Representation of the net flux across the grounding line is key for accurate projections of Antarctic Ice Sheet mass loss and therefore global sea level rise. One important contribution to this balance is the parameterization of ocean-induced basal melt of the floating ice shelves and, specifically, to the adjacent grounding line, i.e., grounding-line melt parameterizations (GLMPs). Using Elmer/Ice's SSA setup, this study investigates future ice sheet dynamics in Wilkes Subglacial Basin (WSB) with respect to four GLMPs under both the upper and lower bounds of climate warming scenarios from the present to 2500. Additionally to the GLMPs we investigate different model resolutions, ice shelf melt parameterizations (ISMPs) and choices of sliding relationships. Results reveal that the choice of GLMP significantly affects the trigger timings of tipping points as well as the overall magnitude of ice mass loss. The main conclusion is that applying full melting to the partially grounded elements, i.e,, including the grounded side of the grounding line, should be avoided under all circumstances due to its poor numerical convergence and substantial overestimation of ice mass loss. We recommend to either not applying any melt immediately adjacent to the grounding line at all or, preferrably, - should the model have such a feature - employing a sub-element parameterization.

Read more: Wang, Y., Zhao, C., Gladstone, R., Zwinger, T., Galton-Fenzi, B. K., and Christoffersen, P., 2024. Sensitivity of the future evolution of the Wilkes Subglacial Basin ice sheet to grounding-line melt parameterizations, The Cryosphere 18, 5117–5137, https://doi.org/10.5194/tc-18-5117-2024