Sensitivity of a spatially-varying Elastic Lithosphere-Relaxed Asthenosphere (ELRA) isostatic model of the Antarctic ice sheet

• Main Authors: Coulon, Violaine, Pattyn, Frank
• Other Authors: UNITER PhD Day (2018-12-07: Bruxelles, Belgique)
• Format: Conference Object
• Language: English
• Published: 2018
• Subjects: Glaciologie; Géodynamique et tectonique; Climatologie; Antarctic; The Antarctic; East Antarctica; West Antarctica; West Antarctic Ice Sheet; Antarc*; Antarctica; Ice Sheet
• Online Access: http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/283593; https://dipot.ulb.ac.be/dspace/bitstream/2013/283593/3/Poster_UNITER_2018_vcoulon.pdf

On glacial-interglacial time scales, isostatic effects of ice sheet volume changes may have a large impact on timingand magnitude of retreating and advancing ice through grounding-line migration. A common isostatic model usedin ice-flow modelling is the Elastic Lithosphere-Relaxed Asthenosphere (ELRA) model. It considers an elasticlithosphere, defined by a given effective lithosphere thickness and a relaxation equation for asthenospheric responsewith a characteristic time scale as a function of asthenosphere viscosity. However, effective lithosphere thicknessin Antarctica ranges from tens (West-Antarctica) to hundreds of meters (East Antarctica), leading to a flexuralrigidity that varies spatially across several orders of magnitude. Furthermore, recent studies also point out to alarge spatial variability in asthenosphere viscosity. Here, we explore in a sensitivity analysis both spatially uniformand spatially varying values of flexural rigidity and asthenosphere viscosity applied to a model of the Antarcticice sheet, forced by background temperature and sea-level changes over the last 40,000 years, thus covering thelast glacial-interglacial transition. Results demonstrate a higher sensitivity for the West Antarctic ice sheet, whereasthenosphere viscosity essentially influences timing and magnitude of grounding-line retreat during the glacialinterglacialtransition. info:eu-repo/semantics/published