HR: 0800h
AN: C51A-0089    [Abstracts]
TI: High Resolution Geothermal Heat Flux Data--Implications for Ice Sheet Dynamics and Model Uncertainty
AU: * Johnson, J V
EM: johnson@cs.umt.edu
AF: Department of Computer Science The University of Montana, 417 Social Science Building, Missoula, MT 59812, United States
AU: Naslund, J A
EM: Jens-Ove.Naslund@skb.se
AF: Swedish Nuclear Fuel and Waste Management Co (SKB), Box 5864, Stockholm, 102 40, Sweden
AU: Pattyn, F
EM: fpattyn@ulb.ac.be
AF: Laboratoire de Glaciologie Département des Sciences de la Terre et de l'Environnement (DSTE), CP 160/03 Université Libre de Bruxelles Av. F. Roosevelt 50, Bruxelles, B-1050, Belgium
AU: Jansson, P
EM: Peter.Jansson@natgeo.su.se
AF: Department of Physical Geography and Quaternary Geology, Stockholm University, Stockholm, SE-106 91, Sweden
AB: Airborne surveys of radiogenic activity in Sweden and Finland have been utilized to create a 5 km resolution map of the geothermal heat flux. Statistical analysis of these data reveal contiguous areas where heat flux is more or less than two standard deviations from the mean. These anomalous areas have a length scale of approximately 22 km. In order to investigate the significance of these findings, thermo-mechanically coupled ice sheet models having both nearly complete and simplified stress treatments are used. Experiments which are formulated for finer scales (~180 km, 10,000 years) utilize the higher order stress treatments, and experiments that treat larger scales (~ 2000 km, 200,000 years) use the reduced stress models. Experiments involve both the measured data, as well as proxies for it, as is appropriate. Experiments also treat a range of sliding relations, and basal water treatments. A novel method of producing synthetic data from the original dataset is formulated, and used to assign confidence intervals to uncertainty estimates. In most all cases, it is found that the ice sheet model is effectively averaging the high resolution geothermal heat flux data, and the results are only marginally different than what would be found using a uniform heat flux boundary condition near the mean of the data set. In cases where it is significantly different, it is the interaction with basal water that provides the mechanism to amplify the impact of a heat flux anomaly.
DE: 0730 Ice streams
DE: 0766 Thermodynamics (1011, 3611, 8411)
DE: 0774 Dynamics
DE: 0798 Modeling
SC: Cryosphere [C]
MN: 2007 Fall Meeting