NSF-NERC: Thwaites Interdisciplinary Margin Evolution (TIME): The Role of Shear Margin Dynamics in the Future Evolution of the Thwaites Drainage Basin

NSF-NERC：思韦茨跨学科边缘演化（TIME）：剪切边缘动力学在思韦茨流域未来演化中的作用

• 批准号: 1739027
• 负责人: Slawek Tulaczyk
• 金额: $ 236.87万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1739027&HistoricalAwards=false
• 关键词: NSF; NERC; Thwaites; Interdisciplinary; Margin

This project contributes to the joint initiative launched by the U.S. National Science Foundation (NSF) and the U.K. Natural Environment Research Council (NERC) to substantially improve decadal and longer-term projections of ice loss and sea-level rise originating from Thwaites Glacier in West Antarctica. Collapse of the West Antarctic Ice Sheet (WAIS) could raise the global sea level by about 5 meters (16 feet) and the scientific community considers it the most significant risk for coastal environments and cities. The risk arises from the deep, marine setting of WAIS. Although scientists have been aware of the precarious setting of this ice sheet since the early 1970s, it is only now that the flow of ice in several large drainage basins is undergoing dynamic change consistent with a potentially irreversible disintegration. Understanding WAIS stability and enabling more accurate prediction of sea-level rise through computer simulation are two of the key objectives facing the polar science community today. This project will directly address both objectives by: (1) using state-of-the-art technologies to observe rapidly deforming parts of Thwaites Glacier that may have significant control over the future evolution of WAIS, and (2) using these new observations to improve ice-sheet models used to predict future sea-level rise. This project brings together a multidisciplinary team of UK and US scientists. This international collaboration will result in new understanding of natural processes that may lead to the collapse of the WAIS and will boost infrastructure for research and education by creating a multidisciplinary network of scientists. This team will mentor three postdoctoral researchers, train four Ph.D. students and integrate undergraduate students in this research project.The project will test the overarching hypothesis that shear-margin dynamics may exert powerful control on the future evolution of ice flow in Thwaites Drainage Basin. To test the hypothesis, the team will set up an ice observatory at two sites on the eastern shear margin of Thwaites Glacier. The team argues that weak topographic control makes this shear margin susceptible to outward migration and, possibly, sudden jumps in response to the drawdown of inland ice when the grounding line of Thwaites retreats. The ice observatory is designed to produce new and comprehensive constraints on englacial properties, including ice deformation rates, ice crystal fabric, ice viscosity, ice temperature, ice water content and basal melt rates. The ice observatory will also establish basal conditions, including thickness and porosity of the till layer and the deeper marine sediments, if any. Furthermore, the team will develop new knowledge with an emphasis on physical processes, including direct assessment of the spatial and temporal scales on which these processes operate. Seismic surveys will be carried out in 2D and 3D using wireless geophones. A network of broadband seismometers will identify icequakes produced by crevassing and basal sliding. Autonomous radar systems with phased arrays will produce sequential images of rapidly deforming internal layers in 3D while potentially also revealing the geometry of a basal water system. Datasets will be incorporated into numerical models developed on different spatial scales. One will focus specifically on shear-margin dynamics, the other on how shear-margin dynamics can influence ice flow in the whole drainage basin. Upon completion, the project aims to have confirmed whether the eastern shear margin of Thwaites Glacier can migrate rapidly, as hypothesized, and if so what the impacts will be in terms of sea-level rise in this century and beyond.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.

