Marine ice sheet models: another intercomparison
In the recently published paper by Drouet et al. (2013), the first comparison of flow-line marine ice sheet models during transient is proposed. Indeed, the transient grounding line (i.e., the junction between the grounded ice sheet and the floating ice shelf) 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 broadly consistent in terms of grounding line position, rate of surface elevation change and surface velocity. However, still small differences appear for these latter variables, and they can lead to large discrepancies (> 100%) observed in terms of ice sheet contribution to sea level when cumulated over time. Despite the recent important improvements of marine ice-sheet models in their ability to compute steady state configurations, our results question the capacity of these models to compute short-term reliable sea-level rise projections.