Comparing glacial‐geological evidence and model simulations of ice sheet change since the last glacial period in the Amundsen Sea sector of Antarctica

Johnson, Joanne S. ORCID: https://orcid.org/0000-0003-4537-4447; Pollard, David; Whitehouse, Pippa L.; Roberts, Stephen J. ORCID: https://orcid.org/0000-0003-3407-9127; Rood, Dylan H.; Schaefer, Joerg M.. 2021 Comparing glacial‐geological evidence and model simulations of ice sheet change since the last glacial period in the Amundsen Sea sector of Antarctica. Journal of Geophysical Research: Earth Surface, 126 (6), e2020JF005827. 20, pp. 10.1029/2020JF005827

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Abstract/Summary

Since the Last Glacial Maximum ∼20,000 years ago, the Antarctic Ice Sheet has undergone extensive changes, resulting in a much smaller present‐day configuration. Improving our understanding of basic physical processes that played important roles during that retreat is critical to providing more robust model projections of future retreat and sea‐level rise. Here, a limited‐area nested ice sheet model was applied to the last deglacial retreat of the West Antarctic Ice Sheet in the Amundsen Sea Embayment (ASE), at 5 km resolution. The ice sheet response to climate and sea‐level forcing was examined at two sites along the flowlines of Pine Island Glacier and Pope Glacier, close to the Hudson Mountains and Mount Murphy respectively, and the simulated responses compared with ice sheet thinning histories derived from glacial‐geological data. The sensitivity of results to selected model parameters was also assessed. The model simulations predict a broadly similar response to ocean forcing in both the central and eastern ASE, with an initial rapid phase of thinning followed by a slower phase to the modern configuration. Although there is a mismatch of up to 5,000 years between the timing of simulated and observed thinning, the modeling suggests that the upstream geological records of ice surface elevation change reflect a response to retreat near the grounding line. The model‐data mismatch could potentially be improved by accounting for regional variations in mantle viscosity, sea‐surface heights and basal sliding properties across the continental shelf.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2020JF005827
ISSN:	21699003
Additional Keywords:	West Antarctic Ice Sheet, cosmogenic nuclide, glacial history, ice sheet model, Holocene, forcing
Date made live:	13 May 2021 10:12 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/528207

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