Basal friction heavily controls the dynamics of fast-flowing glaciers. However, the best approach to modeling friction is unclear, increasing uncertainties in projections of future mass loss and sea-level rise. Here, we compare six friction laws and evaluate them for Petermann Glacier in northern Greenland, using a higher order three-dimensional ice-sheet model. We model glacier retreat and mass loss under an ocean-only warming until year 2300, while not considering the effects of a future warmer atmosphere. Regardless of the friction law, we find that breakup of Petermann's ice shelf is likely to occur within the next decades. However, future grounding-line retreat differs by 10s of km and estimates of sea-level rise may quadruple, depending on the friction law employed. A bedrock ridge halts the retreat for four of the laws, and Petermann retreats furthest when applying a Budd or a Coulomb-type “till law.” Depending on the friction law, sea-level contributions differ by 133% and 282% by 2300 for 2°C and 5°C ocean warming scenarios, respectively.

中文翻译：

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海洋变暖下彼得曼冰川的未来预测很大程度上取决于摩擦定律

基底摩擦在很大程度上控制着快速流动的冰川的动力学。然而，模拟摩擦的最佳方法尚不清楚，这增加了对未来质量损失和海平面上升预测的不确定性。在这里，我们比较了格陵兰岛北部彼得曼冰川的六种摩擦定律，并使用高阶三维冰盖模型对其进行了评估。我们模拟了直到 2300 年仅海洋变暖下的冰川退缩和质量损失，同时没有考虑未来更暖大气的影响。不管摩擦定律如何，我们发现彼得曼冰架的破裂很可能在未来几十年内发生。然而，未来的接地线后退有 10 公里的差异，海平面上升的估计值可能会翻两番，这取决于所采用的摩擦定律。一个基岩山脊阻止了四个法则的撤退，彼得曼在应用 Budd 或 Coulomb 类型的“till law”时退避得最远。根据摩擦定律，到 2300 年，对于 2°C 和 5°C 的海洋变暖情景，海平面的贡献分别相差 133% 和 282%。