HR: 15:10h
AN: C43A-07    [Abstracts]
TI: Fast Flow From the South Pole to Support Force Glacier
AU: * Bingham, R G
EM: r.bingham@bris.ac.uk
AF: Centre for Polar Observation and Modelling, Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS United Kingdom
AU: Siegert, M J
EM: m.j.siegert@bris.ac.uk
AF: Centre for Polar Observation and Modelling, Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS United Kingdom
AU: Blankenship, D D
EM: blank@ig.utexas.edu
AF: Institute for Geophysics, University of Texas, 4412 Spicewood Springs Road, #600, Austin, TX 78759-8500 United States
AB: The flow of the Antarctic Ice Sheet has for some time been conceptualised as consisting of a small number of fast-flowing ice streams draining relatively stable and inactive interior catchment areas, but recent estimates of surface velocities from synthetic aperture radar interferometry (InSAR) and independent estimates of mass balance velocities indicate that tributaries of fast flow may penetrate much deeper into the interior of the ice sheet than previously thought. It is important to test this assertion to improve modelled estimates of the form and flow of this vast ice sheet, its long-term stability, and its potential response to climate change. Here, we use Radio-Echo Sounding (RES) imagery to identify and delineate fast flow from the region surrounding the South Pole to the Support Force Glacier (82°45'S, 046°30'W) draining into the Filchner Ice Shelf. For this region, InSAR imagery implies that ice draining through the Support Force Glacier is derived largely from a fast-flow feature originating south of 87° (500 km inland and the southerly limit of InSAR), suggesting that this Support Force Fast-Flow Feature may be highly significant for the drainage and mass balance of the East Antarctic Ice Sheet (EAIS). Our research has the following objectives: (i) to distinguish between areas of "well-preserved" internal layering which parallels the bed topography and implies slow flow, and "buckled" internal layering which diverges from bed topography and is diagnostic of fast flow; (ii) to determine the extent to which the fast-flow features inferred from the RES analysis correspond with fast flow at the surface as identified by InSAR where that is available; and (iii) to assess the degree to which the fast-flow features identified by RES correlate with inferred regions of fast flow from recent estimates of balance velocities. We find that buckled internal layering, indicative of fast flow, corresponds with areas of fast surface flow identified by InSAR within our analytical domain (this has also been found for the Siple Coast Ice Streams), hence we are confident that buckled RES layering can be applied to identify fast flow where no other information is available. South of 87° S, the distribution of fast flow identified by RES matches well the inferred distribution of fast flow suggested by balance velocity estimates. These data represent the first empirical confirmation that fast flow takes place at and/or near to the South Pole, and suggest that this Support Force Fast-Flow Feature may contribute significant discharge to the Filchner Ice Shelf.
DE: 0726 Ice sheets
DE: 0730 Ice streams
DE: 0794 Instruments and techniques
DE: 1621 Cryospheric change (0776)
DE: 4540 Ice mechanics and air/sea/ice exchange processes (0700, 0750, 0752, 0754)
SC: Cryosphere [C]
MN: Fall Meeting 2005