How does glacier runoff impact the stability of glaciers and their proglacial environment?


  • Supervisors: Dr James Lea, University of Liverpool
    Dr Stephen Brough, University of Liverpool
    Prof Claire Mahaffey, University of Liverpool Prof Alessandro Tagliabue, University of Liverpool
    Dr Rob Duller, University of Liverpool
  • External Supervisors:

  • Contact:

    Dr James Lea, University of Liverpool, j.lea@liverpool.ac.uk

  • CASE Partner:

Application deadline: 10 January 2020

Introduction:

Meltwater runoff to ice sheet and glacier margins represents a fundamental component of overall mass balance, impacting tidewater glacier stability, proglacial sediment dynamics, and ocean biogeochemistry (e.g. Straneo and Heinbach, 2013; Hawkings et al., 2017). Recent advances in approaches to remote sensing of glacial environments allow analysis of these systems at previously unprecedented scales, meaning that for the first time it is possible to understand how the frequency, size and timing of these plumes impact regional/ice sheet scales. This project will seek to address questions linked to the impacts of plumes on (1) past, present and future glacier stability; (2) terrestrial proglacial environments and/or; (3) fjord and ocean biogeochemistry. One (or more) of these topics for the project will be agreed with the lead supervisor based on the interests of the applicant.

Project Summary:

A workflow for the automated identification of plumes/proglacial streams from MODIS/Sentinel 3 imagery will be developed within the Google Earth Engine platform to detect plume/river extent, duration and intensity (cf. Chu et al., 2012). Comparisons will be made with pre-existing datasets quantifying runoff, supraglacial lake drainage and glacier terminus change to determine their impacts on (1) tidewater glacier stability (cf. Cowton et al., 2019); (2) sandur geomorphology and sediment budgets and/or; (3) impacts on marine primary productivity (cf. Hopwood et al., 2018). 

Medium resolution satellite imagery from Landsat and Sentinel sensors will be used for validating the higher temporal resolution, but lower spatial resolution data of MODIS/Sentinel 3. These will be used to evaluate potential uncertainties and under-estimates of plume/stream extent, frequency and duration. Together, these will allow near-real time monitoring of proglacial conditions at ice sheet and glacier margins and their downstream impacts.

References:

Chu, V.W., Smith, L.C., Rennermalm, A.K., Forster, R.R. and Box, J.E., 2012. Hydrologic controls on coastal suspended sediment plumes around the Greenland Ice Sheet. The Cryosphere6(1), pp.1-19. 

Cowton, T.R., Todd, J.A. and Benn, D.I., 2019. Sensitivity of tidewater glaciers to submarine melting governed by plume locations. Geophysical Research Letters

Hawkings, J.R., Wadham, J.L., Benning, L.G., Hendry, K.R., Tranter, M., Tedstone, A., Nienow, P. and Raiswell, R., 2017. Ice sheets as a missing source of silica to the polar oceans. Nature communications8, p.14198. 

Hopwood, M.J., Carroll, D., Browning, T.J., Meire, L., Mortensen, J., Krisch, S. and Achterberg, E.P., 2018. Non-linear response of summertime marine productivity to increased meltwater discharge around Greenland. Nature communications9(1), p.3256. 

Nienow, P.W., Sole, A.J., Slater, D.A. and Cowton, T.R., 2017. Recent advances in our understanding of the role of meltwater in the Greenland ice sheet system. Current Climate Change Reports3(4), pp.330-344. 

Straneo, F. and Heimbach, P., 2013. North Atlantic warming and the retreat of Greenland's outlet glaciers. Nature504(7478), p.36.

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