Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet
The mass balance of polythermal ice masses is critically dependent on the proportion of surface-generated meltwater that subsequently refreezes in the snowpack and firn. In order to quantify this effect and to characterize its spatial variability, we measured near-surface (<10 m) snow and firn de...
Published in: | Annals of Glaciology |
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International Glaciological Society
2007
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ftnerc:oai:nora.nerc.ac.uk:5914 2024-06-09T07:38:34+00:00 Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet Parry, Victoria Nienow, Peter Mair, Douglas Scott, Julian Hubbard, Bryn Steffen, Konrad Wingham, Duncan 2007 http://nora.nerc.ac.uk/id/eprint/5914/ http://www.ingentaconnect.com/content/igsoc/agl/2007/00000046/00000001/art00011 unknown International Glaciological Society Parry, Victoria; Nienow, Peter; Mair, Douglas; Scott, Julian; Hubbard, Bryn; Steffen, Konrad; Wingham, Duncan. 2007 Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet. Annals of Glaciology, 46. 61-68. https://doi.org/10.3189/172756407782871332 <https://doi.org/10.3189/172756407782871332> Glaciology Publication - Article PeerReviewed 2007 ftnerc https://doi.org/10.3189/172756407782871332 2024-05-15T08:52:26Z The mass balance of polythermal ice masses is critically dependent on the proportion of surface-generated meltwater that subsequently refreezes in the snowpack and firn. In order to quantify this effect and to characterize its spatial variability, we measured near-surface (<10 m) snow and firn densities at an elevation of ∼1945 m a. s. l. in the percolation zone of the Greenland ice sheet in spring and autumn 2004. Results indicate that local snowpack depth above the previous end-of-summer 2003 melt surface increased by ∼5% (7.6 cm) from spring to autumn while, over the same period, snowpack density increased by >26%, resulting in a 32% increase in net accumulation. This 'seasonal densification' increased at lower elevations, rising to 47% 10 km closer to the ice-sheet margin at 1860 m a. s. l. Density/depth profiles from nine sites within 1 km2 at ∼1945 m a.s.l. reveal complex stratigraphies that change over short spatial scales and seasonally. We conclude that estimates of mass-balance change cannot be calculated solely from observed changes in surface elevation, but that near-surface densification must also be considered. However, predicting spatial and temporal variations in densification may not be straightforward. Further, the development of complex firn-density profiles both masks discernible annual layers in the near-surface firn and ice stratigraphy and is likely to introduce error into radar-derived estimates of surface elevation. Article in Journal/Newspaper Annals of Glaciology Greenland Ice Sheet Natural Environment Research Council: NERC Open Research Archive Greenland Annals of Glaciology 46 61 68 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Glaciology |
spellingShingle |
Glaciology Parry, Victoria Nienow, Peter Mair, Douglas Scott, Julian Hubbard, Bryn Steffen, Konrad Wingham, Duncan Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet |
topic_facet |
Glaciology |
description |
The mass balance of polythermal ice masses is critically dependent on the proportion of surface-generated meltwater that subsequently refreezes in the snowpack and firn. In order to quantify this effect and to characterize its spatial variability, we measured near-surface (<10 m) snow and firn densities at an elevation of ∼1945 m a. s. l. in the percolation zone of the Greenland ice sheet in spring and autumn 2004. Results indicate that local snowpack depth above the previous end-of-summer 2003 melt surface increased by ∼5% (7.6 cm) from spring to autumn while, over the same period, snowpack density increased by >26%, resulting in a 32% increase in net accumulation. This 'seasonal densification' increased at lower elevations, rising to 47% 10 km closer to the ice-sheet margin at 1860 m a. s. l. Density/depth profiles from nine sites within 1 km2 at ∼1945 m a.s.l. reveal complex stratigraphies that change over short spatial scales and seasonally. We conclude that estimates of mass-balance change cannot be calculated solely from observed changes in surface elevation, but that near-surface densification must also be considered. However, predicting spatial and temporal variations in densification may not be straightforward. Further, the development of complex firn-density profiles both masks discernible annual layers in the near-surface firn and ice stratigraphy and is likely to introduce error into radar-derived estimates of surface elevation. |
format |
Article in Journal/Newspaper |
author |
Parry, Victoria Nienow, Peter Mair, Douglas Scott, Julian Hubbard, Bryn Steffen, Konrad Wingham, Duncan |
author_facet |
Parry, Victoria Nienow, Peter Mair, Douglas Scott, Julian Hubbard, Bryn Steffen, Konrad Wingham, Duncan |
author_sort |
Parry, Victoria |
title |
Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet |
title_short |
Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet |
title_full |
Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet |
title_fullStr |
Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet |
title_full_unstemmed |
Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet |
title_sort |
investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the greenland ice sheet |
publisher |
International Glaciological Society |
publishDate |
2007 |
url |
http://nora.nerc.ac.uk/id/eprint/5914/ http://www.ingentaconnect.com/content/igsoc/agl/2007/00000046/00000001/art00011 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Annals of Glaciology Greenland Ice Sheet |
genre_facet |
Annals of Glaciology Greenland Ice Sheet |
op_relation |
Parry, Victoria; Nienow, Peter; Mair, Douglas; Scott, Julian; Hubbard, Bryn; Steffen, Konrad; Wingham, Duncan. 2007 Investigations of meltwater refreezing and density variations in the snowpack and firn within the percolation zone of the Greenland ice sheet. Annals of Glaciology, 46. 61-68. https://doi.org/10.3189/172756407782871332 <https://doi.org/10.3189/172756407782871332> |
op_doi |
https://doi.org/10.3189/172756407782871332 |
container_title |
Annals of Glaciology |
container_volume |
46 |
container_start_page |
61 |
op_container_end_page |
68 |
_version_ |
1801373691192279040 |