Precursor of disintegration of Greenland's largest floating ice tongue

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Angelika Humbert - , Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research (Author)
  • Veit Helm - , Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research (Author)
  • Niklas Neckel - , Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research (Author)
  • Ole Zeising - , Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research (Author)
  • Martin Rückamp - , Bayerische Akademie der Wissenschaften, Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research (Author)
  • Shfaqat abbas Khan - , DTU Space – National Space Institute, Kongens Lyngby, Denmark (Author)
  • Erik Loebel - , Chair of Geodetic Earth System Research (Author)
  • Jörg Brauchle - , German Aerospace Center (DLR) - Berlin-Adlershof (Author)
  • Karsten Stebner - , German Aerospace Center (DLR) - Berlin-Adlershof (Author)
  • Dietmar Gross - , Technische Universität Darmstadt (Author)
  • Rabea Sondershaus - , Technische Universität Darmstadt (Author)
  • Ralf Müller - , Technische Universität Darmstadt (Author)

Abstract

The largest floating tongue of Greenland’s ice sheet, Nioghalvfjerdsbræ, has been relatively stable with respect to areal retreat until 2022. Draining more than 6 % of the ice sheet, a disintegration of Nioghalvfjerdsbræ's floating tongue and subsequent acceleration due to loss in buttressing are likely to lead to sea level rise. Therefore, the stability of the floating tongue is a focus of this study. We employed a suite of observational methods to detect recent changes at the calving front. We found that the calving style has changed since 2016 at the southern part of the eastern calving front, from tongue-type calving to a crack evolution initiated at frontal ice rises reaching 5–7 km and progressing further upstream compared to 2010. The calving front area is further weakened by an area upstream of the main calving front that consists of open water and an ice mélange that has substantially expanded, leading to the formation of a narrow ice bridge. These geometric and mechanical changes may be a precursor of instability of the floating tongue. We complement our study by numerical ice flow simulations to estimate the impact of future ice-front retreat and complete ice shelf disintegration on the discharge of grounded ice. These idealized scenarios reveal that a loss of the south-eastern area of the ice shelf would lead to a 0.2 % increase in ice discharge at the grounding line, while a sudden collapse of the frontal area (46 % of the floating tongue area) will enhance the ice discharge by 5.1 % due to loss in buttressing. Eventually, a full collapse of the floating tongue increases the grounding line flux by 166 %.

Details

Original languageEnglish
Pages (from-to)2851-2870
Number of pages20
JournalThe Cryosphere
Volume17
Issue number7
Publication statusPublished - 14 Jul 2023
Peer-reviewedYes

External IDs

WOS 001027660200001
ORCID /0000-0001-9874-9295/work/142255132
Scopus 85169686905

Keywords

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Subject groups, research areas, subject areas according to Destatis

Keywords

  • Northeast greenland, Jakobshavn isbrae, Mass-balance, Break-up, Shelf, Retreat, Sheet, Speed, Deformation, Dynamics

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