Recent changes in drainage route and outburst magnitude of Russell Glacier ice-dammed lake, West Greenland
Glacial lake outburst floods (GLOFs) or ‘jökulhlaups’ from ice-dammed lakes are frequent in Greenland and can influence local ice dynamics, bedrock displacement, geomorphological changes and flooding hazards. Multidecadal time series of lake drainage dates, drainage volumes and flood outlets are rar...
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ftcopernicus:oai:publications.copernicus.org:egusphere104881 2023-05-15T16:21:15+02:00 Recent changes in drainage route and outburst magnitude of Russell Glacier ice-dammed lake, West Greenland Dømgaard, Mads Kjeldsen, Kristian Kjellerup Huiban, Flora Carrivick, Jonathan Lee Khan, Shfaqat Abbas Bjørk, Anders Anker 2022-08-03 application/pdf https://doi.org/10.5194/egusphere-2022-566 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-566/ eng eng doi:10.5194/egusphere-2022-566 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-566/ eISSN: Text 2022 ftcopernicus https://doi.org/10.5194/egusphere-2022-566 2022-08-08T16:22:56Z Glacial lake outburst floods (GLOFs) or ‘jökulhlaups’ from ice-dammed lakes are frequent in Greenland and can influence local ice dynamics, bedrock displacement, geomorphological changes and flooding hazards. Multidecadal time series of lake drainage dates, drainage volumes and flood outlets are rare but essential for understanding the impact on and interaction with the surroundings, identifying drainage mechanisms, and for mitigating downstream flood effects. In this study, we use ultra-high-resolution structure-from-motion (SfM) digital elevation models (DEM) and orthophotos from unmanned aerial vehicle field surveys in combination with optical satellite imagery to reconstruct robust lake volume changes associated with 14 GLOFs between 2007 and 2021 at Russell Glacier, West Greenland. This makes it, one of the most comprehensive and longest records of ice-dammed lake drainages in Greenland. We find a mean difference of 10 % between the lake drainage volumes compared with estimates derived from a gauged hydrograph 27 km downstream. Due to ice dam thinning, the potential maximum drainage volume in 2021 is c. 60 % smaller than that estimated to have drained in 2007. Our time series reveals variations in the drainage dates ranging from late May to mid-September and moreover that drained volumes range between 0.9–37.7 M m 3 . We attribute these fluctuations between short periods of relatively high and low drainage volumes to a weakening of the ice dam and an incomplete sealing of the englacial tunnel following the large GLOFs. The syphoning drainage mechanism is triggered by a reduction in englacial meltwater, likely driven by late seasonal drainages and sudden temperature reductions, as well as annual variations in the glacial drainage system. Furthermore, we provide geomorphological evidence of an additional drainage route first observed following the 2021 GLOF with a sub- or englacial and supraglacial water flow across the ice margin. It seems probable that the new drainage route will become dominant in the ... Text glacier Greenland Copernicus Publications: E-Journals Dammed Lake ENVELOPE(-68.258,-68.258,68.496,68.496) Glacial Lake ENVELOPE(-129.463,-129.463,58.259,58.259) Greenland |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Glacial lake outburst floods (GLOFs) or ‘jökulhlaups’ from ice-dammed lakes are frequent in Greenland and can influence local ice dynamics, bedrock displacement, geomorphological changes and flooding hazards. Multidecadal time series of lake drainage dates, drainage volumes and flood outlets are rare but essential for understanding the impact on and interaction with the surroundings, identifying drainage mechanisms, and for mitigating downstream flood effects. In this study, we use ultra-high-resolution structure-from-motion (SfM) digital elevation models (DEM) and orthophotos from unmanned aerial vehicle field surveys in combination with optical satellite imagery to reconstruct robust lake volume changes associated with 14 GLOFs between 2007 and 2021 at Russell Glacier, West Greenland. This makes it, one of the most comprehensive and longest records of ice-dammed lake drainages in Greenland. We find a mean difference of 10 % between the lake drainage volumes compared with estimates derived from a gauged hydrograph 27 km downstream. Due to ice dam thinning, the potential maximum drainage volume in 2021 is c. 60 % smaller than that estimated to have drained in 2007. Our time series reveals variations in the drainage dates ranging from late May to mid-September and moreover that drained volumes range between 0.9–37.7 M m 3 . We attribute these fluctuations between short periods of relatively high and low drainage volumes to a weakening of the ice dam and an incomplete sealing of the englacial tunnel following the large GLOFs. The syphoning drainage mechanism is triggered by a reduction in englacial meltwater, likely driven by late seasonal drainages and sudden temperature reductions, as well as annual variations in the glacial drainage system. Furthermore, we provide geomorphological evidence of an additional drainage route first observed following the 2021 GLOF with a sub- or englacial and supraglacial water flow across the ice margin. It seems probable that the new drainage route will become dominant in the ... |
format |
Text |
author |
Dømgaard, Mads Kjeldsen, Kristian Kjellerup Huiban, Flora Carrivick, Jonathan Lee Khan, Shfaqat Abbas Bjørk, Anders Anker |
spellingShingle |
Dømgaard, Mads Kjeldsen, Kristian Kjellerup Huiban, Flora Carrivick, Jonathan Lee Khan, Shfaqat Abbas Bjørk, Anders Anker Recent changes in drainage route and outburst magnitude of Russell Glacier ice-dammed lake, West Greenland |
author_facet |
Dømgaard, Mads Kjeldsen, Kristian Kjellerup Huiban, Flora Carrivick, Jonathan Lee Khan, Shfaqat Abbas Bjørk, Anders Anker |
author_sort |
Dømgaard, Mads |
title |
Recent changes in drainage route and outburst magnitude of Russell Glacier ice-dammed lake, West Greenland |
title_short |
Recent changes in drainage route and outburst magnitude of Russell Glacier ice-dammed lake, West Greenland |
title_full |
Recent changes in drainage route and outburst magnitude of Russell Glacier ice-dammed lake, West Greenland |
title_fullStr |
Recent changes in drainage route and outburst magnitude of Russell Glacier ice-dammed lake, West Greenland |
title_full_unstemmed |
Recent changes in drainage route and outburst magnitude of Russell Glacier ice-dammed lake, West Greenland |
title_sort |
recent changes in drainage route and outburst magnitude of russell glacier ice-dammed lake, west greenland |
publishDate |
2022 |
url |
https://doi.org/10.5194/egusphere-2022-566 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-566/ |
long_lat |
ENVELOPE(-68.258,-68.258,68.496,68.496) ENVELOPE(-129.463,-129.463,58.259,58.259) |
geographic |
Dammed Lake Glacial Lake Greenland |
geographic_facet |
Dammed Lake Glacial Lake Greenland |
genre |
glacier Greenland |
genre_facet |
glacier Greenland |
op_source |
eISSN: |
op_relation |
doi:10.5194/egusphere-2022-566 https://egusphere.copernicus.org/preprints/2022/egusphere-2022-566/ |
op_doi |
https://doi.org/10.5194/egusphere-2022-566 |
_version_ |
1766009256596733952 |