气候变化领域集成服务门户(CCPortal): Antarctic subglacial lakes drain through sediment-floored canals: Theory and model testing on real and idealized domains

CCPortal

DOI	10.5194/tc-11-381-2017
	Antarctic subglacial lakes drain through sediment-floored canals: Theory and model testing on real and idealized domains
	Carter S.P.; Fricker H.A.; Siegfried M.R.
发表日期	2017
ISSN	19940416
卷号	11 期号:1
英文摘要	Over the past decade, satellite observations of ice surface height have revealed that active subglacial lake systems are widespread under the Antarctic Ice Sheet, including the ice streams. For some of these systems, additional observations of ice-stream motion have shown that lake activity can affect ice-stream dynamics. Despite all this new information, we still have insufficient understanding of the lake-drainage process to incorporate it into ice-sheet models. Process models for drainage of ice-dammed lakes based on conventional R-channels incised into the base of the ice through melting are unable to reproduce the timing and magnitude of drainage from Antarctic subglacial lakes estimated from satellite altimetry given the low hydraulic gradients along which such lakes drain. We have developed an alternative process model, in which channels are mechanically eroded into the underlying deformable subglacial sediment. When applied to the known active lakes of the Whillans-Mercer ice-stream system, the model successfully reproduced both the inferred magnitudes and recurrence intervals of lake-volume changes, derived from Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data for the period 2003-2009. Water pressures in our model changed as the flood evolved: during drainage, water pressures initially increased as water flowed out of the lake primarily via a distributed system, then decreased as the channelized system grew, establishing a pressure gradient that drew water away from the distributed system. This evolution of the drainage system can result in the observed internal variability of ice flow over time. If we are correct that active subglacial lakes drain through canals in the sediment, this mechanism also implies that active lakes are typically located in regions underlain by thick subglacial sediment, which may explain why they are not readily observed using radio-echo-sounding techniques. © 2017 Author(s).
学科领域	altimeter; canal; drain; echo sounding; ice flow; ice stream; ICESat; lacustrine environment; model test; numerical model; pressure gradient; satellite altimetry; satellite data; subglacial environment; water flow; Antarctic Ice Sheet; Antarctica; West Antarctic Ice Sheet; West Antarctica; Whillans Ice Stream
语种	英语
scopus关键词	altimeter; canal; drain; echo sounding; ice flow; ice stream; ICESat; lacustrine environment; model test; numerical model; pressure gradient; satellite altimetry; satellite data; subglacial environment; water flow; Antarctic Ice Sheet; Antarctica; West Antarctic Ice Sheet; West Antarctica; Whillans Ice Stream
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/119446
作者单位	Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA, United States
推荐引用方式 GB/T 7714	Carter S.P.,Fricker H.A.,Siegfried M.R.. Antarctic subglacial lakes drain through sediment-floored canals: Theory and model testing on real and idealized domains[J],2017,11(1).
APA	Carter S.P.,Fricker H.A.,&Siegfried M.R..(2017).Antarctic subglacial lakes drain through sediment-floored canals: Theory and model testing on real and idealized domains.Cryosphere,11(1).
MLA	Carter S.P.,et al."Antarctic subglacial lakes drain through sediment-floored canals: Theory and model testing on real and idealized domains".Cryosphere 11.1(2017).