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The Cryosphere Discuss., 5, 2723-2764, 2011
www.the-cryosphere-discuss.net/5/2723/2011/ doi:10.5194/tcd-5-2723-2011 © Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. |
Refreezing on the Greenland ice sheet: a comparison of parameterizations
1Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, The Netherlands
*now at: Faculty of Geo-Information and Earth Observations, University of Twente, Enschede, The Netherlands
Abstract. Retention and refreezing of meltwater are acknowledged to be important processes for the mass budget of polar glaciers and ice sheets. Several parameterizations of these processes exist for use in energy and mass balance models. Due to a lack of direct observations, validation of these parameterizations is difficult. In this study we compare a set of 6 refreezing parameterizations against output of the Regional Atmospheric Climate Model (RACMO2), applied to the Greenland ice sheet. In RACMO2, refreezing is explicitly calculated in a snow model that calculates vertical profiles of temperature, density and liquid water content. For consistency, the parameterizations are forced with output (surface temperature, precipitation and melt) of RACMO2. For the ice sheet-integrated amount of refreezing and its inter-annual variations, all parameterizations give similar results, especially after some tuning. However, the spatial distributions differ significantly. Results are especially sensitive to the choice of the depth of the thermally active layer, which determines the cold content of the snow in most parameterizations.
Citation: Reijmer, C. H., van den Broeke, M. R., Ettema, J., and Stap, L. B.: Refreezing on the Greenland ice sheet: a comparison of parameterizations, The Cryosphere Discuss., 5, 2723-2764, doi:10.5194/tcd-5-2723-2011, 2011.