DOI: 10.1038/ngeo2179
论文题名: Deformation, warming and softening of Greenland's ice by refreezing meltwater
作者: Bell R.E. ; Tinto K. ; Das I. ; Wolovick M. ; Chu W. ; Creyts T.T. ; Frearson N. ; Abdi A. ; Paden J.D.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2014
卷: 7, 期: 7 起始页码: 497
结束页码: 502
语种: 英语
Scopus关键词: data set
; deformation
; gravity anomaly
; gravity field
; grounding line
; ice flow
; ice sheet
; ice thickness
; melting
; meltwater
; radar
; temperature profile
; warming
; Arctic
; Greenland
; Greenland Ice Sheet
; Petermann Glacier
英文摘要: Meltwater beneath the large ice sheets can influence ice flow by lubrication at the base or by softening when meltwater refreezes to form relatively warm ice. Refreezing has produced large basal ice units in East Antarctica. Bubble-free basal ice units also outcrop at the edge of the Greenland ice sheet, but the extent of refreezing and its influence on Greenland's ice flow dynamics are unknown. Here we demonstrate that refreezing of meltwater produces distinct basal ice units throughout northern Greenland with thicknesses of up to 1,100 m. We compare airborne gravity data with modelled gravity anomalies to show that these basal units are ice. Using radar data we determine the extent of the units, which significantly disrupt the overlying ice sheet stratigraphy. The units consist of refrozen basal water commonly surrounded by heavily deformed meteoric ice derived from snowfall. We map these units along the ice sheet margins where surface melt is the largest source of water, as well as in the interior where basal melting is the only source of water. Beneath Petermann Glacier, basal units coincide with the onset of fast flow and channels in the floating ice tongue. We suggest that refreezing of meltwater and the resulting deformation of the surrounding basal ice warms the Greenland ice sheet, modifying the temperature structure of the ice column and influencing ice flow and grounding line melting. © 2014 Macmillan Publishers Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106498
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States; Center for the Remote Sensing of Ice Sheets, Kansas University, Lawrence, KS 66045, United States; Department of Physical Geography and Ecosystem Science, Lund University, 210 00, Sweden
Recommended Citation:
Bell R.E.,Tinto K.,Das I.,et al. Deformation, warming and softening of Greenland's ice by refreezing meltwater[J]. Nature Geoscience,2014-01-01,7(7)