| DOI: | 10.5194/tc-15-1587-2021
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| 论文题名: | Winter drainage of surface lakes on the Greenland Ice Sheet from Sentinel-1 SAR imagery |
| 作者: | Benedek C.L.; Willis I.C.
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| 刊名: | Cryosphere
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| ISSN: | 19940416
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| 出版年: | 2021
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| 卷: | 15, 期:3 | | 起始页码: | 1587
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| 结束页码: | 1606
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| 语种: | 英语
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| 英文关键词: | backscatter
; digital elevation model
; ice sheet
; lacustrine deposit
; lacustrine environment
; lake water
; radar
; satellite imagery
; seasonal variation
; Sentinel
; winter
; Arctic
; Greenland
; Greenland Ice Sheet
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| 英文摘要: | Surface lakes on the Greenland Ice Sheet play a key role in its surface mass balance, hydrology and biogeochemistry. They often drain rapidly in the summer via hydrofracture, which delivers lake water to the ice sheet base over timescales of hours to days and then can allow meltwater to reach the base for the rest of the summer. Rapid lake drainage, therefore, influences subglacial drainage evolution; water pressures; ice flow; biogeochemical activity; and ultimately the delivery of water, sediments and nutrients to the ocean. It has generally been assumed that rapid lake drainage events are confined to the summer, as this is typically when observations are made using satellite optical imagery. Here we develop a method to quantify backscatter changes in satellite radar imagery, which we use to document the drainage of six different lakes during three winters (2014/15, 2015/16 and 2016/17) in fast-flowing parts of the Greenland Ice Sheet. Analysis of optical imagery from before and after the three winters supports the radar-based evidence for winter lake drainage events and also provides estimates of lake drainage volumes, which range between 0.000046 ± 0.000017 and 0.0200 ± 0.002817 km3. For three of the events, optical imagery allows repeat photoclinometry (shape from shading) calculations to be made showing mean vertical collapse of the lake surfaces ranging between 1.21 ± 1.61 and 7.25 ± 1.61 m and drainage volumes of 0.002 ± 0.002968 to 0.044 ± 0.009858 km3. For one of these three, time-stamped ArcticDEM strips allow for DEM differencing, which demonstrates a mean collapse depth of 2.17 ± 0.28 m across the lake area. The findings show that lake drainage can occur in the winter in the absence of active surface melt and notable ice flow acceleration, which may have important implications for subglacial hydrology and biogeochemical processes. © Author(s) 2021. |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/164655
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| Appears in Collections: | 气候变化与战略
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作者单位: | Scott Polar Research Institute, University of Cambridge, Cambridge, CB2 1ER, United Kingdom
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| Recommended Citation: | |
Benedek C.L.,Willis I.C.. Winter drainage of surface lakes on the Greenland Ice Sheet from Sentinel-1 SAR imagery[J]. Cryosphere,2021-01-01,15(3)
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