Debris-covered glacier energy balance model for Imja–Lhotse Shar Glacier in the Everest region of Nepal
Debris thickness plays an important role in regulating ablation rates on debris-covered glaciers as well as controlling the likely size and location of supraglacial lakes. Despite its importance, lack of knowledge about debris properties and associated energy fluxes prevents the robust inclusion of...
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Copernicus Publications
2015
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Online Access: | https://doi.org/10.5194/tc-9-2295-2015 http://www.the-cryosphere.net/9/2295/2015/tc-9-2295-2015.pdf https://doaj.org/article/985ebbb795894a01be3eb707dbbe9ac7 |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:985ebbb795894a01be3eb707dbbe9ac7 2023-05-15T18:32:22+02:00 Debris-covered glacier energy balance model for Imja–Lhotse Shar Glacier in the Everest region of Nepal D. R. Rounce D. J. Quincey D. C. McKinney 2015-12-01 https://doi.org/10.5194/tc-9-2295-2015 http://www.the-cryosphere.net/9/2295/2015/tc-9-2295-2015.pdf https://doaj.org/article/985ebbb795894a01be3eb707dbbe9ac7 en eng Copernicus Publications 1994-0416 1994-0424 doi:10.5194/tc-9-2295-2015 http://www.the-cryosphere.net/9/2295/2015/tc-9-2295-2015.pdf https://doaj.org/article/985ebbb795894a01be3eb707dbbe9ac7 undefined The Cryosphere, Vol 9, Iss 6, Pp 2295-2310 (2015) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2015 fttriple https://doi.org/10.5194/tc-9-2295-2015 2023-01-22T19:12:29Z Debris thickness plays an important role in regulating ablation rates on debris-covered glaciers as well as controlling the likely size and location of supraglacial lakes. Despite its importance, lack of knowledge about debris properties and associated energy fluxes prevents the robust inclusion of the effects of a debris layer into most glacier surface energy balance models. This study combines fieldwork with a debris-covered glacier energy balance model to estimate debris temperatures and ablation rates on Imja–Lhotse Shar Glacier located in the Everest region of Nepal. The debris properties that significantly influence the energy balance model are the thermal conductivity, albedo, and surface roughness. Fieldwork was conducted to measure thermal conductivity and a method was developed using Structure from Motion to estimate surface roughness. Debris temperatures measured during the 2014 melt season were used to calibrate and validate a debris-covered glacier energy balance model by optimizing the albedo, thermal conductivity, and surface roughness at 10 debris-covered sites. Furthermore, three methods for estimating the latent heat flux were investigated. Model calibration and validation found the three methods had similar performance; however, comparison of modeled and measured ablation rates revealed that assuming the latent heat flux is zero may overestimate ablation. Results also suggest that where debris moisture is unknown, measurements of the relative humidity or precipitation may be used to estimate wet debris periods, i.e., when the latent heat flux is non-zero. The effect of temporal resolution on the model was also assessed and results showed that both 6 h data and daily average data slightly underestimate debris temperatures and ablation rates; thus these should only be used to estimate rough ablation rates when no other data are available. Article in Journal/Newspaper The Cryosphere Unknown The Cryosphere 9 6 2295 2310 |
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geo envir D. R. Rounce D. J. Quincey D. C. McKinney Debris-covered glacier energy balance model for Imja–Lhotse Shar Glacier in the Everest region of Nepal |
topic_facet |
geo envir |
description |
Debris thickness plays an important role in regulating ablation rates on debris-covered glaciers as well as controlling the likely size and location of supraglacial lakes. Despite its importance, lack of knowledge about debris properties and associated energy fluxes prevents the robust inclusion of the effects of a debris layer into most glacier surface energy balance models. This study combines fieldwork with a debris-covered glacier energy balance model to estimate debris temperatures and ablation rates on Imja–Lhotse Shar Glacier located in the Everest region of Nepal. The debris properties that significantly influence the energy balance model are the thermal conductivity, albedo, and surface roughness. Fieldwork was conducted to measure thermal conductivity and a method was developed using Structure from Motion to estimate surface roughness. Debris temperatures measured during the 2014 melt season were used to calibrate and validate a debris-covered glacier energy balance model by optimizing the albedo, thermal conductivity, and surface roughness at 10 debris-covered sites. Furthermore, three methods for estimating the latent heat flux were investigated. Model calibration and validation found the three methods had similar performance; however, comparison of modeled and measured ablation rates revealed that assuming the latent heat flux is zero may overestimate ablation. Results also suggest that where debris moisture is unknown, measurements of the relative humidity or precipitation may be used to estimate wet debris periods, i.e., when the latent heat flux is non-zero. The effect of temporal resolution on the model was also assessed and results showed that both 6 h data and daily average data slightly underestimate debris temperatures and ablation rates; thus these should only be used to estimate rough ablation rates when no other data are available. |
format |
Article in Journal/Newspaper |
author |
D. R. Rounce D. J. Quincey D. C. McKinney |
author_facet |
D. R. Rounce D. J. Quincey D. C. McKinney |
author_sort |
D. R. Rounce |
title |
Debris-covered glacier energy balance model for Imja–Lhotse Shar Glacier in the Everest region of Nepal |
title_short |
Debris-covered glacier energy balance model for Imja–Lhotse Shar Glacier in the Everest region of Nepal |
title_full |
Debris-covered glacier energy balance model for Imja–Lhotse Shar Glacier in the Everest region of Nepal |
title_fullStr |
Debris-covered glacier energy balance model for Imja–Lhotse Shar Glacier in the Everest region of Nepal |
title_full_unstemmed |
Debris-covered glacier energy balance model for Imja–Lhotse Shar Glacier in the Everest region of Nepal |
title_sort |
debris-covered glacier energy balance model for imja–lhotse shar glacier in the everest region of nepal |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/tc-9-2295-2015 http://www.the-cryosphere.net/9/2295/2015/tc-9-2295-2015.pdf https://doaj.org/article/985ebbb795894a01be3eb707dbbe9ac7 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 9, Iss 6, Pp 2295-2310 (2015) |
op_relation |
1994-0416 1994-0424 doi:10.5194/tc-9-2295-2015 http://www.the-cryosphere.net/9/2295/2015/tc-9-2295-2015.pdf https://doaj.org/article/985ebbb795894a01be3eb707dbbe9ac7 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-9-2295-2015 |
container_title |
The Cryosphere |
container_volume |
9 |
container_issue |
6 |
container_start_page |
2295 |
op_container_end_page |
2310 |
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1766216483012083712 |