Modelling channelized surface drainage of supraglacial lakes ...

• Main Authors: Kingslake, Jonathan, Ng, F., Sole, A.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Columbia University 2015
• Subjects: Ice sheets > Remote sensing; Ice > Dynamics; Glacial lakes; Geophysics; FOS: Earth and related environmental sciences; Hydrology; East Antarctica; Nivlisen; Antarc*; Antarctica; Ice Sheet; Ice Shelf
• Online Access: https://dx.doi.org/10.7916/d8kk9bpp; https://academiccommons.columbia.edu/doi/10.7916/D8KK9BPP

Supraglacial lakes can drain to the bed of ice sheets, affecting ice dynamics, or over their surface, relocating surface water. Focusing on surface drainage, we first discuss observations of lake drainage. In particular, for the first time, lakes are observed to drain <70 km across the Nivlisen ice shelf, East Antarctica. Inspired by these observations, we develop a model of lake drainage through a channel that incises into an ice-sheet surface by frictional heat dissipated in the flow. Modelled lake drainage can be stable or unstable. During stable drainage, the rate of lake-level drawdown exceeds the rate of channel incision, so discharge from the lake decreases with time; this can prevent the lake from emptying completely. During unstable drainage, discharge grows unstably with time and always empties the lake. Model lakes are more prone to drain unstably when the initial lake area, the lake input and the channel slope are larger. These parameters will vary during atmospheric-warming-induced ...