G33B-1150
Assessment of Glacial Isostatic Adjustment in Greenland using GPS
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Shfaqat Abbas Khan1, Michael G Bevis2, Ingo Sasgen3, Tonie M van Dam4, John M Wahr5, Bert Wouters5, Jonathan L Bamber6, Michael J Willis7, Per Knudsen1, Veit Helm8, Peter Kuipers Munneke9 and Ioana Stefania Muresan1, (1)Technical University of Denmark - Space, Kongens Lyngby, Denmark, (2)Ohio State University, Columbus, OH, United States, (3)Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany, (4)University of Luxembourg, Luxembourg, Luxembourg, (5)Univ of Colorado, Boulder, CO, United States, (6)University of Bristol, Bristol, United Kingdom, (7)Cornell University, Department of Earth and Atmospheric Sciences, Ithaca, NY, United States, (8)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (9)Institute for Marine and Atmospheric Research Utrecht, Utrecht, Netherlands
Abstract:
The Greenland GPS network (GNET) was constructed to provide a new means to assess viscoelastic and elastic adjustments driven by past and present-day changes in ice mass. Here we assess existing glacial isostatic adjustments (GIA) predictions by analysing 1995–2015 data from 61 continuous GPS receivers located along the margin of the Greenland ice sheet. Since GPS receivers measure both the GIA and elastic signals, we isolate GIA, by removing the elastic adjustments of the lithosphere due to present-day mass changes using high-resolution fields of ice surface elevation change derived from satellite and airborne altimetry measurements (ERS1/2, ICESat, ATM, ENVISAT, and CryoSat-2). For most GPS stations, our observed GIA rates contradict GIA predictions; particularly, we find huge uplift rates in southeast Greenland of up to 14 mm/yr while models predict rates of 0-2 mm/yr. Our results suggest possible improvements of GIA predictions, and hence of the poorly constrained ice load history and Earth structure models for Greenland.
