Understanding Firn Rheology Through Laboratory Compaction Experiments and Radar Data

通过实验室压实实验和雷达数据了解冷杉流变学

基本信息

  • 批准号:
    1935438
  • 负责人:
  • 金额:
    $ 73.75万
  • 依托单位:
  • 依托单位国家:
    美国
  • 项目类别:
    Standard Grant
  • 财政年份:
    2020
  • 资助国家:
    美国
  • 起止时间:
    2020-04-01 至 2025-03-31
  • 项目状态:
    未结题

项目摘要

The ice sheets of Antarctica and Greenland are losing mass and contributing to accelerating global sea-level rise. Satellite altimetry provides precise measurement of ice-sheet volume change, but computing ice-sheet mass change—the quantity relevant for estimating the ice sheet’s sea-level contribution—requires knowing the density of the ice sheet. The density near the ice-sheet surface also affects age estimates of air bubbles recovered in ice cores, which are a key source of information on past climate changes. Ice-sheet density is primarily controlled by the rate at which firn (snow that has persisted for a year or more on ice sheets) compacts into ice, but there is currently no widely accepted theory of how this compaction occurs. The goal of this project is thus to advance understanding of how firn densifies. The team will conduct laboratory experiments and analyze ice-penetrating radar and ice-core data from Antarctica. A key desired outcome of the project is a new model of firn densification that can be used to improve satellite-based altimetry measurements of present-day ice-sheet change and reconstructions of past climate changes from ice cores. This project will combine laboratory experiments, numerical modeling, and geophysical techniques to determine the rheology of firn as it compacts to form ice. The team will use two methods to measure firn compaction: (1) lab-based experiments and (2) analysis of ice-core and radar data. For the lab-based work, the team will conduct a suite of compaction experiments on synthetic firn samples under uni-axial strain and constant temperature and axial stress. They will also measure the grain-size evolution. By running a large number of experiments ( 25), the team will constrain key parameters that determine how firn compaction rate depends on density, temperature, grain size, and axial stress. The experiments will be conducted in a table-top apparatus at temperatures as low as -40 degrees C and axial stresses up to 4 MPa. For the field-data-based component, the team will analyze ice-core and ice-penetrating radar data to produce the first coincident set of radar-derived firn compaction rates, borehole temperatures, firn densities, and firn grain sizes. Results from lab and field data will be tied together using a numerical firn compaction model. This model is formulated using conservation of mass, momentum, and energy, along with an explicit description of firn rheology and grain-size evolution. Constraints on firn rheology will be incorporated into this model and the team will use it to examine fundamental questions about how changes in the climate affect firn density. This is a crucial unknown that contributes significant measurement uncertainty in estimates of past and present climate change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
南极和格陵兰的冰盖正在失去质量,并有助于加速全球海平面上升。卫星高度测定提供了冰片体积变化的精确度量,但是计算冰片质量变化(与估计冰盖海平面贡献相关的数量)需要了解冰盖的密度。冰盖表面附近的密度还会影响冰芯中回收气泡的年龄估计,这是过去气候变化的关键信息来源。冰片密度主要由FIR(在冰盖上持续了一年或更长时间的雪)紧凑到冰中的速度(降雪)的速度控制,但是目前尚无关于这种压实如何发生的广泛接受的理论。因此,该项目的目的是提高人们对首次致密方式的理解。该团队将进行实验室实验,并分析来自南极洲的冰根雷达和冰核数据。该项目的一个关键期望结果是一种新的FIR致密化模型,可用于改善基于卫星的高度测量测量值,对当今的冰层变化以及对冰核过去气候变化的重建。该项目将结合实验室实验,数值建模和地球物理技术,以确定FIR的流变形成冰。该团队将使用两种方法来测量FIR压实:(1)基于实验室的实验和(2)冰核和雷达数据的分析。对于基于实验室的工作,该团队将在单轴应变以及恒定温度和轴向应力下对合成FIR样品进行一系列压实实验。他们还将测量晶粒大小的演变。通过运行大量实验(25),团队将限制关键参数,以确定FIR压实率如何取决于密度,温度,晶粒尺寸和轴向应力。该实验将在低至-40摄氏度的温度下进行台式设备进行,轴向应力高达4 MPa。对于基于野外DATA的组件,该团队将分析冰核和冰冰雷达数据,以产生首个雷达衍生的FIR压实率,井眼温度,FIR密度和第一粒度的一致集合。实验室和现场数据的结果将使用数值FIR压实模型将其绑定在一起。该模型是使用质量,动量和能量的保护,以及对firheology和晶粒大小进化的明确描述来制定的。对Firheology的限制将纳入该模型,团队将使用它来研究有关气候变化如何影响FIR密度的基本问题。这是一个至关重要的未知,在过去和当前气候变化的估计中造成了重大的衡量不确定性。该奖项反映了NSF的法定任务,并且使用基金会的知识分子优点和更广泛的审查标准,被视为值得通过评估来获得支持。

