The Cryosphere Discussions www.the-cryosphere-discuss.net 1994-0432 1994-0440 1 1 2007 10.5194/tcd-1-41-2007 http://www.the-cryosphere-discuss.net/1/41/2007/ http://www.the-cryosphere-discuss.net/1/41/2007/tcd-1-41-2007.html http://www.the-cryosphere-discuss.net/1/41/2007/tcd-1-41-2007.pdf 41 76 2007-06-20 The effect of the north-east ice stream on the Greenland ice sheet in changing climates R. Greve greve@lowtem.hokudai.ac.jp S. Otsu Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo 060-0819, Japan Graduate School of Environmental Science, Hokkaido University, Kita-10, Nishi-5, Kita-ku, Sapporo 060-0810, Japan The north-east Greenland ice stream (NEGIS) was discovered as a large fast-flow feature of the Greenland ice sheet by synthetic aperture radar (SAR) imaginary of the ERS-1 satellite. In this study, the NEGIS is implemented in the dynamic/thermodynamic, large-scale ice-sheet model SICOPOLIS (Simulation Code for POLythermal Ice Sheets). In the first step, we simulate the evolution of the ice sheet on a 10-km grid for the period from 250 ka ago until today, driven by a climatology reconstructed from a combination of present-day observations and GCM results for the past. We assume that the NEGIS area is characterized by enhanced basal sliding compared to the "normal", slowly-flowing areas of the ice sheet, and find that the misfit between simulated and observed ice thicknesses and surface velocities is minimized for a sliding enhancement by the factor three. In the second step, the consequences of the NEGIS, and also of surface-meltwater-induced acceleration of basal sliding, for the possible decay of the Greenland ice sheet in future warming climates are investigated. 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