HR: 0800h
AN: C11A-0087    [Abstracts]
TI: Annual layer mapping and net snowfall measurements across the southern Greenland ice sheet using shallow radar and ice cores
AU: * Spikes, V B
EM: vbs@earthscienceagency.com
AF: Earth Science Agency, LLC, PO Box 2858, Stateline, NV 89449, United States
AU: McConnell, J R
EM: joe.mcconnell@dri.edu
AF: Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512, United States
AU: Banta, J R
EM: ryan.banta@dri.edu
AF: Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512, United States
AB: Ground penetrating radar was used to detect internal layers along a 200 km, east-west snowmobile traverse across the Greenland ice sheet at 66oN latitude. The traverse also included 5 shallow to intermediate depth ice cores and extends from a region of recent strong thickening of the ice sheet in the west to a region of recent strong thinning in the east. Density and high resolution glaciochemistry measurements from the ice cores were used to establish precise depth-age relationships along the traverse. Radar events corresponding to annual layers were identified using one ice core and then mapped across the entire radar profile. Independent comparisons to the depth-age relationships at the remaining ice core sites show that uncertainty in the annual layers determined from the radar traverse are on the order of 0.1 years. The result is an accurate, continuous ~1950 to 2002 record of annual net snowfall along the 200 km traverse. Elevation measurements from global positioning system surveys show that accumulation rates correlate highly with surface undulations. After accommodating for surface undulations, results show that temporal changes in accumulation rate are spatially coherent and likely reflect changes in annual snowfall resulting from large scale changes in atmospheric circulation.
DE: 0726 Ice sheets
DE: 0742 Avalanches
DE: 0758 Remote sensing
DE: 0762 Mass balance (1218, 1223)
DE: 0776 Glaciology (1621, 1827, 1863)
SC: Cryosphere [C]
MN: 2007 Fall Meeting