Small-scale variation of snow in a regional permafrost model
The strong winds prevalent in high altitude and arctic environments heavily redistribute the snow cover, causing a small-scale pattern of highly variable snow depths. This has profound implications for the ground thermal regime, resulting in highly variable near-surface ground temperatures on the me...
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ftdoajarticles:oai:doaj.org/article:2f487cf17d164992b4981906f67b44eb 2023-05-15T15:14:48+02:00 Small-scale variation of snow in a regional permafrost model K. Gisnås S. Westermann T. V. Schuler K. Melvold B. Etzelmüller 2016-06-01T00:00:00Z https://doi.org/10.5194/tc-10-1201-2016 https://doaj.org/article/2f487cf17d164992b4981906f67b44eb EN eng Copernicus Publications http://www.the-cryosphere.net/10/1201/2016/tc-10-1201-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-1201-2016 https://doaj.org/article/2f487cf17d164992b4981906f67b44eb The Cryosphere, Vol 10, Iss 3, Pp 1201-1215 (2016) Environmental sciences GE1-350 Geology QE1-996.5 article 2016 ftdoajarticles https://doi.org/10.5194/tc-10-1201-2016 2022-12-31T13:17:57Z The strong winds prevalent in high altitude and arctic environments heavily redistribute the snow cover, causing a small-scale pattern of highly variable snow depths. This has profound implications for the ground thermal regime, resulting in highly variable near-surface ground temperatures on the metre scale. Due to asymmetric snow distributions combined with the nonlinear insulating effect of snow, the spatial average ground temperature in a 1 km 2 area cannot be determined based on the average snow cover for that area. Land surface or permafrost models employing a coarsely classified average snow depth will therefore not yield a realistic representation of ground temperatures. In this study we employ statistically derived snow distributions within 1 km 2 grid cells as input to a regional permafrost model in order to represent sub-grid variability of ground temperatures. This improves the representation of both the average and the total range of ground temperatures. The model reproduces observed sub-grid ground temperature variations of up to 6 °C, and 98 % of borehole observations match the modelled temperature range. The mean modelled temperature of the grid cell reproduces the observations with an accuracy of 1.5 °C or better. The observed sub-grid variations in ground surface temperatures from two field sites are very well reproduced, with estimated fractions of sub-zero mean annual ground surface temperatures within ±10 %. We also find that snow distributions within areas of 1 km 2 in Norwegian mountain environments are closer to a gamma than to a lognormal theoretical distribution. The modelled permafrost distribution seems to be more sensitive to the choice of distribution function than to the fine-tuning of the coefficient of variation. When incorporating the small-scale variation of snow, the modelled total permafrost area of mainland Norway is nearly twice as large compared to the area obtained with grid-cell average snow depths without a sub-grid approach. Article in Journal/Newspaper Arctic permafrost The Cryosphere Directory of Open Access Journals: DOAJ Articles Arctic Norway The Cryosphere 10 3 1201 1215 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 K. Gisnås S. Westermann T. V. Schuler K. Melvold B. Etzelmüller Small-scale variation of snow in a regional permafrost model |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
The strong winds prevalent in high altitude and arctic environments heavily redistribute the snow cover, causing a small-scale pattern of highly variable snow depths. This has profound implications for the ground thermal regime, resulting in highly variable near-surface ground temperatures on the metre scale. Due to asymmetric snow distributions combined with the nonlinear insulating effect of snow, the spatial average ground temperature in a 1 km 2 area cannot be determined based on the average snow cover for that area. Land surface or permafrost models employing a coarsely classified average snow depth will therefore not yield a realistic representation of ground temperatures. In this study we employ statistically derived snow distributions within 1 km 2 grid cells as input to a regional permafrost model in order to represent sub-grid variability of ground temperatures. This improves the representation of both the average and the total range of ground temperatures. The model reproduces observed sub-grid ground temperature variations of up to 6 °C, and 98 % of borehole observations match the modelled temperature range. The mean modelled temperature of the grid cell reproduces the observations with an accuracy of 1.5 °C or better. The observed sub-grid variations in ground surface temperatures from two field sites are very well reproduced, with estimated fractions of sub-zero mean annual ground surface temperatures within ±10 %. We also find that snow distributions within areas of 1 km 2 in Norwegian mountain environments are closer to a gamma than to a lognormal theoretical distribution. The modelled permafrost distribution seems to be more sensitive to the choice of distribution function than to the fine-tuning of the coefficient of variation. When incorporating the small-scale variation of snow, the modelled total permafrost area of mainland Norway is nearly twice as large compared to the area obtained with grid-cell average snow depths without a sub-grid approach. |
format |
Article in Journal/Newspaper |
author |
K. Gisnås S. Westermann T. V. Schuler K. Melvold B. Etzelmüller |
author_facet |
K. Gisnås S. Westermann T. V. Schuler K. Melvold B. Etzelmüller |
author_sort |
K. Gisnås |
title |
Small-scale variation of snow in a regional permafrost model |
title_short |
Small-scale variation of snow in a regional permafrost model |
title_full |
Small-scale variation of snow in a regional permafrost model |
title_fullStr |
Small-scale variation of snow in a regional permafrost model |
title_full_unstemmed |
Small-scale variation of snow in a regional permafrost model |
title_sort |
small-scale variation of snow in a regional permafrost model |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-1201-2016 https://doaj.org/article/2f487cf17d164992b4981906f67b44eb |
geographic |
Arctic Norway |
geographic_facet |
Arctic Norway |
genre |
Arctic permafrost The Cryosphere |
genre_facet |
Arctic permafrost The Cryosphere |
op_source |
The Cryosphere, Vol 10, Iss 3, Pp 1201-1215 (2016) |
op_relation |
http://www.the-cryosphere.net/10/1201/2016/tc-10-1201-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-1201-2016 https://doaj.org/article/2f487cf17d164992b4981906f67b44eb |
op_doi |
https://doi.org/10.5194/tc-10-1201-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
3 |
container_start_page |
1201 |
op_container_end_page |
1215 |
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1766345213819748352 |