该项目有助于美国国家科学基金会（NSF）和英国联合发起的联合倡议。自然环境研究理事会（NERC）将大幅改善对南极洲西部Thwaites冰川造成的冰损失和海平面上升的十年期和长期预测。 西南极冰盖（WAIS）的崩溃可能使全球海平面上升约5米（16英尺），科学界认为这是沿海环境和城市面临的最重大风险。风险来自WAIS的深海环境。尽管科学家们从20世纪70年代初就已经意识到这一冰盖的不稳定性，但直到现在，几个大型流域的冰流才经历了与潜在的不可逆转的解体相一致的动态变化。了解WAIS的稳定性和通过计算机模拟更准确地预测海平面上升是当今极地科学界面临的两个关键目标。该项目将通过以下方式直接解决这两个目标：（1）使用最先进的技术来观察思韦茨冰川的快速变形部分，这些部分可能对WAIS的未来演变具有重要的控制作用，以及（2）使用这些新的观测结果来改进用于预测未来海平面上升的冰盖模型。该项目汇集了英国和美国科学家的多学科团队。这种国际合作将导致对可能导致WAIS崩溃的自然过程的新理解，并将通过创建多学科科学家网络来促进研究和教育基础设施。该团队将指导3名博士后研究人员，培养4名博士。该项目将测试总体假设，即剪切边缘动力学可能对斯威茨流域冰流的未来演变产生强大的控制。为了验证这一假设，研究小组将在思韦茨冰川东部剪切边缘的两个地点建立一个冰观测站。该团队认为，薄弱的地形控制使得这种剪切边缘容易向外迁移，并可能突然跳跃，以应对内陆冰的下降时，接地线的思韦茨撤退。冰观测站的设计是为了对冰的性质产生新的和全面的限制，包括冰的变形率、冰晶结构、冰的粘度、冰的温度、冰水含量和基础融化率。冰观测站还将确定基本条件，包括冰碛层和更深的海洋沉积物的厚度和孔隙度。此外，该小组将发展新的知识，重点是物理过程，包括直接评估这些过程运作的空间和时间尺度。将使用无线地震检波器进行2D和3D地震勘测。一个宽带地震仪网络将识别由裂缝和基底滑动产生的冰震。具有相控阵的自主雷达系统将产生快速变形的3D内部层的连续图像，同时还可能揭示基底水系统的几何形状。数据集将被纳入在不同空间尺度上开发的数值模型。一个将特别关注剪切边缘动力学，另一个剪切边缘动力学如何影响整个流域的冰流。项目完成后，将确认思韦茨冰川的东部剪切边缘是否会像假设的那样迅速迁移，如果是的话，在本世纪及以后的海平面上升方面将产生什么样的影响。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Modelling thermomechanical ice deformation using an implicit pseudo-transient method (FastICE v1.0) based on graphical processing units (GPUs)

使用基于图形处理单元 (GPU) 的隐式伪瞬态方法 (FastICE v1.0) 对热机械冰变形进行建模

• DOI: 10.5194/gmd-13-955-2020
• 发表时间: 2020
• 期刊: Geoscientific Model Development
• 影响因子: 5.1
• 作者: Räss, Ludovic;Licul, Aleksandar;Herman, Frédéric;Podladchikov, Yury Y.;Suckale, Jenny
• 通讯作者: Suckale, Jenny

Ambient high-frequency seismic surface waves in the firn column of central west Antarctica

南极洲中西部冷杉柱中的环境高频地震面波

• DOI: 10.1017/jog.2021.135
• 发表时间: 2022
• 期刊: Journal of Glaciology
• 影响因子: 3.4
• 作者: Chaput, Julien;Aster, Rick;Karplus, Marianne;Nakata, Nori
• 通讯作者: Nakata, Nori

When floods hit the road: Resilience to flood-related traffic disruption in the San Francisco Bay Area and beyond

• DOI: 10.1126/sciadv.aba2423
• 发表时间: 2020-08-01
• 期刊: SCIENCE ADVANCES
• 影响因子: 13.6
• 作者: Kasmalkar, Indraneel G.;Serafin, Katherine A.;Suckale, Jenny
• 通讯作者: Suckale, Jenny

Rapid and accurate polarimetric radar measurements of ice crystal fabric orientation at the Western Antarctic Ice Sheet (WAIS) Divide ice core site

• DOI: 10.5194/tc-15-4117-2021
• 发表时间: 2021-08
• 期刊: The Cryosphere
• 作者: T. J. Young;C. Martín;P. Christoffersen;D. Schroeder;S. Tulaczyk;E. Dawson

Migration of the Shear Margins at Thwaites Glacier: Dependence on Basal Conditions and Testability Against Field Data

思韦茨冰川剪切边缘的迁移：对基础条件的依赖和针对现场数据的可测试性

• DOI: 10.1029/2022jf006958
• 发表时间: 2023
• 期刊: Journal of Geophysical Research: Earth Surface
• 作者: Summers, Paul T.;Elsworth, Cooper W.;Dow, Christine F.;Suckale, Jenny
• 通讯作者: Suckale, Jenny