Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Deeply incised submarine glacial valleys beneath the Greenland ice sheet

Abstract

The bed topography beneath the Greenland ice sheet controls the flow of ice and its discharge into the ocean. Outlet glaciers move through a set of narrow valleys whose detailed geometry is poorly known, especially along the southern coasts1,2,3. As a result, the contribution of the Greenland ice sheet and its glaciers to sea-level change in the coming century is uncertain4. Here, we combine sparse ice-thickness data derived from airborne radar soundings with satellite-derived high-resolution ice motion data through a mass conservation optimization scheme5. We infer ice thickness and bed topography along the entire periphery of the Greenland ice sheet at an unprecedented level of spatial detail and precision. We detect widespread ice-covered valleys that extend significantly deeper below sea level and farther inland than previously thought. Our findings imply that the outlet glaciers of Greenland, and the ice sheet as a whole, are probably more vulnerable to ocean thermal forcing and peripheral thinning than inferred previously from existing numerical ice-sheet models.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: Bed elevation of the Greenland ice sheet colour-coded between −500 and +2,000 m, with submarine areas in blue.
Figure 2: Bed elevation of Upernavik Isstrøm South, West Greenland.

References

  1. 1

    Bindschadler, R. et al. Ice-sheet model sensitivities to environmental forcing and their use in projecting future sea-level (the SeaRISE project). J. Glaciol. 59, 195–224 (2013).

    Article  Google Scholar 

  2. 2

    Nick, F. M. et al. Future sea-level rise from Greenland’s main outlet glaciers in a warming climate. Nature 497, 235–238 (2013).

    Article  Google Scholar 

  3. 3

    Howat, I. M., Joughin, I., Fahnestock, M., Smith, B. E. & Scambos, T. A. Synchronous retreat and acceleration of southeast Greenland outlet glaciers 2000–06: Ice dynamics and coupling to climate. J. Glaciol. 54, 646–660 (2008).

    Article  Google Scholar 

  4. 4

    IPCC-AR4 Fourth Assessment Report: Climate Change 2007: The AR4 Synthesis Report (IPCC, 2007)

  5. 5

    Morlighem, M. et al. A mass conservation approach for mapping glacier ice thickness. Geophys. Res. Lett. 38, L19503 (2011).

    Article  Google Scholar 

  6. 6

    Evans, S. & Robin, G. d. Q. Glacier depth-sounding from air. Nature 210, 883–885 (1966).

    Article  Google Scholar 

  7. 7

    Bamber, J., Layberry, R. & Gogineni, S. A new ice thickness and bed data set for the Greenland Ice Sheet: 1. Measurement, data reduction, and errors. J. Geophys. Res. 106, 33773–33780 (2001).

    Article  Google Scholar 

  8. 8

    Rignot, E. & Mouginot, J. Ice flow in Greenland for the International Polar Year 2008–2009. Geophys. Res. Lett. 39, L11501 (2012).

    Article  Google Scholar 

  9. 9

    Holt, J., Peters, M., Kempf, S., Morse, D. & Blankenship, D. Echo source discrimination in single-pass airborne radar sounding data from the dry valleys, Antarctica: Implications for orbital sounding of Mars. J. Geophys. Res. 111, E06S24 (2006).

    Article  Google Scholar 

  10. 10

    Jezek, K., Wu, X., Paden, J. & Leuschen, C. Radar mapping of Isunnguata Sermia, Greenland. J. Glaciol. 59, 1135–1146 (2013).

    Article  Google Scholar 

  11. 11

    Forster, R. R. et al. Extensive liquid meltwater storage in firn within the Greenland Ice Sheet. Nature Geosci. 7, 95–98 (2014).

    Article  Google Scholar 

  12. 12

    Deutsch, C. & Journel, A. GSLIB Geostatistical Software Library and User’s Guide 2nd edn (Oxford Univ. Press, 1997).

    Google Scholar 

  13. 13

    Gogineni, P. CReSIS RDS Data (2012); http://data.cresis.ku.edu/

  14. 14

    Howat, I., Negrete, A. & Smith, B. The Greenland Ice Mapping Project (GIMP) land classification and surface elevation datasets. Cryosphere Discuss. 8, 453–478 (2014).

    Article  Google Scholar 

  15. 15

    Morlighem, M. et al. High-resolution bed topography mapping of Russell Glacier, Greenland, inferred from operation Ice Bridge data. J. Glaciol. 59, 1015–1023 (2013).

