HR: 0800h
AN: NS11A-0161    [Abstracts]
TI: Ice penetrating radar surveys along the EGIG line in the percolation zone of Western Greenland
AU: * Brown, J M
EM: jbrown@cgiss.boisestate.edu
AF: CGISS, Department of Geosciences Boise State University 1910 University Drive, Boise, ID 83725,
AU: Bradford, J
EM: jbradfor@boisestate.edu
AF: CGISS, Department of Geosciences Boise State University 1910 University Drive, Boise, ID 83725,
AU: Harper, J T
EM: Joel@mso.umt.edu
AF: University of Montana, Department of Geosciences 32 Campus Drive, #1296, Missoula, MT 59812,
AU: Pfeffer, W T
EM: Tad.Pfeffer@Colorado.EDU
AF: The Institute of Arctic and Alpine Research, University of Colorado Campus Box 450, Boulder, CO 80309-0450,
AU: Humphrey, N F
EM: neil@uwyo.edu
AF: University of Wyoming, Geology and Geophysics Dept. 3006 University of Wyoming, Laramie, WY 82071,
AB: We conducted a variety of ice penetrating radar surveys along the EGIG line on the western side of the Greenland ice sheet. The purpose of these surveys is to1) gain an understanding of the hydrologic pathways of surface generated meltwater, and 2) document the rate of firn densification in the upper 80 m of the percolation zone. Our various data collection techniques included: 1) common midpoint (CMP) gatherers using 100 MHz antennae and a maximum separation of 79 m at six locations spread out along on the EGIG line; 2) single offset 1 GHz transect imaging the approximately the top 2 m of snow. This transect spans a distance of ~40 km from T1 to Crawford point; 3) 1 GHz constant offset imaging of a 100 m x 100 m grid on 10 m grid spacing; 4) a multi-offset transect within the 100 m x 100 m grid utilizing 1 GHz and 500 MHz antennae with a maximum offset of 7.5 m; 5) 20 m x 20 m 3D grid with 20 cm line spacing. This grid images the top 10 m of the snowpack with 500 MHz antennae; and 6) 200 MHz CMP survey of the 3D grid at 5 locations. The radar data is part of a larger data set that includes 21 cores to 10 m depth, logged for detailed density and stratigraphy and 10 m temperature strings at all CMP locations. These additional data provide control for interpretation and modeling of the GPR response
DE: 0726 Ice sheets
DE: 0736 Snow (1827, 1863)
DE: 0770 Properties
DE: 1838 Infiltration
DE: 1863 Snow and ice (0736, 0738, 0776, 1827)
SC: Near-Surface Geophysics [NS]
MN: 2007 Fall Meeting