Subglacial processes and their large-scale consequences

冰下过程及其大规模后果

• 批准号: 4327-2008
• 负责人: Clarke, Garry
• 金额: $ 4.01万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=449655
• 关键词: Subglacial; processes; their; large; scale

The leading aim of our research is to understand the operation of subglacial processes and to apply this understanding to improve computer models of the dynamics and hydrology of ice sheets. Inadequate representation of subglacial processes is a major shortcoming of the models that are currently used to predict Earth's glacial future. We need the best possible estimates of future rates of mass loss from polar ice sheets and the consequent rise in global sea level. Additionally, we need good models to increase understanding of past abrupt climate change events. Our strategy is to install instruments within and beneath glaciers to observe processes and their interactions, develop theory to encapsulate the results of these measurements and build numerical models to simulate the natural systems. We aim to extend the classical theory of subglacial drainage systems, based on water flow through circular ice-walled conduits, to include more realistic geometries. Applying these results, we can immediately improve physical models of subglacial and supraglacial outburst floods and develop, for the first time, a realistic model for eskers (a landscape feature) and, we hope, for other subglacial landforms. At a larger scale, we will continue our research on mechanisms of abrupt climate change, focussing on the role of megafloods, such as that from glacial Lake Agassiz, and on "Heinrich events" which seem to involve a coupled instability of water and ice flow. To complement our research on megafloods we will launch a modest field program to study the outburst floods and flood bedforms of Neoglacial Lake Alsek, Yukon.

我们研究的主要目的是了解冰下过程的运作，并将这种理解应用于改进冰盖动力学和水文的计算机模型。目前用于预测地球冰川未来的模式的一个主要缺点是对冰下过程的描述不足。我们需要对极地冰盖未来的质量损失率以及由此导致的全球海平面上升作出尽可能准确的估计。此外，我们需要好的模型来增加对过去气候突变事件的理解。我们的策略是在冰川内部和下方安装仪器来观察过程及其相互作用，发展理论来概括这些测量结果，并建立数值模型来模拟自然系统。我们的目标是扩展冰下排水系统的经典理论，以水流通过圆形冰壁管道为基础，包括更现实的几何形状。应用这些结果，我们可以立即改进冰下和冰上溃决洪水的物理模型，并首次开发出一个适用于eskers（景观特征）的现实模型，我们希望也适用于其他冰下地貌。在更大的范围内，我们将继续研究气候突变的机制，重点关注特大洪水的作用，比如来自阿加西冰川湖的洪水，以及似乎涉及水和冰流动耦合不稳定的“海因里希事件”。为了补充我们对特大洪水的研究，我们将启动一个适度的实地研究项目，研究育空地区阿尔塞克新冰湖的溃决洪水和洪水河床。