Ocean Science www.ocean-sci.net 1812-0784 1812-0792 6 3 2010 10.5194/os-6-749-2010 http://www.ocean-sci.net/6/749/2010/ http://www.ocean-sci.net/6/749/2010/os-6-749-2010.html http://www.ocean-sci.net/6/749/2010/os-6-749-2010.pdf 749 760 2010-07-23 Short-term impacts of enhanced Greenland freshwater fluxes in an eddy-permitting ocean model R. Marsh rma@noc.soton.ac.uk D. Desbruyères J. L. Bamber B. A. de Cuevas A. C. Coward Y. Aksenov School of Ocean and Earth Science, University of Southampton, European Way, Southampton, Hampshire SO14 3ZH, UK Lab. de Physique des Océans, Univ. de Bretagne Occidentale, 6 av. Le Gorgeu CS 93837, 29238 Brest Cedex 3, France Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, UK National Oceanography Centre, European Way, Southampton, Hampshire SO14 3ZH, UK In a sensitivity experiment, an eddy-permitting ocean general circulation model is forced with realistic freshwater fluxes from the Greenland Ice Sheet, averaged for the period 1991–2000. The fluxes are obtained with a mass balance model for the ice sheet, forced with the ERA-40 reanalysis dataset. The freshwater flux is distributed around Greenland as an additional term in prescribed runoff, representing seasonal melting of the ice sheet and a fixed year-round iceberg calving flux, for 8.5 model years. By adding Greenland freshwater fluxes with realistic geographical distribution and seasonality, the experiment is designed to investigate the oceanic response to a sudden and spatially/temporally uniform amplification of ice sheet melting and discharge, rather than localized or gradual changes in freshwater flux. The impacts on regional hydrography and circulation are investigated by comparing the sensitivity experiment to a control experiment, without additional fluxes. By the end of the sensitivity experiment, the majority of additional fresh water has accumulated in Baffin Bay, and only a small fraction has reached the interior of the Labrador Sea, where winter mixed layer depth is sensitive to small changes in salinity. As a consequence, the impact on large-scale circulation is very slight. 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