Short-term impacts of enhanced Greenland freshwater fluxes in an eddy-permitting ocean model

Type Article
Date 2010
Language English
Author(s) Marsh R.1, Desbruyeres DamienORCID2, Bamber J. L.3, de Cuevas B. A.4, Coward A. C.4, Aksenov Y.4
Affiliation(s) 1 : Univ Southampton, Sch Ocean & Earth Sci, Southampton SO14 3ZH, Hants, England.
2 : Univ Bretagne Occidentale, Lab Phys Oceans, F-29238 Brest 3, France.
3 : Univ Bristol, Bristol Glaciol Ctr, Sch Geog Sci, Bristol BS8 1TH, Avon, England.
4 : Natl Oceanog Ctr, Southampton SO14 3ZH, Hants, England.
Source Ocean Science (1812-0784) (Copernicus Gesellschaft Mbh), 2010 , Vol. 6 , N. 3 , P. 749-760
DOI 10.5194/os-6-749-2010
WOS© Times Cited 33
Abstract 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. An indirect impact of strong freshening off the west coast of Greenland is a small anti-cyclonic component to the circulation around Greenland, which opposes the wind-driven cyclonic circulation and reduces net southward flow through the Canadian Archipelago by similar to 10%. Implications for the post-2000 acceleration of Greenland mass loss are discussed.
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