The Cryosphere Discuss., 5, 2115-2157, 2011
www.the-cryosphere-discuss.net/5/2115/2011/
doi:10.5194/tcd-5-2115-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal The Cryosphere (TC). Please refer to the corresponding final paper in TC.
Towards direct coupling of regional climate models and ice sheet models by mass balance gradients: application to the Greenland Ice Sheet
M. M. Helsen, R. S. W. van de Wal, M. R. van den Broeke, W. J. van de Berg, and J. Oerlemans
Institute for Marine and Atmospheric Research Utrecht, P.O. Box 80000, 3508 TA Utrecht, The Netherlands

Abstract. It is notoriously difficult to couple surface mass balance (SMB) results from climate models to the changing geometry of an ice sheet model. This problem is traditionally avoided by using only accumulation fields from a climate model, and deriving SMB by parameterizing the run-off as a function of temperature, which is often related to surface elevation. In this study, a new parameterization of SMB is presented, designed for use in ice dynamical models to allow a direct adjustment of SMB as a result of a change in elevation (Hs) or a change in climate forcing. This method is based on spatial gradients in the present-day SMB field as computed by a regional climate model. Separate linear relations are derived for ablation and accumulation regimes, using only those pairs of Hs an SMB that are found within a minimum search radius. This approach enables a dynamic SMB forcing of ice sheet models, also for initially non-glaciated areas in the peripheral areas of an ice sheet, and circumvents traditional temperature lapse rate assumptions. The method is applied to the Greenland Ice Sheet (GrIS). Model experiments using both steady-state forcing and more realistic glacial-interglacial forcing result in ice sheet reconstructions and behavior that compare favorably with present-day observations of ice thickness.

Citation: Helsen, M. M., van de Wal, R. S. W., van den Broeke, M. R., van de Berg, W. J., and Oerlemans, J.: Towards direct coupling of regional climate models and ice sheet models by mass balance gradients: application to the Greenland Ice Sheet, The Cryosphere Discuss., 5, 2115-2157, doi:10.5194/tcd-5-2115-2011, 2011.
 
Search TCD
Discussion Paper
    XML
    Citation
    Final Revised Paper
    Share