Dynamic modelling of future glacier changes: mass-balance/elevation feedback in projections for the Vestfonna ice cap, Nordaustlandet, Svalbard
Dynamic modelling of future glacier changes: mass-balance/elevation feedback in projections for the Vestfonna ice cap, Nordaustlandet, Svalbard
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DOI：
10.3189/2015jog14j184
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发表时间：
2015
影响因子：
3.4
通讯作者：
M. Schäfer;M. Möller;T. Zwinger;J. Moore
中科院分区：
文献类型：
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作者：
M. Schäfer;M. Möller;T. Zwinger;J. Moore
未来对冰盖和冰盖演化以及随之而来的海平面上升的预测面临着一些方法论挑战，其中之一是冰流和质量平衡模型之间的双向耦合。由于巨大的技术挑战，质量平衡模型（或者更广泛的气候模型）和冰流模型之间的完全双向耦合很少被实现。在这里，我们通过分析不同耦合间隔对质量平衡和海平面上升预测的影响，研究了斯瓦尔巴特群岛 Nordaustlandet 的 Vestfonna 冰盖的一些耦合效应。通过将耦合策略与传统部署的非耦合策略进行比较，我们证明忽略耦合中的地形反馈会导致模型中世纪时间尺度的海平面上升预测被低估 10-20%。随着强加的气候情景日益改变质量平衡，快速流动的出口冰川的未知演化的不确定性变得越来越重要，因为它们在变薄和从海岸退缩时减速和质量通量减少。使用递减率作为完全耦合的经济高效替代方案，针对地形变化进行参数化质量平衡调整，可以在温和的气候变化情景下产生令人满意的结果。我们引入了一种方法来估计所提出的部分耦合模型相对于尚未执行的双向完全耦合结果的误差。
Future projections of the evolution of ice caps as well as ice sheets and consequent sealevel rise face several methodological challenges, one being the two-way coupling between ice flow and mass-balance models. Full two-way coupling between mass-balance models – or, in a wider scope, climate models – and ice flow models has rarely been implemented due to substantial technical challenges. Here we examine some coupling effects for the Vestfonna ice cap, Nordaustlandet, Svalbard, by analysing the impacts of different coupling intervals on mass-balance and sea-level rise projections. By comparing coupled to traditionally deployed uncoupled strategies, we prove that neglecting the topographic feedbacks in the coupling leads to underestimations of 10–20% in sea-level rise projections on century timescales in our model. As imposed climate scenarios increasingly change mass balance, uncertainties in the unknown evolution of the fast-flowing outlet glaciers decrease in importance due to their deceleration and reduced mass flux as they thin and retreat from the coast. Parameterizing mass-balance adjustment for changes in topography using lapse rates as a cost-effective alternative to full coupling produces satisfactory results for modest climate change scenarios. We introduce a method to estimate the error of the presented partially coupled model with respect to as yet unperformed two-way fully coupled results.