Characterising englacial R-channels using artificial moulins
Abstract The englacial and subglacial drainage systems exert key controls on glacier dynamics. However, due to their inaccessibility, they are still only poorly understood and more detailed observations are important, particularly to validate and tune physical models describing their dynamics. By cr...
Published in: | Journal of Glaciology |
---|---|
Main Authors: | , , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Cambridge University Press (CUP)
2022
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1017/jog.2022.4 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000041 |
id |
crcambridgeupr:10.1017/jog.2022.4 |
---|---|
record_format |
openpolar |
spelling |
crcambridgeupr:10.1017/jog.2022.4 2024-05-12T08:06:15+00:00 Characterising englacial R-channels using artificial moulins Pohle, Annegret Werder, Mauro A. Gräff, Dominik Farinotti, Daniel Eidgenössische Technische Hochschule Zürich Eidgenössische Technische Hochschule Zürich 2022 http://dx.doi.org/10.1017/jog.2022.4 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000041 en eng Cambridge University Press (CUP) https://creativecommons.org/licenses/by/4.0/ Journal of Glaciology page 1-12 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 2022 crcambridgeupr https://doi.org/10.1017/jog.2022.4 2024-04-18T06:54:07Z Abstract The englacial and subglacial drainage systems exert key controls on glacier dynamics. However, due to their inaccessibility, they are still only poorly understood and more detailed observations are important, particularly to validate and tune physical models describing their dynamics. By creating artificial glacier moulins – boreholes connected to the subglacial drainage system and supplied with water from surface streams – we present a novel method to monitor the evolution of an englacial hydrological system with high temporal resolution. Here, we use artificial moulins as representations for vertical, pressurised, englacial R-channels. From tracer and pressure measurements, we derive time series of the hydraulic gradient, discharge, flow speed and channel cross-sectional area. Using these, we compute the Darcy–Weisbach friction factor, obtaining values which increase from 0.1 to 13 within five days of channel evolution. Furthermore, we simulate the growth of the cross-sectional area using different temperature gradients. The comparison to our measurements largely supports the common assumption that the temperature follows the pressure melting point. The deviations from this behaviour are analysed using various heat transfer parameterisations to assess their applicability. Finally, we discuss how artificial moulins could be combined with glacier-wide tracer experiments to constrain parameters of subglacial drainage more precisely. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Journal of Glaciology 1 12 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
spellingShingle |
Earth-Surface Processes Pohle, Annegret Werder, Mauro A. Gräff, Dominik Farinotti, Daniel Characterising englacial R-channels using artificial moulins |
topic_facet |
Earth-Surface Processes |
description |
Abstract The englacial and subglacial drainage systems exert key controls on glacier dynamics. However, due to their inaccessibility, they are still only poorly understood and more detailed observations are important, particularly to validate and tune physical models describing their dynamics. By creating artificial glacier moulins – boreholes connected to the subglacial drainage system and supplied with water from surface streams – we present a novel method to monitor the evolution of an englacial hydrological system with high temporal resolution. Here, we use artificial moulins as representations for vertical, pressurised, englacial R-channels. From tracer and pressure measurements, we derive time series of the hydraulic gradient, discharge, flow speed and channel cross-sectional area. Using these, we compute the Darcy–Weisbach friction factor, obtaining values which increase from 0.1 to 13 within five days of channel evolution. Furthermore, we simulate the growth of the cross-sectional area using different temperature gradients. The comparison to our measurements largely supports the common assumption that the temperature follows the pressure melting point. The deviations from this behaviour are analysed using various heat transfer parameterisations to assess their applicability. Finally, we discuss how artificial moulins could be combined with glacier-wide tracer experiments to constrain parameters of subglacial drainage more precisely. |
author2 |
Eidgenössische Technische Hochschule Zürich Eidgenössische Technische Hochschule Zürich |
format |
Article in Journal/Newspaper |
author |
Pohle, Annegret Werder, Mauro A. Gräff, Dominik Farinotti, Daniel |
author_facet |
Pohle, Annegret Werder, Mauro A. Gräff, Dominik Farinotti, Daniel |
author_sort |
Pohle, Annegret |
title |
Characterising englacial R-channels using artificial moulins |
title_short |
Characterising englacial R-channels using artificial moulins |
title_full |
Characterising englacial R-channels using artificial moulins |
title_fullStr |
Characterising englacial R-channels using artificial moulins |
title_full_unstemmed |
Characterising englacial R-channels using artificial moulins |
title_sort |
characterising englacial r-channels using artificial moulins |
publisher |
Cambridge University Press (CUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1017/jog.2022.4 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000041 |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology page 1-12 ISSN 0022-1430 1727-5652 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2022.4 |
container_title |
Journal of Glaciology |
container_start_page |
1 |
op_container_end_page |
12 |
_version_ |
1798848706718466048 |