Subglacial drainage and slip modeling in Antarctica: relating lakes to ice discharge

1043481/CreytsThis award supports a project to develop models of subglacial hydrophobic to understand the dynamics of water movement，lake drainage，and how drainage affects ice slip over deformable till with understanding the present and future behavior of fast flowing regions of Antarctica.冰下水的排泄福尔斯分为两大类：分布式的和渠道化的。在分布式系统中，水是被迫沿着冰？床界面。相反，在渠化系统中，水被引向几条主要动脉。湖泊填充和排水的观测支持冰下水流的变化，并建议从低流量状态切换到高流量状态，反之亦然。填充或排水可以将冰下系统从一种排水形态移动到另一种。排水类型的切换将影响沿沿着冰床界面的滑动，因为分布的形态往往会导致增强的滑动，而通道化的形态往往会导致增强的耦合的冰床界面。南极洲西部快速流动的冰流下面的条件是冰下排水形态之间切换的理想条件。南极洲西部的快速流动冰通常位于冰下冰碛上，在某些地区，与观测到的冰下湖泊填充和排水相一致。这项工作的目标是开发下一代空间分布的水力模型，捕捉湖泊填充和排水现象，并调查对冰下冰碛物的影响。模型将是理论上的，基于过程的描述排水和直到故障沿着快速流动的冰流。模型将基于质量、动量和能量的平衡。在以往研究的基础上，我们将把二维运动的水调查分布式基础水文，分布式基础水文耦合到渠道，并耦合这些模型与直到变形。这些模型将提供一个框架，以确定如何湖泊排水和填充影响冰排放提供了一个限制冰？床耦合 这项工作的智力价值在于，它将推进有关南极洲冰下水的排放以及水如何影响冰运动的知识。我们的建模提供了一个独特的机会，了解冰下水文在关键出口冰川和冰流的动态中所起的作用。 这项工作的更广泛影响包括培训一名博士后科学家和培训一名暑期学生进行模拟实验的简单实验室技术。此外，该提案通过在为高中和中学课堂访问，教师研讨会和社区活动开发的计划中包括物理，数字和比例模型的组成部分，从而融入现有的极地教育和推广计划。此外，由于冰川水文学的知识正在迅速增加，我们将召开一个关于冰下水文学观测和模型的研讨会，以促进知识和想法的转让。

1043481/CreytsThis award supports a project to develop models of subglacial hydrology in order to understand dynamics of water movement, lake drainage, and how drainage affects ice slip over deformable till with the goal of understanding present and future behavior of fast flowing regions of Antarctica. Drainage of subglacial water falls into two broad categories: distributed and channelized. In distributed systems, water is forced out along the ice?bed interface. Conversely, in channelized systems water is drawn toward a few major arteries. Observations of lake filling and draining sup- port changes in subglacial water flow and suggest a switch from a low to high discharge state or vice versa. Filling or draining can move the subglacial system from one type of drainage morphology to the other. A switch of drainage type will affect slip along the ice-bed interface because distributed morphologies tend to cause enhanced sliding whereas channelized morphologies tend to cause enhanced coupling of the ice-bed interface. Conditions beneath fast flowing ice streams of West Antarctica are ideal for switching between subglacial drainage morphologies. Fast flowing ice in West Antarctica commonly rests on sub- glacial tills and is coincident, in some areas, with observed subglacial lake filling and draining. The goal of the work is to develop the next generation of spatially distributed hydraulic models that capture lake filling and draining phenomena and investigate the effects on subglacial till. Models will be theoretical, process-based descriptions of water drainage and till failure along fast flowing ice streams. Models will be based on balance of mass, momentum, and energy. Building on previous studies, we will incorporate two dimensional movement of water to investigate distributed basal hydrology, distributed basal hydrology coupled to channels, and couple these models with till deformation. These models will provide a framework for determining how lake draining and filling affects ice discharge by providing a constraints on ice?bed coupling. The intellectual merit of the work is that it will advance knowledge about drainage of water subglacially beneath Antarctica and how water affects ice motion. Our modeling provides a unique opportunity to understand the role subglacial hydrology plays in the dynamics of key outlet glaciers and ice streams. The broader impacts of the work include training for one postdoctoral scientist and training for a summer student in simple laboratory techniques for analog experiments. In addition, the proposal dovetails into an existing polar education and outreach plan by including a component of physical, numerical, and scale models in programs developed for high school and middle school classroom visits, teacher workshops and community events. Additionally, because knowledge of glacial hydrology is increasing rapidly, we will convene a workshop on observations and models of subglacial hydrology to facilitate transfer of knowledge and ideas.