PT  - JOURNAL ARTICLE
AU  - van de Wal, R. S. W.
AU  - Boot, W.
AU  - van den Broeke, M. R.
AU  - Smeets, C. J. P. P.
AU  - Reijmer, C. H.
AU  - Donker, J. J. A.
AU  - Oerlemans, J.
TI  - Large and Rapid Melt-Induced Velocity Changes in the Ablation Zone of the Greenland Ice Sheet
AID  - 10.1126/science.1158540
DP  - 2008 Jul 04
TA  - Science
PG  - 111--113
VI  - 321
IP  - 5885
4099  - http://science.sciencemag.org/content/321/5885/111.short
4100  - http://science.sciencemag.org/content/321/5885/111.full
SO  - Science2008 Jul 04; 321
AB  - Continuous Global Positioning System observations reveal rapid and large ice velocity fluctuations in the western ablation zone of the Greenland Ice Sheet. Within days, ice velocity reacts to increased meltwater production and increases by a factor of 4. Such a response is much stronger and much faster than previously reported. Over a longer period of 17 years, annual ice velocities have decreased slightly, which suggests that the englacial hydraulic system adjusts constantly to the variable meltwater input, which results in a more or less constant ice flux over the years. The positive-feedback mechanism between melt rate and ice velocity appears to be a seasonal process that may have only a limited effect on the response of the ice sheet to climate warming over the next decades.