Collaborative Research: Quantifying Heat/Mass Structure and Fluxes Through the Full Thickness of Greenland?s Percolation Zone

合作研究：量化格陵兰岛渗透区全层的热/质结构和通量

基本信息

批准号：
1717241
负责人：
Joel Harper
金额：
$ 75.87万
依托单位：
University of Montana
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-05-15 至 2023-04-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1717241&HistoricalAwards=false
关键词：
Collaborative Research Quantifying Heat Mass

项目摘要

Much of the snow that covers the Greenland Ice Sheet experiences melting during summer months. This meltwater percolates and refreezes within the underlying snow. Over time, this altered snow, which is referred to as firn, can reach to depths of 100 meters. These changes in firn structure consequently alter the heat flow within the ice, and between the ice sheet and the atmosphere. As yet however, the full structure of the firn layer is unclear as observations have been limited to shallow depths. To address this important lack of understanding, the investigators propose a field study focused on drilling a number of deep ice cores, with the goal of characterizing the thermal and physical properties of the deep firn ice. This information is essential to predicting ice sheet changes in volume and sea level rise. The project involves graduate and undergraduate students, an early career scientist, and includes public outreach activities.The project will test the hypothesis that the deep firn in the low elevation regions of Greenland experience densification governed by water infiltration/refreezing and thermally enhanced compaction. The project will develop a novel hot water drilling system to quickly penetrate 100 meters through the technically challenging conditions of intermixed cold and wet firn. In situ data collection will include digital temperature strings, video and core logging, and an instrumented drill stem. This work will yield a full-depth characterization of firn thickness, density, permeability, and thermal status. Moreover, drilling conducted a decade earlier in the region will permit the investigators to assess changes in firn properties over time. Ultimately, understanding meltwater retention and refreezing processes across Greenland?s accumulation area is essential for advancing prediction of ice sheet volume change,flow dynamics, and sea level change. The project will provide field and laboratory research experiences impacting a large number of undergraduate and graduate students. The project will support a newly funded young investigator, and will include outreach activities targeting the general public and middle school students in Greenland and Western Montana.

涵盖格陵兰冰盖的大部分积雪在夏季融化。这种融化的水在下层雪中渗透并重新冻结。随着时间的流逝，这种变化的雪被称为FIRN，可以达到100米的深度。因此，FIRN结构的这些变化会改变冰内以及冰盖和大气之间的热流。然而，由于观测值仅限于浅深度，因此FIRN层的完整结构尚不清楚。为了解决这种重要的理解，研究人员提出了一项旨在钻探许多深层冰芯的现场研究，其目的是表征深FIRN冰的热和物理特性。此信息对于预测体积和海平面上升的冰盖变化至关重要。该项目涉及毕业生和本科生，即早期职业科学家，并包括公共外展活动。该项目将检验以下假设：在格陵兰山的低海拔地区深处，由水浸润/重新冻结和热增强的压实负责。该项目将开发出一种新型的热水钻井系统，以通过技术融合的冷和湿fire的技术挑战性的条件迅速穿透100米。原位数据收集将包括数字温度字符串，视频和核心记录以及乐器钻头。这项工作将产生FIRN厚度，密度，渗透性和热状态的全深度表征。此外，在该地区进行了十年前进行的钻探将使研究人员能够随着时间的推移评估FIRN特性的变化。最终，了解格陵兰岛积累区域的融合水保留和重新冻结过程对于推进预测冰盖体积变化，流动动态和海平面变化至关重要。该项目将提供影响大量本科生和研究生的现场和实验室研究经验。该项目将支持新资助的年轻调查员，并将包括针对格陵兰和西部蒙大拿州的公众和中学生的外展活动。