Estimating Ice Discharge at Greenland's Three Largest Outlet Glaciers Using Local Bedrock Uplift

• Published in: Geophysical Research Letters
• Main Authors: Hansen, Karina, Truffer, Martin, Aschwanden, Andy, Mankoff, Kenneth, Bevis, Michael, Humbert, Angelika, van den Broeke, Michiel R., Noël, Brice, Bjørk, Anders, Colgan, William, Kjær, Kurt H., Adhikari, Surendra, Barletta, Valentina, Khan, Shfaqat A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: John Wiley and Sons Inc 2021
• Subjects: glaciers; Greenland; ice discharge; ice loss; land uplift; surface mass balance; Dynamic thinning; Elastic displacements; Estimate dynamics; Global Navigation Satellite Systems; Ice discharges; Short term; Solid earth; Geophysics; Earth and Planetary Sciences (all); General Earth and Planetary Sciences; Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; glacier; Jakobshavn; Jakobshavn isbræ; Kangerlussuaq
• Online Access: https://orbi.uliege.be/handle/2268/301946; https://orbi.uliege.be/bitstream/2268/301946/1/Hansen_2021_GRL.pdf; https://doi.org/10.1029/2021GL094252

peer reviewed We present a novel method to estimate dynamic ice loss of Greenland's three largest outlet glaciers: Jakobshavn Isbræ, Kangerlussuaq Glacier, and Helheim Glacier. We use Global Navigation Satellite System (GNSS) stations attached to bedrock to measure elastic displacements of the solid Earth caused by dynamic thinning near the glacier terminus. When we compare our results with discharge, we find a time lag between glacier speedup/slowdown and onset of dynamic thinning/thickening. Our results show that dynamic thinning/thickening on Jakobshavn Isbræ occurs 0.87 ± 0.07 years before speedup/slowdown. This implies that using GNSS time series we are able to predict speedup/slowdown of Jakobshavn Isbræ by up to 10.4 months. For Kangerlussuaq Glacier the lag between thinning/thickening and speedup/slowdown is 0.37 ± 0.17 years (4.4 months). Our methodology and results could be important for studies that attempt to model and understand mechanisms controlling short-term dynamic fluctuations of outlet glaciers in Greenland.