气候变化领域集成服务门户(CCPortal): From cyclic ice streaming to Heinrich-like events: The grow-And-surge instability in the Parallel Ice Sheet Model

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DOI	10.5194/tc-11-1913-2017
	From cyclic ice streaming to Heinrich-like events: The grow-And-surge instability in the Parallel Ice Sheet Model
	Feldmann J.; Levermann A.
发表日期	2017
ISSN	19940416
卷号	11 期号:4
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.
语种	英语
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/119356
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
推荐引用方式 GB/T 7714	Feldmann J.,Levermann A.. From cyclic ice streaming to Heinrich-like events: The grow-And-surge instability in the Parallel Ice Sheet Model[J],2017,11(4).
APA	Feldmann J.,&Levermann A..(2017).From cyclic ice streaming to Heinrich-like events: The grow-And-surge instability in the Parallel Ice Sheet Model.Cryosphere,11(4).
MLA	Feldmann J.,et al."From cyclic ice streaming to Heinrich-like events: The grow-And-surge instability in the Parallel Ice Sheet Model".Cryosphere 11.4(2017).