Geodynamics
Research is carried out within solid earth deformation and ice sheet mass balance utilizing GNSS.
Contact
Shfaqat Abbas Khan Professor sakh@dtu.dk
Valentina Roberta Barletta Senior scientist vrba@dtu.dk
Danjal Longfors Berg PhD student dnjllg@dtu.dk
Eigil Yuichi Hyldgaard Lippert PhD student eyhli@dtu.dk
Kuba Oniszk PhD Student jagon@space.dtu.dk
Thomas Henry Nylen GNSS Engineer thony@dtu.dk
Finn Bo Madsen Section Head bm@space.dtu.dk
Ole Bjerregaard Hansen Systemadministrator olebj@dtu.dk
We have developed a novel method to estimate dynamic ice loss of Greenland’s three largest outlet glaciers: Jakobshavn Isbræ, Kangerlussuaq Glacier, and Helheim Glacier.
We use data from GNET stations founded on bedrock to measure elastic displacements of the solid Earth caused by dynamic thinning near the glacier terminus. We find a time lag between glacier speedup/slowdown and onset of dynamic thinning/thickening.
Our methodology and results are important for studies that attempt to model and understand mechanisms controlling short-term dynamic fluctuations of outlet glaciers in Greenland. Our results are published in two GRL publications.
We have used historical photographs to calculate ice loss from 1880-2012 for Jakobshavn, Helheim, and Kangerlussuaq glacier. We estimate ice loss corresponding to a sea level rise of 8.1±1.1 millimetres from these three glaciers. Projections of mass loss for these glaciers, using the worst-case scenario, Representative Concentration Pathways 8.5, suggest a sea level contribution of 9.1-14.9 mm by 2100. RCP8.5 implies an additional global temperature increase of 3.7 C by 2100, approximately four times larger than that which has taken place since 1880.
We infer that projections forced by RCP8.5 underestimate glacier mass loss which could exceed this worst-case scenario.