Oceanography The Official Magazine of
The Oceanography Society
Volume 29 Issue 04

View Issue TOC
Volume 29, No. 4
Pages 62 - 71

Improving Bed Topography Mapping of Greenland Glaciers Using NASA’s Oceans Melting Greenland (OMG) Data

Mathieu Morlighem Eric Rignot Josh K. Willis
Article Abstract

Melting of the Greenland Ice Sheet has the potential to raise sea level by 7.36 m and is already contributing to global sea level rise at a rate higher than 1 mm yr–1. Computer models are our best tools to make projections of the mass balance of Greenland over the next centuries, but these models rely on bed topography data that remain poorly constrained near glacier termini. Accurate bed topography in the vicinity of calving fronts is critical for numerical models, as the shapes of the glacier bed and of the nearby bathymetry control both the ocean circulation in the fjord and the stability and response of the ice sheet to climate warming. NASA’s Oceans Melting Greenland (OMG) mission is collecting bathymetry data along Greenland fjords at several glacier termini. Here, we show that these measurements are transforming our knowledge of fjord and glacier depths. Using a mass conservation approach, we combine OMG bathymetry with observations of ice velocity and thickness to produce estimates of bed depth and ice thickness across the ice-ocean boundary with unprecedented accuracy and reliability. Our results along the northwest coast of Greenland reveal complex structural features in bed elevation, such as valleys, ridges, bumps, and hollows. These features have important implications for both channeling ice flow toward the continental margin, and for controlling the amount of warm, salty Atlantic Water that reaches the glaciers. 

Citation

Morlighem, M., E. Rignot, and J.K. Willis. 2016. Improving bed topography mapping of Greenland glaciers using NASA’s Oceans Melting Greenland (OMG) data. Oceanography 29(4):62–71, https://doi.org/10.5670/oceanog.2016.99.

References

Aschwanden, A., M. Fahnestock, and M. Truffer. 2016. Complex Greenland outlet glacier flow captured. Nature Communications 7:1–8, https://doi.org/10.1038/ncomms10524.

Bamber, J.L., J.A. Griggs, R.T.W.L. Hurkmans, J.A. Dowdeswell, S.P. Gogineni, I. Howat, J. Mouginot, J. Paden, S. Palmer, E. Rignot, and D. Steinhage. 2013. A new bed elevation dataset for Greenland. Cryosphere 7:499–510, https://doi.org/10.5194/tc-7-499-2013.

Enderlin, E.M., I.M. Howat, S. Jeong, M.-J. Noh, J.H. van Angelen, and M.R. van den Broeke. 2014. An improved mass budget for the Greenland ice sheet. Geophysical Research Letters 41(3):866–872, https://doi.org/​10.1002/2013GL059010.

Ettema, J., M.R. van den Broeke, E. van Meijgaard, W.J. van de Berg, J.L. Bamber, J.E. Box, and R.C. Bales. 2009. Higher surface mass balance of the Greenland Ice Sheet revealed by high-resolution climate modeling. Geophysical Research Letters 36:1–5, https://doi.org/10.1029/​2009GL038110.

Evans, S., and G. de Q. Robin. 1966. Glacier depth-sounding from air. Nature 210:883–885, https://doi.org/10.1038/210883a0.

Gogineni, S., T. Chuah, C. Allen, K. Jezek, and R. Moore. 1998. An improved coherent radar depth sounder. Journal of Glaciology 44(148):659–669.

Gudmundsson, G.H., J. Krug, G. Durand, L. Favier, and O. Gagliardini. 2012. The stability of grounding lines on retrograde slopes. Cryosphere 6(6):1,497–1,505, https://doi.org/10.5194/tc-6-1497-2012.

Holt, J., M. Peters, S. Kempf, D. Morse, and D. Blankenship. 2006. Echo source discrimination in single-pass airborne radar sounding data from the Dry Valleys, Antarctica: Implications for orbital sounding of Mars. Journal of Geophysical Research 111(E6):1–13, https://doi.org/10.1029/2005JE002525.

Howat, I.M., I. Joughin, and T.A. Scambos. 2007. Rapid changes in ice discharge from Greenland outlet glaciers. Science 315:1,559–1,561, https://doi.org/10.1126/science.1138478.

Howat, I.M., A. Negrete, and B.E. Smith. 2014. The Greenland Ice Mapping Project (GIMP) land classification and surface elevation datasets. Cryosphere 8(4):1,509–1,518, https://doi.org/10.5194/tc-8-1509-2014.

Jakobsson, M., L. Mayer, B. Coakley, J.A. Dowdeswell, S. Forbes, B. Fridman, H. Hodnesdal, R. Noormets, R. Pedersen, M. Rebesco, and others. 2012. The International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 3.0. Geophysical Research Letters 39:1–6, https://doi.org/10.1029/2012GL052219.

Joughin, I., R.B. Alley, and D.M. Holland. 2012. Ice-sheet response to oceanic forcing. Science 338:1,172–1,176, https://doi.org/10.1126/science.1226481.

Kessler, M.A., R.S. Anderson, and J.P. Briner. 2008. Fjord insertion into continental margins driven by topographic steering of ice. Nature Geoscience 1(6):365–369, https://doi.org/10.1038/ngeo201.

