HR: 12:05h
AN: C32A-07    [Abstracts]
TI: Greenland ice sheet surface mass balance sensitivity
AU: * Box, J E
EM: box.11@osu.edu
AF: Byrd Polar Research Center, 1090 Carmack Rd, Scott Hall rm 108 The Ohio State University, Columbus, OH 43210-1002 United States
AU: Steffen, K
EM: konrad.steffen@colorado.edu
AF: Cooperative Institute for Research in Environmental Sciences, CB 216 University of Colorado, Boulder, CO 80309-0216 United States
AU: Stroeve, J
EM: box.11@osu.edu
AF: National Snow and Ice Data Center, 449 UCB University of Colorado, Boulder, CO 80309 United States
AU: Bromwich, D H
EM: bromwich@polarmet1,mps.ohio-state.edu
AF: Byrd Polar Research Center, 1090 Carmack Rd, Scott Hall rm 108 The Ohio State University, Columbus, OH 43210-1002 United States
AB: Results from a 16-year data assimilation (1988-2003) using the Polar MM5 regional climate model, reveal coherent spatial and temporal variability patterns in temperature, precipitation, cloud radiative forcing, albedo, and surface mass balance. Constraint of systematic model biases was provided by automatic weather station, glacier survey, and remotely-sensed data. Spatial variability in temperature is concentrated along the western slope of the ice sheet, while precipitation variability exhibits a more complex pattern related to the influence of topography on prevailing storm tracks. Albedo variability during this period contributes significantly to ablation trends. Downward longwave radiation increased during this period over much of the ice sheet. Temperature and precipitation trends were also positive over much of the ice sheet. An increase in equilibrium line altitude around much of the ice sheet and a consequent expansion of the ablation zone is evident in the model results. While increasing temperatures led to an increase in the duration of the melt period and an increase in meltwater runoff, increases in precipitation offset a negative perturbation of the surface mass balance. We may expect an increasing dynamic response of the ice sheet to this period of apparent warming and steepening of the ice sheet balance profile.
DE: 9315 Arctic region
DE: 3349 Polar meteorology
DE: 4556 Sea level variations
DE: 1827 Glaciology (1863)
DE: 1600 GLOBAL CHANGE (New category)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting