Cristin-resultat-ID: 1826298
Sist endret: 15. september 2020 11:59
NVI-rapporteringsår: 2020
Resultat
Vitenskapelig artikkel
2020

Present day Jakobshavn Isbræ close to the Holocene minimum extent

Bidragsytere:
  • Karita Anneli Kajanto
  • Hélène Seroussi
  • Basile de Fleurian og
  • Kerim Hestnes Nisancioglu

Tidsskrift

Quaternary Science Reviews
ISSN 0277-3791
e-ISSN 1873-457X
NVI-nivå 2

Om resultatet

Vitenskapelig artikkel
Publiseringsår: 2020
Publisert online: 2020
Trykket: 2020
Volum: 246

Beskrivelse Beskrivelse

Tittel

Present day Jakobshavn Isbræ close to the Holocene minimum extent

Sammendrag

Marine terminating glaciers evolve on millenial timescales in response to changes in oceanic and atmospheric conditions. However, the relative role of oceanic and atmospheric drivers remains uncertain. The evolution of marine terminating glaciers under the warmer than present Holocene Climate Optimum climate can give important insights into the dynamics of ice streams as the climate evolves. The early Holocene evolution of Jakobshavn Isbræ, from the Last Glacial Maximum extent up to 8.2 ka BP is well constrained by geomorphological studies in the area. However, the Holocene minimum extent of the glacier is unknown. Here, we use a high-resolution regional ice sheet model to study the retreat and readvance of Jakobshavn Isbræ from the Mid-Holocene to the Little Ice Age. This model of Jakobshavn Isbræ accurately tracks the terrestrial ice margin and agrees with available estimates of marine grounding line evolution. We find that the Holocene minimum extent of both the terrestrial ice margin and the grounding line, reached at 6–5 ka BP, is close to the present day extent of the glacier. We also find that the glacier is currently located close to a tipping point, from beyond which readvance would require a longer and more significant cooling than the Little Ice Age. We assess the importance of the ocean forcing in explaining the Holocene evolution of Jakobshavn, and find that cooling within the fjord during the Mid-Holocene is critical for the glacier to readvance. This finding emphasizes the role of ocean forcing when trying to understand the millenial scale evolution of marine terminating glaciers.

Bidragsytere

Karita Anneli Kajanto

  • Tilknyttet:
    Forfatter
    ved Institutt for geovitenskap ved Universitetet i Bergen

Hélène Seroussi

  • Tilknyttet:
    Forfatter
    ved Jet Propulsion Laboratory

Basile de Fleurian

  • Tilknyttet:
    Forfatter
    ved Institutt for geovitenskap ved Universitetet i Bergen

Kerim Hestnes Nisancioglu

  • Tilknyttet:
    Forfatter
    ved Institutt for geovitenskap ved Universitetet i Bergen
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