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: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=388941
• 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学的计算机模型。冰下过程的代表性不足是目前用于预测地球冰川未来的模型的一个主要缺点。我们需要对极地冰盖未来的质量损失率以及随之而来的全球海平面上升做出尽可能准确的估计。此外，我们需要良好的模型来增加对过去气候突变事件的了解。我们的战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，开发理论来封装这些测量的结果，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，通过圆形冰壁管道的水流的基础上，包括更现实的几何形状。应用这些结果，我们可以立即改善冰下和冰上爆发洪水的物理模型，并首次为埃斯克斯（一种景观特征）开发一个现实的模型，我们希望，为其他冰下地貌。在更大的范围内，我们将继续研究气候突变的机制，重点是大洪水的作用，如冰川湖阿加西，以及“海因里希事件”，这似乎涉及水和冰流的耦合不稳定性。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项目，研究育空地区新冰川湖Alsek的突发洪水和洪水床型。