Grounding line transient response in marine ice sheet models

• Main Authors: Drouet, Anne-Sophie, Docquier, David, Hindmarsh, Richard, Durand, Gael, Pattyn, Frank, Gagliardini, Olivier, Zwinger, Thomas
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2013
• Subjects: Sciences exactes et naturelles; Ice Sheet; Ice Shelf; The Cryosphere
• Online Access: http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/124112; https://dipot.ulb.ac.be/dspace/bitstream/2013/124112/8/Drouet2013_TC.pdf; https://dipot.ulb.ac.be/dspace/bitstream/2013/124112/11/doi_105283.pdf

Marine ice sheet stability is mostly controlled by the dynamics of the grounding line, i.e.the junction between the grounded ice sheet and the floating ice shelf. Grounding line migration has been investigated in the framework of MISMIP (Marine Ice Sheet Model Intercomparison Project), which principally aimed at investigating steady state solutions. Here we focus on transient behaviour, executing short-term simulations (200 years) of a steady ice sheet perturbed by the release of the buttressing restraint exerted by the ice shelf on the grounded ice upstream. The transient grounding line behaviour of four different flowline ice sheet models has been compared. The models differ in the physics implemented (full-Stokes and Shallow Shelf Approximation), the numerical approach, as well as the grounding line treatment. Their overall response to the loss of buttressing is found to be consistent in terms of grounding line position, rate of surface elevation change and surface velocity. However, large discrepancies (>100%) are observed in terms of ice sheet contribution to sea level. Despite the recent important improvements of marine ice sheet models in their ability to compute steady-state configurations, our results question the reliability of models’ ability to compute reliable sea-level rise projections. info:eu-repo/semantics/published