NSFGEO-NERC: Collaborative Research: Two-Phase Dynamics of Temperate Ice

NSFGEO-NERC：合作研究：温带冰的两相动力学

基本信息

批准号：
1643120
负责人：
Neal Iverson
金额：
$ 44.18万
依托单位：
Iowa State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-03-01 至 2023-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1643120&HistoricalAwards=false
关键词：
NSFGEO NERC Collaborative Research Two

项目摘要

Iverson/1643120This award supports a project to study temperate ice, using both experimental methods and modeling, in order to determine the effect of water on its flow resistance and structure and to study the mobility of water within the ice. A new mathematical model of ice stream flow and temperature is developed in conjunction with these experiments. The model includes water production, storage, and movement in deforming ice and their effects on flow resistance at ice stream margins and on water availability for lubrication of ice stream beds. Results will improve estimates of the evolution of ice stream speed and geometry in a warming climate, and so improve the accuracy of assessments of the contribution of the Antarctic ice sheet to sea level rise over the next century. Ice streams are zones of rapid flow within the Antarctic ice sheet and are primarily responsible for its discharge of ice to the ocean and major effect on sea-level rise. Water plays a central role in the flow of ice streams. It lubricates their bases and softens their margins, where flow speeds abruptly transition from rapid to slow. Within ice stream margins some ice is "temperate", meaning that it is at its melting temperature and thus contains intercrystalline water that significantly softens the ice. Two postdoctoral researchers will be supported, trained, and mentored for academic careers, and three undergraduates will be introduced to research in the geosciences.This award is part the NSF/GEO-UK NERC lead agency opportunity (NSF 14-118) and is a collaboration between Iowa State University in the United States and Oxford University in the United Kingdom. The two-phase deformation of temperate ice will be studied, with the objective of determining its effect on the flow of Antarctic ice streams. The project has two components that reinforce each other. First there will be laboratory experiments in which a rotary device at Iowa State University will be used to determine relationships between the water content of temperate ice and its rheology and permeability. The second component will involve the development at Oxford University of a two-phase, fluid-dynamical theory of temperate ice and application of this theory in models of ice-stream dynamics. Results of the experiments will guide the constitutive rules and parameter ranges considered in the theory, and application of elements of the theory will improve interpretations of the experimental results. The theory and resultant models will predict the coupled distributions of temperate ice, water, stress, deformation, and basal slip that control the evolution of ice-stream speed and geometry. The modeling will result in parameterizations that allow ice streaming to be included in continental-scale models of ice sheets in a simplified but physically defensible way.

Iverson/1643120此奖项支持使用实验方法和建模研究温带冰的项目，以确定水对水的耐药性和结构的影响，并研究水在冰中的迁移率。与这些实验结合开发了冰流流量和温度的新数学模型。该模型包括冰的变形冰的水生产，存储和移动，及其对冰流边缘的流动阻力以及对冰流床润滑的水的影响。结果将改善对温暖气候下冰流速和几何形状演变的估计，从而提高评估南极冰盖对海平面在下一世纪的贡献的准确性。冰流是南极冰盖中快速流动的区域，主要是将冰送入海洋，并且对海平面上升的主要影响。水在冰流的流动中起着核心作用。它润滑了他们的基础并软化了边缘，其中流速从迅速转变为缓慢。在冰河边缘内，一些冰是“温带”，这意味着它处于其熔化温度，因此含有晶层的水，可以显着柔和冰。将为学术职业提供支持，培训和指导的两名博士后研究人员，将向三名本科生介绍地球科学研究。这是NSF/GEO-OK NERC NERC LEAC-LEad Agency机会（NSF 14-118）的一部分，并且是爱荷华州立大学在美国和牛津大学之间在英国王国统治的Iowa州立大学之间的合作。将研究温带冰的两相变形，目的是确定其对南极冰流的影响。该项目有两个组件相互加强。首先，将进行实验室实验，其中将使用爱荷华州立大学的旋转装置来确定温带冰的水含量与其流变学和渗透性之间的关系。第二个组成部分将涉及牛津大学的发展，即温带冰的两相，流体动力学理论以及该理论在冰流动力学模型中的应用。实验的结果将指导理论中考虑的本构规则和参数范围，该理论要素的应用将改善实验结果的解释。理论和结果模型将预测控制冰流速度和几何形状演变的温带，水，应力，变形和基础滑移的耦合分布。该建模将导致参数化，从而使冰流以简化但可辩护的方式包括在冰盖的大陆规模模型中。