项目成果

期刊论文数量(1)
专著数量(0)
科研奖励数量(0)
会议论文数量(0)
专利数量(0)
Grain-size evolution controls the accumulation dependence of modelled firn thickness
晶粒尺寸演化控制模拟云层厚度的累积依赖性
  • DOI:
    10.5194/tc-16-3413-2022
  • 发表时间:
    2022
  • 期刊:
  • 影响因子:
    0
  • 作者:
    Kingslake, Jonathan;Skarbek, Robert;Case, Elizabeth;McCarthy, Christine
  • 通讯作者:
    McCarthy, Christine
共 1 条
  • 1
前往

Christine McCarthy其他文献

Theoretical design of topological materials
拓扑材料的理论设计
  • DOI:
  • 发表时间:
    2011
    2011
  • 期刊:
  • 影响因子:
    0
  • 作者:
    栗原佑太朗;上岡隼人;守友浩;山本一博;Christine McCarthy;N.Nagaosa
    栗原佑太朗;上岡隼人;守友浩;山本一博;Christine McCarthy;N.Nagaosa
  • 通讯作者:
    N.Nagaosa
    N.Nagaosa
Cultural Studies of Science Education: An Appraisal
科学教育的文化研究:评价
  • DOI:
    10.1007/978-3-319-62616-1_4
    10.1007/978-3-319-62616-1_4
  • 发表时间:
    2018
    2018
  • 期刊:
  • 影响因子:
    0
  • 作者:
    Christine McCarthy
    Christine McCarthy
  • 通讯作者:
    Christine McCarthy
    Christine McCarthy
Attenuation and dispersion in melt-free and melt-bearing Earth analogue materials
无熔体和含熔体地球模拟材料中的衰减和色散
  • DOI:
  • 发表时间:
    2011
    2011
  • 期刊:
  • 影响因子:
    0
  • 作者:
    栗原佑太朗;上岡隼人;守友浩;山本一博;Christine McCarthy
    栗原佑太朗;上岡隼人;守友浩;山本一博;Christine McCarthy
  • 通讯作者:
    Christine McCarthy
    Christine McCarthy
Frictional Strength, Stability, and Potential Shear Heating on Icy Satellite Faults
冰卫星断层上的摩擦强度、稳定性和潜在的剪切加热
Anti-CD19 Chimeric Antigen Receptor T-Cell Therapy for Richter's Transformation: An International Multicenter Retrospective Study
  • DOI:
    10.1182/blood-2023-180858
    10.1182/blood-2023-180858
  • 发表时间:
    2023-11-02
    2023-11-02
  • 期刊:
  • 影响因子:
  • 作者:
    Adam S Kittai;David A. Bond;Ying Huang;Seema A Bhat;Emily Blyth;John C. Byrd;Julio C Chavez;Matthew S Davids;Jamie P Dela Cruz;Mark R Dowling;Caitlyn Duffy;Carrie I Ho;Caron A Jacobson;Samantha M. Jaglowski;Nitin Jain;Kevin H Lin;Christine McCarthy;Erin M Parry;Manoj Rai;Kerry A Rogers
    Adam S Kittai;David A. Bond;Ying Huang;Seema A Bhat;Emily Blyth;John C. Byrd;Julio C Chavez;Matthew S Davids;Jamie P Dela Cruz;Mark R Dowling;Caitlyn Duffy;Carrie I Ho;Caron A Jacobson;Samantha M. Jaglowski;Nitin Jain;Kevin H Lin;Christine McCarthy;Erin M Parry;Manoj Rai;Kerry A Rogers
  • 通讯作者:
    Kerry A Rogers
    Kerry A Rogers
共 8 条
  • 1
  • 2
前往

