• Medientyp: E-Artikel
  • Titel: Exploration of Antarctic Ice Sheet 100-year contribution to sea level rise and associated model uncertainties using the ISSM framework
  • Beteiligte: Schlegel, Nicole-Jeanne; Seroussi, Helene; Schodlok, Michael P.; Larour, Eric Y.; Boening, Carmen; Limonadi, Daniel; Watkins, Michael M.; Morlighem, Mathieu; van den Broeke, Michiel R.
  • Erschienen: Copernicus GmbH, 2018
  • Erschienen in: The Cryosphere, 12 (2018) 11, Seite 3511-3534
  • Sprache: Englisch
  • DOI: 10.5194/tc-12-3511-2018
  • ISSN: 1994-0424
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  • Beschreibung: Abstract. Estimating the future evolution of the Antarctic Ice Sheet (AIS) is critical for improving futuresea level rise (SLR) projections. Numerical ice sheet models are invaluable tools for boundingAntarctic vulnerability; yet, few continental-scale projections of century-scale AIS SLRcontribution exist, and those that do vary by up to an order of magnitude. This is partlybecause model projections of future sea level are inherently uncertain and depend largely on themodel's boundary conditions and climate forcing, which themselves are unknown due tothe uncertainty in the projections of future anthropogenic emissions and subsequent climateresponse. Here, we aim to improve the understanding of how uncertainties in modelforcing and boundary conditions affect ice sheet model simulations. With use of samplingtechniques embedded within the Ice Sheet System Model (ISSM) framework, we assess howuncertainties in snow accumulation, ocean-induced melting, ice viscosity, basal friction, bedrockelevation, and the presence of ice shelves impact continental-scale 100-year modelsimulations of AIS future sea level contribution. Overall, we find that AIS sea levelcontribution is strongly affected by grounding line retreat, which is driven by the magnitude ofice shelf basal melt rates and by variations in bedrock topography. In addition, we find thatover 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 andcontinental ice shelf collapse. Regionally, we find that under our most extreme 100-year warmingexperiment generalized for the entire ice sheet, the Amundsen Sea sector is the most significantsource of model uncertainty (1032 mm 6σ spread) and the region with the largest potentialfor future sea level contribution (297 mm). In contrast, under a more plausible forcing informedregionally by literature and model sensitivity studies, the Ronne basin has a greater potentialfor local increases in ice shelf basal melt rates. As a result, under this more likelyrealization, where warm waters reach the continental shelf under the Ronne ice shelf, it is theRonne basin, particularly the Evans and Rutford ice streams, that are the greatest contributorsto potential SLR (161 mm) and to simulation uncertainty (420 mm 6σ spread).
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