Melt-under-cutting and buoyancy-driven calving from tidewater glaciers: new insights from discrete element and continuum model simulations
Melt-under-cutting and buoyancy-driven calving from tidewater glaciers: new insights from discrete element and continuum model simulations
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DOI：
10.1017/jog.2017.41
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发表时间：
2017-08-01
影响因子：
3.4
通讯作者：
Luckman, Adrian
中科院分区：
文献类型：
--
作者：
Benn, Douglas I.;Astrom, Jan;Luckman, Adrian
目前在冰盖模型中使用的简单产犊规律不能充分反映产犊过程的复杂性和多样性。为了有效，产犊法必须建立在对产犊过程的正确理解的基础上。在这里，我们开发了一种新的策略来制定产犊规律，使用(a)赫尔辛基离散元模型（HiDEM）来明确地模拟破裂和产犊过程，(b)连续体模型Elmer/Ice来识别与HiDEM产犊事件相关的临界应力状态。一系列观测到的产犊过程自发地从HiDEM中出现，以响应冰锋浮力的变化和水下切口的大小。现有的产犊规律对浮力和熔体下切驱动的产犊预测不足，但我们表明，可以通过特征应力模式预测Elmer/Ice中HiDEM产犊事件的位置和大小。我们的研究结果为发展产犊规律开辟了道路，这些规律适当地反映了产犊过程的多样性，并为产犊过程连续体的统一理论提供了框架。
The simple calving laws currently used in ice-sheet models do not adequately reflect the complexity and diversity of calving processes. To be effective, calving laws must be grounded in a sound understanding of how calving actually works. Here, we develop a new strategy for formulating calving laws, using (a) the Helsinki Discrete Element Model (HiDEM) to explicitly model fracture and calving processes, and (b) the continuum model Elmer/Ice to identify critical stress states associated with HiDEM calving events. A range of observed calving processes emerges spontaneously from HiDEM in response to variations in ice-front buoyancy and the size of subaqueous undercuts. Calving driven by buoyancy and melt under-cutting is under-predicted by existing calving laws, but we show that the location and magnitude of HiDEM calving events can be predicted in Elmer/Ice from characteristic stress patterns. Our results open the way to developing calving laws that properly reflect the diversity of calving processes, and provide a framework for a unified theory of the calving process continuum.