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

GSTDTAP

项目编号	1643123
	NSFGEO-NERC: Collaborative Research: Two-Phase Dynamics of Temperate Ice
	Lucas Zoet
主持机构	University of Wisconsin-Madison
项目开始年	2017
	2017-03-01
项目结束日期	2020-02-29
资助机构	US-NSF
项目类别	Continuing grant
项目经费	29806(USD)
国家	美国
语种	英语
英文摘要	Iverson/1643120 This 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.
来源学科分类	Geosciences - Polar Programs
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/70806
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Lucas Zoet.NSFGEO-NERC: Collaborative Research: Two-Phase Dynamics of Temperate Ice.2017.