Continued evolution of Jakobshavn Isbrae following its rapid speedup
Article first published online: 28 OCT 2008
Copyright 2008 by the American Geophysical Union.
Journal of Geophysical Research: Earth Surface (2003–2012)
Volume 113, Issue F4, December 2008
How to Cite
2008), Continued evolution of Jakobshavn Isbrae following its rapid speedup, J. Geophys. Res., 113, F04006, doi:10.1029/2008JF001023., , , , , , , and (
- Issue published online: 28 OCT 2008
- Article first published online: 28 OCT 2008
- Manuscript Accepted: 27 AUG 2008
- Manuscript Revised: 27 JUN 2008
- Manuscript Received: 21 MAR 2008
- Jakobshavn Isbrae
 Several new data sets reveal that thinning and speedup of Jakobshavn Isbrae continue, following its recent rapid increase in speed as its floating ice tongue disintegrated. The present speedup rate of ∼5% a−1 over much of the fast-moving region appears to be a diffusive response to the initial much larger speedup near the front. There is strong seasonality in speed over much of the fast-flowing main trunk that shows a good inverse correlation with the seasonally varying length of a short (typically ∼6 km) floating ice tongue. This modulation of speed with ice front position supports the hypothesis that the major speedup was caused by loss of the larger floating ice tongue from 1998 to 2003. Analysis of image time series suggests that the transient winter ice tongue is formed when sea ice bonds glacier ice in the fjord to produce a nearly rigid mass that almost entirely suppresses calving. Major calving only resumes in late winter when much of this ice clears from the fjord. The collapse of the ice tongue in the late 1990s followed almost immediately after a sharp decline in winter sea-ice concentration in Disko Bay. This decline may have extended the length of the calving season for several consecutive years, leading to the ice tongue's collapse.