气候变化领域集成服务门户(CCPortal): Marine ice sheet model performance depends on basal sliding physics and sub-shelf melting

CCPortal

DOI	10.5194/tc-11-319-2017
	Marine ice sheet model performance depends on basal sliding physics and sub-shelf melting
	Michael Gladstone R.; Charles Warner R.; Keith Galton-Fenzi B.; Gagliardini O.; Zwinger T.; Greve R.
发表日期	2017
ISSN	19940416
卷号	11 期号:1
英文摘要	Computer models are necessary for understanding and predicting marine ice sheet behaviour. However, there is uncertainty over implementation of physical processes at the ice base, both for grounded and floating glacial ice. Here we implement several sliding relations in a marine ice sheet flow-line model accounting for all stress components and demonstrate that model resolution requirements are strongly dependent on both the choice of basal sliding relation and the spatial distribution of ice shelf basal melting. Sliding relations that reduce the magnitude of the step change in basal drag from grounded ice to floating ice (where basal drag is set to zero) show reduced dependence on resolution compared to a commonly used relation, in which basal drag is purely a power law function of basal ice velocity. Sliding relations in which basal drag goes smoothly to zero as the grounding line is approached from inland (due to a physically motivated incorporation of effective pressure at the bed) provide further reduction in resolution dependence. A similar issue is found with the imposition of basal melt under the floating part of the ice shelf: melt parameterisations that reduce the abruptness of change in basal melting from grounded ice (where basal melt is set to zero) to floating ice provide improved convergence with resolution compared to parameterisations in which high melt occurs adjacent to the grounding line. Thus physical processes, such as sub-glacial outflow (which could cause high melt near the grounding line), impact on capability to simulate marine ice sheets. If there exists an abrupt change across the grounding line in either basal drag or basal melting, then high resolution will be required to solve the problem. However, the plausible combination of a physical dependency of basal drag on effective pressure, and the possibility of low ice shelf basal melt rates next to the grounding line, may mean that some marine ice sheet systems can be reliably simulated at a coarser resolution than currently thought necessary. © Author(s) 2017.
学科领域	basal ice; basal melting; computer simulation; floating ice; glaciology; grounding line; ice sheet; ice shelf; outflow; power law; sea ice; sliding; spatial distribution
语种	英语
scopus关键词	basal ice; basal melting; computer simulation; floating ice; glaciology; grounding line; ice sheet; ice shelf; outflow; power law; sea ice; sliding; spatial distribution
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/119450
作者单位	VAW, Eidgenössische Technische Hochschule Zürich, ETHZ, Zürich, Switzerland; Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Australia; Arctic Centre, University of Lapland, Rovaniemi, Finland; Australian Antarctic Division, Kingston, TAS, Australia; Univ. Grenoble Alpes, CNRS, IRD, IGE, Grenoble, 38000, France; CSC-IT Center for Science Ltd., Espoo, Finland; Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
推荐引用方式 GB/T 7714	Michael Gladstone R.,Charles Warner R.,Keith Galton-Fenzi B.,et al. Marine ice sheet model performance depends on basal sliding physics and sub-shelf melting[J],2017,11(1).
APA	Michael Gladstone R.,Charles Warner R.,Keith Galton-Fenzi B.,Gagliardini O.,Zwinger T.,&Greve R..(2017).Marine ice sheet model performance depends on basal sliding physics and sub-shelf melting.Cryosphere,11(1).
MLA	Michael Gladstone R.,et al."Marine ice sheet model performance depends on basal sliding physics and sub-shelf melting".Cryosphere 11.1(2017).