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

该奖项支持一个开发冰下水文学模型的项目，以了解水运动的动力学，湖泊排水，以及排水如何影响冰在可变形土层上的滑动，目的是了解南极洲快速流动地区的现在和未来行为。冰下水的排水分为两大类：分布式和渠化。在分布式系统中，水沿着冰被挤出来。床上的接口。相反，在渠化系统中，水被吸引到几个主要的动脉。湖泊蓄水和排水的观测支持了冰下水流的变化，并表明从低流量到高流量状态的转换，反之亦然。充填或排水可以使冰下系统从一种类型的排水形态移动到另一种类型。排水类型的切换会影响沿冰床界面的滑动，因为分布形态倾向于导致滑动增强，而渠化形态倾向于导致冰床界面的耦合增强。在南极洲西部快速流动的冰流下的条件是在冰下排水形态之间切换的理想条件。南极洲西部快速流动的冰通常位于冰下斜坡上，在某些地区，与观测到的冰下湖泊填充和排水是一致的。这项工作的目标是开发下一代空间分布的水力模型，以捕获湖泊填充和排水现象，并研究对冰下till的影响。模型将是理论的，基于过程的描述，沿着快速流动的冰流排水和直到失败。模型将基于质量、动量和能量的平衡。在前人研究的基础上，我们将结合水的二维运动来研究分布的基础水文、分布的基础水文与河道的耦合以及这些模型与土壤变形的耦合。这些模型将提供一个框架，以确定湖泊排水和填充如何通过提供对冰的限制来影响冰的排放。床上耦合。这项工作的学术价值在于，它将推动人们对南极洲冰川下的排水以及水如何影响冰的运动的认识。我们的模型提供了一个独特的机会来了解冰下水文在关键出口冰川和冰流动力学中的作用。这项工作的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简单的模拟实验实验室技术。此外，该提案与现有的极地教育和推广计划相吻合，在为高中和初中课堂参观、教师研讨会和社区活动开发的项目中包括物理、数字和比例模型的组成部分。此外，由于对冰川水文学的了解正在迅速增加，我们将召开一次关于冰下水文学观测和模型的研讨会，以促进知识和思想的转移。

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.