Mass loss from the Greenland ice sheet contributes significantly to present sea level rise1. High meltwater runoff is responsible for half of Greenland’s mass loss2. Surface melt has been spreading and intensifying in Greenland, with the highest ever surface area melt and runoff recorded in 20123. However, how surface melt water reaches the ocean, and how fast it does so, is poorly understood. Firn—partially compacted snow from previous years—potentially has the capacity to store significant amounts of melt water in liquid or frozen form4, and thus delay its contribution to sea level. Here we present direct observations from ground and airborne radar, as well as ice cores, of liquid water within firn in the southern Greenland ice sheet. We find a substantial amount of water in this firn aquifer that persists throughout the winter, when snow accumulation and melt rates are high. This represents a previously unknown storage mode for water within the ice sheet. We estimate, using a regional climate model, aquifer area at about 70,000 km2 and the depth to the top of the water table as 5–50 m. The perennial firn aquifer could be important for estimates of ice sheet mass and energy budget.

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  1. 1.

    , , , & Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise. Geophys. Res. Lett. 38, L05503 (2011).

  2. 2.

    et al. Partitioning recent Greenland mass loss. Science 326, 984–986 (2009).

  3. 3.

    et al. The extreme melt across the Greenland ice sheet in 2012. Geophys. Res. Lett. 39, L20502 (2012).

  4. 4.

    , , , & Greenland ice-sheet contribution to sea-level rise buffered by meltwater storage in firn. Nature 491, 240–243 (2012).

  5. 5.

    , & Thermal tracking of meltwater retention in Greenland’s accumulation area. J. Geophys. Res. Earth Surf. 117, F01010 (2012).

  6. 6.

    & Persistent englacial drainage features in the Greenland Ice Sheet. Geophys. Res. Lett. 37, L02501 (2010).

  7. 7.

    et al. Proglacial river stage, discharge, and temperature datasets from the Akuliarusiarsuup Kuua River northern tributary, Southwest Greenland, 2008–2011. Earth Syst. Sci. Data 4, 1–12 (2012).

  8. 8.

    et al. Sensitivity of Greenland Ice Sheet surface mass balance to surface albedo parameterization: A study with a regional climate model. Cryosphere 6, 1175–1186 (2012).

  9. 9.

    et al. Higher surface mass balance of the Greenland ice sheet revealed by high-resolution climate modelling. Geophys. Res. Lett. 36, L12501 (2009).

  10. 10.

    et al. A spatially calibrated model of annual accumulation rate on the Greenland Ice Sheet (1958–2007). J. Geophys. Res. Earth Surf. 115, F02004 (2010).

  11. 11.

    et al. Greenland ice sheet: The state of the climate in 2011. Bull. Am. Meteorol. Soc. 93, 148–151 (2012).

  12. 12.

    , , & Stratigraphic continuity in 400 MHz short-pulse radar profiles of firn in West Antarctica. Ann. Glaciol. 39, 195–200 (2004).

  13. 13.

    et al. Southeast Greenland high accumulation rates derived from firn cores and ground-penetrating radar. Ann. Glaciol. 54, 322–332 (2013).

  14. 14.

    , & Radioglaciology (D. Reidel Publishing Company, 1985).

  15. 15.

    IceBridge Accumulation Radar L1B Geolocated Radar Echo Strength Profiles (NASA DAAC at the National Snow and Ice Data Center, 2011).

  16. 16.

    The storage of water in, and hydraulic characteristics of, the firn of South Cascade Glacier, Washington State, U.S.A. Ann. Glaciol. 13, 69–75 (1988).

  17. 17.

    & Water flow through temperate glaciers. Rev. Geophys. 36, 299–328 (1998).

  18. 18.

    Stratigraphic studies in the snow and firn of the Greenland Ice Sheet. US Snow, Ice and Permafrost Research Establishment. Research Report No. 70 (US Snow, Ice and Permafrost Research Establishment, 1962).

  19. 19.

    , & Analysis and modelling of melt-water refreezing in dry snow. J. Glaciol. 36, 238–246 (1990).

  20. 20.

    , & Fast draining lakes on the Greenland Ice Sheet. Geophys. Res. Lett. 3810.1029/2011GL047872 (2011).

  21. 21.

    Greenland ice sheet mass balance reconstruction. Part II: Surface mass balance (1840–2010). J. Clim.6974–6989 (2013).

  22. 22.

    et al. Brief communication ‘Important role of the mid-tropospheric atmospheric circulation in the recent surface melt increase over the Greenland ice sheet’. Cryosphere 7, 241–248 (2013).

  23. 23.

    , & A new, high-resolution digital elevation model of Greenland fully validated with airborne laser altimeter data. J. Geophys. Res. 106, 6733–6745 (2001).

  24. 24.

    , & The in-situ dielectric constant of polar firn revisited. Cold Regions Sci. Technol. 23, 245–256.

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This work was supported by National Science Foundation Office of Polar Programs Award ARC-0909499, ARC-0909469, and the Polar Program of the Netherlands Organization for Scientific Research (NWO/ALW). We acknowledge the use of data and/or data products from Center for Remote Sensing of the Ice Sheets generated with support from NSF grant ANT-0424589 and NASA grant NNX10AT68G. CH2MHill Polar Field Services provided vital logistical support. The NASA airborne radar data can be obtained free of charge from the National Snow and Ice Data Center (IceBridge Accumulation Radar L1B Geolocated Radar Echo Strength Profiles, April–May 2010).

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  1. Department of Geography, University of Utah, Salt Lake City, Utah 84112, USA

    • Richard R. Forster
    • , Clément Miège
    •  & Evan W. Burgess
  2. Geological Survey of Denmark and Greenland (GEUS), Copenhagen DK-1350, Denmark

    • Jason E. Box
  3. Byrd Polar Research Center, The Ohio State University, Columbus, Ohio 43210, USA

    • Jason E. Box
  4. Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht 3508 TA, The Netherlands

    • Michiel R. van den Broeke
    • , Jan H. van Angelen
    •  & Jan T. M. Lenaerts
  5. NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA

    • Lora S. Koenig
  6. Center for Remote Sensing of the Ice Sheets, University of Kansas, Lawrence, Kansas 66045, USA

    • John Paden
    • , Cameron Lewis
    • , S. Prasad Gogineni
    •  & Carl Leuschen
  7. Desert Research Institute, University of Nevada, Reno, Nevada 89512, USA

    • Joseph R. McConnell


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R.R.F. and J.E.B conceived the idea of the analysis. M.R.v.d.B., J.H.v.A. and J.T.M.L. conducted the modelling. C.M. processed and analysed the GPR data. E.W.B and C.M. collected the field data. L.S.K., J.P. and S.P.G. assisted with airborne radar data processing and identification of melt features. C.L., S.P.G. and C.L. developed the airborne radar and assisted in its interpretation. J.R.M. dated and analysed the firn cores. R.R.F. analysed the airborne radar. R.R.F., J.E.B. and M.R.v.d.B. wrote the manuscript. All authors commented on the data and the manuscript.

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The authors declare no competing financial interests.

Corresponding author

Correspondence to Richard R. Forster.

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