Seasonal Speedup Along the Western Flank of the Greenland Ice Sheet

• Published in: Science
• Main Authors: Joughin, Ian, Das, Sarah B., King, Matt A., Smith, Ben E., Howat, Ian M., Moon, Twila
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2008
• Subjects: glacier; Greenland; Ice Sheet; Jakobshavn
• Online Access: http://dx.doi.org/10.1126/science.1153288; https://www.science.org/doi/pdf/10.1126/science.1153288

It has been widely hypothesized that a warmer climate in Greenland would increase the volume of lubricating surface meltwater reaching the ice-bedrock interface, accelerating ice flow and increasing mass loss. We have assembled a data set that provides a synoptic-scale view, spanning ice-sheet to outlet-glacier flow, with which to evaluate this hypothesis. On the ice sheet, these data reveal summer speedups (50 to 100%) consistent with, but somewhat larger than, earlier observations. The relative speedup of outlet glaciers, however, is far smaller (<15%). Furthermore, the dominant seasonal influence on Jakobshavn Isbrae's flow is the calving front's annual advance and retreat. With other effects producing outlet-glacier speedups an order of magnitude larger, seasonal melt's influence on ice flow is likely confined to those regions dominated by ice-sheet flow.