HR: 1340h
AN: C43A-0222    [Abstracts]
TI: Shallow (400-MHz) and deep (3-MHz) radar used to image wind erosion features in East Antarctica
AU: * Welch, B C
EM: welchb@stolaf.edu
AF: Physics Department St. Olaf College, 1520 St. olaf Avenue, Northfield, MN 55057
AU: Arcone, S A
EM: Steven.A.Arcone@erdc.usace.army.mil
AF: USACE Engineer Research and Development Center Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755
AU: Jacobel, R W
EM: jacobel@stolaf.edu
AF: Physics Department St. Olaf College, 1520 St. olaf Avenue, Northfield, MN 55057
AU: Helgen, M
EM: helgen@stolaf.edu
AF: Physics Department St. Olaf College, 1520 St. olaf Avenue, Northfield, MN 55057
AB: Two radar systems were used to record data simultaneously along the 2001 and 2002 US-ITASE traverses. A 400-MHz short-pulse radar recorded firn stratigraphy to depths up to 120 m while a 3-MHz radar recorded ice internal stratigraphy and bedrock topography to more than 3 km depth. Because the radars were designed for different purposes (shallow versus deep), the characteristics of each system limited regions of overlap to depths of about 100 m. Nevertheless, data from the two radars have been used to better understand the dynamics of particular sites. We report on a site of wind erosion found over a large bedrock mountain in East Antarctica (87$\deg$S, 108$\deg$W). By geolocating both radar data sets we are able to correlate the internal reflectors recorded by each system. The deep radar shows a large-scale unconformity over the basal mountain and subsequent deposition that extends to a depth of 600 m. We use the shallow radar data to show that currently active wind erosion has removed up to 30 m of snow and firn at this site. The erosion results from increased surface topography as the ice flows over the mountain. Using regional accumulation rates, we estimate the age of the exposed firn surface at less than 200 years. This estimate will be refined when data from nearby US-ITASE shallow ice cores become available.
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
DE: 1894 Instruments and techniques
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting