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Exploration of Antarctic Ice Sheet 100-year contribution to sea level rise and associated model uncertainties using the ISSM framework

Schlegel, Nicole-Jeanne and Seroussi, Helene and Schodlok, Michael P. and Larour, Eric Y. and Boening, Carmen and Limonadi, Daniel and Watkins, Michael M. and Morlighem, Mathieu and van den Broeke, Michiel R. (2018) Exploration of Antarctic Ice Sheet 100-year contribution to sea level rise and associated model uncertainties using the ISSM framework. Cryosphere, 12 (11). pp. 3511-3534. ISSN 1994-0424. doi:10.5194/tc-12-3511-2018.

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Abstract. Estimating the future evolution of the Antarctic Ice Sheet (AIS) is critical for improving future sea level rise (SLR) projections. Numerical ice sheet models are invaluable tools for bounding Antarctic vulnerability; yet, few continental-scale projections of century-scale AIS SLR contribution exist, and those that do vary by up to an order of magnitude. This is partly because model projections of future sea level are inherently uncertain and depend largely on the model's boundary conditions and climate forcing, which themselves are unknown due to the uncertainty in the projections of future anthropogenic emissions and subsequent climate response. Here, we aim to improve the understanding of how uncertainties in model forcing and boundary conditions affect ice sheet model simulations. With use of sampling techniques embedded within the Ice Sheet System Model (ISSM) framework, we assess how uncertainties in snow accumulation, ocean-induced melting, ice viscosity, basal friction, bedrock elevation, and the presence of ice shelves impact continental-scale 100-year model simulations of AIS future sea level contribution. Overall, we find that AIS sea level contribution is strongly affected by grounding line retreat, which is driven by the magnitude of ice shelf basal melt rates and by variations in bedrock topography. In addition, we find that over 1.2 m of AIS global mean sea level contribution over the next century is achievable, but not likely, as it is tenable only in response to unrealistically large melt rates and continental ice shelf collapse. Regionally, we find that under our most extreme 100-year warming experiment generalized for the entire ice sheet, the Amundsen Sea sector is the most significant source of model uncertainty (1032 mm 6σ spread) and the region with the largest potential for future sea level contribution (297 mm). In contrast, under a more plausible forcing informed regionally by literature and model sensitivity studies, the Ronne basin has a greater potential for local increases in ice shelf basal melt rates. As a result, under this more likely realization, where warm waters reach the continental shelf under the Ronne ice shelf, it is the Ronne basin, particularly the Evans and Rutford ice streams, that are the greatest contributors to potential SLR (161 mm) and to simulation uncertainty (420 mm 6σ spread).

Item Type:Article
Related URLs:
URLURL TypeDescription
Schlegel, Nicole-Jeanne0000-0001-8035-448X
Seroussi, Helene0000-0001-9201-1644
Schodlok, Michael P.0000-0002-2479-2079
Larour, Eric Y.0000-0002-4009-4238
Limonadi, Daniel0000-0001-8736-4461
Watkins, Michael M.0000-0001-7524-4833
Morlighem, Mathieu0000-0001-5219-1310
van den Broeke, Michiel R.0000-0003-4662-7565
Additional Information:© Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. The research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Funding was provided by grants from Jet Propulsion Laboratory Research Technology and Development and from NASA Cryospheric Science, Interdisciplinary Research in Earth Science and Modeling, Analysis and Prediction (MAP) programs. We gratefully acknowledge computational resources and support from the NASA Advanced Supercomputing Division. Michiel R. van den Broeke acknowledges support from the Netherlands Earth System Science Centre (NESSC). This work was made possible through model development of the ISSM team. The authors would also like to thank Amy Braverman for her statistical insight and discussions on model uncertainty. Author contributions. All authors discussed results presented in this paper. NJS led the design, execution, and analysis of ISSM UQ experiments. HS was responsible for mesh resolution sensitivity runs, determination of IB sampling bounds, and analysis of results. MPS was responsible for all ocean model runs and determination of ice shelf basal melt sampling bounds. EYL was in charge of the original design and implementation of parallel DAKOTA within ISSM. CB, DL, and MMW managed the UQ tasks and were involved in developing and guiding the scientific strategy for this project. MM contributed MC bedrock topography and development of L1L2 stress balance approximation within ISSM. MRvdB contributed RACMO2.1 estimates of SMB and associated components. Code and data availability. RACMO2.1 model output used in this study (Lenaerts et al., 2012) is available from upon request. ISSM model output used in this study is available from the ISSM model team ( or, last access: 9 August 2017) or from upon request. The MATLAB code used to analyze model results is also available from upon request. The MC bed topography product is currently under preparation for public release, and more details regarding the product and its release can be obtained from The ocean model output used in this study is currently under preparation for public release. Details can be obtained from The authors declare that they have no conflict of interest.
Group:Division of Geological and Planetary Sciences, GALCIT
Funding AgencyGrant Number
Netherlands Earth System Science CentreUNSPECIFIED
Issue or Number:11
Record Number:CaltechAUTHORS:20230307-21929000.6
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:119687
Deposited By: George Porter
Deposited On:08 Mar 2023 03:14
Last Modified:08 Mar 2023 03:14

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