Moon, T., I. Joughin, and B. Smith. 2015. Seasonal to multiyear variability of glacier surface velocity, terminus position, and sea ice/ice melange in northwest Greenland. Journal of Geophysical Research 120(5):818–833, https://doi.org/10.1002/​2015JF003494.

Morlighem, M., J. Bondzio, H. Seroussi, E. Rignot, E. Larour, A. Humbert, and S.-A. Rebuffi. 2016. Modeling of Store Gletscher’s calving dynamics, West Greenland, in response to ocean thermal forcing. Geophysical Research Letters 43(6):2,659–2,666, https://doi.org/​10.1002/2016GL067695.

Morlighem, M., E. Rignot, J. Mouginot, H. Seroussi, and E. Larour. 2014. Deeply incised submarine glacial valleys beneath the Greenland Ice Sheet. Nature Geoscience 7(6):418–422, https://doi.org/​10.1038/ngeo2167.

Morlighem, M., E. Rignot, J. Mouginot, X. Wu, H. Seroussi, E. Larour, and J. Paden. 2013. High-resolution bed topography mapping of Russell Glacier, Greenland, inferred from Operation IceBridge data. Journal of Glaciology 59(218):1,015–1,023, https://doi.org/​10.3189/2013JoG12J235.

Morlighem, M., E. Rignot, H. Seroussi, E. Larour, H. Ben Dhia, and D. Aubry. 2011. A mass conservation approach for mapping glacier ice thickness. Geophysical Research Letters 38, L19503, https://doi.org/10.1029/2011GL048659.

Mouginot, J., E. Rignot, B. Scheuchl, I. Fenty, A. Khazendar, M. Morlighem, A. Buzzi, and J. Paden. 2015. Fast retreat of Zachariæ Isstrøm, Northeast Greenland. Science 350:1,357–1,361, https://doi.org/10.1126/science.aac7111.

OMG Mission. 2016a. Bathymetry (sea floor depth) data from the ship-based bathymetry survey. Ver. 0.1. OMG SDS, CA, https://doi.org/10.5067/OMGEV-BTYSS.

OMG Mission. 2016b. Glacier elevation data from the GLISTIN-A campaigns. Ver. 0.1. OMG SDS, CA, https://doi.org/10.5067/OMGEV-ICEGA.

Pattyn, F., L. Perichon, G. Durand, L. Favier, O. Gagliardini, R.C.A. Hindmarsh, T. Zwinger, T. Albrecht, C. Torsten, S. Cornford, and others. 2013. Grounding-line migration in plan-view marine ice-sheet models: Results of the ice2sea MISMIP3d intercomparison. Journal of Glaciology 59(215):410–422, https://doi.org/10.3189/2013JoG12J129.

Post, A. 1975. Preliminary hydrography and historic terminal changes of Columbia Glacier, Alaska. Hydrologic Atlas 559, US Geological Survey, https://pubs.er.usgs.gov/publication/ha559.

Rignot, E., I. Fenty, Y. Xu, C. Cai, and C. Kemp. 2015. Undercutting of marine-terminating glaciers in West Greenland. Geophysical Research Letters 42(14):5,909–5,917, https://doi.org/10.1002/2015GL064236.

Rignot, E., and J. Mouginot. 2012. Ice flow in Greenland for the International Polar Year 2008–2009. Geophysical Research Letters 39, L11501, https://doi.org/10.1029/2012GL051634.

Rignot, E., I. Velicogna, M. van den Broeke, A. Monaghan, and J. Lenaerts. 2011. Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise. Geophysical Research Letters 38:1–5, https://doi.org/10.1029/2011GL046583.

Schenk, T., and B. Csatho. 2012. A new methodology for detecting ice sheet surface elevation changes from laser altimetry data. IEEE Transactions on Geoscience and Remote Sensing 50(9):3,302–3,316, https://doi.org/10.1109/TGRS.2011.2182357.

Schoof, C. 2007. Ice sheet grounding line dynamics: Steady states, stability, and hysteresis. Journal of Geophysical Research 112, F03S28, https://doi.org/10.1029/2006JF000664.

Seroussi, H., M. Morlighem, E. Rignot, E. Larour, D. Aubry, H. Ben Dhia, and S.S. Kristensen. 2011. Ice flux divergence anomalies on 79north Glacier, Greenland. Geophysical Research Letters 38, L09501, https://doi.org/10.1029/2011GL047338.

Shepherd, A., E.R. Ivins, Geruo A., V.R. Barletta, M.J. Bentley, S. Bettedpur, K.H. Briggs, D.H. Bromwich, R. Forsberg, N. Galin, and others. 2012. A reconciled estimate of ice-sheet mass balance. Science 338:1,183–1,189, https://doi.org/10.1126/science.1228102.

Velicogna, I., T.C. Sutterley, and M.R. van den Broeke. 2014. Regional acceleration in ice mass loss from Greenland and Antarctica using GRACE time-variable gravity data. Geophysical Research Letters 41(22):8,130–8,137, https://doi.org/10.1002/2014GL061052.

Weertman, J. 1974. Stability of the junction of an ice sheet and an ice shelf. Journal of Glaciology 13(67):3–11.