Supraglacial debris thickness variability: impact on ablation and relation to terrain properties
Shallow ground-penetrating radar (GPR) surveys are used to characterize the small-scale spatial variability of supraglacial debris thickness on a Himalayan glacier. Debris thickness varies widely over short spatial scales. Comparison across sites and glaciers suggests that the skewness and kurtosis...
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ftdoajarticles:oai:doaj.org/article:ba8a073dc4c74208afdda58a2d92f274 2023-05-15T18:32:27+02:00 Supraglacial debris thickness variability: impact on ablation and relation to terrain properties L. I. Nicholson M. McCarthy H. D. Pritchard I. Willis 2018-11-01T00:00:00Z https://doi.org/10.5194/tc-12-3719-2018 https://doaj.org/article/ba8a073dc4c74208afdda58a2d92f274 EN eng Copernicus Publications https://www.the-cryosphere.net/12/3719/2018/tc-12-3719-2018.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-12-3719-2018 1994-0416 1994-0424 https://doaj.org/article/ba8a073dc4c74208afdda58a2d92f274 The Cryosphere, Vol 12, Pp 3719-3734 (2018) Environmental sciences GE1-350 Geology QE1-996.5 article 2018 ftdoajarticles https://doi.org/10.5194/tc-12-3719-2018 2022-12-31T12:25:00Z Shallow ground-penetrating radar (GPR) surveys are used to characterize the small-scale spatial variability of supraglacial debris thickness on a Himalayan glacier. Debris thickness varies widely over short spatial scales. Comparison across sites and glaciers suggests that the skewness and kurtosis of the debris thickness frequency distribution decrease with increasing mean debris thickness, and we hypothesize that this is related to the degree of gravitational reworking the debris cover has undergone and is therefore a proxy for the maturity of surface debris covers. In the cases tested here, using a single mean debris thickness value instead of accounting for the observed small-scale debris thickness variability underestimates modelled midsummer sub-debris ablation rates by 11 %–30 %. While no simple relationship is found between measured debris thickness and morphometric terrain parameters, analysis of the GPR data in conjunction with high-resolution terrain models provides some insight into the processes of debris gravitational reworking. Periodic sliding failure of the debris, rather than progressive mass diffusion, appears to be the main process redistributing supraglacial debris. The incidence of sliding is controlled by slope, aspect, upstream catchment area and debris thickness via their impacts on predisposition to slope failure and meltwater availability at the debris–ice interface. Slope stability modelling suggests that the percentage of the debris-covered glacier surface area subject to debris instability can be considerable at glacier scale, indicating that up to 32 % of the debris-covered area is susceptible to developing ablation hotspots associated with patches of thinner debris. Article in Journal/Newspaper The Cryosphere Directory of Open Access Journals: DOAJ Articles The Cryosphere 12 12 3719 3734 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 L. I. Nicholson M. McCarthy H. D. Pritchard I. Willis Supraglacial debris thickness variability: impact on ablation and relation to terrain properties |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Shallow ground-penetrating radar (GPR) surveys are used to characterize the small-scale spatial variability of supraglacial debris thickness on a Himalayan glacier. Debris thickness varies widely over short spatial scales. Comparison across sites and glaciers suggests that the skewness and kurtosis of the debris thickness frequency distribution decrease with increasing mean debris thickness, and we hypothesize that this is related to the degree of gravitational reworking the debris cover has undergone and is therefore a proxy for the maturity of surface debris covers. In the cases tested here, using a single mean debris thickness value instead of accounting for the observed small-scale debris thickness variability underestimates modelled midsummer sub-debris ablation rates by 11 %–30 %. While no simple relationship is found between measured debris thickness and morphometric terrain parameters, analysis of the GPR data in conjunction with high-resolution terrain models provides some insight into the processes of debris gravitational reworking. Periodic sliding failure of the debris, rather than progressive mass diffusion, appears to be the main process redistributing supraglacial debris. The incidence of sliding is controlled by slope, aspect, upstream catchment area and debris thickness via their impacts on predisposition to slope failure and meltwater availability at the debris–ice interface. Slope stability modelling suggests that the percentage of the debris-covered glacier surface area subject to debris instability can be considerable at glacier scale, indicating that up to 32 % of the debris-covered area is susceptible to developing ablation hotspots associated with patches of thinner debris. |
format |
Article in Journal/Newspaper |
author |
L. I. Nicholson M. McCarthy H. D. Pritchard I. Willis |
author_facet |
L. I. Nicholson M. McCarthy H. D. Pritchard I. Willis |
author_sort |
L. I. Nicholson |
title |
Supraglacial debris thickness variability: impact on ablation and relation to terrain properties |
title_short |
Supraglacial debris thickness variability: impact on ablation and relation to terrain properties |
title_full |
Supraglacial debris thickness variability: impact on ablation and relation to terrain properties |
title_fullStr |
Supraglacial debris thickness variability: impact on ablation and relation to terrain properties |
title_full_unstemmed |
Supraglacial debris thickness variability: impact on ablation and relation to terrain properties |
title_sort |
supraglacial debris thickness variability: impact on ablation and relation to terrain properties |
publisher |
Copernicus Publications |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-12-3719-2018 https://doaj.org/article/ba8a073dc4c74208afdda58a2d92f274 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 12, Pp 3719-3734 (2018) |
op_relation |
https://www.the-cryosphere.net/12/3719/2018/tc-12-3719-2018.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-12-3719-2018 1994-0416 1994-0424 https://doaj.org/article/ba8a073dc4c74208afdda58a2d92f274 |
op_doi |
https://doi.org/10.5194/tc-12-3719-2018 |
container_title |
The Cryosphere |
container_volume |
12 |
container_issue |
12 |
container_start_page |
3719 |
op_container_end_page |
3734 |
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1766216563430522880 |