Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling
Abstract Ice ablation is related to air temperature by the positive degree-day factor. Variations of the positive degree-day factor in West Greenland are studied using an energy-balance model to simulate ablation under different conditions. Degree-day factors for simulated and measured ice ablation...
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Cambridge University Press (CUP)
1995
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crcambridgeupr:10.1017/s0022143000017846 2024-06-23T07:53:14+00:00 Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling Braithwaite, Roger J. 1995 http://dx.doi.org/10.1017/s0022143000017846 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000017846 en eng Cambridge University Press (CUP) Journal of Glaciology volume 41, issue 137, page 153-160 ISSN 0022-1430 1727-5652 journal-article 1995 crcambridgeupr https://doi.org/10.1017/s0022143000017846 2024-06-05T04:03:37Z Abstract Ice ablation is related to air temperature by the positive degree-day factor. Variations of the positive degree-day factor in West Greenland are studied using an energy-balance model to simulate ablation under different conditions. Degree-day factors for simulated and measured ice ablation at Nordbogletscher and Qamanârssûp sermia agree well with values around 8 mm d −1 °C −1 . Degree-day factors for snow are less than half those for ice. Energy-balance modelling shows that degree-day factors vary with summer mean temperature, surface albedo and turbulence but there is only evidence of large positive degree-day factors at lower temperatures and with low albedo (0.3). The greatest effect of albedo variations (0.3–0.7) is at lower temperatures while variations in turbulence have greater effect at higher temperatures. Current models may underestimate runoff from the Greenland ice sheet by several tenths because they use a degree-day factor for melting ice that is too small for the colder parts of the ice sheet, i.e. the upper ablation area and the northerly margin. Article in Journal/Newspaper Greenland Ice Sheet Journal of Glaciology Cambridge University Press Greenland Qamanârssûp Sermia ENVELOPE(-49.500,-49.500,64.483,64.483) Journal of Glaciology 41 137 153 160 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Ice ablation is related to air temperature by the positive degree-day factor. Variations of the positive degree-day factor in West Greenland are studied using an energy-balance model to simulate ablation under different conditions. Degree-day factors for simulated and measured ice ablation at Nordbogletscher and Qamanârssûp sermia agree well with values around 8 mm d −1 °C −1 . Degree-day factors for snow are less than half those for ice. Energy-balance modelling shows that degree-day factors vary with summer mean temperature, surface albedo and turbulence but there is only evidence of large positive degree-day factors at lower temperatures and with low albedo (0.3). The greatest effect of albedo variations (0.3–0.7) is at lower temperatures while variations in turbulence have greater effect at higher temperatures. Current models may underestimate runoff from the Greenland ice sheet by several tenths because they use a degree-day factor for melting ice that is too small for the colder parts of the ice sheet, i.e. the upper ablation area and the northerly margin. |
format |
Article in Journal/Newspaper |
author |
Braithwaite, Roger J. |
spellingShingle |
Braithwaite, Roger J. Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling |
author_facet |
Braithwaite, Roger J. |
author_sort |
Braithwaite, Roger J. |
title |
Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling |
title_short |
Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling |
title_full |
Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling |
title_fullStr |
Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling |
title_full_unstemmed |
Positive degree-day factors for ablation on the Greenland ice sheet studied by energy-balance modelling |
title_sort |
positive degree-day factors for ablation on the greenland ice sheet studied by energy-balance modelling |
publisher |
Cambridge University Press (CUP) |
publishDate |
1995 |
url |
http://dx.doi.org/10.1017/s0022143000017846 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000017846 |
long_lat |
ENVELOPE(-49.500,-49.500,64.483,64.483) |
geographic |
Greenland Qamanârssûp Sermia |
geographic_facet |
Greenland Qamanârssûp Sermia |
genre |
Greenland Ice Sheet Journal of Glaciology |
genre_facet |
Greenland Ice Sheet Journal of Glaciology |
op_source |
Journal of Glaciology volume 41, issue 137, page 153-160 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000017846 |
container_title |
Journal of Glaciology |
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41 |
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137 |
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153 |
op_container_end_page |
160 |
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1802644793509019648 |