Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions
The continued use of the Positive Degree-Day (PDD) method to predict ice sheet melt is generally favoured over surface energy balance methods partly due to the computational efficiency of the algorithm and the requirement of only one input variable (temperature). In this paper we revisit some of the...
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International Glaciological Society
2015
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Online Access: | https://nrl.northumbria.ac.uk/id/eprint/21640/ https://doi.org/10.3189/2015JoG14J116 https://nrl.northumbria.ac.uk/id/eprint/21640/1/Wake_L_glaciated_regions.pdf |
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ftunivnorthumb:oai:nrl.northumbria.ac.uk:21640 2023-05-15T16:29:25+02:00 Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions Wake, Leanne Marshall, Shawn 2015 application/pdf https://nrl.northumbria.ac.uk/id/eprint/21640/ https://doi.org/10.3189/2015JoG14J116 https://nrl.northumbria.ac.uk/id/eprint/21640/1/Wake_L_glaciated_regions.pdf en eng International Glaciological Society https://nrl.northumbria.ac.uk/id/eprint/21640/1/Wake_L_glaciated_regions.pdf Wake, Leanne and Marshall, Shawn (2015) Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions. Journal of Glaciology, 61 (226). pp. 329-344. ISSN 0022-1430 F800 Physical and Terrestrial Geographical and Environmental Sciences Article PeerReviewed 2015 ftunivnorthumb https://doi.org/10.3189/2015JoG14J116 2022-09-25T06:01:23Z The continued use of the Positive Degree-Day (PDD) method to predict ice sheet melt is generally favoured over surface energy balance methods partly due to the computational efficiency of the algorithm and the requirement of only one input variable (temperature). In this paper we revisit some of the assumptions governing the application of the PDD method. Using hourly temperature data from the GC-Net network we test the assumption that monthly PDD total (PDDm) can be represented by a Gaussian distribution with fixed standard deviation of monthly temperature (σM). The results presented here show that the common assumption of fixed σM does not hold, and that σM may be represented more accurately as a quadratic function of average monthly temperature. For Greenland, the mean absolute error in predicting PDDm using our methodology is 3.9°C*day, representing a significant improvement on current methods (7.8°C*day, when σM = 4.5°C). Over a range of glaciated settings, our method reproduces PDDm, on average, to within 1.5 - 8.5°C*day, compared to 4.4 - 15.7°C*day when σM = 4.5°. The improvement arises because we capture the systematic reduction in temperature variance that is observed over melting snow and ice, when surface temperatures cannot warm above O°C. Article in Journal/Newspaper Greenland Ice Sheet Journal of Glaciology Northumbria University, Newcastle: Northumbria Research Link (NRL) Greenland Journal of Glaciology 61 226 329 344 |
institution |
Open Polar |
collection |
Northumbria University, Newcastle: Northumbria Research Link (NRL) |
op_collection_id |
ftunivnorthumb |
language |
English |
topic |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
spellingShingle |
F800 Physical and Terrestrial Geographical and Environmental Sciences Wake, Leanne Marshall, Shawn Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions |
topic_facet |
F800 Physical and Terrestrial Geographical and Environmental Sciences |
description |
The continued use of the Positive Degree-Day (PDD) method to predict ice sheet melt is generally favoured over surface energy balance methods partly due to the computational efficiency of the algorithm and the requirement of only one input variable (temperature). In this paper we revisit some of the assumptions governing the application of the PDD method. Using hourly temperature data from the GC-Net network we test the assumption that monthly PDD total (PDDm) can be represented by a Gaussian distribution with fixed standard deviation of monthly temperature (σM). The results presented here show that the common assumption of fixed σM does not hold, and that σM may be represented more accurately as a quadratic function of average monthly temperature. For Greenland, the mean absolute error in predicting PDDm using our methodology is 3.9°C*day, representing a significant improvement on current methods (7.8°C*day, when σM = 4.5°C). Over a range of glaciated settings, our method reproduces PDDm, on average, to within 1.5 - 8.5°C*day, compared to 4.4 - 15.7°C*day when σM = 4.5°. The improvement arises because we capture the systematic reduction in temperature variance that is observed over melting snow and ice, when surface temperatures cannot warm above O°C. |
format |
Article in Journal/Newspaper |
author |
Wake, Leanne Marshall, Shawn |
author_facet |
Wake, Leanne Marshall, Shawn |
author_sort |
Wake, Leanne |
title |
Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions |
title_short |
Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions |
title_full |
Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions |
title_fullStr |
Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions |
title_full_unstemmed |
Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions |
title_sort |
assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions |
publisher |
International Glaciological Society |
publishDate |
2015 |
url |
https://nrl.northumbria.ac.uk/id/eprint/21640/ https://doi.org/10.3189/2015JoG14J116 https://nrl.northumbria.ac.uk/id/eprint/21640/1/Wake_L_glaciated_regions.pdf |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet Journal of Glaciology |
genre_facet |
Greenland Ice Sheet Journal of Glaciology |
op_relation |
https://nrl.northumbria.ac.uk/id/eprint/21640/1/Wake_L_glaciated_regions.pdf Wake, Leanne and Marshall, Shawn (2015) Assessment of current methods of positive degree-day calculation using in situ observations from glaciated regions. Journal of Glaciology, 61 (226). pp. 329-344. ISSN 0022-1430 |
op_doi |
https://doi.org/10.3189/2015JoG14J116 |
container_title |
Journal of Glaciology |
container_volume |
61 |
container_issue |
226 |
container_start_page |
329 |
op_container_end_page |
344 |
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1766019121145708544 |