Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift

Mass‐balance estimates of the polar ice sheets presently rely on static ice masks to identify the area under investigation. However, the vintage of available ice masks can differ by more than a decade and the resolution of the imagery used to delineate ice extent can differ by an order of magnitude,...

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Published in:Journal of Geophysical Research: Earth Surface
Main Authors: Kjeldsen, Kristian Kjellerup, Khan, Shfaqat Abbas, Colgan, William T., MacGregor, Joseph A., Fausto, Robert S.
Format: Article in Journal/Newspaper
Language:English
Published: 2020
Subjects:
Online Access:https://orbit.dtu.dk/en/publications/5c0ba279-6ba0-4223-a9ca-98e48672c939
https://doi.org/10.1029/2020JF005775
https://backend.orbit.dtu.dk/ws/files/238038799/2020JF005775.pdf
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spelling ftdtupubl:oai:pure.atira.dk:publications/5c0ba279-6ba0-4223-a9ca-98e48672c939 2024-04-28T08:21:33+00:00 Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift Kjeldsen, Kristian Kjellerup Khan, Shfaqat Abbas Colgan, William T. MacGregor, Joseph A. Fausto, Robert S. 2020 application/pdf https://orbit.dtu.dk/en/publications/5c0ba279-6ba0-4223-a9ca-98e48672c939 https://doi.org/10.1029/2020JF005775 https://backend.orbit.dtu.dk/ws/files/238038799/2020JF005775.pdf eng eng https://orbit.dtu.dk/en/publications/5c0ba279-6ba0-4223-a9ca-98e48672c939 info:eu-repo/semantics/openAccess Kjeldsen , K K , Khan , S A , Colgan , W T , MacGregor , J A & Fausto , R S 2020 , ' Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift ' , Journal of Geophysical Research: Earth Surface , vol. 125 , no. 12 , e2020JF005775 . https://doi.org/10.1029/2020JF005775 article 2020 ftdtupubl https://doi.org/10.1029/2020JF005775 2024-04-03T15:50:11Z Mass‐balance estimates of the polar ice sheets presently rely on static ice masks to identify the area under investigation. However, the vintage of available ice masks can differ by more than a decade and the resolution of the imagery used to delineate ice extent can differ by an order of magnitude, despite evidence of ongoing ice‐sheet retreat. We show that using a fine‐resolution, time‐varying ice mask significantly improves mass‐balance estimates of the northwestern sector of the Greenland Ice Sheet and affects interpretation of local crustal uplift. Accounting for ice margin retreat using a time‐varying ice mask between 2003–2015 results in 1.0–6.8% less ice‐sheet mass loss relative to assuming one of several existing static ice masks. This indicates that mass‐balance estimates that use a static ice mask will progressively overestimate mass loss where the ice sheet is predominantly retreating, meaning a negative bias on mass‐balance. This trend is anticipated to be amplified in a future warming scenario unless updated ice masks are incorporated. For altimetry‐derived mass‐balance estimates, this ice‐mask‐induced bias approaches the magnitude of the ice‐sheet‐wide uncertainty presently associated with spatiotemporal variability in modeled firn compaction. Further, at five GNET stations, the ice‐mask‐induced bias is equivalent to 5–15% of the modeled uplift due to elastic deformation. Given present and projected negative trends in Greenland Ice Sheet mass‐balance and areal extent, we conclude that studies of its mass‐balance should begin incorporating dynamic, periodically updated, fine‐resolution ice masks. This methodological refinement will reduce bias in estimates of both ice‐sheet mass‐balance and crustal uplift. Article in Journal/Newspaper Greenland Ice Sheet Technical University of Denmark: DTU Orbit Journal of Geophysical Research: Earth Surface 125 12
institution Open Polar
collection Technical University of Denmark: DTU Orbit
op_collection_id ftdtupubl
language English
description Mass‐balance estimates of the polar ice sheets presently rely on static ice masks to identify the area under investigation. However, the vintage of available ice masks can differ by more than a decade and the resolution of the imagery used to delineate ice extent can differ by an order of magnitude, despite evidence of ongoing ice‐sheet retreat. We show that using a fine‐resolution, time‐varying ice mask significantly improves mass‐balance estimates of the northwestern sector of the Greenland Ice Sheet and affects interpretation of local crustal uplift. Accounting for ice margin retreat using a time‐varying ice mask between 2003–2015 results in 1.0–6.8% less ice‐sheet mass loss relative to assuming one of several existing static ice masks. This indicates that mass‐balance estimates that use a static ice mask will progressively overestimate mass loss where the ice sheet is predominantly retreating, meaning a negative bias on mass‐balance. This trend is anticipated to be amplified in a future warming scenario unless updated ice masks are incorporated. For altimetry‐derived mass‐balance estimates, this ice‐mask‐induced bias approaches the magnitude of the ice‐sheet‐wide uncertainty presently associated with spatiotemporal variability in modeled firn compaction. Further, at five GNET stations, the ice‐mask‐induced bias is equivalent to 5–15% of the modeled uplift due to elastic deformation. Given present and projected negative trends in Greenland Ice Sheet mass‐balance and areal extent, we conclude that studies of its mass‐balance should begin incorporating dynamic, periodically updated, fine‐resolution ice masks. This methodological refinement will reduce bias in estimates of both ice‐sheet mass‐balance and crustal uplift.
format Article in Journal/Newspaper
author Kjeldsen, Kristian Kjellerup
Khan, Shfaqat Abbas
Colgan, William T.
MacGregor, Joseph A.
Fausto, Robert S.
spellingShingle Kjeldsen, Kristian Kjellerup
Khan, Shfaqat Abbas
Colgan, William T.
MacGregor, Joseph A.
Fausto, Robert S.
Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift
author_facet Kjeldsen, Kristian Kjellerup
Khan, Shfaqat Abbas
Colgan, William T.
MacGregor, Joseph A.
Fausto, Robert S.
author_sort Kjeldsen, Kristian Kjellerup
title Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift
title_short Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift
title_full Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift
title_fullStr Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift
title_full_unstemmed Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift
title_sort time‐varying ice sheet mask: implications on ice‐sheet mass balance and crustal uplift
publishDate 2020
url https://orbit.dtu.dk/en/publications/5c0ba279-6ba0-4223-a9ca-98e48672c939
https://doi.org/10.1029/2020JF005775
https://backend.orbit.dtu.dk/ws/files/238038799/2020JF005775.pdf
genre Greenland
Ice Sheet
genre_facet Greenland
Ice Sheet
op_source Kjeldsen , K K , Khan , S A , Colgan , W T , MacGregor , J A & Fausto , R S 2020 , ' Time‐Varying Ice Sheet Mask: Implications on Ice‐Sheet Mass Balance and Crustal Uplift ' , Journal of Geophysical Research: Earth Surface , vol. 125 , no. 12 , e2020JF005775 . https://doi.org/10.1029/2020JF005775
op_relation https://orbit.dtu.dk/en/publications/5c0ba279-6ba0-4223-a9ca-98e48672c939
op_rights info:eu-repo/semantics/openAccess
op_doi https://doi.org/10.1029/2020JF005775
container_title Journal of Geophysical Research: Earth Surface
container_volume 125
container_issue 12
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