Christine McCarthy的其他基金

Collaborative Research: Seismic attenuation and anelasticity in the upper mantle: the effect of continuous far-field dislocation creep
合作研究:上地幔的地震衰减和滞弹性:连续远场位错蠕变的影响
  • 批准号:
    1855423
    1855423
  • 财政年份:
    2019
  • 资助金额:
    $ 73.75万
    $ 73.75万
  • 项目类别:
    Continuing Grant
    Continuing Grant
Laboratory Study of Substrate Control and Cryoseismicity of Glacier Basal Motion
冰川基底运动的基质控制和冷震性的室内研究
  • 批准号:
    1854629
    1854629
  • 财政年份:
    2019
  • 资助金额:
    $ 73.75万
    $ 73.75万
  • 项目类别:
    Standard Grant
    Standard Grant
Laboratory Study of Ice Deformation under Tidal Loading Conditions with Application to Antarctic Glaciers
潮汐载荷条件下冰变形的室内研究及其在南极冰川中的应用
  • 批准号:
    1245871
    1245871
  • 财政年份:
    2013
  • 资助金额:
    $ 73.75万
    $ 73.75万
  • 项目类别:
    Continuing Grant
    Continuing Grant

相似海外基金

CAREER: Improving Estimates of Changing Firn Meltwater Storage and Flux in Temperate Glacier Systems
职业:改进对温带冰川系统中冰雪融水储存和通量变化的估计
  • 批准号:
    2239668
    2239668
  • 财政年份:
    2023
  • 资助金额:
    $ 73.75万
    $ 73.75万
  • 项目类别:
    Continuing Grant
    Continuing Grant
Postdoctoral Fellowship: OPP-PRF: Spatiotemporal Evolution of Firn Hydrology on the Juneau Icefield, Alaska
博士后奖学金:OPP-PRF:阿拉斯加朱诺冰原冰水文的时空演化
  • 批准号:
    2318348
    2318348
  • 财政年份:
    2023
  • 资助金额:
    $ 73.75万
    $ 73.75万
  • 项目类别:
    Standard Grant
    Standard Grant
Collaborative Research: A New Approach to Firn Evolution using the Taylor Dome Natural Laboratory
合作研究:利用泰勒穹顶自然实验室研究杉木进化的新方法
  • 批准号:
    2024469
    2024469
  • 财政年份:
    2021
  • 资助金额:
    $ 73.75万
    $ 73.75万
  • 项目类别:
    Standard Grant
    Standard Grant
Collaborative Research: A New Approach to Firn Evolution using the Taylor Dome Natural Laboratory
合作研究:利用泰勒穹顶自然实验室研究杉木进化的新方法
  • 批准号:
    2024163
    2024163
  • 财政年份:
    2021
  • 资助金额:
    $ 73.75万
    $ 73.75万
  • 项目类别:
    Standard Grant
    Standard Grant
Collaborative Research: Arctic Observing Network For Observing Transformation of the Greenland Ice Sheet Firn Layer
合作研究:观测格陵兰冰盖冰层变化的北极观测网络
  • 批准号:
    2113392
    2113392
  • 财政年份:
    2021
  • 资助金额:
    $ 73.75万
    $ 73.75万
  • 项目类别:
    Standard Grant
    Standard Grant