High-resolution modelling of the seasonal evolution of surface water storage on the Greenland Ice Sheet
Seasonal meltwater lakes on the Greenland Ice Sheet form when surface runoff is temporarily trapped in surface topographic depressions. The development of such lakes affects both the surface energy balance and dynamics of the ice sheet. Although areal extents, depths, and lifespans of lakes can be i...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/273621 2024-01-14T10:07:15+01:00 High-resolution modelling of the seasonal evolution of surface water storage on the Greenland Ice Sheet Arnold, NS Banwell, A Willis, IC 2014 application/pdf https://www.repository.cam.ac.uk/handle/1810/273621 https://doi.org/10.17863/CAM.20690 eng eng Copernicus Publications http://dx.doi.org/10.5194/tc-8-1149-2014 The Cryosphere https://www.repository.cam.ac.uk/handle/1810/273621 doi:10.17863/CAM.20690 Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ 3707 Hydrology 3709 Physical Geography and Environmental Geoscience 37 Earth Sciences 3705 Geology Article 2014 ftunivcam https://doi.org/10.17863/CAM.20690 2023-12-21T23:28:43Z Seasonal meltwater lakes on the Greenland Ice Sheet form when surface runoff is temporarily trapped in surface topographic depressions. The development of such lakes affects both the surface energy balance and dynamics of the ice sheet. Although areal extents, depths, and lifespans of lakes can be inferred from satellite imagery, such observational studies have a limited temporal resolution. Here, we adopt a modelling-based strategy to estimate the seasonal evolution of surface water storage for the ~3600 km2 Paakitsoq region of W. Greenland. We use a high-resolution time dependent surface mass balance model to calculate surface melt, a supraglacial water routing model to calculate lake filling and a prescribed water-volume based threshold to predict rapid lake drainage events. This threshold assumes that drainage will occur through a fracture if V = Fa.H, where V is lake volume, H is the local ice thickness and Fa is the potential fracture area. The model shows good agreement between modelled lake locations and volumes and those observed in 9 Landsat 7 ETM+ images from 2001, 2002 and 2005. We use the model to investigate the lake water volume required to trigger drainage, and the impact that varying this threshold volume has on the proportion of meltwater that is stored in surface lakes and enters the subglacial drainage system. Model performance is maximised with values of Fa between 4000 and 7500 m2. For these thresholds, lakes transiently store <40% of available meltwater at the beginning of the melt season, decreasing to ~5 to 10% by the middle of the melt season; over the course of a melt-season, 40 to 50% of total meltwater production enters the subglacial drainage system through moulins at the bottom of drained lakes. This work was partially funded by the UK Natural Environment Research Council Doctoral Training grant to A. F. Banwell (LCAG/ 133) (CASE Studentship with The Geological Survey of Denmark and Greenland (GEUS)). Article in Journal/Newspaper Greenland Ice Sheet Apollo - University of Cambridge Repository Greenland Rapid Lake ENVELOPE(177.619,177.619,52.064,52.064) |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
3707 Hydrology 3709 Physical Geography and Environmental Geoscience 37 Earth Sciences 3705 Geology |
spellingShingle |
3707 Hydrology 3709 Physical Geography and Environmental Geoscience 37 Earth Sciences 3705 Geology Arnold, NS Banwell, A Willis, IC High-resolution modelling of the seasonal evolution of surface water storage on the Greenland Ice Sheet |
topic_facet |
3707 Hydrology 3709 Physical Geography and Environmental Geoscience 37 Earth Sciences 3705 Geology |
description |
Seasonal meltwater lakes on the Greenland Ice Sheet form when surface runoff is temporarily trapped in surface topographic depressions. The development of such lakes affects both the surface energy balance and dynamics of the ice sheet. Although areal extents, depths, and lifespans of lakes can be inferred from satellite imagery, such observational studies have a limited temporal resolution. Here, we adopt a modelling-based strategy to estimate the seasonal evolution of surface water storage for the ~3600 km2 Paakitsoq region of W. Greenland. We use a high-resolution time dependent surface mass balance model to calculate surface melt, a supraglacial water routing model to calculate lake filling and a prescribed water-volume based threshold to predict rapid lake drainage events. This threshold assumes that drainage will occur through a fracture if V = Fa.H, where V is lake volume, H is the local ice thickness and Fa is the potential fracture area. The model shows good agreement between modelled lake locations and volumes and those observed in 9 Landsat 7 ETM+ images from 2001, 2002 and 2005. We use the model to investigate the lake water volume required to trigger drainage, and the impact that varying this threshold volume has on the proportion of meltwater that is stored in surface lakes and enters the subglacial drainage system. Model performance is maximised with values of Fa between 4000 and 7500 m2. For these thresholds, lakes transiently store <40% of available meltwater at the beginning of the melt season, decreasing to ~5 to 10% by the middle of the melt season; over the course of a melt-season, 40 to 50% of total meltwater production enters the subglacial drainage system through moulins at the bottom of drained lakes. This work was partially funded by the UK Natural Environment Research Council Doctoral Training grant to A. F. Banwell (LCAG/ 133) (CASE Studentship with The Geological Survey of Denmark and Greenland (GEUS)). |
format |
Article in Journal/Newspaper |
author |
Arnold, NS Banwell, A Willis, IC |
author_facet |
Arnold, NS Banwell, A Willis, IC |
author_sort |
Arnold, NS |
title |
High-resolution modelling of the seasonal evolution of surface water storage on the Greenland Ice Sheet |
title_short |
High-resolution modelling of the seasonal evolution of surface water storage on the Greenland Ice Sheet |
title_full |
High-resolution modelling of the seasonal evolution of surface water storage on the Greenland Ice Sheet |
title_fullStr |
High-resolution modelling of the seasonal evolution of surface water storage on the Greenland Ice Sheet |
title_full_unstemmed |
High-resolution modelling of the seasonal evolution of surface water storage on the Greenland Ice Sheet |
title_sort |
high-resolution modelling of the seasonal evolution of surface water storage on the greenland ice sheet |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://www.repository.cam.ac.uk/handle/1810/273621 https://doi.org/10.17863/CAM.20690 |
long_lat |
ENVELOPE(177.619,177.619,52.064,52.064) |
geographic |
Greenland Rapid Lake |
geographic_facet |
Greenland Rapid Lake |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/273621 doi:10.17863/CAM.20690 |
op_rights |
Attribution 4.0 International http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.17863/CAM.20690 |
_version_ |
1788061662647943168 |