DOI: 10.5194/tc-7-1679-2013
Scopus记录号: 2-s2.0-84887463064
论文题名: Changing basal conditions during the speed-up of Jakobshavn Isbræ, Greenland
作者: Habermann M ; , Truffer M ; , Maxwell D
刊名: Cryosphere
ISSN: 19940416
出版年: 2013
卷: 7, 期: 6 起始页码: 1679
结束页码: 1692
语种: 英语
英文关键词: acceleration
; baseline conditions
; glacier flow
; ice sheet
; parameterization
; shear stress
; stress change
; uncertainty analysis
; Arctic
; Greenland
; Jakobshavn Isbrae
英文摘要: Ice-sheet outlet glaciers can undergo dynamic changes such as the rapid speed-up of Jakobshavn Isbræ following the disintegration of its floating ice tongue. These changes are associated with stress changes on the boundary of the ice mass. We invert for basal conditions from surface velocity data throughout a well-observed period of rapid change and evaluate parameterizations currently used in ice-sheet models. A Tikhonov inverse method with a shallow-shelf approximation forward model is used for diagnostic inversions for the years 1985, 2000, 2005, 2006 and 2008. Our ice-softness, model norm, and regularization parameter choices are justified using the data-model misfit metric and the L curve method. The sensitivity of the inversion results to these parameter choices is explored. We find a lowering of effective basal yield stress in the first 7 km upstream from the 2008 grounding line and no significant changes higher upstream. The temporal evolution in the fast flow area is in broad agreement with a Mohr-Coulomb parameterization of basal shear stress, but with a till friction angle much lower than has been measured for till samples. The lowering of effective basal yield stress is significant within the uncertainties of the inversion, but it cannot be ruled out that there are other significant contributors to the acceleration of the glacier. © 2013 Author(s). CC Attribution 3.0 License. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75012
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775-7320, United States; Department of Mathematics and Statistics, University of Alaska Fairbanks, Fairbanks, AK 99775, United States
Recommended Citation:
Habermann M,, Truffer M,, Maxwell D. Changing basal conditions during the speed-up of Jakobshavn Isbræ, Greenland[J]. Cryosphere,2013-01-01,7(6)