A comparison of two Antarctic ice sheet models applied to the glacial cycles

• Main Authors: Huybrechts, Philippe, Ritz, C.
• Format: Conference Object
• Language: unknown
• Published: 1999
• Subjects: Antarctic; Antarc*; Ice Sheet; Ice Shelf
• Online Access: https://epic.awi.de/id/eprint/6994/; https://hdl.handle.net/10013/epic.17539

We compared two 3-D thermomechanic Antarctic ice-sheet models that dealexplicitly with the coupled ice-sheet/ice-shelf system as part of the EISMINTModel Intercomparison exercise. Both models are similar in their treatmentof grounded ice, but dier in the way grounding-line dynamics are accountedfor. The grounding zone is treated either as a special case where all stressesare incorporated in the effective stress of the ow law (Huybrechts model), or as a 'shelfy stream' conditional on effective normal pressure and/or basal shear stress at the margin (Ritz et al. model, unpublished). Model tests dealt with simulations of the present ice sheet and of its behaviour during the last two glacial cycles, both for prescribed datasets and parameters as well as forpreferred input data. The major difference between the two models concerned the amplitude and chronology of the last glacial-interglacial transition, which affects the evolution of all other variables in the ice sheet. Also large marginal areas of low surface slopes and high velocities occurred at times in the Grenoble model, but were absent in the Huybrechts model. Results are discussed with special emphasis on variables important for interpreting and locating ice cores.