Towards a Hydrological Model for Computerized Ice-Sheet Simulations

Alley, Richard B.

doi:10.1002/(sici)1099-1085(199604)10:4<649::aid-hyp397>3.0.co;2-1

Cited by 45 publications

(46 citation statements)

References 43 publications

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“…Most models of this generation are two-dimensional plan-view models employing a single element type to describe the morphology of the drainage system, e.g. a macroporous medium [61,62], a Weertman-type water film [57,59,63,81] or Röthlisberger channels [60] (table 2). A notable exception is the two-dimensional model of Arnold & Sharp [168] which combines descriptions of cavity-and channel-based drainage on a cell-by-cell basis, becoming the first plan-view model to incorporate multiple drainage elements.…”

Section: Next-generation Glaciological Modelsmentioning

confidence: 99%

“…The possibility of turbulent flow was noted by Alley [59], and included by Johnson & Fastook [63] for film thicknesses d > 10 cm. Instead of (6.2), they write…”

Section: (A) Ice-sheet Hydrologymentioning

confidence: 99%

“…with Manning roughness η, hydraulic radius R H , p = 2 and q = 1 for laminar flow and p = with c = 2 and r = 1 [59] or r = 0.5 − 1 [63]. An empirical approach is taken by LeBrocq et al [81] in correlating modelled film thickness d to an inferred sliding parameter B in u b = Bτ b ; in this case, B is taken to be a hyperbolic tangent function of film thickness.…”

Section: (A) Ice-sheet Hydrologymentioning

confidence: 99%

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Modelling water flow under glaciers and ice sheets

2015

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Recent observations of dynamic water systems beneath the Greenland and Antarctic ice sheets have sparked renewed interest in modelling subglacial drainage. The foundations of today's models were laid decades ago, inspired by measurements from mountain glaciers, discovery of the modern ice streams and the study of landscapes evacuated by former ice sheets. Models have progressed from strict adherence to the principles of groundwater flow, to the incorporation of flow 'elements' specific to the subglacial environment, to sophisticated twodimensional representations of interacting distributed and channelized drainage. Although presently in a state of rapid development, subglacial drainage models, when coupled to models of ice flow, are now able to reproduce many of the canonical phenomena that characterize this coupled system. Model calibration remains generally out of reach, whereas widespread application of these models to large problems and real geometries awaits the next level of development.

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Section: Next-generation Glaciological Modelsmentioning

confidence: 99%

“…The possibility of turbulent flow was noted by Alley [59], and included by Johnson & Fastook [63] for film thicknesses d > 10 cm. Instead of (6.2), they write…”

Section: (A) Ice-sheet Hydrologymentioning

confidence: 99%

Section: (A) Ice-sheet Hydrologymentioning

confidence: 99%

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Modelling water flow under glaciers and ice sheets

2015

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“…Alley [1996], Budd and Jenssen [1987], and Arnold et al [1998] have pioneered one-and two-dimensional models and two-dimensional multicomponent models of glacier hydrology, respectively. The recent model of Arnold et al [1998] consists of three independent submodels to handle surface ablation, meltwater routing, and englacial/subglacial conduit flow.…”

Section: Introductionmentioning

confidence: 99%

A multicomponent coupled model of glacier hydrology 1. Theory and synthetic examples

2002

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[1] Basal hydrology is acknowledged as a fundamental control on glacier dynamics, especially in cases where surface meltwater reaches the bed. For many glaciers at midlatitudes, basal drainage is influenced by subaerial, englacial, and subsurface water flow. One of the major shortcomings of existing basal hydrology models is the treatment of the glacier bed as an isolated system. We present theoretical and computational models that couple glacier surface runoff, englacial water storage and transport, subglacial drainage, and subsurface groundwater flow. Each of the four model components is represented as a two-dimensional, vertically integrated layer that communicates with its neighbors through water exchange. Governing equations are derived from the law of mass conservation and are expressed as a balance between the internal distribution of water and external sources. The numerical exposition of this theory is a time-dependent finite difference model that can be used to simulate glacier drainage. In this paper we outline the theory and conduct simple tests using an idealized glacier geometry. In the companion paper, the model is tailored to Trapridge Glacier, Yukon Territory, Canada, where results are compared with measurements of subglacial water pressure.

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“…Assuming a distributed water flow system this expression can be simplified while stating that the effective pressure at the ice base (ice overburden pressure p i minus water pressure p w at the ice base) is close to zero (e.g., Budd and Jenssen, 1987;Alley, 1996). Under the approximation p w = p i the hydraulic potential can be written as…”

Section: General Formulationmentioning

confidence: 99%

A balanced water layer concept for subglacial hydrology in large-scale ice sheet models

et al. 2013

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Abstract. There is currently no doubt about the existence of a widespread hydrological network under the Antarctic Ice Sheet, which lubricates the ice base and thus leads to increased ice velocities. Consequently, ice models should incorporate basal hydrology to obtain meaningful results for future ice dynamics and their contribution to global sea level rise. Here, we introduce the balanced water layer concept, covering two prominent subglacial hydrological features for ice sheet modeling on a continental scale: the evolution of subglacial lakes and balance water fluxes. We couple it to the thermomechanical ice-flow model RIMBAY and apply it to a synthetic model domain. In our experiments we demonstrate the dynamic generation of subglacial lakes and their impact on the velocity field of the overlaying ice sheet, resulting in a negative ice mass balance. Furthermore, we introduce an elementary parametrization of the water flux-basal sliding coupling and reveal the predominance of the ice loss through the resulting ice streams against the stabilizing influence of less hydrologically active areas. We point out that established balance flux schemes quantify these effects only partially as their ability to store subglacial water is lacking.

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Towards a Hydrological Model for Computerized Ice-Sheet Simulations

Cited by 45 publications

References 43 publications

Modelling water flow under glaciers and ice sheets

Modelling water flow under glaciers and ice sheets

A multicomponent coupled model of glacier hydrology 1. Theory and synthetic examples

A balanced water layer concept for subglacial hydrology in large-scale ice sheet models

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