Multi-scale models of thermo-mechanical feedbacks on a soft, wet bed

据观测，海平面正在加速上升。这种上升的很大一部分来自冰川。冰川的滑动速度和冰流的排出速率以及排出地球的冰川？美国的主要冰原主要受其床上条件的控制。该项目将使用模型来探索控制滑动的床况约束条件。这将从小尺度开始，从实验中了解物理原理，结果将用于严格解释观察到的冰川流动和相关景观发展的大尺度上的异质性的影响。该项目将改进冰川模型，并最终有助于改善未来海平面上升的情景。它将通过为博士后助理的培训提供支持，促进STEM劳动力的发展。五名本科生将被有效地纳入研究计划。我们会透过计划向中学推广服务。美国参加暑期教师讲习班，随后共同开发和共同教学一个关于冰川和海平面上升的项目。这将包括动手演示的开发。首席研究员建议建立一个层次模型，旨在探索冰、水和土壤之间热-机械耦合的后果。他的研究将跨越非常广泛的时间尺度：从河床短暂锁定部分的潮汐强迫的弹性响应，到发生重大地形变化的十年周期。他还将研究大范围的长度尺度，包括管道之间渗流进入的过渡区域，以及对模拟和观察到的地形粗糙度的全流域响应。靠近浮选的水压降低了对摩擦滑动的阻力，使泥沙颗粒接触所支撑的有效应力在地面环境中上几米土壤的典型范围内。在这种条件下，长期建立的实验支持的冰-水-沉积物相互作用的热力学处理直到最近才应用于冰下环境。需要进一步的工作来充分整合这一认识及其对冰川滑动和景观发展的影响。该建议的目标是选择一些模型问题，旨在阐明基本性质转变附近行为的热力学约束，严格考虑与现代观测相关的尺度范围内的异质性影响。通过对精心挑选的系统进行集中研究获得的直觉，首席研究员将制定参数化模型预测的策略，以便将其纳入冰川和冰盖动力学的大规模模拟中。

Sea level is observed to be rising at an accelerating rate. A significant portion of this rise is derived from glaciers. Glacier sliding speeds and the discharge rates of the ice streams and outlet glaciers that drain Earth?s major ice sheets are primarily controlled by conditions at their beds. This project will use models to explore constraints on the bed conditions that control sliding. This will begin at small scales where the physics are understood from experiments and the results will be used to rigorously account for the effects of heterogeneities across the larger scales of observed glacier flow and associated landscape development.The project will improve glacier modeling and, ultimately, contribute to improved scenarios of future sea level rise. It will contribute to STEM workforce development by providing support for the training of a post-doctoral associate. Five undergraduate students will be entrained effectively into the research program. Outreach to middle schools will be achieved through the PI?s participation in summer teacher workshops, followed by co-development and co-teaching of a project on glaciers and sea level rise. This will include the development of a hands-on demonstration.The principal investigator proposes to develop a hierarchy of models aimed at exploring the consequences of thermo-mechanical coupling between ice, water, and till. His studies will span a very wide range of time scales: from the elastic response to tidal forcing at transiently locked portions of the bed, to the decadal periods over which significant topographic modifications take place. He will also examine a broad range of length scales, including the transitional regions accessed by seepage flows between conduits, and basin-wide responses to modeled and observed topographic roughness. Water pressures close to flotation reduce the resistance to frictional sliding and bring the effective stress supported by sediment particle contacts to within the range typical of the upper few meters of soil in subaerial environments. Long-established, experimentally supported thermo-mechanical treatments of ice-water-sediment interactions under such conditions have only recently been applied to the subglacial environment. Further work is needed to fully integrate this understanding and its implications for glacier sliding and landscape development. This proposal targets a selection of model problems aimed at elucidating the thermo-mechanical constraints on behavior near transitions in basal properties, rigorously accounting for the effects of heterogeneities across the range of scales relevant to modern observations. With the intuition gained from focused studies on carefully selected systems, the principal investigator will develop strategies for parameterizing the model predictions so that they can be incorporated in large-scale simulations of glacier and ice sheet dynamics.