Incorporating modelled subglacial hydrology into inversions for basal drag

A key challenge in modelling coupled ice-flow–subglacial hydrology is initializing the state and parameters of the system. We address this problem by presenting a workflow for initializing these values at the start of a summer melt season. The workflow depends on running a subglacial hydrology model...

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Bibliographic Details
Published in:The cryosphere 2017-12, Vol.11 (6), p.2783-2797
Main Authors: Koziol, Conrad P, Arnold, Neil
Format: Article
Language:English
Subjects:
Analysis
Boundary conditions
Control theory
Drag
Drag (Fluid dynamics)
Glaciers
Hydrologic models
Hydrology
Hydrostatic pressure
Inversions
Iterative methods
Laws, regulations and rules
Legislation
Mathematical models
Meltwater
Modelling
Parameters
Radar
Seasons
Sliding
Slumping
Summer
Velocity
Viscosity
Water pressure
Winter
Workflow
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Summary:A key challenge in modelling coupled ice-flow–subglacial hydrology is initializing the state and parameters of the system. We address this problem by presenting a workflow for initializing these values at the start of a summer melt season. The workflow depends on running a subglacial hydrology model for the winter season, when the system is not forced by meltwater inputs, and ice velocities can be assumed constant. Key parameters of the winter run of the subglacial hydrology model are determined from an initial inversion for basal drag using a linear sliding law. The state of the subglacial hydrology model at the end of winter is incorporated into an inversion of basal drag using a non-linear sliding law which is a function of water pressure. We demonstrate this procedure in the Russell Glacier area and compare the output of the linear sliding law with two non-linear sliding laws. Additionally, we compare the modelled winter hydrological state to radar observations and find that it is in line with summer rather than winter observations.
ISSN:1994-0424
1994-0416
1994-0424
1994-0416
DOI:10.5194/tc-11-2783-2017