Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements
Observational data allowing the validation of jökulhlaup models are sparse. We were able to inject dye tracer directly into the drainage channel of a glacial lake during the onset of its outburst. This made it possible to test an established jökulhlaup model, not only against discharge measurements,...
Published in: | Journal of Glaciology |
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Format: | Article in Journal/Newspaper |
Language: | English |
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2009
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Online Access: | https://hdl.handle.net/1983/a6f5484d-b84d-45c8-8f2e-6254c39c9f28 https://research-information.bris.ac.uk/en/publications/a6f5484d-b84d-45c8-8f2e-6254c39c9f28 https://doi.org/10.3189/002214309790152375 |
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ftubristolcris:oai:research-information.bris.ac.uk:publications/a6f5484d-b84d-45c8-8f2e-6254c39c9f28 2024-02-04T10:01:42+01:00 Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements Werder, Mauro A Funk, Martin 2009 https://hdl.handle.net/1983/a6f5484d-b84d-45c8-8f2e-6254c39c9f28 https://research-information.bris.ac.uk/en/publications/a6f5484d-b84d-45c8-8f2e-6254c39c9f28 https://doi.org/10.3189/002214309790152375 eng eng info:eu-repo/semantics/restrictedAccess Werder , M A & Funk , M 2009 , ' Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements ' , Journal of Glaciology , vol. 55 , no. 193 , pp. 899-908 . https://doi.org/10.3189/002214309790152375 article 2009 ftubristolcris https://doi.org/10.3189/002214309790152375 2024-01-11T23:37:45Z Observational data allowing the validation of jökulhlaup models are sparse. We were able to inject dye tracer directly into the drainage channel of a glacial lake during the onset of its outburst. This made it possible to test an established jökulhlaup model, not only against discharge measurements, but for the first time also against water flow speeds inferred from measurements. We drive the jökulhlaup model, based on the Spring-Hutter equations, with measured subglacial water pressure, lake water temperature and lake level. The model is fitted to the measured lake discharge and inferred flow speeds using the initial channel size, the channel roughness and sinuosity. Our calculations show that an ingenuous application of the model, fitting it to the lake discharge only, overestimates water flow speeds. For the second day of the outburst, this can be remedied by fitting the model to the inferred flow speeds as well, requiring that either the heat transfer or the sinuosity of the channel be increased. However, the low inferred flow speeds on the first day of the outburst cannot be fitted with any parameter combination, showing that, initially, the water does not flow through an R channel. Hence, the early stages of this jökulhlaup cannot be simulated by an R-channel model. Article in Journal/Newspaper Journal of Glaciology University of Bristol: Bristol Research Glacial Lake ENVELOPE(-129.463,-129.463,58.259,58.259) Journal of Glaciology 55 193 899 908 |
institution |
Open Polar |
collection |
University of Bristol: Bristol Research |
op_collection_id |
ftubristolcris |
language |
English |
description |
Observational data allowing the validation of jökulhlaup models are sparse. We were able to inject dye tracer directly into the drainage channel of a glacial lake during the onset of its outburst. This made it possible to test an established jökulhlaup model, not only against discharge measurements, but for the first time also against water flow speeds inferred from measurements. We drive the jökulhlaup model, based on the Spring-Hutter equations, with measured subglacial water pressure, lake water temperature and lake level. The model is fitted to the measured lake discharge and inferred flow speeds using the initial channel size, the channel roughness and sinuosity. Our calculations show that an ingenuous application of the model, fitting it to the lake discharge only, overestimates water flow speeds. For the second day of the outburst, this can be remedied by fitting the model to the inferred flow speeds as well, requiring that either the heat transfer or the sinuosity of the channel be increased. However, the low inferred flow speeds on the first day of the outburst cannot be fitted with any parameter combination, showing that, initially, the water does not flow through an R channel. Hence, the early stages of this jökulhlaup cannot be simulated by an R-channel model. |
format |
Article in Journal/Newspaper |
author |
Werder, Mauro A Funk, Martin |
spellingShingle |
Werder, Mauro A Funk, Martin Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements |
author_facet |
Werder, Mauro A Funk, Martin |
author_sort |
Werder, Mauro A |
title |
Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements |
title_short |
Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements |
title_full |
Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements |
title_fullStr |
Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements |
title_full_unstemmed |
Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements |
title_sort |
dye tracing a jökulhlaup: ii. testing a jökulhlaup model against flow speeds inferred from measurements |
publishDate |
2009 |
url |
https://hdl.handle.net/1983/a6f5484d-b84d-45c8-8f2e-6254c39c9f28 https://research-information.bris.ac.uk/en/publications/a6f5484d-b84d-45c8-8f2e-6254c39c9f28 https://doi.org/10.3189/002214309790152375 |
long_lat |
ENVELOPE(-129.463,-129.463,58.259,58.259) |
geographic |
Glacial Lake |
geographic_facet |
Glacial Lake |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Werder , M A & Funk , M 2009 , ' Dye tracing a jökulhlaup: II. Testing a jökulhlaup model against flow speeds inferred from measurements ' , Journal of Glaciology , vol. 55 , no. 193 , pp. 899-908 . https://doi.org/10.3189/002214309790152375 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.3189/002214309790152375 |
container_title |
Journal of Glaciology |
container_volume |
55 |
container_issue |
193 |
container_start_page |
899 |
op_container_end_page |
908 |
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1789967835198390272 |