DOI: 10.5194/tc-9-1649-2015
Scopus记录号: 2-s2.0-84939833352
论文题名: Temporal variations in the flow of a large Antarctic ice stream controlled by tidally induced changes in the subglacial water system
作者: Rosier S ; H ; R ; , Gudmundsson G ; H ; , Green J ; A ; M
刊名: Cryosphere
ISSN: 19940416
出版年: 2015
卷: 9, 期: 4 起始页码: 1649
结束页码: 1661
语种: 英语
英文关键词: amplitude
; data set
; glacial hydrology
; hydrological modeling
; low pressure
; nonlinearity
; numerical model
; pressure effect
; temporal variation
; three-dimensional modeling
; tidal cycle
; Antarctica
英文摘要: Observations show that the flow of Rutford Ice Stream (RIS) is strongly modulated by the ocean tides, with the strongest tidal response at the 14.77-day tidal period (Msf). This is striking because this period is absent in the tidal forcing. A number of mechanisms have been proposed to account for this effect, yet previous modelling studies have struggled to match the observed large amplitude and decay length scale. We use a nonlinear 3-D viscoelastic full-Stokes model of ice-stream flow to investigate this open issue. We find that the long period Msf modulation of ice-stream velocity observed in data cannot be reproduced quantitatively without including a coupling between basal sliding and tidally induced subglacial water pressure variations, transmitted through a highly conductive drainage system at low effective pressure. Furthermore, the basal sliding law requires a water pressure exponent that is strongly nonlinear with q Combining double low line 10 and a nonlinear basal shear exponent of m Combining double low line 3. Coupled model results show that sub-ice shelf tides result in a ∼12 % increase in mean horizontal velocity of the adjoining ice stream. Observations of tidally induced variations in flow of ice streams provide stronger constraints on basal sliding processes than provided by any other set of measurements. © Author(s) 2015. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75257
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: School of Ocean Sciences, Bangor University, Menai Bridge, United Kingdom; British Antarctic Survey, High Cross, Madingley Rd., Cambridge, United Kingdom
Recommended Citation:
Rosier S,H,R,et al. Temporal variations in the flow of a large Antarctic ice stream controlled by tidally induced changes in the subglacial water system[J]. Cryosphere,2015-01-01,9(4)