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Future Antarctic bed topography and its implications for ice sheet dynamics

Adhikari, S. and Ivins, E. R. and Larour, E. and Seroussi, H. and Morlighem, M. and Nowicki, S. (2014) Future Antarctic bed topography and its implications for ice sheet dynamics. Solid Earth, 5 (1). pp. 569-584. ISSN 1869-9510 . http://resolver.caltech.edu/CaltechAUTHORS:20140807-103537794

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Abstract

The Antarctic bedrock is evolving as the solid Earth responds to the past and ongoing evolution of the ice sheet. A recently improved ice loading history suggests that the Antarctic Ice Sheet (AIS) has generally been losing its mass since the Last Glacial Maximum. In a sustained warming climate, the AIS is predicted to retreat at a greater pace, primarily via melting beneath the ice shelves. We employ the glacial isostatic adjustment (GIA) capability of the Ice Sheet System Model (ISSM) to combine these past and future ice loadings and provide the new solid Earth computations for the AIS. We find that past loading is relatively less important than future loading for the evolution of the future bed topography. Our computations predict that the West Antarctic Ice Sheet (WAIS) may uplift by a few meters and a few tens of meters at years AD 2100 and 2500, respectively, and that the East Antarctic Ice Sheet is likely to remain unchanged or subside minimally except around the Amery Ice Shelf. The Amundsen Sea Sector in particular is predicted to rise at the greatest rate; one hundred years of ice evolution in this region, for example, predicts that the coastline of Pine Island Bay will approach roughly 45 mm yr−1 in viscoelastic vertical motion. Of particular importance, we systematically demonstrate that the effect of a pervasive and large GIA uplift in the WAIS is generally associated with the flattening of reverse bed slope, reduction of local sea depth, and thus the extension of grounding line (GL) towards the continental shelf. Using the 3-D higher-order ice flow capability of ISSM, such a migration of GL is shown to inhibit the ice flow. This negative feedback between the ice sheet and the solid Earth may promote stability in marine portions of the ice sheet in the future.


Item Type:Article
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http://dx.doi.org/10.5194/se-5-569-2014 DOIArticle
http://www.solid-earth.net/5/569/2014/se-5-569-2014.htmlPublisherArticle
http://dx.doi.org/10.5194/se-5-569-2014-supplementPublisherSupplement
Additional Information:© 2014 Author(s). This work is distributed under the Creative Commons Attribution 3.0 License. Received: 24 December 2013 – Published in Solid Earth Discuss.: 17 January 2014; Revised: 9 May 2014 – Accepted: 12 May 2014 – Published: 30 June 2014. This study was performed at the Caltech Jet Propulsion Laboratory under a contract with the NASA’s Cryosphere Science and the Solid Earth Surface and Interior Focus Area programs. The authors are indebted to the SeaRISE participants for providing them with the valuable data. Conversations with Volker Klemann and Pippa Whitehouse are acknowledged. Constructive comments by two anonymous reviewers greatly improved this manuscript. Surendra Adhikari is thankful to Victor Tsai for hosting him as a postdoctoral scholar at Caltech, which made the completion of this writeup possible.
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Record Number:CaltechAUTHORS:20140807-103537794
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140807-103537794
Official Citation:Adhikari, S., Ivins, E. R., Larour, E., Seroussi, H., Morlighem, M., and Nowicki, S.: Future Antarctic bed topography and its implications for ice sheet dynamics, Solid Earth, 5, 569-584, doi:10.5194/se-5-569-2014, 2014
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48178
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:07 Aug 2014 20:53
Last Modified:07 Aug 2014 20:53

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