Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change
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...
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ftcopernicus:oai:publications.copernicus.org:tc50229 2023-05-15T16:21:26+02:00 Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change Åkesson, Henning Nisancioglu, Kerim H. Giesen, Rianne H. Morlighem, Mathieu 2018-09-27 application/pdf https://doi.org/10.5194/tc-11-281-2017 https://tc.copernicus.org/articles/11/281/2017/ eng eng doi:10.5194/tc-11-281-2017 https://tc.copernicus.org/articles/11/281/2017/ eISSN: 1994-0424 Text 2018 ftcopernicus https://doi.org/10.5194/tc-11-281-2017 2020-07-20T16:23:51Z 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. Text glacier glacier glacier Greenland Ice cap Iceland Copernicus Publications: E-Journals Greenland Norway Patagonia The Cryosphere 11 1 281 302 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
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. |
format |
Text |
author |
Åkesson, Henning Nisancioglu, Kerim H. Giesen, Rianne H. Morlighem, Mathieu |
spellingShingle |
Åkesson, Henning Nisancioglu, Kerim H. Giesen, Rianne H. Morlighem, Mathieu Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change |
author_facet |
Åkesson, Henning Nisancioglu, Kerim H. Giesen, Rianne H. Morlighem, Mathieu |
author_sort |
Åkesson, Henning |
title |
Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change |
title_short |
Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change |
title_full |
Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change |
title_fullStr |
Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change |
title_full_unstemmed |
Simulating the evolution of Hardangerjøkulen ice cap in southern Norway since the mid-Holocene and its sensitivity to climate change |
title_sort |
simulating the evolution of hardangerjøkulen ice cap in southern norway since the mid-holocene and its sensitivity to climate change |
publishDate |
2018 |
url |
https://doi.org/10.5194/tc-11-281-2017 https://tc.copernicus.org/articles/11/281/2017/ |
geographic |
Greenland Norway Patagonia |
geographic_facet |
Greenland Norway Patagonia |
genre |
glacier glacier glacier Greenland Ice cap Iceland |
genre_facet |
glacier glacier glacier Greenland Ice cap Iceland |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-11-281-2017 https://tc.copernicus.org/articles/11/281/2017/ |
op_doi |
https://doi.org/10.5194/tc-11-281-2017 |
container_title |
The Cryosphere |
container_volume |
11 |
container_issue |
1 |
container_start_page |
281 |
op_container_end_page |
302 |
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1766009440465584128 |