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NSFGEO-NERC:A new mechanistic framework for modeling rift processes in Antarctic ice shelves validated through improved strain-rate and seismic obser

NSFGEO-NERC：通过改进的应变率和地震观测器验证南极冰架裂谷过程的新机制框架

基本信息

批准号：
NE/V013319/1
负责人：
Hilmar Gudmundsson
金额：
$ 27.54万
依托单位：
Northumbria University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2021
资助国家：
英国
起止时间：
2021 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FV013319%2F1
关键词：
NSFGEO NERC new mechanistic framework

项目摘要

Tabular iceberg calving accounts for a significant fraction of ice mass loss from Antarctica and is the culmination of the propagation of full-thickness fractures-known as rifts-in ice shelves. Understanding theprocesses and drivers of rifting and how best to represent rifts in large-scale ice-flow models are among thegreat challenges of modern glaciology. To date, much work has focused on developing parameterized calving laws that consider velocity, thickness, crevasse depth, and/or damage proxies at or near the calving front to represent calving (e.g., Nick et al., 2010; Duddu and Waisman, 2012; Borstad et al., 2012; Albrecht and Levermann, 2012; Bassis and Jacobs, 2013; Ultee and Bassis, 2016). Other recent work has improved ourunderstanding of the processes, drivers, and effects of rifting, often with emphasis on relating the rift path tothe stress field of the ice shelf and the mean rate of rift propagation to spatial heterogeneities in the mechanical properties of the ice (e.g., Hulbe et al., 2005; Khazendar et al., 2009; Larour et al., 2014; Borstad et al.,2017). Despite these efforts, several fundamental questions remain. What drives rift propagation? How fastdo rifts propagate and what controls the rate of propagation? How important is inelastic deformation at therift tip? Here, we propose to address each of these fundamental questions and thereby markedly contributeto our understanding of rift propagation and tabular iceberg formation in ice shelves.More specifically, we propose to test the hypotheses that large-scale rifting is driven by viscous stresseswithin the ice shelf, that rifting processes can be well-represented by linear elastic fracture mechanics, thatthe rate of rift propagation is controlled by the local geometry and mechanical properties of the ice, and thatocean induced loads (e.g., swells and tides) play an important role in rift propagation by combining remotesensing, seismic, and GPS observations with state-of-the-art ice-flow and fracture models. We propose toexploit a unique situation currently developing on Brunt Ice Shelf (BIS) and Stancomb-Wills Glacier Tongue(SWGT), Antarctica, to study the propagation of several active rift systems through remotely sensed and insitu observations and fracture modeling.

板状冰山崩解是南极洲冰块质量损失的重要组成部分，也是冰架上全厚度裂缝--即裂缝--传播的顶峰。理解裂谷的过程和驱动因素，以及如何在大规模冰流模型中最好地表示裂谷，是现代冰川学面临的巨大挑战之一。到目前为止，许多工作都集中在开发参数化的崩解定律，该定律考虑了崩解锋面上或附近的速度、厚度、裂缝深度和/或损伤指标来表示崩解(例如，Nick等人，2010；Duddu和Waisman，2012；Borstad等人，2012；Albrecht和Levermann，2012；Bassis和Jacobs，2013；Ultee和Bassis，2016)。最近的其他工作提高了我们对裂谷的过程、驱动因素和影响的理解，通常侧重于将裂谷路径与冰架的应力场以及裂谷扩展的平均速率与冰层力学性质的空间非均质性联系起来(例如，Hulbe等人，2005；Khazendar等人，2009；Larour等人，2014；Borstad等人，2017)。尽管做出了这些努力，但仍存在几个根本性的问题。是什么驱动了裂缝的传播？裂缝的传播速度有多快？是什么控制了传播的速度？隆起尖端的非弹性变形有多重要？更具体地说，我们建议检验以下假设：大规模裂谷是由冰架内的粘性应力驱动的，裂谷过程可以用线弹性断裂力学很好地描述，裂谷的传播速度由冰层的局部几何和力学特性控制，海洋诱导的载荷(例如，海浪和潮汐)通过结合遥感、地震和GPS观测与最先进的冰流和断裂模型，在裂谷传播中发挥重要作用。我们建议利用目前在南极布伦特冰架(BIS)和斯坦科姆-威尔斯冰川舌(SWGT)上发展起来的独特情况，通过遥感和现场观测以及断裂模拟来研究几个活动裂谷系统的传播。