A Study of the Tidal Modulation of Ice-shelf Flow using a Viscoelastic Model of the Ross Ice Shelf

该奖项支持一项为期两年的南极罗斯冰架流动研究，罗斯冰架是漂浮在罗斯海上的南极冰盖的一部分。罗斯冰架（与费尔奇纳-罗恩冰架一起）为南极西部冰架的向海流动提供了一个重要的、稳定的背压，南极西部冰架是南极冰盖最容易发生灾难性解体的部分。这项研究旨在通过开发一个二维平面粘弹性冰流模型来了解罗斯冰架和海洋之间的相互作用。这个模型将探讨平均时间平均冰架流速的潮汐调制。然后，该模型将根据之前在现场收集的GPS测量数据进行评估，这些测量数据位于靠近向海的冰架冰山崩解前沿中心的一个地点。这项冰动力学研究的结果将对冰盖模拟界做出重大贡献，因为：1)提供了对冰架对海潮响应的粘性和弹性分量的独立评估；2)更好地理解海洋/冰架耦合系统的敏感性；3)将粘性和弹性因素结合到一个综合的海洋/冰架/冰流系统中，以解决冰川冰流过接地线的潮汐调制问题。对冰架流动动力学的进一步了解，以及对冰架和冰盖之间通过冰流的远距联系的了解，将有助于冰盖建模者更好地了解南极西部冰盖的演变，这是目前南极对平均海平面上升的最大贡献。

This award supports a two-year study of the flow of the Ross Ice Shelf, Antarctica, which is the portion of the Antarctic ice sheet that is floating on the Ross Sea. The Ross Ice Shelf (along with the Filchner-Ronne Ice Shelf) provides an important, stabilizing back-pressure on the seaward flow of the West Antarctic Ice Sheet, which is the portion of the Antarctic ice sheet that is most at risk of catastrophic disintegration. The study aims to understand the interaction between the Ross Ice Shelf and the ocean by developing a map-plane two-dimensional, viscoelastic, ice-flow model. This model will explore the tidal modulation of mean, time-averaged ice-shelf flow velocity. The model will then be assessed based on GPS measurements that have previously been collected in the field, at a site near the center of the seaward, iceberg-calving front of the ice shelf. The results of this ice-dynamics study will contribute significantly to the ice-sheet modeling community by: 1) providing an independent assessment of both the viscous and elastic components of the ice-shelf response to the ocean tide; 2) providing a better understanding of the sensitivities of the coupled ocean/ice-shelf system; and 3) incorporating both viscous and elastic elements into an integrated ocean/ice-shelf/ice-stream system that addresses tidal modulation of the flow of glacial ice across the grounding line. Having an increased understanding of the ice-shelf-flow dynamics, and an understanding of the teleconnection between the ice shelves and the ice sheets via the ice streams, will assist ice-sheet modelers to better understand the evolution of the West Antarctic Ice Sheet, which is currently the largest Antarctic contribution to mean-sea-level rise.