Rift Propagation for Ice Sheet Models

对南极冰盖对本世纪海平面上升贡献的模拟预测从几厘米到一米多不等--这一巨大的不确定性削弱了海平面上升预测的可信度。这种不确定性的原因在于对冰架的处理--冰盖的漂浮延伸限制了冰从内陆流向海洋。假设冰架将会解体，导致对冰排出量的估计比假设它们保持在原地要高得多。然而，到目前为止，还没有预测包括导致冰架解体的冰裂和裂缝传播过程。这些过程破坏了冰盖模型固有的连续性的正常假设，并高度依赖于冰架的异质性。我们将克服海平面上升预测中的这一根本限制，明确表示冰架的异质性，并率先在冰盖模型中纳入裂谷过程。我们将通过收集新的现场和卫星数据来量化冰架的非均质性，并开发一种断裂物理方法来模拟裂缝的传播，以应对这些挑战。RIPFISH将使新一代冰盖模型在量化和减少海平面上升预测的不确定性方面实现阶段性改进。

Modelled projections of the contribution of the Antarctic ice sheets to sea level rise over this century vary from a few centimetres to more than one metre - a huge uncertainty which undermines the credibility of sea level rise projections. The reasons for this uncertainty lie in the treatment of ice shelves - the floating extensions of ice sheets which constrain the flow of ice from the interior to the ocean. Assuming that ice shelves will disintegrate leads to a much higher estimate of ice discharge than assuming they remain in place. No forecast so far, however, has included the processes of ice fracture and rift propagation that lead to ice shelf disintegration. These processes disrupt the normal assumptions of continuity inherent in ice sheet models and are highly dependent on the heterogeneous nature of ice shelves. We will overcome this fundamental limitation in sea level rise projections by explicitly representing heterogeneity in ice shelves and pioneering the inclusion of rift processes in an ice sheet model. We will meet these challenges by collecting new field and satellite data to quantify ice shelf heterogeneity and developing a fracture physics approach to simulate rift propagation. RIPFISH will enable a new generation of ice sheet models to achieve a step-change improvement in quantifying and reducing uncertainties in sea level rise projections.