DOI: 10.1002/2017JF004529
Scopus记录号: 2-s2.0-85042407431
论文题名: Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland
作者: Doyle S.H. ; Hubbard B. ; Christoffersen P. ; Young T.J. ; Hofstede C. ; Bougamont M. ; Box J.E. ; Hubbard A.
刊名: Journal of Geophysical Research: Earth Surface
ISSN: 21699003
出版年: 2018
卷: 123, 期: 2 起始页码: 324
结束页码: 348
语种: 英语
英文关键词: borehole
; dynamics
; Greenland
; hydrology
; ice sheet
; sediment
Scopus关键词: borehole
; deformation
; electrical conductivity
; englacial process
; glacial deposit
; glacial hydrology
; glacier dynamics
; glacier flow
; ice sheet
; turbidity
; water temperature
; Arctic
; Greenland
; Store Glacier
英文摘要: Marine-terminating outlet glaciers of the Greenland Ice Sheet make significant contributions to global sea level rise, yet the conditions that facilitate their fast flow remain poorly constrained owing to a paucity of data. We drilled and instrumented seven boreholes on Store Glacier, Greenland, to monitor subglacial water pressure, temperature, electrical conductivity, and turbidity along with englacial ice temperature and deformation. These observations were supplemented by surface velocity and meteorological measurements to gain insight into the conditions and mechanisms of fast glacier flow. Located 30 km from the calving front, each borehole drained rapidly on attaining ∼600 m depth indicating a direct connection with an active subglacial hydrological system. Persistently high subglacial water pressures indicate low effective pressure (180–280 kPa), with small-amplitude variations correlated with notable peaks in surface velocity driven by the diurnal melt cycle and longer periods of melt and rainfall. The englacial deformation profile determined from borehole tilt measurements indicates that 63–71% of total ice motion occurred at the bed, with the remaining 29–37% predominantly attributed to enhanced deformation in the lowermost 50–100 m of the ice column. We interpret this lowermost 100 m to be formed of warmer, pre-Holocene ice overlying a thin (0–8 m) layer of temperate basal ice. Our observations are consistent with a spatially extensive and persistently inefficient subglacial drainage system that we hypothesize comprises drainage both at the ice-sediment interface and through subglacial sediments. This configuration has similarities to that interpreted beneath dynamically analogous Antarctic ice streams, Alaskan tidewater glaciers, and glaciers in surge. ©2018. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114546
Appears in Collections: 气候减缓与适应
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作者单位: Centre for Glaciology, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, United Kingdom; Scott Polar Research Institute, Cambridge University, Cambridge, United Kingdom; British Antarctic Survey, National Environmental Research Council, Cambridge, United Kingdom; Helmholtz Centre for Polar and Marine Research, Alfred Wegener Institute, Bremerhaven, Germany; Glaciology and Climate, Geological Survey of Denmark and Greenland, Copenhagen, Denmark; Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, Arctic University of Norway, Tromsø, Norway
Recommended Citation:
Doyle S.H.,Hubbard B.,Christoffersen P.,et al. Physical Conditions of Fast Glacier Flow: 1. Measurements From Boreholes Drilled to the Bed of Store Glacier, West Greenland[J]. Journal of Geophysical Research: Earth Surface,2018-01-01,123(2)