The Importance of Meltwater to the Peripheral Thinning of Greenland
Participants:
Tom Neumann, University of Vermont
Julie Rumrill, University of Vermont
Ginny Catania,
University of Texas at Austin
With collaboration from:
Steve Price,
Los Alamos National Lab
Funding agency: NASA Jan 06 - Jan 10
Project Goals: Our goal in this proposal is to study the importance
of short-term ice velocity changes near Swiss Camp, Greenland to the stability
of the ice sheet interior. Several areas in Greenland are thinning (particularly
those below 2000 m elevation). While this observed thinning coincides with
increased surface melt, in the past decade thinning is more rapid than expected
from increased surface melting alone, suggesting an ice dynamical cause.
Our work will focus on the connection between increased surface melt and
increased ice velocity in the vicinity of Swiss Camp first measured in the
mid 1990s.
We propose to: (1) measure the spatial and temporal
extent of seasonal changes in ice velocity on a network of poles using global
positioning system (GPS) measurements, (2) use surface-based radio-echo
sounding (RES) to determine the characteristics and water content of the
glacier bed and measure how the water content changes during the melt season,
(3) use RES to study the englacial drainage system and changes to the system
during the melt season, (4) use our measurements in an ice-flow model to
determine the effect of seasonal changes in ice velocity on the stability
of the interior ice near Swiss Camp, (5) correlate these data to melt proxy
data available at NSIDC, and (6) use these results to assess the importance
of seasonal melt water in other areas of Greenland, and determine to what
extent increased melt is responsible for the observed thinning in Greenland.
Project Highlights:
We have finished our fieldwork in Greenland and are busy publishing our
results. For a general overview of what we were doing you can watch this
talk that I gave last year at UT. Check out the pictures.
Published/Presented Results:
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G. Catania, T. Neumann and S. Price, 2008, Characterizing englacial drainage in the ablation zone of the Greenland Ice Sheet, Journal of Glaciology*, 54(187), 567-578. *profiled paper
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S. Price, A. Payne, G. Catania, T. Neumann, 2008, Seasonal acceleration of inland ice via longitudinal coupling to marginal ice, Journal of Glaciology*, 54(185), 213-219. *profiled paper
- G. Catania, T. Neumann, C. Hulbe and H. Conway, 2008 (invited) Understanding changes in the subglacial environment using internal layers, AGU, 89(53), Fall Meeting, Abstract C42A-04.
- J. Rumrill, T. Neumann, G. Catania, Analysis of spatial and temporal variations in longitudinal strain rates near Swiss Camp, Greenland, AGU, 89(53), Fall Meeting, Abstract C31C-0523.
- T. Neumann, S. Price, G. Catania, J. Rumrill, Melt-water induced velocity variations on the Greenland ice sheet and the role of longitudinal stress coupling, IGS Symposium on Ice Dynamics, Ireland, July 2008.
- J. Rumrill, T. Neumann, G. Catania, Analysis of spatial and temporal variations in longitudinal strain rates near Swiss Camp, Greenland, IGS Symposium on Ice Dynamics, Ireland, July 2008.
- G. Catania, T. Neumann, S. Price, Investigations of moulins with ground-based ice-penetrating radar, 2008, IGS Symposium on Radioglaciology, Spain, June 2008.
- G. Catania, T. Neumann, S. Price, Radar and model investigations of englacial drainage through the Greenland Ice Sheet, 2008 NASA-PARCA meeting, Boulder CO, Feb. 2008.
- J. Greenbaum, G. Catania, T. Neumann, T. Hess, N. Bangs, Seismic processing for radar sounding of moulins in Greenland, 2008 NASA-PARCA meeting, Boulder CO, Feb. 2008.
- T. Neumann, G. Catania, J. Rumrill, Surface velocity variation during the 2007 melt season near Swiss Camp, 2008 NASA-PARCA meeting, Boulder CO, Feb. 2008.
- Rumrill, J., T. Neumann, and G. Catania, 2006, Assessing the Spatial and Temporal Extent of Velocity Variations near Swiss Camp, Greenland, Fall AGU, C11A-1136.
- G. Catania, T. Neuumann, and L. Koenig, 2007, Radar Across the Equilibrium Line of the Greenland Ice Sheet: Evidence for surface water drainage, NASA-PARCA meeting, JPL
This is a satellite image of our GPS locations. Jacobshavn Glacier is at the bottom of the image.
Check out these great pictures from inside the ice sheet.
