HR: 11:35h
AN: C21D-06    [PDF]
TI: Recent Increase in Flow Rates of the the Jakobshavn Isbrae, Greenland
AU: * Abdalati, W
EM: wabdalat@hq.nasa.gov
AF: NASA Headquarters, Office of Earth Science 300 E Street SW, Washington, DC 20546 United States
AU: Manizade, S
EM: manizade@osb1.wff.nasa.gov
AF: EG&G, Code 972 NASA Wallops Flight Facility, Wallops Island, VA 23336 United States
AU: Golder, J
EM: golder@pop500.gsfc.nasa.gov
AF: Raytheon ITSS, Code 971 Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Thomas, R H
EM: robert_thomas@hotmail.com
AF: EG&G, Code 972 NASA Wallops Flight Facility, Wallops Island, VA 23336 United States
AU: Krabill, W
EM: krabill@osb1.wff.nasa.gov
AF: NASA WFF, Code 972 Wallops Flight Facility, Wallops Island, VA 23336 United States
AU: Csatho, B
EM: csatho.1@osu.edu
AF: Byrd Polar Research Center, 171 Scott Hall 1090 Carmack Road The Ohio State University, Columbus, OH 43210 United States
AB: Greenland's Jakobshavn Isbrae is one of the world's fastest-moving ice streams and accounts for approximately fifteen percent of the ice sheet's total annual discharge. During the early and mid 1990's, while many of Greenland's outlet glaciers and near-coastal areas were thinning, the Jakobshavn drainage basin remained relatively unchanged. Since 1997, however, the ice stream has been thinning at rates that far exceed those that could be attributed to increased ablation or reduced accumulation, even after taking into account the recent high melt-rates observed on the ice sheet. Analyses of feature movement in various Landsat image pairs from 2001 and 2002 reveal that coincident with that thinning there has been an increase in ice stream surface velocity to levels that are much greater than the historically observed 7 km/yr. These velocity increases coincide with recent warm temperatures of the last several years and, unlike previous observations, the flow rates appear to be greater in summer than in spring. Although this seasonal velocity increase suggests an association with enhanced basal lubrication as increased surface melt water drains to the glacier bed, the larger overall velocity increase most probably results from very rapid thinning and breakup of the glacier's floating ice tongue that began in 1997. Both of these processes indicate a significant link between glacier flow rates and recent climate characteristics in the region, and represent glacier dynamic responses that are not included in current assessments of sea-level change in a warming climate.
DE: 1640 Remote sensing
DE: 1699 General or miscellaneous
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
DE: 9315 Arctic region
SC: Cryosphere [C]
MN: 2003 Fall Meeting