气候变化领域集成服务门户(CCPortal): Creep deformation and buttressing capacity of damaged ice shelves: Theory and application to Larsen C ice shelf

CCPortal

DOI	10.5194/tc-7-1931-2013
	Creep deformation and buttressing capacity of damaged ice shelves: Theory and application to Larsen C ice shelf
	Borstad C.P.; Rignot E.; Mouginot J.; Schodlok M.P.
发表日期	2013
ISSN	19940416
卷号	7 期号:6
英文摘要	Around the perimeter of Antarctica, much of the ice sheet discharges to the ocean through floating ice shelves. The buttressing provided by ice shelves is critical for modulating the flux of ice into the ocean, and the presently observed thinning of ice shelves is believed to be reducing their buttressing capacity and contributing to the acceleration and thinning of the grounded ice sheet. However, relatively little attention has been paid to the role that fractures play in the ability of ice shelves to sustain and transmit buttressing stresses. Here, we present a new framework for quantifying the role that fractures play in the creep deformation and buttressing capacity of ice shelves. We apply principles of continuum damage mechanics to derive a new analytical relation for the creep of an ice shelf that accounts for the softening influence of fractures on longitudinal deformation using a state damage variable. We use this new analytical relation, combined with a temperature calculation for the ice, to partition an inverse method solution for ice shelf rigidity into independent solutions for softening damage and stabilizing backstress. Using this new approach, field and remote sensing data can be utilized to monitor the structural integrity of ice shelves, their ability to buttress the flow of ice at the grounding line, and thus their indirect contribution to ice sheet mass balance and global sea level. We apply this technique to the Larsen C ice shelf using remote sensing and Operation IceBridge data, finding damage in areas with known crevasses and rifts. Backstress is highest near the grounding line and upstream of ice rises, in agreement with patterns observed on other ice shelves. The ice in contact with the Bawden ice rise is weakened by fractures, and additional damage or thinning in this area could diminish the backstress transmitted upstream. We model the consequences for the ice shelf if it loses contact with this small ice rise, finding that flow speeds would increase by 25% or more over an area the size of the former Larsen B ice shelf. Such a perturbation could potentially destabilize the northern part of Larsen C along pre-existing lines of weakness, highlighting the importance of the feedback between buttressing and fracturing in an ice shelf. © Author(s) 2013.
学科领域	acceleration; deformation mechanism; ice sheet; ice shelf; mass balance; monitoring; numerical model; sea level; stabilization; Antarctica
语种	英语
scopus关键词	acceleration; deformation mechanism; ice sheet; ice shelf; mass balance; monitoring; numerical model; sea level; stabilization; Antarctica
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/120222
作者单位	Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States; Department of Earth System Science, University of California Irvine, Irvine, CA, United States; Joint Institute for Regional Earth System Science and Engineering, University of California Los Angeles, Los Angeles, CA, United States
推荐引用方式 GB/T 7714	Borstad C.P.,Rignot E.,Mouginot J.,et al. Creep deformation and buttressing capacity of damaged ice shelves: Theory and application to Larsen C ice shelf[J],2013,7(6).
APA	Borstad C.P.,Rignot E.,Mouginot J.,&Schodlok M.P..(2013).Creep deformation and buttressing capacity of damaged ice shelves: Theory and application to Larsen C ice shelf.Cryosphere,7(6).
MLA	Borstad C.P.,et al."Creep deformation and buttressing capacity of damaged ice shelves: Theory and application to Larsen C ice shelf".Cryosphere 7.6(2013).