HR: 12:05h
AN: C42A-08 INVITED    [Abstracts]
TI: A need for more realistic ice-sheet models
AU: * van der Veen, C J
EM: cjvdv@ku.edu
AF: Department of Geography and Center for Remote Sensing of Ice Sheets University of Kansas, 213 Lindley Hall 1475 Jayhawk Blvd, Lawrence, KS 66045, United States
AB: The current generation of prognostic ice-sheet models fails to adequately capture rapid and non-linear responses of the polar ice masses to environmental forcings, such as dramatic increase in ice discharge following weakening and disintegration of buttressing ice shelves and ice tongues. While the Intergovernmental Panel on Climate Change acknowledged the potential importance of ice-dynamical effects, processes that could render the Greenland and Antarctic ice sheets more vulnerable to future warming are not incorporated into forecasts of future sea-level rise, primarily because of limited understanding of the processes involved. The challenge facing the glaciological community is to move beyond the prevailing "shallow ice paradigm" - which necessarily produces sluggish ice masses - and to develop the next generation of models that include non-linear processes in a more realistic manner. To achieve this goal, a concerted community effort will be needed that involves targeted data collection and interpretation for better process understanding, novel modeling approaches to incorporate processes acting over small spatial scales into models simulating the evolution of entire ice sheets, and model evaluation against current behavior as well as paleo-reconstructions. Many of the controlling processes are not well understood. Particular challenges include documenting and analyzing the response of grounded outlet glaciers and ice streams to ice-marginal forcings, and how this response may be modulated by bed topography and ice-dynamical flow adjustments. Fortuitously, ongoing ice shelf collapse in the Antarctic Peninsula as well as collapse of floating fjord glaciers in Greenland, offer the opportunity to study grounding-line instability at various stages of ice-shelf retreat and collapse. Coupled with advances in remote-sensing techniques that allow us to better constrain the geological nature of the bed, and geothermal heat supplied to the basal ice, major advances in understanding physical processes are possible through concerted multi- disciplinary efforts that involve both targeted field campaigns and theoretical developments and data interpretation. The objective of this contribution is to summarize the discussion ongoing in the glaciological community and to present possible directions for future research efforts.
DE: 0726 Ice sheets
DE: 0758 Remote sensing
DE: 0774 Dynamics
DE: 0794 Instruments and techniques
DE: 0798 Modeling
SC: Cryosphere [C]
MN: 2007 Fall Meeting