Laura Stevens

Laura Stevens

Associate Professor of Climate and Earth Surface Processes

My research program aims to determine how ice sheets flow and fall apart. Understanding ice sheet dynamics on Earth is critical for the prediction of past and future global ice volumes, which have direct implications for global sea level. At present, the question that drives our research is: How does ice-sheet melting modulate ice-sheet flow? To approach this question, we pair geophysical observations with time-dependent inverse methods and computational modeling. We investigate Greenland and Antarctic ice sheet, ice shelf, and outlet glacier flow dynamics to better understand the physical mechanisms that destabilize ice sheets with increased surface meltwater production in our warming climate.

Link to CV (October 2021).

Doctoral Research Projects through the Oxford DTP in Environmental Research:

We are advertising for two DPhil researchers to join in the fall of 2021. Please check out the project descriptions below, and get in touch prior to submitting an application!

Project EARTH-21-LS1: Stress transmission between neighbouring Greenland supraglacial lakes from geodetic observations, co-supervised with Prof. Ian Hewitt.

Project EARTH-21-LS2: Drainage dynamics of neighbouring Greenland supraglacial lakes from satellite remote sensing observations, co-supervised with Prof. Helen Johnson.

Supraglacial lake on the western margin of the Greenland Ice Sheet.


Current research projects include:

Greenland Ice Sheet dynamic response to the inland expansion of a hydrologically active ice-sheet bed. 

This project combines on-ice geodetic and radar observations with geophysical inverse and forward modeling techniques to investigate stress transmission between neighboring supraglacial lakes and moulins on the western margin of the Greenland Ice Sheet. Field observations of ice-sheet surface and englacial deformation will be collected over a 16-month period from May 2022 through August 2023. Collaborators include Drs. Meredith Nettles and Jonathan Kingslake (Columbia University).

Antarctic ice-shelf instability caused by active surface meltwater production, movement, ponding, and hydro-fracture. 

Funded by NSFGEO–NERC, this project combines field observations, numerical modeling, and remote sensing techniques to better understand ice-shelf flexure and fracture due to surface meltwater loading. Field observations of ice-shelf surface height, local weather conditions, and water body depths are currently being collected on the George VIth Ice Shelf, Antarctic Peninsula through February 2023. This project is jointly supported by the US NSF and UK NERC, with field support provided by the British Antarctic Survey in coordination with the United States Antarctic Program. Collaborators include Drs. Alison Banwell (University of Colorado Boulder), Douglas MacAyeal (University of Chicago), and Ian Willis (University of Cambridge).

Velocity fluctuations driven by surface melt and lake drainage at Helheim Glacier, East Greenland. 

Investigating dynamics at the ice-ocean boundary brings together researchers in seismology, geodesy, applied mathematics, and oceanography. In my postdoctoral research supported by the Lamont-Doherty Earth Observatory, we worked to mechanistically understand tidally and atmospherically driven tidewater glacier flow of Helheim Glacier, one of Greenland’s fastest outlet glaciers. Through stochastic analysis of geodetic, environmental, and oceanographic observations, we characterized glacier-wide diurnal velocity variations and the glacier’s flow response to a rapid lake drainage event.

Hydraulic transmissivity beneath Greenland supraglacial lakes. 

In collaboration with Drs. Ching-Yao Lai (Princeton University) and Timothy Creyts (Lamont-Doherty Earth Observatory), this project uses observations of ice-sheet surface relaxation following supraglacial lake drainages to reveal hydraulic transmissivity of subglacial drainage systems beneath the Greenland Ice Sheet.

 

  1. Stevens, L.A., Nettles, M., Davis, J.L., Creyts, T.C., Kingslake, J., Ahlstrøm, A.P., and T.B. Larsen (2021). Helheim Glacier diurnal velocity fluctuations driven by surface melt forcing. Journal of Glaciology, 1-13. doi:10.1017/jog.2021.74.
  2. Lai, C.-Y., Stevens, L.A., Chase, D.L., Creyts, T.C., Behn, M.D., Das, S.B., and H.A. Stone (2021). Hydraulic transmissivity inferred from ice-sheet relaxation fol- lowing Greenland supraglacial lake drainages. Nature Communications, 12:3955. doi:10.1038/s41467-021-24186-6.
  3. Stevens, L.A., Hewitt, I., Das, S.B., Behn, M.D. (2018). Relationship between Greenland Ice Sheet surface speed and modeled effective pressure. Journal of Geophysical Research: Earth Surface, 123. doi:10.1029/2017JF004581.
  4. Stevens, L.A., Behn, M.D., Das, S.B., Joughin, I., Noel, B. P. Y., van den Broeke, M., and T. Herring (2016). Greenland Ice Sheet flow response to runoff variability. Geophysical Research Letters, 43:11,295–11,303. doi:10.1002/2016GL070414.
  5. Stevens, L.A., Straneo, F., Das, S.B., Plueddemann, A.J., Kukulya, A.L., and M. Morlighem (2016). Linking glacially modified waters to catchment-scale subglacial discharge using autonomous underwater vehicle observations. The Cryosphere, 10:417–432. doi:10.5194/tc-10-417-2016.
  6. Stevens, L.A., Behn, M.D., McGuire, J.J., Das, S.B., Joughin, I., Herring, T., Shean, D.E., and M.A. King (2015). Greenland supraglacial lake drainages triggered by hydrologically induced basal slip. Nature, 522:73–76. doi:10.1038/nature14480.
  1. Keisling, B.A., Bryant, R., Golden, N., Stevens, L.A., and E. Alexander (2020). Does our Vision of Diversity Reduce Harm and Promote Justice? Geological Society of America (GSA) Today. 30. doi:10.1130/GSATG429GW.1
  2. Wagner, T. J. W., Straneo, F., Rickards, C. G., Slater, D., Stevens, L. A., Das, S. B., Singh, H. (2019). Large spatial variations in the flux balance along the front of a Greenland tidewater glacier. The Cryosphere, 13:911–925. doi:10.5194/tc-13-911-2019.
  3. Chaput, J., Aster, R.C., McGrath, D., Baker, M.G., Anthony, R.E., Gerstoft, P., Bromirski, P., Nyblade, A., Stephen, R.A., Wiens, D., Das, S.B., and Stevens, L.A. (2018). Near-surface environmentally forced changes in the Ross Ice Shelf observed with ambient seismic noise. Geophysical Research Letters, 45:181–187. doi:10.1029/2018GL079665.
  4. Carmichael, J.D., Joughin, I., Behn, M.D., Das, S.B., King, M.A., Stevens, L.A., and D. Lizarralde (2015). Seismicity on the Western Greenland Ice Sheet: Surface Fracture in the Vicinity of Active Moulins. Journal of Geophysical Research: Earth Surface, 120:1082–1106. doi:10.1002/2014JF003398.