial isostatic adjustment models to accurately predict the spatial variation of ongoing solid Earth deformation, once the independently-constrained effects of present-day ice mass loss have been accounted for. Comparisons between the GPS data and glacial isostatic adjustment model predictions reveal a substantial misfit. The misfit is localized on the southwestern Weddell Sea, where current ice models under-predict uplift rates by approximately 2 mm yr−1. This under-prediction suggests that either the retreat of the ice sheet grounding line in this region occurred significantly later in the Holocene than currently assumed, or that the region previously hosted more ice than currently assumed. This finding demonstrates the need for further fieldwork to obtain direct constraints on the timing of Holocene grounding line retreat in the southwestern Weddell Sea and that GRACE estimates of ice sheet mass balance will be unreliable in this region until this is resolved.

Citation

Wolstencroft, M., King, M., Whitehouse, P., Bentley, M., Nield, G., King, E., …Gunter, B. (2015). Uplift rates from a new high-density GPS network in Palmer Land indicate significant late Holocene ice loss in the southwestern Weddell Sea. Geophysical Journal International, 203(1), 737-754. https://doi.org/10.1093/gji/ggv327

Journal Article Type Article
Acceptance Date Aug 13, 2015
Publication Date Oct 1, 2015
Deposit Date Oct 24, 2014
Publicly Available Date Sep 8, 2015
Journal Geophysical Journal International
Print ISSN 0956-540X
Electronic ISSN 1365-246X
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 203
Issue 1
Pages 737-754
DOI https://doi.org/10.1093/gji/ggv327
Keywords Sea level change, Space geodetic surveys, Global change from geodesy, Glaciology, Antarctica.

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Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/

Copyright Statement
© The Authors 2015. Published by Oxford University Press on behalf of The Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.







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