Drainage system and thermal structure of a High Arctic polythermal glacier: Waldemarbreen, western Svalbard

Understanding glacier drainage system behaviour and its response to increased meltwater production faces several challenges in the High Arctic because many glaciers are transitioning from polythermal to almost entirely cold thermal structures. We, therefore, used ground-penetrating radar data to inv...

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Bibliographic Details
Published in:Journal of Glaciology
Main Authors: Karušs, Janis, Lamsters, Kristaps, Sobota, Ireneusz, Ješkins, Jurijs, Džerinš, Peteris, Hodson, Andrew
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press 2021
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Online Access:https://hdl.handle.net/11250/2983400
https://doi.org/10.1017/jog.2021.125
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Summary:Understanding glacier drainage system behaviour and its response to increased meltwater production faces several challenges in the High Arctic because many glaciers are transitioning from polythermal to almost entirely cold thermal structures. We, therefore, used ground-penetrating radar data to investigate the thermal structure and drainage system of Waldemarbreen in Svalbard: a small High Arctic glacier believed to be undergoing thermal change. We found that Waldemarbreen retains up to 80 m of temperate ice in its upper reaches, but this thickness most likely is a relict from the Little Ice Age when greater ice volumes were insulated from winter cooling and caused greater driving stresses. Since then, negative mass balance and firn loss have prevented latent heat release and allowed near-surface ice temperatures to cool in winter, thus reducing the thickness of the temperate ice. Numerous reflectors that can be traced up-glacier are interpreted as englacial channels formed by hydrofracturing in the crevassed upper region of the glacier. The alternative cut and closure mechanism of conduit initiation only forms conduits in parts of the lower ablation area. Consequently, Waldemarbreen provides evidence that hydrofracturing at higher elevations can play a major role in englacial water drainage through cold ice. publishedVersion