Articles | Volume 9, issue 3
https://doi.org/10.5194/tc-9-1183-2015
https://doi.org/10.5194/tc-9-1183-2015
Research article
 | 
05 Jun 2015
Research article |  | 05 Jun 2015

Winter speed-up of quiescent surge-type glaciers in Yukon, Canada

T. Abe and M. Furuya

Abstract. Glacier surges often initiate in winter, but the mechanism remains unclear in contrast to the well-known summer speed-up at normal glaciers. To better understand the mechanism, we used radar images to examine spatial-temporal changes in the ice velocity of surge-type glaciers near the border of Alaska and the Yukon, focusing on their quiescent phase. We found significant accelerations in the upstream region from autumn to winter, regardless of surging episodes. Moreover, the winter speed-up propagated from upstream to downstream. Given the absence of surface meltwater input in winter, we suggest the presence of water storage near the base that does not directly connect to the surface, yet can promote basal sliding through increased water pressure. Our findings have implications for the modelling of glacial hydrology in winter, which may help us better understand glacier dynamics.

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Short summary
Whereas glacier surge is known to often initiate in winter, we show significant winter speed-up signals in the upstream region even at quiescent surge-type glaciers in Yukon, Canada. Moreover, the winter speed-up region expanded from upstream to downstream. Given the absence of surface meltwater input in winter, we speculate the presence of englacial water storage that does not directly connect to the surface, yet can promote basal sliding through increased water pressure.