Modelling intra-annual dynamics of a major marine-terminating Arctic glacier

• Published in: Annals of Glaciology
• Main Authors: Pimentel, Sam, Flowers, Gwenn E., Sharp, Martin J., Danielson, Bradley, Copland, Luke, Van Wychen, Wesley, Duncan, Angus, Kavanaugh, Jeffrey L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2017
• Subjects: Arctic; Devon Island; Belcher; Belcher Glacier; Annals of Glaciology; Ice cap; Sea ice; Tidewater
• Online Access: http://dx.doi.org/10.1017/aog.2017.23; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305517000234

ABSTRACT Significant intra-annual variability in flow rates of tidewater-terminating Arctic glaciers has been observed in recent years. These changes may result from oceanic and/or atmospheric forcing through (1) perturbations at the terminus, such as enhanced submarine melt and changes in sea-ice buttressing, or (2) increased surface melt, in response to atmospheric warming, reaching the bed and promoting glacier slip. We examine the influence of these processes on Belcher Glacier, a large fast-flowing tidewater outlet of the Devon Island ice cap in the Canadian Arctic. A hydrologically-coupled higher-order ice flow model is used to estimate changes in glacier flow speed as a result of changes in sea-ice buttressing and hydrologically-driven melt-season dynamics. Daily run-off from five sub-catchments over the 2008 and 2009 melt seasons provides meltwater forcing for the model simulations. Model results are compared with remotely-sensed and in situ ice-surface velocity measurements. Sea-ice effects are found to have a minor influence on glacier flow speed relative to that of meltwater drainage, which is clearly implicated in short-term velocity variations during the melt season. We find that threshold drainage is essential in determining the timing of these short-lived accelerations.