Viscous and elastic buoyancy stresses as drivers of ice-shelf calving
Viscous and elastic buoyancy stresses as drivers of ice-shelf calving
复制标题
DOI：
10.1017/jog.2020.35
复制
发表时间：
2020-08-01
影响因子：
3.4
通讯作者：
Fricker, Helen A.
中科院分区：
文献类型：
--
作者：
Mosbeux, Cyrille;Wagner, Till J. W.;Fricker, Helen A.
南极冰盖主要通过两个过程通过其冰架失去质量：基底融化和冰山崩解。冰山崩解是偶发性的和罕见的，并没有很好地参数化冰盖模型。在这里，我们调查的影响，静水压力对产犊。我们开发了二维弹性和粘性数值框架来模拟“自由”产犊机制。这种机制是由冰前缘的水下冰突起触发的，这会引起不平衡的浮力，从而导致断裂。我们比较的结果，以确定不同的角色，粘性和弹性变形在设置产犊事件的速率和幅度。我们的研究结果表明，虽然在这两个框架的弯曲应力有一些共同的特点，他们的差异有重要的意义建模产犊过程。特别是，弹性模型预测，最大应力出现在更远的冰前比在粘性模型，导致更大的崩解事件。我们还发现，弹性模型可能会导致更频繁的事件比粘性的。我们的工作提供了一个理论框架的发展，更好地理解的物理过程，管理冰川和冰架崩解周期。
The Antarctic Ice Sheet loses mass via its ice shelves predominantly through two processes: basal melting and iceberg calving. Iceberg calving is episodic and infrequent, and not well parameterized in ice-sheet models. Here, we investigate the impact of hydrostatic forces on calving. We develop two-dimensional elastic and viscous numerical frameworks to model the 'footloose' calving mechanism. This mechanism is triggered by submerged ice protrusions at the ice front, which induce unbalanced buoyancy forces that can lead to fracturing. We compare the results to identify the different roles that viscous and elastic deformations play in setting the rate and magnitude of calving events. Our results show that, although the bending stresses in both frameworks share some characteristics, their differences have important implications for modeling the calving process. In particular, the elastic model predicts that maximum stresses arise farther from the ice front than in the viscous model, leading to larger calving events. We also find that the elastic model would likely lead to more frequent events than the viscous one. Our work provides a theoretical framework for the development of a better understanding of the physical processes that govern glacier and ice-shelf calving cycles.