Variability in the vertical temperature profile within crevasses at an alpine glacier
Abstract Tasman Glacier, a temperate maritime glacier in the New Zealand Southern Alps, is rapidly receding. Climate warming is resulting in lengthening of the ablation season, meaning crevasses in the accumulation area are becoming exposed at the surface for longer. We combine measurements of air t...
Published in: | Journal of Glaciology |
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Language: | English |
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Cambridge University Press (CUP)
2022
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Online Access: | http://dx.doi.org/10.1017/jog.2022.73 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000739 |
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crcambridgeupr:10.1017/jog.2022.73 2024-06-23T07:54:15+00:00 Variability in the vertical temperature profile within crevasses at an alpine glacier Purdie, Heather Zawar-Reza, Peyman Katurji, Marwan Schumacher, Benjamin Kerr, Tim Bealing, Paul Royal Society Te Apārangi Royal Society Te Apārangi 2022 http://dx.doi.org/10.1017/jog.2022.73 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000739 en eng Cambridge University Press (CUP) https://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 69, issue 274, page 410-424 ISSN 0022-1430 1727-5652 journal-article 2022 crcambridgeupr https://doi.org/10.1017/jog.2022.73 2024-06-12T04:04:49Z Abstract Tasman Glacier, a temperate maritime glacier in the New Zealand Southern Alps, is rapidly receding. Climate warming is resulting in lengthening of the ablation season, meaning crevasses in the accumulation area are becoming exposed at the surface for longer. We combine measurements of air temperature and wind speed from inside crevasses with surface meteorological data, finding that during summer, in-crevasse air temperature is frequently positive, and can at times exceed surface air temperature. Greatest warming occurred in the widest crevasses during clear-sky conditions, but full depth warming of crevasses also occurred at night. Net shortwave radiation contributes to heating of air in the upper regions of crevasses, but turbulent sensible heat transfer was responsible for driving warm air deeper into crevasses. Crevasses orientated to maximise radiation retrieval, and running parallel to wind flow, have the greatest potential for warming and heat storage. We hypothesise a positive feedback loop in the surface energy-balance system, where crevasses entrain and trap heat, which enhances melting, that in turn enlarges the crevasses, enabling greater heat storage and further melting. Energy-balance models that treat accumulation areas of alpine glaciers as homogeneous surfaces will therefore underestimate snow melt and overestimate mass balance. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press New Zealand Journal of Glaciology 1 15 |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Tasman Glacier, a temperate maritime glacier in the New Zealand Southern Alps, is rapidly receding. Climate warming is resulting in lengthening of the ablation season, meaning crevasses in the accumulation area are becoming exposed at the surface for longer. We combine measurements of air temperature and wind speed from inside crevasses with surface meteorological data, finding that during summer, in-crevasse air temperature is frequently positive, and can at times exceed surface air temperature. Greatest warming occurred in the widest crevasses during clear-sky conditions, but full depth warming of crevasses also occurred at night. Net shortwave radiation contributes to heating of air in the upper regions of crevasses, but turbulent sensible heat transfer was responsible for driving warm air deeper into crevasses. Crevasses orientated to maximise radiation retrieval, and running parallel to wind flow, have the greatest potential for warming and heat storage. We hypothesise a positive feedback loop in the surface energy-balance system, where crevasses entrain and trap heat, which enhances melting, that in turn enlarges the crevasses, enabling greater heat storage and further melting. Energy-balance models that treat accumulation areas of alpine glaciers as homogeneous surfaces will therefore underestimate snow melt and overestimate mass balance. |
author2 |
Royal Society Te Apārangi Royal Society Te Apārangi |
format |
Article in Journal/Newspaper |
author |
Purdie, Heather Zawar-Reza, Peyman Katurji, Marwan Schumacher, Benjamin Kerr, Tim Bealing, Paul |
spellingShingle |
Purdie, Heather Zawar-Reza, Peyman Katurji, Marwan Schumacher, Benjamin Kerr, Tim Bealing, Paul Variability in the vertical temperature profile within crevasses at an alpine glacier |
author_facet |
Purdie, Heather Zawar-Reza, Peyman Katurji, Marwan Schumacher, Benjamin Kerr, Tim Bealing, Paul |
author_sort |
Purdie, Heather |
title |
Variability in the vertical temperature profile within crevasses at an alpine glacier |
title_short |
Variability in the vertical temperature profile within crevasses at an alpine glacier |
title_full |
Variability in the vertical temperature profile within crevasses at an alpine glacier |
title_fullStr |
Variability in the vertical temperature profile within crevasses at an alpine glacier |
title_full_unstemmed |
Variability in the vertical temperature profile within crevasses at an alpine glacier |
title_sort |
variability in the vertical temperature profile within crevasses at an alpine glacier |
publisher |
Cambridge University Press (CUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1017/jog.2022.73 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000739 |
geographic |
New Zealand |
geographic_facet |
New Zealand |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 69, issue 274, page 410-424 ISSN 0022-1430 1727-5652 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2022.73 |
container_title |
Journal of Glaciology |
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1 |
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15 |
_version_ |
1802646354984435712 |