Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 6, 255-272, 2012
http://www.the-cryosphere.net/6/255/2012/
doi:10.5194/tc-6-255-2012
© Author(s) 2012. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
08 Mar 2012
Coupling of climate models and ice sheet models by surface 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 from a climate model, and parameterizing the meltwater run-off as a function of temperature, which is often related to surface elevation (Hs). In this study, we propose a new strategy to calculate SMB, to allow a direct adjustment of SMB to a change in ice sheet topography and/or a change in climate forcing. This method is based on elevational gradients in the SMB field as computed by a regional climate model. Separate linear relations are derived for ablation and accumulation, using pairs of Hs and SMB within a minimum search radius. The continuously adjusting SMB forcing is consistent with climate model forcing fields, also for initially non-glaciated areas in the peripheral areas of an ice sheet. When applied to an asynchronous coupled ice sheet – climate model setup, this method circumvents traditional temperature lapse rate assumptions. Here we apply it to the Greenland Ice Sheet (GrIS). Experiments using both steady-state forcing and glacial-interglacial forcing result in realistic ice sheet reconstructions.

Citation: Helsen, M. M., van de Wal, R. S. W., van den Broeke, M. R., van de Berg, W. J., and Oerlemans, J.: Coupling of climate models and ice sheet models by surface mass balance gradients: application to the Greenland Ice Sheet, The Cryosphere, 6, 255-272, doi:10.5194/tc-6-255-2012, 2012.
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