Greenland basal water distribution from airborne radar sounding (2003-2014)
There is widespread, but often indirect, evidence that a significant fraction of the bed beneath the Greenland Ice Sheet is thawed (at or above the pressure melting point for ice). This includes the beds of major outlet glaciers and their tributaries and a large area around the NorthGRIP borehole in...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.893097 2023-05-15T16:21:29+02:00 Greenland basal water distribution from airborne radar sounding (2003-2014) Jordan, Thomas M Williams, Christopher N Schroeder, Dustin M Martos, Yasmina M Cooper, Michael A Siegert, Martin J Paden, John D Huybrechts, Philippe Bamber, Jonathan L MEDIAN LATITUDE: 72.000000 * MEDIAN LONGITUDE: -40.000000 * SOUTH-BOUND LATITUDE: 60.000000 * WEST-BOUND LONGITUDE: -65.000000 * NORTH-BOUND LATITUDE: 84.000000 * EAST-BOUND LONGITUDE: -15.000000 * DATE/TIME START: 2003-01-01T00:00:00 * DATE/TIME END: 2014-12-31T00:00:00 2018-08-16 text/tab-separated-values, 70 data points https://doi.pangaea.de/10.1594/PANGAEA.893097 https://doi.org/10.1594/PANGAEA.893097 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.893097 https://doi.org/10.1594/PANGAEA.893097 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Jordan, Thomas M; Williams, Christopher N; Schroeder, Dustin M; Martos, Yasmina M; Cooper, Michael A; Siegert, Martin J; Paden, John D; Huybrechts, Philippe; Bamber, Jonathan L (2018): A constraint upon the basal water distribution and thermal state of the Greenland Ice Sheet from radar bed echoes. The Cryosphere, 12(9), 2831-2854, https://doi.org/10.5194/tc-12-2831-2018 DATE/TIME File content File format File name File size Greenland Uniform resource locator/link to file Dataset 2018 ftpangaea https://doi.org/10.1594/PANGAEA.893097 https://doi.org/10.5194/tc-12-2831-2018 2023-01-20T09:11:23Z There is widespread, but often indirect, evidence that a significant fraction of the bed beneath the Greenland Ice Sheet is thawed (at or above the pressure melting point for ice). This includes the beds of major outlet glaciers and their tributaries and a large area around the NorthGRIP borehole in the ice-sheet interior. The ice-sheet scale distribution of basal water is, however, poorly constrained by existing observations. In principle, airborne radio-echo sounding (RES) enables the detection of basal water from bed-echo reflectivity, but unambiguous mapping is limited by uncertainty in signal attenuation within the ice. Here we introduce a new, RES diagnostic for basal water that is associated with wet-dry transitions in bed material: bed-echo reflectivity variability. This technique acts as a form of edge detector and is a sufficient, but not necessary, criteria for basal water. However, the technique has the advantage of being attenuation-insensitive and suited to data combination enabling combined analysis of over a decade of Operation IceBridge survey data. The basal water predictions are compared with existing analyses of the basal thermal state (frozen and thawed beds) and geothermal heat flux. In addition to the outlet glaciers, we demonstrate widespread water storage in the northern and eastern interior. Notably, we observe a quasi-linear 'corridor' of basal water extending from NorthGRIP to Petermann glacier that spatially correlates with elevated heat flux predicted by a recent magnetic model. Finally, with a general aim to stimulate regional- and process-specific investigations, the basal water predictions are compared with bed topography, subglacial flow paths, and ice-sheet motion. The basal water distribution, and its relationship with the thermal state, provides a new constraint for numerical models. Dataset glacier Greenland Ice Sheet Petermann glacier The Cryosphere PANGAEA - Data Publisher for Earth & Environmental Science Greenland ENVELOPE(-65.000000,-15.000000,84.000000,60.000000) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
DATE/TIME File content File format File name File size Greenland Uniform resource locator/link to file |
spellingShingle |
DATE/TIME File content File format File name File size Greenland Uniform resource locator/link to file Jordan, Thomas M Williams, Christopher N Schroeder, Dustin M Martos, Yasmina M Cooper, Michael A Siegert, Martin J Paden, John D Huybrechts, Philippe Bamber, Jonathan L Greenland basal water distribution from airborne radar sounding (2003-2014) |
