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

Abstract

[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.

The annual glaciohydrology cycle in the ablation zone of the Greenland ice sheet: Part 1. Hydrology model

“…one horizontal layer (or 'component') representing both the englacial and subglacial systems, it can be viewed as a simplification of more advanced multicomponent models that parameterize the supraglacial, englacial, subglacial and groundwater hydrology components independently (Flowers and Clarke, 2002;Kessler and Anderson, 2004). As a consequence of not explicitly representing the supraglacial hydrologic system and the hydraulic retention time therein (i.e.…”

“…the lumped fractional volumes of surface and basal crevasses, conduits, moulins, etc. ; Flowers and Clarke, 2002). The geometry of these discrete water-storage elements remains unspecified (Kessler and Anderson, 2004).…”

Effects of ice deformation on Röthlisberger channels and implications for transitions in subglacial hydrology

“…Furthermore, observations show that the style of subglacial drainage influences sliding speed (Kamb and others, 1985;Brugman, 1986;Raymond, 1987). There are generally thought to be two modes of drainage in subglacial hydrology: (1) concentrated channels such as Röthlisberger channels (R-channels) incised into the ice (Röthlisberger, 1972;Shreve, 1972;Weertman, 1972) or Nye channels eroded into hard bedrock (Weertman, 1972;Nye, 1973;Walder and Hallet, 1979), that operate at low water pressure relative to the overburden pressure of the overlying ice, (2) distributed water systems, including a network of linked cavities (Lliboutry, 1979;Anderson and others, 1982;Walder, 1986) or canals (Walder and Fowler, 1994;Fowler and Ng, 1996;Ng, 1998) connected by thin sheets of water at high pressure (Flowers and Clarke, 2002a;Creyts and Schoof, 2009;Hewitt, 2011).…”

SHaKTI: Subglacial Hydrology and Kinetic Transient Interactions v1.0

“…Along with more detailed observations, several efforts were made in the early 2000s to accurately simulate subglacial hydrology. Some of these studies treated the subglacial system as a water sheet of uniform thickness (e.g., Flowers and Clarke, 2001;Flowers and Clarke, 2002;Johnson and Fastook, 2002;Creyts and Schoof, 2009;LeBrocq et al, 2009). Arnold and Sharp (2002) presented a model with both distributed and channel flow, but only one configuration could 20 operate at a time.…”