Hydrological controls on Greenland Ice Sheet motion
An improved understanding of the processes controlling the dynamics of the Greenland Ice Sheet is needed to enable more accurate determination of the response of the ice sheet to projected climate change. Meltwater produced on the ice sheet surface can penetrate to the bed and cause ice motion to sp...
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The University of Edinburgh
2015
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ftunivedinburgh:oai:era.ed.ac.uk:1842/14169 2023-07-30T04:03:47+02:00 Hydrological controls on Greenland Ice Sheet motion Tedstone, Andrew Jachnik Nienow, Peter Natural Environment Research Council (NERC) 26/11/2015 application/pdf http://hdl.handle.net/1842/14169 en eng The University of Edinburgh Hawkings, J. R., J. L. Wadham, M. Tranter, R. Raiswell, L. G. Benning, P. J. Statham, A. J. Tedstone, P. Nienow, K. Lee and J. Telling, 2014. Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans, Nature Communications, 5, 3929. Sole, A., P. Nienow, I. Bartholomew, D. Mair, T. Cowton, A. Tedstone and M. King, 2013. Winter motion mediates dynamic response of the Greenland ice sheet to warmer summers, Geophys. Res. Lett., 40, 3940–3944. Tedstone, A. J. and N. S. Arnold, 2012. Automated remote sensing of sediment plumes for identification of runoff from the Greenland ice sheet, J. Glaciol., 58(210), 699–712. Tedstone, A. J., P. W. Nienow, N. Gourmelen and A. J. Sole, 2014. Greenland ice sheet annual motion insensitive to spatial variations in subglacial hydraulic structure, Geophysical Research Letters, 41(24), 8910–8917. Tedstone, A. J., P. W. Nienow, A. J. Sole, D. W. Mair, T. R. Cowton, I. D. Bartholomew and M. A. King, 2013. Greenland ice sheet motion insensitive to exceptional meltwater forcing, Proceedings of the National Academy of Sciences, 110(49), 19719–19724. http://hdl.handle.net/1842/14169 Greenland ice sheets ice flow subglacial hydrology GPS remote sensing Thesis or Dissertation Doctoral PhD Doctor of Philosophy 2015 ftunivedinburgh 2023-07-09T20:28:58Z An improved understanding of the processes controlling the dynamics of the Greenland Ice Sheet is needed to enable more accurate determination of the response of the ice sheet to projected climate change. Meltwater produced on the ice sheet surface can penetrate to the bed and cause ice motion to speed up through enhanced basal sliding. However, the importance of coupled hydro-dynamics both to current ice sheet motion and future stability over the coming century is unclear. This thesis presents observations from the south-west Greenland Ice Sheet which improve our understanding of coupled hydro-dynamics. It commences with an investigation of the response of ice motion to exceptional meltwater forcing during summer 2012. Simultaneous field observations of ice motion (by GPS) and proglacial discharge show that, despite two extreme melt events during July 2012 and summer ice sheet runoff 3.9 s.d. above the 1958– 2011 mean which resulted in faster summer motion, net annual motion was slower than in the average melt year of 2009. This suggests that surface melt-induced acceleration of land-terminating regions of the ice sheet will remain insignificant even under extreme melting scenarios. The thesis then examines spatial variability in ice motion, in relation to an inferred subglacial drainage axis, using GPS and satellite radar observations from a land-terminating margin up to 20 km inland where ice is 800 m thick. Whilst spatial variability in subglacial drainage system configuration is found to control ice motion at short timescales, the proportional contribution of summer motion to annual motion is almost invariant. The structure of the subglacial drainage system does not therefore appear to significantly influence spatial variations in net summer speedup. Lastly, observations are made by applying feature tracking to 30 years of optical satellite imagery in a ~170 by 50 km area along the ice sheet margin (where ice reaches ~850 m thick) to examine whether coupled hydrology-dynamics affects inter-annual ice ... Doctoral or Postdoctoral Thesis Greenland Ice Sheet Edinburgh Research Archive (ERA - University of Edinburgh) Greenland |
institution |
Open Polar |
collection |
Edinburgh Research Archive (ERA - University of Edinburgh) |
op_collection_id |
ftunivedinburgh |