topic_facet |
DATE/TIME File content File format File name File size Greenland Uniform resource locator/link to file |
description |
There is widespread, but often indirect, evidence that a significant fraction of the bed beneath the Greenland Ice Sheet is thawed (at or above the pressure melting point for ice). This includes the beds of major outlet glaciers and their tributaries and a large area around the NorthGRIP borehole in the ice-sheet interior. The ice-sheet scale distribution of basal water is, however, poorly constrained by existing observations. In principle, airborne radio-echo sounding (RES) enables the detection of basal water from bed-echo reflectivity, but unambiguous mapping is limited by uncertainty in signal attenuation within the ice. Here we introduce a new, RES diagnostic for basal water that is associated with wet-dry transitions in bed material: bed-echo reflectivity variability. This technique acts as a form of edge detector and is a sufficient, but not necessary, criteria for basal water. However, the technique has the advantage of being attenuation-insensitive and suited to data combination enabling combined analysis of over a decade of Operation IceBridge survey data. The basal water predictions are compared with existing analyses of the basal thermal state (frozen and thawed beds) and geothermal heat flux. In addition to the outlet glaciers, we demonstrate widespread water storage in the northern and eastern interior. Notably, we observe a quasi-linear 'corridor' of basal water extending from NorthGRIP to Petermann glacier that spatially correlates with elevated heat flux predicted by a recent magnetic model. Finally, with a general aim to stimulate regional- and process-specific investigations, the basal water predictions are compared with bed topography, subglacial flow paths, and ice-sheet motion. The basal water distribution, and its relationship with the thermal state, provides a new constraint for numerical models. |
format |
Dataset |
author |
Jordan, Thomas M Williams, Christopher N Schroeder, Dustin M Martos, Yasmina M Cooper, Michael A Siegert, Martin J Paden, John D Huybrechts, Philippe Bamber, Jonathan L |
author_facet |
Jordan, Thomas M Williams, Christopher N Schroeder, Dustin M Martos, Yasmina M Cooper, Michael A Siegert, Martin J Paden, John D Huybrechts, Philippe Bamber, Jonathan L |
author_sort |
Jordan, Thomas M |
title |
Greenland basal water distribution from airborne radar sounding (2003-2014) |
title_short |
Greenland basal water distribution from airborne radar sounding (2003-2014) |
title_full |
Greenland basal water distribution from airborne radar sounding (2003-2014) |
title_fullStr |
Greenland basal water distribution from airborne radar sounding (2003-2014) |
title_full_unstemmed |
Greenland basal water distribution from airborne radar sounding (2003-2014) |
title_sort |
greenland basal water distribution from airborne radar sounding (2003-2014) |
publisher |
PANGAEA |
publishDate |
2018 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.893097 https://doi.org/10.1594/PANGAEA.893097 |
op_coverage |
MEDIAN LATITUDE: 72.000000 * MEDIAN LONGITUDE: -40.000000 * SOUTH-BOUND LATITUDE: 60.000000 * WEST-BOUND LONGITUDE: -65.000000 * NORTH-BOUND LATITUDE: 84.000000 * EAST-BOUND LONGITUDE: -15.000000 * DATE/TIME START: 2003-01-01T00:00:00 * DATE/TIME END: 2014-12-31T00:00:00 |
long_lat |
ENVELOPE(-65.000000,-15.000000,84.000000,60.000000) |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland Ice Sheet Petermann glacier The Cryosphere |
genre_facet |
glacier Greenland Ice Sheet Petermann glacier The Cryosphere |
op_source |
Supplement to: Jordan, Thomas M; Williams, Christopher N; Schroeder, Dustin M; Martos, Yasmina M; Cooper, Michael A; Siegert, Martin J; Paden, John D; Huybrechts, Philippe; Bamber, Jonathan L (2018): A constraint upon the basal water distribution and thermal state of the Greenland Ice Sheet from radar bed echoes. The Cryosphere, 12(9), 2831-2854, https://doi.org/10.5194/tc-12-2831-2018 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.893097 https://doi.org/10.1594/PANGAEA.893097 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.893097 https://doi.org/10.5194/tc-12-2831-2018 |
_version_ |
1766009485382385664 |