Response of surface topography to basal variability along glacial flowlines
Predicting the amplitude and distribution of surface undulations on ice sheets and glaciers is useful because of their influence on surface mass and energy balance, atmospheric boundary-layer processes, and supraglacial meltwater routing. We develop an approximate method of calculating the surface e...
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American Geophysical Union
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ftleedsuniv:oai:eprints.whiterose.ac.uk:132865 2023-05-15T16:20:38+02:00 Response of surface topography to basal variability along glacial flowlines Ng, F.S.L. Igneczi, A. Sole, A.J. Livingstone, S.J. 2018-11-21 text https://eprints.whiterose.ac.uk/132865/ https://eprints.whiterose.ac.uk/132865/16/Ng_et_al-2018-Journal_of_Geophysical_Research%253A_Earth_Surface.pdf en eng American Geophysical Union https://eprints.whiterose.ac.uk/132865/16/Ng_et_al-2018-Journal_of_Geophysical_Research%253A_Earth_Surface.pdf Ng, F.S.L. orcid.org/0000-0001-6352-0351 , Igneczi, A., Sole, A.J. et al. (1 more author) (2018) Response of surface topography to basal variability along glacial flowlines. Journal of Geophysical Research: Earth Surface, 123 (10). pp. 2319-2340. ISSN 2169-9011 cc_by_nc_nd_4 CC-BY-NC-ND Article PeerReviewed 2018 ftleedsuniv 2023-01-30T22:08:19Z Predicting the amplitude and distribution of surface undulations on ice sheets and glaciers is useful because of their influence on surface mass and energy balance, atmospheric boundary-layer processes, and supraglacial meltwater routing. We develop an approximate method of calculating the surface elevation response due to spatial perturbations in basal topography and slipperiness, on two-dimensional flow sections whose thickness, surface slope and basal slip ratio vary along flow. Our main result is an integral expressing nonuniform transfer of basal variability to the surface. It uses published Fourier transfer functions derived through perturbing plane-slab Stokes flow, but circumvents the need to sub-window the spatial domain to estimate the response. We test the method on ice flow synthesised by a finite-element model of Stokes flow with constant viscosity and known basal topography and slipperiness perturbations; in this case, it predicts the observed size and shape of the surface undulations well, capturing more than 90% of their variance. Application of the method to the central flowline of Columbia Glacier, Alaska and a flowline on the Greenland Ice Sheet ending on Nordenskiöld Glacier, using knowledge of the approximate bed topography and ignoring the unknown slipperiness forcing, yields less faithful prediction of their surface undulations (40–50% of their variance) but demonstrates the method’s potential to reproduce their qualitative features. We discuss the factors limiting the method’s performance on real flowlines. Article in Journal/Newspaper glacier glacier glaciers Greenland Ice Sheet Alaska White Rose Research Online (Universities of Leeds, Sheffield & York) Greenland |
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Open Polar |
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White Rose Research Online (Universities of Leeds, Sheffield & York) |
op_collection_id |
ftleedsuniv |
language |
English |
description |
Predicting the amplitude and distribution of surface undulations on ice sheets and glaciers is useful because of their influence on surface mass and energy balance, atmospheric boundary-layer processes, and supraglacial meltwater routing. We develop an approximate method of calculating the surface elevation response due to spatial perturbations in basal topography and slipperiness, on two-dimensional flow sections whose thickness, surface slope and basal slip ratio vary along flow. Our main result is an integral expressing nonuniform transfer of basal variability to the surface. It uses published Fourier transfer functions derived through perturbing plane-slab Stokes flow, but circumvents the need to sub-window the spatial domain to estimate the response. We test the method on ice flow synthesised by a finite-element model of Stokes flow with constant viscosity and known basal topography and slipperiness perturbations; in this case, it predicts the observed size and shape of the surface undulations well, capturing more than 90% of their variance. Application of the method to the central flowline of Columbia Glacier, Alaska and a flowline on the Greenland Ice Sheet ending on Nordenskiöld Glacier, using knowledge of the approximate bed topography and ignoring the unknown slipperiness forcing, yields less faithful prediction of their surface undulations (40–50% of their variance) but demonstrates the method’s potential to reproduce their qualitative features. We discuss the factors limiting the method’s performance on real flowlines. |
format |
Article in Journal/Newspaper |
author |
Ng, F.S.L. Igneczi, A. Sole, A.J. Livingstone, S.J. |
spellingShingle |
Ng, F.S.L. Igneczi, A. Sole, A.J. Livingstone, S.J. Response of surface topography to basal variability along glacial flowlines |
author_facet |
Ng, F.S.L. Igneczi, A. Sole, A.J. Livingstone, S.J. |
author_sort |
Ng, F.S.L. |
title |
Response of surface topography to basal variability along glacial flowlines |
title_short |
Response of surface topography to basal variability along glacial flowlines |
title_full |
Response of surface topography to basal variability along glacial flowlines |
title_fullStr |
Response of surface topography to basal variability along glacial flowlines |
title_full_unstemmed |
Response of surface topography to basal variability along glacial flowlines |
title_sort |
response of surface topography to basal variability along glacial flowlines |
publisher |
American Geophysical Union |
publishDate |
2018 |
url |
https://eprints.whiterose.ac.uk/132865/ https://eprints.whiterose.ac.uk/132865/16/Ng_et_al-2018-Journal_of_Geophysical_Research%253A_Earth_Surface.pdf |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier glacier glaciers Greenland Ice Sheet Alaska |
genre_facet |
glacier glacier glaciers Greenland Ice Sheet Alaska |
op_relation |
https://eprints.whiterose.ac.uk/132865/16/Ng_et_al-2018-Journal_of_Geophysical_Research%253A_Earth_Surface.pdf Ng, F.S.L. orcid.org/0000-0001-6352-0351 , Igneczi, A., Sole, A.J. et al. (1 more author) (2018) Response of surface topography to basal variability along glacial flowlines. Journal of Geophysical Research: Earth Surface, 123 (10). pp. 2319-2340. ISSN 2169-9011 |
op_rights |
cc_by_nc_nd_4 |
op_rightsnorm |
CC-BY-NC-ND |
_version_ |
1766008572324347904 |