Brief Communication: Further summer speedup of Jakobshavn Isbræ

We have extended the record of flow speed on Jakobshavn Isbræ through the summer of 2013. These new data reveal large seasonal speedups, 30 to 50% greater than previous summers. At a point a few kilometres inland from the terminus, the mean annual speed for 2012 is nearly three times as great as tha...

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Bibliographic Details
Published in:The Cryosphere
Main Authors: I. Joughin, B. E. Smith, D. E. Shean, D. Floricioiu
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2014
Subjects:
geo
Online Access:https://doi.org/10.5194/tc-8-209-2014
http://www.the-cryosphere.net/8/209/2014/tc-8-209-2014.pdf
https://doaj.org/article/06a181843e834498bf61d9f500fb3b7d
Description
Summary:We have extended the record of flow speed on Jakobshavn Isbræ through the summer of 2013. These new data reveal large seasonal speedups, 30 to 50% greater than previous summers. At a point a few kilometres inland from the terminus, the mean annual speed for 2012 is nearly three times as great as that in the mid-1990s, while the peak summer speeds are more than a factor of four greater. These speeds were achieved as the glacier terminus appears to have retreated to the bottom of an over-deepened basin with a depth of ~ 1300 m below sea level. The terminus is likely to reach the deepest section of the trough within a few decades, after which it could rapidly retreat to the shallower regions ~ 50 km farther upstream, potentially by the end of this century.