Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming
Atmospheric warming over the Greenland Ice Sheet during the last 2 decades has increased the amount of surface meltwater production, resulting in the migration of melt and percolation regimes to higher altitudes and an increase in the amount of ice content from refrozen meltwater found in the firn a...
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Online Access: | http://www.osti.gov/servlets/purl/1224048 https://www.osti.gov/biblio/1224048 https://doi.org/10.5194/tc-9-1203-2015 |
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ftosti:oai:osti.gov:1224048 2023-07-30T04:03:46+02:00 Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming de la Peña, S. Howat, I. M. Nienow, P. W. van den Broeke, M. R. Mosley-Thompson, E. Price, S. F. Mair, D. Noël, B. Sole, A. J. 2023-06-26 application/pdf http://www.osti.gov/servlets/purl/1224048 https://www.osti.gov/biblio/1224048 https://doi.org/10.5194/tc-9-1203-2015 unknown http://www.osti.gov/servlets/purl/1224048 https://www.osti.gov/biblio/1224048 https://doi.org/10.5194/tc-9-1203-2015 doi:10.5194/tc-9-1203-2015 58 GEOSCIENCES 2023 ftosti https://doi.org/10.5194/tc-9-1203-2015 2023-07-11T09:03:46Z Atmospheric warming over the Greenland Ice Sheet during the last 2 decades has increased the amount of surface meltwater production, resulting in the migration of melt and percolation regimes to higher altitudes and an increase in the amount of ice content from refrozen meltwater found in the firn above the superimposed ice zone. Here we present field and airborne radar observations of buried ice layers within the near-surface (0–20 m) firn in western Greenland, obtained from campaigns between 1998 and 2014. We find a sharp increase in firn-ice content in the form of thick widespread layers in the percolation zone, which decreases the capacity of the firn to store meltwater. The estimated total annual ice content retained in the near-surface firn in areas with positive surface mass balance west of the ice divide in Greenland reached a maximum of 74 ± 25 Gt in 2012, when compared to the 1958–1999 average of 13 ± 2 Gt, while the percolation zone area more than doubled between 2003 and 2012. Increased melt and column densification resulted in surface lowering averaging -0.80 ± 0.39 m yr -1 between 1800 and 2800 m in the accumulation zone of western Greenland. Since 2007, modeled annual melt and refreezing rates in the percolation zone at elevations below 2100 m surpass the annual snowfall from the previous year, implying that mass gain in the region is retained after melt in the form of refrozen meltwater. Furthermore, if current melt trends over high elevation regions continue, subsequent changes in firn structure will have implications for the hydrology of the ice sheet and related abrupt seasonal densification could become increasingly significant for altimetry-derived ice sheet mass balance estimates. Other/Unknown Material Greenland Ice Sheet SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Greenland The Cryosphere 9 3 1203 1211 |
institution |
Open Polar |
collection |
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
58 GEOSCIENCES |
spellingShingle |
58 GEOSCIENCES de la Peña, S. Howat, I. M. Nienow, P. W. van den Broeke, M. R. Mosley-Thompson, E. Price, S. F. Mair, D. Noël, B. Sole, A. J. Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming |
topic_facet |
58 GEOSCIENCES |
description |
Atmospheric warming over the Greenland Ice Sheet during the last 2 decades has increased the amount of surface meltwater production, resulting in the migration of melt and percolation regimes to higher altitudes and an increase in the amount of ice content from refrozen meltwater found in the firn above the superimposed ice zone. Here we present field and airborne radar observations of buried ice layers within the near-surface (0–20 m) firn in western Greenland, obtained from campaigns between 1998 and 2014. We find a sharp increase in firn-ice content in the form of thick widespread layers in the percolation zone, which decreases the capacity of the firn to store meltwater. The estimated total annual ice content retained in the near-surface firn in areas with positive surface mass balance west of the ice divide in Greenland reached a maximum of 74 ± 25 Gt in 2012, when compared to the 1958–1999 average of 13 ± 2 Gt, while the percolation zone area more than doubled between 2003 and 2012. Increased melt and column densification resulted in surface lowering averaging -0.80 ± 0.39 m yr -1 between 1800 and 2800 m in the accumulation zone of western Greenland. Since 2007, modeled annual melt and refreezing rates in the percolation zone at elevations below 2100 m surpass the annual snowfall from the previous year, implying that mass gain in the region is retained after melt in the form of refrozen meltwater. Furthermore, if current melt trends over high elevation regions continue, subsequent changes in firn structure will have implications for the hydrology of the ice sheet and related abrupt seasonal densification could become increasingly significant for altimetry-derived ice sheet mass balance estimates. |
author |
de la Peña, S. Howat, I. M. Nienow, P. W. van den Broeke, M. R. Mosley-Thompson, E. Price, S. F. Mair, D. Noël, B. Sole, A. J. |
author_facet |
de la Peña, S. Howat, I. M. Nienow, P. W. van den Broeke, M. R. Mosley-Thompson, E. Price, S. F. Mair, D. Noël, B. Sole, A. J. |
author_sort |
de la Peña, S. |
title |
Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming |
title_short |
Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming |
title_full |
Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming |
title_fullStr |
Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming |
title_full_unstemmed |
Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming |
title_sort |
changes in the firn structure of the western greenland ice sheet caused by recent warming |
publishDate |
2023 |
url |
http://www.osti.gov/servlets/purl/1224048 https://www.osti.gov/biblio/1224048 https://doi.org/10.5194/tc-9-1203-2015 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_relation |
http://www.osti.gov/servlets/purl/1224048 https://www.osti.gov/biblio/1224048 https://doi.org/10.5194/tc-9-1203-2015 doi:10.5194/tc-9-1203-2015 |
op_doi |
https://doi.org/10.5194/tc-9-1203-2015 |
container_title |
The Cryosphere |
container_volume |
9 |
container_issue |
3 |
container_start_page |
1203 |
op_container_end_page |
1211 |
_version_ |
1772814847558287360 |