Thermo-Mechanics and Hydrology of Western Antarctic Ice Stream Margins

莱斯/1341499沿着西南极洲西珀尔海岸的冰川流动，形成20-80公里宽的快速流动的冰流，随着冰流接近海洋，冰流以每年100米的速度移动。这些冰流的边界是几乎停滞的冰脊，冰盖床中没有任何地形特征被确定为指导宽度的因素，相反，似乎是动态选择的。利用理论模型和计算物理，这项研究旨在了解(1)冰流中活跃的机械、水文和热过程，(2)流形态的起源和控制快速流动冰边缘位置的因素，以及(3)西南极冰盖的冰排放将如何响应与气候有关的大气和海洋温度和降水的变化。初步研究表明，西伯利亚海岸所有活动冰流的边缘都有相当大的温带，即冰层在海床上方几十米至数百米处处于熔点。温带冰层中含有融化的水，因此首先要了解切变边缘海床附近的水的产生和传输如何在一定程度上稳定边缘位置和控制冰流中冰的排放速度。这些研究的理论价值在于它将有助于理解是什么控制了西南极冰盖(WAIS)中冰流的沟道化以及其冰向邻近海洋的排放速率。这项工作的更广泛的影响是，提高我们对冰流动力学的知识对于预测未来大气和海洋温度、洋流、降水和太阳辐射的变化将如何影响冰的排放至关重要。基于这项研究的结果，研究人员将尝试开发一个冰流及其剪切边缘的数学模型，该模型可以包括在更大规模的冰盖过程和气候模型的数值模拟中。该项目将有助于培养两名研究生。该奖项没有在南极洲的任何实地工作。

Rice/1341499Flow of glacial ice along the Siple Coast, West Antarctica, localizes into fast-flowing ice streams of 20-80 km width, moving at speeds of 100s of m/yr as the ice streams approach the sea. These ice streams are bordered by ridges of nearly stagnant ice and no topographic feature in the ice sheet bed has been identified as guiding that width, which instead seems to be chosen dynamically. Using theoretical modeling and computational physics, this study aims to understand (1) the mechanical, hydrologic and thermal processes active within the ice streams, (2) the origin of the stream morphology and what controls the margin locations of the fast-flowing ice, and (3) how ice discharge from the West Antarctic Ice Sheet will respond to climate-related changes in atmospheric and ocean temperatures and precipitation. Preliminary studies suggest that the margins of all active ice streams in the Siple Coast have substantial ?temperate zones?, i.e., ice is at the melting point for several dozens to hundreds of meters above the bed. Temperate ice contains melt water, and thus a first focus is to understand how water generation and transport near the bed in the shear margins might partially stabilize the margin locations and control the speed of ice discharge within the ice stream.The intellectual merit of these studies is that it will contribute to understanding what controls the channelization of ice flow in the West Antarctic Ice Sheet (WAIS) and the rate at which its ice is discharged to the adjacent ocean. The broader impacts of the work are that advancing our knowledge of ice-stream dynamics is crucial for predicting how ice discharge will be impacted by future variations in atmospheric and ocean temperatures, ocean currents, precipitation, and solar radiation. Based on the results from this study, the investigators will attempt to develop a mathematical model of ice stream and their shear margins, that can be included in larger scale numerical simulations of ice sheet processes and climate models. This project will contribute to the training of two graduate students.This award does not have any field work in Antarctica.