Spatially distributed runoff at the grounding line of a large Greenlandic tidewater glacier inferred from plume modelling



Slater, D, Nienow, PW, Sole, A, Cowton, T, Mottram, R, Langen, P and Mair, D ORCID: 0000-0001-7009-5461
(2017) Spatially distributed runoff at the grounding line of a large Greenlandic tidewater glacier inferred from plume modelling. Journal of Glaciology, 63 (238). pp. 309-323.

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Abstract

Understanding the drivers of recent change at Greenlandic tidewater glaciers is of great importance if we are to predict how these glaciers will respond to climatic warming. A poorly constrained component of tidewater glacier processes is the near-terminus subglacial hydrology. Here we present a novel method for constraining near-terminus subglacial hydrology with application to marine-terminating Kangiata Nunata Sermia in South-west Greenland. By simulating proglacial plume dynamics using buoyant plume theory and a general circulation model, we assess the critical subglacial discharge, if delivered through a single compact channel, required to generate a plume that reaches the fjord surface. We then compare catchment runoff to a time series of plume visibility acquired from a time-lapse camera. We identify extended periods throughout the 2009 melt season where catchment runoff significantly exceeds the discharge required for a plume to reach the fjord surface, yet we observe no plume. We attribute these observations to spatial spreading of runoff across the grounding line. Persistent distributed drainage near the terminus would lead to more spatially homogeneous submarine melting and may promote more rapid basal sliding during warmer summers, potentially providing a mechanism independent of ocean forcing for increases in atmospheric temperature to drive tidewater glacier acceleration.

Item Type: Article
Uncontrolled Keywords: glacier hydrology, ice/ocean interactions, subglacial processes
Depositing User: Symplectic Admin
Date Deposited: 02 Mar 2017 13:16
Last Modified: 19 Jan 2023 07:14
DOI: 10.1017/jog.2016.139
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3006155

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