Modelling water flow under glaciers and ice sheets

Abstract

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.

Recent Advances in Our Understanding of the Role of Meltwater in the Greenland Ice Sheet System

“…Numerical modelling using two-dimensional multi-element drainage systems largely support the evidence for the development of efficient subglacial drainage [11]. These models, driven by seasonally varying supraglacial meltwater inputs, demonstrate a seasonal evolution in subglacial hydrology from distributed to channelised drainage [70][71][72] which build on the earlier theoretical work of Kamb [61].…”

“…The realisation of this direct hydro-dynamic ice sheet coupling, and the potential implications for a mechanism by which the ice sheet might respond rapidly to climate warming, has seen a proliferation of research into the hydrology of the GrIS. This activity is reflected in recent detailed review papers which consider GrIS hydrology [1,10] and the modelling of water flow under ice sheets [11]. These papers (each with > 220 references) cover the topic thoroughly, so this paper does not aim to replicate these reviews.…”

A confined–unconfined aquifer model for subglacial hydrology and its application to the North East Greenland Ice Stream

“…While these models produce remarkable results for spontaneously evolving channel networks, it is still a challenge to apply them on continental scale. A comprehensive overview of the various existing and newly emerging glaciological hydrology models is given in Flowers (2015).…”

Determining Ice-Sheet Uplift Surrounding Subglacial Lakes with a Viscous Plate Model

“…Hydrological models that allow the sheet thickness to evolve (e.g., Werder et al, 2013) contain an opening rate o due to ice sliding over obstacles and a closing rate c due to viscous creep, and the flexural uplift rate ∂ t w should behave similarly. We can add this rate to the water sheet continuity equation (e.g., Flowers, 2015) to obtain:…”