Ice velocity changes on Penny Ice Cap, Baffin Island, since the 1950s

• Published in: Journal of Glaciology
• Main Authors: Schaffer, Nicole, Copland, Luke, Zdanowicz, Christian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Uppsala universitet, Luft-, vatten- och landskapslära 2017
• Subjects: Arctic glaciology; Ice velocity; Remote sensing; Ice cap; Glacier mass balance; Physical Geography; Naturgeografi; Arctic; Baffin Island; Highway Glacier; Penny Ice Cap; Baffin; Journal of Glaciology
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-317567; https://doi.org/10.1017/jog.2017.40

Predicting the velocity response of glaciers to increased surface melt is a major topic of ongoing research with significant implications for accurate sea level rise forecasting. In this study we use optical and radar satellite imagery as well as comparisons with historical ground measurements to produce a multi-decadal record of ice velocity variations on Penny Ice Cap, Baffin Island. Over the period 1985 to 2011, the six largest outlet glaciers on the ice cap decelerated at an average rate of 21 m a-1 , or 12% per decade. The change was not monotonous, however, as most glaciers accelerated until the 1990s, then decelerated. A comparison of recent imagery with historical velocity measurements on Highway Glacier, on the southern part of Penny Ice Cap,shows that this glacier decelerated by 71% between 1953 and 2009/11, from 57 to 17 m a-1 . The recent slowdown of outlet glaciers has coincided with increases in mass loss, terminus retreat and an inferred reduction in basal sliding. Measured decelerations are greater than the total short term variability measured from both seasonal and interannual fluctuations, and supports the hypothesis that glacier thinning and/or increased meltwater production promotes a long-term reduction in ice motion.