Cristin-resultat-ID: 1454142
Sist endret: 14. mars 2018 10:55
NVI-rapporteringsår: 2017
Resultat
Vitenskapelig artikkel
2017

Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change

Bidragsytere:
  • Henning Åkesson
  • Kerim Hestnes Nisancioglu
  • Rianne H. Giesen og
  • Mathieu Morlighem

Tidsskrift

The Cryosphere
ISSN 1994-0416
e-ISSN 1994-0424
NVI-nivå 2

Om resultatet

Vitenskapelig artikkel
Publiseringsår: 2017
Volum: 11
Sider: 281 - 302
Open Access

Importkilder

Scopus-ID: 2-s2.0-85011066918

Beskrivelse Beskrivelse

Tittel

Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change

Sammendrag

Understanding of long-term dynamics of glaciers and ice caps is vital to assess their recent and future changes, yet few long-term reconstructions using ice flow models exist. Here we present simulations of the maritime Hardangerjøkulen ice cap in Norway from the mid-Holocene through the Little Ice Age (LIA) to the present day, using a numerical ice flow model combined with glacier and climate reconstructions. In our simulation, under a linear climate forcing, we find that Hardangerjøkulen grows from ice-free conditions in the mid-Holocene to its maximum extent during the LIA in a nonlinear, spatially asynchronous fashion. During its fastest stage of growth (2300–1300 BP), the ice cap triples its volume in less than 1000 years. The modeled ice cap extent and outlet glacier length changes from the LIA until today agree well with available observations. Volume and area for Hardangerjøkulen and several of its outlet glaciers vary out-of-phase for several centuries during the Holocene. This volume–area disequilibrium varies in time and from one outlet glacier to the next, illustrating that linear relations between ice extent, volume and glacier proxy records, as generally used in paleoclimatic reconstructions, have only limited validity. We also show that the present-day ice cap is highly sensitive to surface mass balance changes and that the effect of the ice cap hypsometry on the mass balance–altitude feedback is essential to this sensitivity. A mass balance shift by +0.5 m w.e. relative to the mass balance from the last decades almost doubles ice volume, while a decrease of 0.2 m w.e. or more induces a strong mass balance–altitude feedback and makes Hardangerjøkulen disappear entirely. Furthermore, once disappeared, an additional +0.1 m w.e. relative to the present mass balance is needed to regrow the ice cap to its present-day extent. We expect that other ice caps with comparable geometry in, for example, Norway, Iceland, Patagonia and peripheral Greenland may behave similarly, making them particularly vulnerable to climate change.

Bidragsytere

Henning Martin Åkesson

Bidragsyterens navn vises på dette resultatet som Henning Åkesson
  • Tilknyttet:
    Forfatter
    ved University of California, Irvine
  • Tilknyttet:
    Forfatter
    ved Institutt for geovitenskap ved Universitetet i Bergen

Kerim Hestnes Nisancioglu

  • Tilknyttet:
    Forfatter
    ved Senter for Jordens utvikling og dynamikk ved Universitetet i Oslo
  • Tilknyttet:
    Forfatter
    ved Institutt for geovitenskap ved Universitetet i Bergen

Rianne H. Giesen

  • Tilknyttet:
    Forfatter
    ved Universiteit Utrecht

Mathieu Morlighem

  • Tilknyttet:
    Forfatter
    ved University of California, Irvine
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