    Article  Google Scholar 

  16. 16

    Bamber, J. L. et al. A new bed elevation dataset for Greenland. Cryosphere 7, 499–510 (2013).

    Article  Google Scholar 

  17. 17

    Seroussi, H. et al. Ice flux divergence anomalies on 79north Glacier, Greenland. Geophys. Res. Lett. 38, L09501 (2011).

    Article  Google Scholar 

  18. 18

    Durand, G., Gagliardini, O., Favier, L., Zwinger, T. & le Meur, E. Impact of bedrock description on modeling ice sheet dynamics. Geophys. Res. Lett. 38, L20501 (2011).

    Google Scholar 

  19. 19

    Kessler, M. A., Anderson, R. S. & Briner, J. P. Fjord insertion into continental margins driven by topographic steering of ice. Nature Geosci. 1, 365–369 (2008).

    Article  Google Scholar 

  20. 20

    Harbor, J. Numerical modeling of the development of U-shaped valleys by glacial erosion. Geol. Soc. Am. Bull. 104, 1364–1375 (1992).

    Article  Google Scholar 

  21. 21

    Ekholm, S., Keller, K., Bamber, J. & Gogineni, S. Unusual surface morphology from digital elevation models of the Greenland Ice Sheet. Geophys. Res. Lett. 25, 3623–3626 (1998).

    Article  Google Scholar 

  22. 22

    Swift, D. A., Persano, C., Stuart, F. M., Gallagher, K. & Whitham, A. A reassessment of the role of ice sheet glaciation in the long-term evolution of the East Greenland fjord region. Geomorphology 97, 109–125 (2008).

    Article  Google Scholar 

  23. 23

    Rignot, E., Koppes, M. & Velicogna, I. Rapid submarine melting of the calving faces of West Greenland glaciers. Nature Geosci. 3, 187–191 (2010).

    Article  Google Scholar 

  24. 24

    Holland, D., Thomas, R., De Young, B., Ribergaard, M. & Lyberth, B. Acceleration of Jakobshavn Isbrae triggered by warm subsurface ocean waters. Nature Geosci. 1, 659–664 (2008).

    Article  Google Scholar 

  25. 25

    Joughin, I., Smith, B., Howat, I., Scambos, T. & Moon, T. Greenland flow variability from ice-sheet-wide velocity mapping. J. Glaciol. 56, 416–430 (2010).

    Google Scholar 

  26. 26

    Howat, I. M. & Eddy, A. Multi-decadal retreat of Greenland’s marine-terminating glaciers. J. Glaciol. 57, 389–396 (2011).

    Article  Google Scholar 

  27. 27

    Wu, X. et al. Ice sheet bed mapping with airborne SAR tomography. IEEE Trans. Geos. Rem. Sens. 49, 3791–3802 (2011).

    Article  Google Scholar 

  28. 28

    Ettema, J. et al. Higher surface mass balance of the Greenland Ice Sheet revealed by high-resolution climate modeling. Geophys. Res. Lett. 36, 1–5 (2009).

    Article  Google Scholar 

  29. 29

    Schenk, T. & Csatho, B. A new methodology for detecting ice sheet surface elevation changes from laser altimetry data. IEEE Trans. Geosc. Rem. Sens. 50, 3302–3316 (2012).

    Article  Google Scholar 

Download references

Acknowledgements

This work was performed at the University of California Irvine and the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA, Cryospheric Sciences Program grant NNX12AB86G. CReSIS data products are from NSF grant ANT-0424589 and NASA grant NNX10AT68G. Ice-thinning rates are from NCAR/EOL funded by NSF. SMB data is from M. van den Broeke, University of Utrecht, The Netherlands. The bathymetry data described in Supplementary Information are a product of Grant 2980 from the Gordon and Betty Moore Foundation.

Author information

Affiliations

Authors

Contributions

M.M. developed the algorithm and led the calculations. H.S. assisted in implementing the algorithm. J.M. provided velocity mapping. All authors contributed to the writing of the paper.

Corresponding author

Correspondence to M. Morlighem.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 9931 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Morlighem, M., Rignot, E., Mouginot, J. et al. Deeply incised submarine glacial valleys beneath the Greenland ice sheet. Nature Geosci 7, 418–422 (2014). https://doi.org/10.1038/ngeo2167

Download citation

Further reading

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing