Collaborative Research: Stability and Dynamics of Antarctic Marine Outlet Glaciers

货车der Veen/1543530本研究的目的是更好地了解南极西部从地面冰到浮冰架过渡区的冰流，并调查这些冰川开始和维持大规模退缩的条件。将使用一套观测技术和建模工具对南极几个主要的出口冰川和冰流进行调查。冰川包括思韦茨冰川（Thwaites Glacier），它已成为西南极洲撤退讨论的焦点，惠兰斯冰流（Whillans Ice Stream）是典型冰流的例子，伯德冰川（Byrd Glacier）是东南极洲通过横贯南极山脉进入罗斯冰架的主要出口冰川。这项研究将调查这些冰川的持续变化是否会导致长期的质量损失（冰盖崩溃的开始），或者这些冰川是否会以新的几何形状迅速稳定下来。为了充分纳入出口冰川和冰流的动态行为，需要纳入相关的物理过程，开发区域模型，采用水平网格间距足够精确的数值网格，以捕捉可能控制这些冰川流动的较小尺度河床地形特征。该奖项重新审视了海洋终止冰川的稳定性问题，其接地线位于退化的河床斜坡上。特别是，将试图解决的问题，是否观察到的快速变化是在终点或接地线的扰动的结果，或者这些变化是否反映了冰动力学强迫接地达到。高分辨率卫星图像将用于在比以往更小的空间尺度上调查冰流扰动，以评价高基底阻力的局部地点对接地线稳定性的重要性。该合作项目涉及一系列建模策略，包括力预算分析，流带建模，用于当地研究的全斯托克斯建模，以及使用JPL开发的冰盖系统模型进行区域建模。更广泛的影响包括培训两名研究生在计算机模拟和冰盖建模算法。这项工作还将扩大基于网络的交互式流线模型，使其包括更现实的接地线动态。

Van der Veen/1543530The objective of this research is to gain better understanding of the West Antarctic ice flow in the transition region from grounded ice to floating ice shelves and investigate the conditions that can initiate and sustain major retreat of these glaciers. Several major Antarctic outlet glaciers and ice streams will be investigated using a suite of observational techniques and modeling tools. Glaciers include Thwaites Glacier, which has become a focal point in the discussion of West Antarctic retreat, Whillans Ice Stream as an example of the archetype ice stream, and Byrd Glacier, a major outlet glacier draining East Antarctica through the Transantarctic Mountains into the Ross Ice Shelf. This study will investigate whether the ongoing changes in these glaciers will lead to long-term mass loss (the onset of ice sheet collapse), or whether these glaciers will quickly stabilize with a new geometry.To adequately incorporate the dynamic behavior of outlet glaciers and ice streams requires inclusion of the relevant physical processes, and the development of regional models that employ a numerical grid with a horizontal grid spacing sufficiently refined to capture smaller-scale bed topographic features that may control the flow of these glaciers. This award revisits the issue of stability of marine-terminating glaciers whose grounding line is located on a retrograded bed slope. In particular, an attempt will be made to resolve the question whether observed rapid changes are the result of perturbations at the terminus or grounding line, or whether these changes reflect ice-dynamical forcing over the grounded reaches. High-resolution satellite imagery will be used to investigate ice-flow perturbations on smaller spatial scales than has been done before, to evaluate the importance of localized sites of high basal resistance on grounding-line stability. This collaborative project involves a range of modeling strategies including force-budget analysis, flow-band modeling, Full Stokes modeling for local studies, and using the Ice Sheet System Model developed at JPL for regional modeling. Broader Impacts include training two graduate students in computer simulations and ice sheet modeling algorithms. The work will also expand on a web-based interactive flowline model, so that it includes more realistic grounding line dynamics.