气候变化领域集成服务门户(CCPortal): Implementing an empirical scalar constitutive relation for ice with flow-induced polycrystalline anisotropy in large-scale ice sheet models

CCPortal

DOI	10.5194/tc-12-1047-2018
	Implementing an empirical scalar constitutive relation for ice with flow-induced polycrystalline anisotropy in large-scale ice sheet models
	Graham F.S.; Morlighem M.; Warner R.C.; Treverrow A.
发表日期	2018
ISSN	19940416
卷号	12 期号:3
英文摘要	The microstructure of polycrystalline ice evolves under prolonged deformation, leading to anisotropic patterns of crystal orientations. The response of this material to applied stresses is not adequately described by the ice flow relation most commonly used in large-scale ice sheet models-the Glen flow relation. We present a preliminary assessment of the implementation in the Ice Sheet System Model (ISSM) of a computationally efficient, empirical, scalar, constitutive relation which addresses the influence of the dynamically steady-state flow-compatible induced anisotropic crystal orientation patterns that develop when ice is subjected to the same stress regime for a prolonged period-sometimes termed tertiary flow. We call this the ESTAR flow relation. The effect on ice flow dynamics is investigated by comparing idealised simulations using ESTAR and Glen flow relations, where we include in the latter an overall flow enhancement factor. For an idealised embayed ice shelf, the Glen flow relation overestimates velocities by up to 17ĝ€% when using an enhancement factor equivalent to the maximum value prescribed in the ESTAR relation. Importantly, no single Glen enhancement factor can accurately capture the spatial variations in flow across the ice shelf generated by the ESTAR flow relation. For flow line studies of idealised grounded flow over varying topography or variable basal friction-both scenarios dominated at depth by bed-parallel shear-the differences between simulated velocities using ESTAR and Glen flow relations depend on the value of the enhancement factor used to calibrate the Glen flow relation. These results demonstrate the importance of describing the deformation of anisotropic ice in a physically realistic manner, and have implications for simulations of ice sheet evolution used to reconstruct paleo-ice sheet extent and predict future ice sheet contributions to sea level. © 2018 Author(s).
学科领域	anisotropy; constitutive equation; crystal structure; deformation; empirical analysis; flow measurement; ice flow; ice sheet; microstructure; orientation; spatial variation
语种	英语
scopus关键词	anisotropy; constitutive equation; crystal structure; deformation; empirical analysis; flow measurement; ice flow; ice sheet; microstructure; orientation; spatial variation
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/119193
作者单位	Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, TAS 7001, Australia; Department of Earth System Science, University of California, Irvine, CA, United States; Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, TAS 7001, Australia
推荐引用方式 GB/T 7714	Graham F.S.,Morlighem M.,Warner R.C.,et al. Implementing an empirical scalar constitutive relation for ice with flow-induced polycrystalline anisotropy in large-scale ice sheet models[J],2018,12(3).
APA	Graham F.S.,Morlighem M.,Warner R.C.,&Treverrow A..(2018).Implementing an empirical scalar constitutive relation for ice with flow-induced polycrystalline anisotropy in large-scale ice sheet models.Cryosphere,12(3).
MLA	Graham F.S.,et al."Implementing an empirical scalar constitutive relation for ice with flow-induced polycrystalline anisotropy in large-scale ice sheet models".Cryosphere 12.3(2018).