DOI: 10.5194/tc-11-1913-2017
Scopus记录号: 2-s2.0-85027495452
论文题名: From cyclic ice streaming to Heinrich-like events: The grow-And-surge instability in the Parallel Ice Sheet Model
作者: Feldmann J ; , Levermann A
刊名: Cryosphere
ISSN: 19940416
出版年: 2017
卷: 11, 期: 4 起始页码: 1913
结束页码: 1932
语种: 英语
英文摘要: >Here we report on a cyclic, physical ice-discharge instability in the Parallel Ice Sheet Model, simulating the flow of a three-dimensional, inherently buttressed ice-sheet-shelf system which periodically surges on a millennial timescale. The thermomechanically coupled model on 1 km horizontal resolution includes an enthalpy-based formulation of the thermodynamics, a nonlinear stress-balance-based sliding law and a very simple subglacial hydrology. The simulated unforced surging is characterized by rapid ice streaming through a bed trough, resulting in abrupt discharge of ice across the grounding line which is eventually calved into the ocean. We visualize the central feedbacks that dominate the subsequent phases of ice buildup, surge and stabilization which emerge from the interaction between ice dynamics, thermodynamics and the subglacial till layer. Results from the variation of surface mass balance and basal roughness suggest that ice sheets of medium thickness may be more susceptible to surging than relatively thin or thick ones for which the surge feedback loop is damped. We also investigate the influence of different basal sliding laws (ranging from purely plastic to nonlinear to linear) on possible surging. The presented mechanisms underlying our simulations of self-maintained, periodic ice growth and destabilization may play a role in large-scale ice-sheet surging, such as the surging of the Laurentide Ice Sheet, which is associated with Heinrich events, and ice-stream shutdown and reactivation, such as observed in the Siple Coast region of West Antarctica. © Author(s) 2017. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75514
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: Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany; Institute of Physics, University of Potsdam, Potsdam, Germany; LDEO, Columbia University, New York, United States
Recommended Citation:
Feldmann J,, Levermann A. From cyclic ice streaming to Heinrich-like events: The grow-And-surge instability in the Parallel Ice Sheet Model[J]. Cryosphere,2017-01-01,11(4)