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Oceanic transport of surface meltwater from the southern Greenland ice sheet

Nature Geoscience volume 9, pages 528532 (2016) | Download Citation


The Greenland ice sheet has undergone accelerating mass losses during recent decades. Freshwater runoff from ice melt can influence fjord circulation and dynamics1 and the delivery of bioavailable micronutrients to the ocean2. It can also have climate implications, because stratification in the adjacent Labrador Sea may influence deep convection and the strength of the Atlantic meridional overturning circulation3. Yet, the fate of the meltwater in the ocean remains unclear. Here, we use a high-resolution ocean model to show that only 1–15% of the surface meltwater runoff originating from southwest Greenland is transported westwards. In contrast, up to 50–60% of the meltwater runoff originating from southeast Greenland is transported westwards into the northern Labrador Sea, leading to significant salinity and stratification anomalies far from the coast. Doubling meltwater runoff, as predicted in future climate scenarios, results in a more-than-double increase in anomalies offshore that persists further into the winter. Interannual variability in offshore export of meltwater is tightly related to variability in wind forcing. The new insight that meltwaters originating from the west and east coasts have different fates indicates that future changes in mass loss rates and surface runoff will probably impact the ocean differently, depending on their Greenland origins.

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We thank J. T. Hollibaugh for valuable comments and suggestions, which led to a greatly improved manuscript. We gratefully acknowledge support by NASA (NNX14AD98G, NNX14AM70G and NNX13AD80G). Additional support was provided by NSF (PLR-01304807 and OCE-1357373).

Author information


  1. Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA

    • Hao Luo
    • , Renato M. Castelao
    •  & Patricia L. Yager
  2. Department of Geography, Rutgers University, Piscataway, New Jersey 08854, USA

    • Asa K. Rennermalm
  3. Lamont Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA

    • Marco Tedesco
  4. NASA Goddard Institute for Space Studies, New York, New York 10025, USA

    • Marco Tedesco
  5. School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA

    • Annalisa Bracco
  6. Department of Geography, University of Georgia, Athens, Georgia 30602, USA

    • Thomas L. Mote


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H.L. and R.M.C. conceived and designed the research; H.L. ran the model; A.K.R., M.T., A.B., P.L.Y. and T.L.M. contributed materials/analysis tools; H.L. and R.M.C. analysed the data/model outputs and wrote the paper; all authors commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Renato M. Castelao.

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