DOI: 10.5194/tc-15-897-2021
论文题名: The cooling signature of basal crevasses in a hard-bedded region of the Greenland Ice Sheet
作者: McDowell I.E. ; Humphrey N.F. ; Harper J.T. ; Meierbachtol T.W.
刊名: Cryosphere
ISSN: 19940416
出版年: 2021
卷: 15, 期: 2 起始页码: 897
结束页码: 907
语种: 英语
英文关键词: ablation
; basal ice
; borehole
; cooling
; discrete element method
; freezing
; heat source
; installation
; sensor
; thermal conductivity
; Arctic
; Greenland
; Greenland Ice Sheet
英文摘要: Temperature sensors installed in a grid of nine full-depth boreholes drilled in the southwestern ablation zone of the Greenland Ice Sheet recorded cooling in discrete sections of ice over time within the lowest third of the ice column in most boreholes. Rates of temperature change outpace cooling expected from vertical conduction alone. Additionally, observed temperature profiles deviate significantly from the site-Average thermal profile that is shaped by all thermomechanical processes upstream. These deviations imply recent, localized changes to the basal thermal state in the boreholes. Although numerous heat sources exist to add energy and warm ice as it moves from the central divide towards the margin such as strain heat from internal deformation, latent heat from refreezing meltwater, and the conduction of geothermal heat across the ice-bedrock interface, identifying heat sinks proves more difficult. After eliminating possible mechanisms that could cause cooling, we find that the observed cooling is a manifestation of previous warming in near-basal ice. Thermal decay after latent heat is released from freezing water in basal crevasses is the most likely mechanism resulting in the transient evolution of temperature and the vertical thermal structure observed at our site. We argue basal crevasses are a viable englacial heat source in the basal ice of Greenland's ablation zone and may have a controlling influence on the temperature structure of the near-basal ice. © 2021 Copernicus GmbH. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164757
Appears in Collections: 气候变化与战略
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作者单位: Department of Geology and Geophysics, University of Wyoming, Laramie, WY 82071, United States; Department of Geosciences, University of Montana, Missoula, MT 59812, United States; Graduate Program of Hydrologic Sciences, University of Nevada, Reno, NV 89557, United States
Recommended Citation:
McDowell I.E.,Humphrey N.F.,Harper J.T.,et al. The cooling signature of basal crevasses in a hard-bedded region of the Greenland Ice Sheet[J]. Cryosphere,2021-01-01,15(2)