DOI: 10.5194/tc-11-381-2017
Scopus记录号: 2-s2.0-85011596040
论文题名: Antarctic subglacial lakes drain through sediment-floored canals: Theory and model testing on real and idealized domains
作者: Carter S ; P ; , Fricker H ; A ; , Siegfried M ; R
刊名: Cryosphere
ISSN: 19940416
出版年: 2017
卷: 11, 期: 1 起始页码: 381
结束页码: 405
语种: 英语
英文关键词: 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
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). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75604
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA, United States
Recommended Citation:
Carter S,P,, Fricker H,et al. Antarctic subglacial lakes drain through sediment-floored canals: Theory and model testing on real and idealized domains[J]. Cryosphere,2017-01-01,11(1)