Intra-seasonal variability in supraglacial stream sediment on the Greenland Ice Sheet

On the surface of the Greenland Ice Sheet, the presence of low-albedo features greatly contributes to ablation zone meltwater production. Some of the lowest albedo features on the Ice Sheet are water-filled supraglacial stream channels, especially those with abundant deposits of consolidated cryocon...

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Published in:Frontiers in Earth Science
Main Authors: Leidman, Sasha Z., Rennermalm, Åsa K., Muthyala, Rohi, Skiles, S. McKenzie, Getraer, Alexander
Other Authors: National Science Foundation
Format: Article in Journal/Newspaper
Language:unknown
Published: Frontiers Media SA 2023
Subjects:
Online Access:http://dx.doi.org/10.3389/feart.2023.969629
https://www.frontiersin.org/articles/10.3389/feart.2023.969629/full
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spelling crfrontiers:10.3389/feart.2023.969629 2024-02-11T10:04:16+01:00 Intra-seasonal variability in supraglacial stream sediment on the Greenland Ice Sheet Leidman, Sasha Z. Rennermalm, Åsa K. Muthyala, Rohi Skiles, S. McKenzie Getraer, Alexander National Science Foundation 2023 http://dx.doi.org/10.3389/feart.2023.969629 https://www.frontiersin.org/articles/10.3389/feart.2023.969629/full unknown Frontiers Media SA https://creativecommons.org/licenses/by/4.0/ Frontiers in Earth Science volume 11 ISSN 2296-6463 General Earth and Planetary Sciences journal-article 2023 crfrontiers https://doi.org/10.3389/feart.2023.969629 2024-01-26T10:05:13Z On the surface of the Greenland Ice Sheet, the presence of low-albedo features greatly contributes to ablation zone meltwater production. Some of the lowest albedo features on the Ice Sheet are water-filled supraglacial stream channels, especially those with abundant deposits of consolidated cryoconite sediment. Because these sediments enhance melting by disproportionately lowering albedo, studying their spatial extent can provide a better understanding of Greenland’s contribution to global sea level rise. However, little is known about the spatial distribution of supraglacial stream sediment, or how it changes in response to seasonal flow regimes. Here, we surveyed a supraglacial stream network in Southwest Greenland, collecting imagery from seven uncrewed aerial vehicle (UAV) flights over the course of 24 days in 2019. Using Structure-from-Motion-generated orthomosaic imagery and digital elevation models (DEMs), we manually digitized the banks of the supraglacial stream channels, classified the areal coverage of sediment deposits, and modeled how the terrain influences the amount of incoming solar radiation at the Ice Sheet surface. We used imagery classified by surface types and in-situ spectrometer measurements to determine how changes in sediment cover altered albedo. We found that, within our study area, only 15% of cryoconite sediment was consolidated in cryoconite holes; the remaining 85% was located within supraglacial streams mostly concentrated on daily inundated riverbanks (hereafter termed floodplains). Sediment cover and stream width are highly correlated, suggesting that sediment influx into supraglacial drainage systems widens stream channels or darkens previously widened channels. This reduces albedo in floodplains that already receive greater solar radiation due to their flatness. Additionally, the areal extent of stream sediments increased in August following seasonal peak flow, suggesting that as stream power decreases, more sediment accumulates in supraglacial channels. This negative ... Article in Journal/Newspaper Greenland Ice Sheet Frontiers (Publisher) Greenland Frontiers in Earth Science 11
institution Open Polar
collection Frontiers (Publisher)
op_collection_id crfrontiers
language unknown
topic General Earth and Planetary Sciences
spellingShingle General Earth and Planetary Sciences
Leidman, Sasha Z.
Rennermalm, Åsa K.
Muthyala, Rohi
Skiles, S. McKenzie
Getraer, Alexander
Intra-seasonal variability in supraglacial stream sediment on the Greenland Ice Sheet
topic_facet General Earth and Planetary Sciences
description On the surface of the Greenland Ice Sheet, the presence of low-albedo features greatly contributes to ablation zone meltwater production. Some of the lowest albedo features on the Ice Sheet are water-filled supraglacial stream channels, especially those with abundant deposits of consolidated cryoconite sediment. Because these sediments enhance melting by disproportionately lowering albedo, studying their spatial extent can provide a better understanding of Greenland’s contribution to global sea level rise. However, little is known about the spatial distribution of supraglacial stream sediment, or how it changes in response to seasonal flow regimes. Here, we surveyed a supraglacial stream network in Southwest Greenland, collecting imagery from seven uncrewed aerial vehicle (UAV) flights over the course of 24 days in 2019. Using Structure-from-Motion-generated orthomosaic imagery and digital elevation models (DEMs), we manually digitized the banks of the supraglacial stream channels, classified the areal coverage of sediment deposits, and modeled how the terrain influences the amount of incoming solar radiation at the Ice Sheet surface. We used imagery classified by surface types and in-situ spectrometer measurements to determine how changes in sediment cover altered albedo. We found that, within our study area, only 15% of cryoconite sediment was consolidated in cryoconite holes; the remaining 85% was located within supraglacial streams mostly concentrated on daily inundated riverbanks (hereafter termed floodplains). Sediment cover and stream width are highly correlated, suggesting that sediment influx into supraglacial drainage systems widens stream channels or darkens previously widened channels. This reduces albedo in floodplains that already receive greater solar radiation due to their flatness. Additionally, the areal extent of stream sediments increased in August following seasonal peak flow, suggesting that as stream power decreases, more sediment accumulates in supraglacial channels. This negative ...
author2 National Science Foundation
format Article in Journal/Newspaper
author Leidman, Sasha Z.
Rennermalm, Åsa K.
Muthyala, Rohi
Skiles, S. McKenzie
Getraer, Alexander
author_facet Leidman, Sasha Z.
Rennermalm, Åsa K.
Muthyala, Rohi
Skiles, S. McKenzie
Getraer, Alexander
author_sort Leidman, Sasha Z.
title Intra-seasonal variability in supraglacial stream sediment on the Greenland Ice Sheet
title_short Intra-seasonal variability in supraglacial stream sediment on the Greenland Ice Sheet
title_full Intra-seasonal variability in supraglacial stream sediment on the Greenland Ice Sheet
title_fullStr Intra-seasonal variability in supraglacial stream sediment on the Greenland Ice Sheet
title_full_unstemmed Intra-seasonal variability in supraglacial stream sediment on the Greenland Ice Sheet
title_sort intra-seasonal variability in supraglacial stream sediment on the greenland ice sheet
publisher Frontiers Media SA
publishDate 2023
url http://dx.doi.org/10.3389/feart.2023.969629
https://www.frontiersin.org/articles/10.3389/feart.2023.969629/full
geographic Greenland
geographic_facet Greenland
genre Greenland
Ice Sheet
genre_facet Greenland
Ice Sheet
op_source Frontiers in Earth Science
volume 11
ISSN 2296-6463
op_rights https://creativecommons.org/licenses/by/4.0/
op_doi https://doi.org/10.3389/feart.2023.969629
container_title Frontiers in Earth Science
container_volume 11
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