Controls on Greenland moulin geometry and evolution from the Moulin Shape model
Nearly all meltwater from glaciers and ice sheets is routed englacially through moulins, which collectively comprise approximately 10–14 % of the efficient englacial–subglacial hydrologic system. Therefore, the geometry and evolution of moulins has the potential to influence subglacial water pressur...
Main Authors: | , , |
---|---|
Format: | Text |
Language: | English |
Published: |
2021
|
Subjects: | |
Online Access: | https://doi.org/10.5194/tc-2021-41 https://tc.copernicus.org/preprints/tc-2021-41/ |
id |
ftcopernicus:oai:publications.copernicus.org:tcd92764 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:tcd92764 2023-05-15T16:29:17+02:00 Controls on Greenland moulin geometry and evolution from the Moulin Shape model Andrews, Lauren C. Poinar, Kristin Trunz, Celia 2021-02-25 application/pdf https://doi.org/10.5194/tc-2021-41 https://tc.copernicus.org/preprints/tc-2021-41/ eng eng doi:10.5194/tc-2021-41 https://tc.copernicus.org/preprints/tc-2021-41/ eISSN: 1994-0424 Text 2021 ftcopernicus https://doi.org/10.5194/tc-2021-41 2021-03-01T17:22:14Z Nearly all meltwater from glaciers and ice sheets is routed englacially through moulins, which collectively comprise approximately 10–14 % of the efficient englacial–subglacial hydrologic system. Therefore, the geometry and evolution of moulins has the potential to influence subglacial water pressure variations, ice motion, and the runoff hydrograph delivered to the ocean. We develop the Mou lin Sh ape (MouSh) model, a time-evolving model of moulin geometry. MouSh models ice deformation around a moulin using both viscous and elastic rheologies and models melting within the moulin through heat dissipation from turbulent water flow, both above and below the water line. We force MouSh with idealized and realistic surface melt inputs. Our results show that variations in surface melt change the geometry of a moulin by approximately 30 % daily and by over 100 % seasonally. These size variations cause observable differences in moulin water storage capacity, moulin water levels, and subglacial channel size compared to a static, cylindrical moulin. Our results suggest that moulins are significant storage reservoirs for meltwater, with storage capacity and water levels varying over multiple timescales. Representing moulin geometry within subglacial hydrologic models would therefore improve their accuracy, especially over seasonal periods or in regions where overburden pressures are high. Text Greenland Copernicus Publications: E-Journals Greenland |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Nearly all meltwater from glaciers and ice sheets is routed englacially through moulins, which collectively comprise approximately 10–14 % of the efficient englacial–subglacial hydrologic system. Therefore, the geometry and evolution of moulins has the potential to influence subglacial water pressure variations, ice motion, and the runoff hydrograph delivered to the ocean. We develop the Mou lin Sh ape (MouSh) model, a time-evolving model of moulin geometry. MouSh models ice deformation around a moulin using both viscous and elastic rheologies and models melting within the moulin through heat dissipation from turbulent water flow, both above and below the water line. We force MouSh with idealized and realistic surface melt inputs. Our results show that variations in surface melt change the geometry of a moulin by approximately 30 % daily and by over 100 % seasonally. These size variations cause observable differences in moulin water storage capacity, moulin water levels, and subglacial channel size compared to a static, cylindrical moulin. Our results suggest that moulins are significant storage reservoirs for meltwater, with storage capacity and water levels varying over multiple timescales. Representing moulin geometry within subglacial hydrologic models would therefore improve their accuracy, especially over seasonal periods or in regions where overburden pressures are high. |
format |
Text |
author |
Andrews, Lauren C. Poinar, Kristin Trunz, Celia |
spellingShingle |
Andrews, Lauren C. Poinar, Kristin Trunz, Celia Controls on Greenland moulin geometry and evolution from the Moulin Shape model |
author_facet |
Andrews, Lauren C. Poinar, Kristin Trunz, Celia |
author_sort |
Andrews, Lauren C. |
title |
Controls on Greenland moulin geometry and evolution from the Moulin Shape model |
title_short |
Controls on Greenland moulin geometry and evolution from the Moulin Shape model |
title_full |
Controls on Greenland moulin geometry and evolution from the Moulin Shape model |
title_fullStr |
Controls on Greenland moulin geometry and evolution from the Moulin Shape model |
title_full_unstemmed |
Controls on Greenland moulin geometry and evolution from the Moulin Shape model |
title_sort |
controls on greenland moulin geometry and evolution from the moulin shape model |
publishDate |
2021 |
url |
https://doi.org/10.5194/tc-2021-41 https://tc.copernicus.org/preprints/tc-2021-41/ |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-2021-41 https://tc.copernicus.org/preprints/tc-2021-41/ |
op_doi |
https://doi.org/10.5194/tc-2021-41 |
_version_ |
1766018973854334976 |