language |
English |
topic |
Greenland ice sheets ice flow subglacial hydrology GPS remote sensing |
spellingShingle |
Greenland ice sheets ice flow subglacial hydrology GPS remote sensing Tedstone, Andrew Jachnik Hydrological controls on Greenland Ice Sheet motion |
topic_facet |
Greenland ice sheets ice flow subglacial hydrology GPS remote sensing |
description |
An improved understanding of the processes controlling the dynamics of the Greenland Ice Sheet is needed to enable more accurate determination of the response of the ice sheet to projected climate change. Meltwater produced on the ice sheet surface can penetrate to the bed and cause ice motion to speed up through enhanced basal sliding. However, the importance of coupled hydro-dynamics both to current ice sheet motion and future stability over the coming century is unclear. This thesis presents observations from the south-west Greenland Ice Sheet which improve our understanding of coupled hydro-dynamics. It commences with an investigation of the response of ice motion to exceptional meltwater forcing during summer 2012. Simultaneous field observations of ice motion (by GPS) and proglacial discharge show that, despite two extreme melt events during July 2012 and summer ice sheet runoff 3.9 s.d. above the 1958– 2011 mean which resulted in faster summer motion, net annual motion was slower than in the average melt year of 2009. This suggests that surface melt-induced acceleration of land-terminating regions of the ice sheet will remain insignificant even under extreme melting scenarios. The thesis then examines spatial variability in ice motion, in relation to an inferred subglacial drainage axis, using GPS and satellite radar observations from a land-terminating margin up to 20 km inland where ice is 800 m thick. Whilst spatial variability in subglacial drainage system configuration is found to control ice motion at short timescales, the proportional contribution of summer motion to annual motion is almost invariant. The structure of the subglacial drainage system does not therefore appear to significantly influence spatial variations in net summer speedup. Lastly, observations are made by applying feature tracking to 30 years of optical satellite imagery in a ~170 by 50 km area along the ice sheet margin (where ice reaches ~850 m thick) to examine whether coupled hydrology-dynamics affects inter-annual ice ... |
author2 |
Nienow, Peter Natural Environment Research Council (NERC) |
format |
Doctoral or Postdoctoral Thesis |
author |
Tedstone, Andrew Jachnik |
author_facet |
Tedstone, Andrew Jachnik |
author_sort |
Tedstone, Andrew Jachnik |
title |
Hydrological controls on Greenland Ice Sheet motion |
title_short |
Hydrological controls on Greenland Ice Sheet motion |
title_full |
Hydrological controls on Greenland Ice Sheet motion |
title_fullStr |
Hydrological controls on Greenland Ice Sheet motion |
title_full_unstemmed |
Hydrological controls on Greenland Ice Sheet motion |
title_sort |
hydrological controls on greenland ice sheet motion |
publisher |
The University of Edinburgh |
publishDate |
2015 |
url |
http://hdl.handle.net/1842/14169 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_relation |
Hawkings, J. R., J. L. Wadham, M. Tranter, R. Raiswell, L. G. Benning, P. J. Statham, A. J. Tedstone, P. Nienow, K. Lee and J. Telling, 2014. Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans, Nature Communications, 5, 3929. Sole, A., P. Nienow, I. Bartholomew, D. Mair, T. Cowton, A. Tedstone and M. King, 2013. Winter motion mediates dynamic response of the Greenland ice sheet to warmer summers, Geophys. Res. Lett., 40, 3940–3944. Tedstone, A. J. and N. S. Arnold, 2012. Automated remote sensing of sediment plumes for identification of runoff from the Greenland ice sheet, J. Glaciol., 58(210), 699–712. Tedstone, A. J., P. W. Nienow, N. Gourmelen and A. J. Sole, 2014. Greenland ice sheet annual motion insensitive to spatial variations in subglacial hydraulic structure, Geophysical Research Letters, 41(24), 8910–8917. Tedstone, A. J., P. W. Nienow, A. J. Sole, D. W. Mair, T. R. Cowton, I. D. Bartholomew and M. A. King, 2013. Greenland ice sheet motion insensitive to exceptional meltwater forcing, Proceedings of the National Academy of Sciences, 110(49), 19719–19724. http://hdl.handle.net/1842/14169 |
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