title: Seasonal speedup along the western flank of the Greenland Ice Sheet.
abstract: 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.
authors.affiliation: Polar Science Center, Applied Physics Lab, University of Washington, 1013 NE 40th Street, Seattle, WA 98105-6698, USA. ian@apl.washington.edu
authors.forename: Ian
authors.initials: I
authors.lastname: Joughin
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Das
authors.forename: Matt A
authors.initials: MA
authors.lastname: King
authors.forename: Ben E
authors.initials: BE
authors.lastname: Smith
authors.forename: Ian M
authors.initials: IM
authors.lastname: Howat
authors.forename: Twila
authors.initials: T
authors.lastname: Moon