Brief Communication: Further summer speedup of Jakobshavn Isbræ

• 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: Environmental sciences; GE1-350; Geology; QE1-996.5; Jakobshavn Isbræ; Jakobshavn; Jakobshavn isbræ; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-8-209-2014; https://doaj.org/article/06a181843e834498bf61d9f500fb3b7d

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.