气候变化领域集成服务门户(CCPortal): The cooling signature of basal crevasses in a hard-bedded region of the Greenland Ice Sheet

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DOI	10.5194/tc-15-897-2021
	The cooling signature of basal crevasses in a hard-bedded region of the Greenland Ice Sheet
	McDowell I.E.; Humphrey N.F.; Harper J.T.; Meierbachtol T.W.
发表日期	2021
ISSN	19940416
起始页码	897
结束页码	907
卷号	15 期号:2
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.
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
语种	英语
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/202379
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
推荐引用方式 GB/T 7714	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],2021,15(2).
APA	McDowell I.E.,Humphrey N.F.,Harper J.T.,&Meierbachtol T.W..(2021).The cooling signature of basal crevasses in a hard-bedded region of the Greenland Ice Sheet.Cryosphere,15(2).
MLA	McDowell I.E.,et al."The cooling signature of basal crevasses in a hard-bedded region of the Greenland Ice Sheet".Cryosphere 15.2(2021).