Seasonal evolution of basal environment conditions of Russell sector, West Greenland, inverted from satellite observation of surface flow
Due to increasing surface melting on the Greenland ice sheet, better constraints on seasonally evolving basal water pressure and sliding speed are required by models. Here we assess the potential of using inverse methods on a dense time series of surface speeds to recover the seasonal evolution of t...
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ftcopernicus:oai:publications.copernicus.org:tc95024 2023-05-15T16:27:23+02:00 Seasonal evolution of basal environment conditions of Russell sector, West Greenland, inverted from satellite observation of surface flow Derkacheva, Anna Gillet-Chaulet, Fabien Mouginot, Jeremie Jager, Eliot Maier, Nathan Cook, Samuel 2021-12-17 application/pdf https://doi.org/10.5194/tc-15-5675-2021 https://tc.copernicus.org/articles/15/5675/2021/ eng eng doi:10.5194/tc-15-5675-2021 https://tc.copernicus.org/articles/15/5675/2021/ eISSN: 1994-0424 Text 2021 ftcopernicus https://doi.org/10.5194/tc-15-5675-2021 2021-12-20T17:22:29Z Due to increasing surface melting on the Greenland ice sheet, better constraints on seasonally evolving basal water pressure and sliding speed are required by models. Here we assess the potential of using inverse methods on a dense time series of surface speeds to recover the seasonal evolution of the basal conditions in a well-documented region in southwest Greenland. Using data compiled from multiple satellite missions, we document seasonally evolving surface velocities with a temporal resolution of 2 weeks between 2015 and 2019. We then apply the inverse control method using the ice flow model Elmer/Ice to infer the basal sliding and friction corresponding to each of the 24 surface velocity data sets. Near the margin where the uncertainty in the velocity and bed topography are small, we obtain clear seasonal variations that can be mostly interpreted in terms of an effective-pressure-based hard-bed friction law. We find for valley bottoms or “troughs” in the bed topography that the changes in modelled basal conditions directly respond to local modelled water pressure variations, while the link is more complex for subglacial “ridges” which are often non-locally forced. At the catchment scale, in-phase variations in the water pressure, surface velocities, and surface runoff variations are found. Our results show that time series inversions of observed surface velocities can be used to understand the evolution of basal conditions over different timescales and could therefore serve as an intermediate validation for subglacial hydrology models to achieve better coupling with ice flow models. Text Greenland Ice Sheet Copernicus Publications: E-Journals Greenland The Cryosphere 15 12 5675 5704 |
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Open Polar |
collection |
Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Due to increasing surface melting on the Greenland ice sheet, better constraints on seasonally evolving basal water pressure and sliding speed are required by models. Here we assess the potential of using inverse methods on a dense time series of surface speeds to recover the seasonal evolution of the basal conditions in a well-documented region in southwest Greenland. Using data compiled from multiple satellite missions, we document seasonally evolving surface velocities with a temporal resolution of 2 weeks between 2015 and 2019. We then apply the inverse control method using the ice flow model Elmer/Ice to infer the basal sliding and friction corresponding to each of the 24 surface velocity data sets. Near the margin where the uncertainty in the velocity and bed topography are small, we obtain clear seasonal variations that can be mostly interpreted in terms of an effective-pressure-based hard-bed friction law. We find for valley bottoms or “troughs” in the bed topography that the changes in modelled basal conditions directly respond to local modelled water pressure variations, while the link is more complex for subglacial “ridges” which are often non-locally forced. At the catchment scale, in-phase variations in the water pressure, surface velocities, and surface runoff variations are found. Our results show that time series inversions of observed surface velocities can be used to understand the evolution of basal conditions over different timescales and could therefore serve as an intermediate validation for subglacial hydrology models to achieve better coupling with ice flow models. |
format |
Text |
author |
Derkacheva, Anna Gillet-Chaulet, Fabien Mouginot, Jeremie Jager, Eliot Maier, Nathan Cook, Samuel |
spellingShingle |
Derkacheva, Anna Gillet-Chaulet, Fabien Mouginot, Jeremie Jager, Eliot Maier, Nathan Cook, Samuel Seasonal evolution of basal environment conditions of Russell sector, West Greenland, inverted from satellite observation of surface flow |
author_facet |
Derkacheva, Anna Gillet-Chaulet, Fabien Mouginot, Jeremie Jager, Eliot Maier, Nathan Cook, Samuel |
author_sort |
Derkacheva, Anna |
title |
Seasonal evolution of basal environment conditions of Russell sector, West Greenland, inverted from satellite observation of surface flow |
title_short |
Seasonal evolution of basal environment conditions of Russell sector, West Greenland, inverted from satellite observation of surface flow |
title_full |
Seasonal evolution of basal environment conditions of Russell sector, West Greenland, inverted from satellite observation of surface flow |
title_fullStr |
Seasonal evolution of basal environment conditions of Russell sector, West Greenland, inverted from satellite observation of surface flow |
title_full_unstemmed |
Seasonal evolution of basal environment conditions of Russell sector, West Greenland, inverted from satellite observation of surface flow |
title_sort |
seasonal evolution of basal environment conditions of russell sector, west greenland, inverted from satellite observation of surface flow |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-15-5675-2021 https://tc.copernicus.org/articles/15/5675/2021/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-15-5675-2021 https://tc.copernicus.org/articles/15/5675/2021/ |
op_doi |
https://doi.org/10.5194/tc-15-5675-2021 |
container_title |
The Cryosphere |
container_volume |
15 |
container_issue |
12 |
container_start_page |
5675 |
op_container_end_page |
5704 |
_version_ |
1766016536858853376 |