HR: 09:45h
AN: C41C-08    [Abstracts]
TI: Thinning and Acceleration of East Antarctic Outlet Glaciers
AU: * Stearns, L A
EM: leigh.stearns@maine.edu
AF: Climate Change Institute, University of Maine, 5790 Bryand Global Sciences Center, Orono, ME 04469, United States
AU: Hamilton, G S
EM: gordon.hamilton@maine.edu
AF: Climate Change Institute, University of Maine, 5790 Bryand Global Sciences Center, Orono, ME 04469, United States
AB: The East Antarctic Ice Sheet (EAIS) is Earth's largest freshwater reservoir and has the potential to raise global sea level by ~55 meters. Because of its large size and the logistical challenge of conducting measurements, as well as limits on latitudinal coverage or spatial resolution of some existing remote sensing instruments, potential regional-scale mass imbalances of the EAIS are difficult to detect with the datasets currently available. ASTER satellite imagery provides high-resolution coverage farther south than many existing datasets, opening up new possibilities for investigation. Here, we describe ice dynamic characteristics and mass balance estimates for four large outlet glaciers draining the EAIS through the Transantarctic Mountains -- David, Mulock, Byrd and Nimrod -- based on an analysis of new ASTER-derived ice velocity and surface elevation maps. The conventional view of largely-stable outlet glaciers in this sector of East Antarctica may be open for reassessment. Results indicate that Byrd Glacier, one of the largest glaciers in Antarctica, entered a phase of modest acceleration and thinning beginning in 2006-2007. The current flow speeds are anomalous in the context of an historical record of velocity measurements dating back to the 1960s. Similar changes also appear to be occurring on Mulock and Nimrod glaciers, although their historical records are of much shorter duration. These results are interesting because they demonstrate the dynamic nature of outlet glaciers draining Earth's largest ice sheet, and point to a possible mechanism for a significant EAIS contribution to near-term sea level rise.
DE: 0726 Ice sheets
DE: 0730 Ice streams
DE: 0758 Remote sensing
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 9310 Antarctica (4207)
SC: Cryosphere [C]
MN: 2007 Fall Meeting