Thermo-Mechanics and Hydrology of Western Antarctic Ice Stream Margins

南极西部冰流边缘的热力学和水文学

• 批准号: 1341499
• 负责人: James Rice
• 金额: $ 38.45万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-01 至 2019-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1341499&HistoricalAwards=false
• 关键词: Thermo; Mechanics; Hydrology; Western; Antarctic

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.

沿着南极洲西部simple海岸的冰川冰流，局部形成20-80公里宽的快速流动的冰流，当冰流接近海洋时，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，没有发现冰盖床上的地形特征在指导这种宽度，相反，它似乎是动态选择的。利用理论建模和计算物理，本研究旨在了解(1)冰流内部活跃的机械、水文和热过程；(2)冰流形态的起源和控制快速流动冰边缘位置的因素；(3)南极西部冰盖冰流量如何响应与气候相关的大气、海洋温度和降水变化。初步研究表明，在简单海岸所有活动冰流的边缘都有大量的？温带地区吗?也就是说，在床上几十到几百米的地方，冰处于熔点。温带冰含有融水，因此，首先要了解的是，剪切边缘床附近的水生成和输送如何在一定程度上稳定边缘位置，并控制冰流内冰排放的速度。这些研究的智力价值在于，它将有助于理解是什么控制着南极西部冰盖（WAIS）冰流的渠道化，以及它的冰向邻近海洋排放的速度。这项工作的更广泛的影响是，推进我们对冰流动力学的了解对于预测冰排放将如何受到未来大气和海洋温度、洋流、降水和太阳辐射变化的影响至关重要。基于这项研究的结果，研究人员将尝试建立一个冰流及其切变边缘的数学模型，该模型可用于更大规模的冰盖过程和气候模型的数值模拟。这个项目将有助于培养两名研究生。这个奖项没有任何在南极洲的实地工作。