The Cryosphere Discuss., 7, 2703-2723, 2013
www.the-cryosphere-discuss.net/7/2703/2013/
doi:10.5194/tcd-7-2703-2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal The Cryosphere (TC). Please refer to the corresponding final paper in TC.
Modeling surface response of the Greenland Ice Sheet to interglacial climate
D. Rau and I. Rogozhina
Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 1.3: Earth System Modelling, Telegrafenberg A20, 14473 Potsdam, Germany

Abstract. This study presents a~new approach to parameterizing surface mass balance (SMB) of the Greenland Ice Sheet (GIS) under interglacial climate validated against recent satellite observations and the results of a high-resolution model on a regional scale. Based on detailed analysis of the modeled SMB, we conclude that existing parameterizations fail to capture either spatial pattern or amplitude of the observed surface responses of the GIS. This is due to multiple simplifying assumptions adopted by the majority of modeling studies within the framework of a positive degree-day method. Modeled surface melting is found to be highly sensitive to a choice of daily temperature standard deviation (SD), which is generally assumed to have uniform distribution across Greenland. The range of commonly used SD values does not however receive support from climate datasets available. In this region, SD distribution is highly inhomogeneous and characterized by low values during summer months in areas where most surface melting occurs. Our approach is to make use of spatially variable SD and here we show that this leads to significant improvements in the modeled SMB over the instrumental record. Our findings necessitate evaluating potential consequences of the simplified SMB treatment for assessment of the history and future of glaciation on Earth.

Citation: Rau, D. and Rogozhina, I.: Modeling surface response of the Greenland Ice Sheet to interglacial climate, The Cryosphere Discuss., 7, 2703-2723, doi:10.5194/tcd-7-2703-2013, 2013.
 
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