Recent progress on combining geomorphological and geochronological data with ice sheet modelling, demonstrated using the last British-Irish Ice Sheet
Recent progress on combining geomorphological and geochronological data with ice sheet modelling, demonstrated using the last British-Irish Ice Sheet
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DOI：
10.1002/jqs.3098
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发表时间：
2021-07-01
影响因子：
2.3
通讯作者：
Small, David
中科院分区：
文献类型：
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作者：
Ely, Jeremy C.;Clark, Chris D.;Small, David
古冰盖是理解当代冰盖的重要类似物，提供了跨越数千年的冰盖行为记录。重建古冰盖有两种主要方法。经验重建使用现有的冰川地质和年代学证据来估计冰盖的范围和动态，但缺乏直接考虑冰物理。相比之下，数值模拟实现冰物理学，但往往缺乏直接的定量比较与经验证据。尽管长期以来被认为是一项卓有成效的科学工作，但很少有冰盖重建试图调和经验和基于模型的方法。为了实现这一目标，需要模型数据比较程序。在这里，我们比较了三个数值模拟模拟的前英国-爱尔兰冰盖与以下证据：（一）位置和形状的前边缘位置，记录的冰碛;（B）前冰流的方向和流量开关，记录的冰下bedforms的flowsets;和（c）无冰条件的时间，记录的地质年代学数据。这些模型数据比较提供了一个有用的框架，量化数值模型模拟和经验约束之间的拟合程度。这些工具对于协调数值模拟和经验证据至关重要，两者结合将导致更强大的古冰盖重建，具有更大的解释力和最终的预测力。
Palaeo-ice sheets are important analogues for understanding contemporary ice sheets, offering a record of ice sheet behaviour that spans millennia. There are two main approaches to reconstructing palaeo-ice sheets. Empirical reconstructions use the available glacial geological and chronological evidence to estimate ice sheet extent and dynamics but lack direct consideration of ice physics. In contrast, numerically modelled simulations implement ice physics, but often lack direct quantitative comparison with empirical evidence. Despite being long identified as a fruitful scientific endeavour, few ice sheet reconstructions attempt to reconcile the empirical and model-based approaches. To achieve this goal, model-data comparison procedures are required. Here, we compare three numerically modelled simulations of the former British-Irish Ice Sheet with the following lines of evidence: (a) position and shape of former margin positions, recorded by moraines; (b) former ice-flow direction and flow-switching, recorded by flowsets of subglacial bedforms; and (c) the timing of ice-free conditions, recorded by geochronological data. These model-data comparisons provide a useful framework for quantifying the degree of fit between numerical model simulations and empirical constraints. Such tools are vital for reconciling numerical modelling and empirical evidence, the combination of which will lead to more robust palaeo-ice sheet reconstructions with greater explicative and ultimately predictive power.