Arctic Field Projects

Project Title: Collaborative Research: In Situ Borehole Measurements To Partition The Velocity Of The Greenland Ice Sheet Into Ice Deformation And Basal Sliding Components (Award# 1203451)

PI: Humphrey, Neil F (
Phone: (307) 766.2728 
Institute/Department: U of Wyoming, Department of Geology and Geophysics 
IPY Project?
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ANS
Program Manager: Dr. Marc Stieglitz ( )
Discipline(s): | Cryosphere |

Project Web Site(s):

Science Summary:
Sliding of an ice mass along its basal boundary is a fundamental component of motion where bed conditions are wet. Estimates of basal sliding generally result from an inverse analysis of observed surface motion using a model assuming Glen's generalized constitutive law for isotropic ice. Evidence suggests that this law does not adequately represent ice deformation, due to a variety of issues including ice thermal variations, preferred fabric, and chemical impurities in the ice. The PIs will use an innovative experimental design to improve our understanding of the ice deformation and sliding. A grid of 9 boreholes, each approximately 750 m in depth and extending to the bed, will be drilled through the Greenland Ice Sheet and instrumented with more than 675 sensors to observe ice temperature, ice deformation, and basal sliding. Analysis of the resulting data set will yield the full 3D velocity field and full stress and strain rate tensors for a 420x106 m3 block of ice. The results will be used to assess and improve the constitutive law and will provide a data set for testing inversion methodologies. The Greenland and Antarctic Ice Sheets contain enough water to cause massive inundation of heavily populated coastal regions and associated infrastructure, if they were to degrade significantly through melting or delivery of icebergs to the coastal ocean. Our ability to predict future sea level rise is hampered by an inability to accurately model glacier dynamics that connect these ice sheets to the ocean. This project will provide data sets and consequent insight into processes that will lead to improved models of glacier dynamics.

Logistics Summary:
This collaboration between Harper (1203418, U of MT, Lead) and Humphrey (1203451, U of WY) is an continuation of work begun under NSF grant 0909495 and will conduct a detailed study of ice deformation in Western Greenland. Researchers will drill and instrument a grid of 9 boreholes, each ~750 m and extending to the bed. Sensors will be installed in the boreholes for measuring ice temperature and ice deformation and basal sliding, and will make other supporting measurements such as surface velocity and basal water pressure. See 1203418 for logistic details.

SeasonField SiteDate InDate Out#People
2014Greenland - GL-14-S10
2014Greenland - Kangerlussuaq0
2014Greenland - Point 6600
2015Greenland - Kangerlussuaq0
2015Greenland - Point 6600
2016Greenland - Kangerlussuaq0
2016Greenland - Point 6600
2017Greenland - GL-14-S10
2017Greenland - Kangerlussuaq0
2017Greenland - Point 6600

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