| DOI: | 10.5194/tc-10-1201-2016
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| Scopus记录号: | 2-s2.0-84973321092
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| 论文题名: | Small-scale variation of snow in a regional permafrost model |
| 作者: | Gisnas K; , Westermann S; , Vikhamar Schuler T; , Melvold K; , Etzelmüller B
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| 刊名: | Cryosphere
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| ISSN: | 19940416
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| 出版年: | 2016
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| 卷: | 10, 期:3 | | 起始页码: | 1201
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| 结束页码: | 1215
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| 语种: | 英语
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| 英文关键词: | altitude
; arctic environment
; borehole
; estimation method
; insulation
; land surface
; permafrost
; snow cover
; surface temperature
; temperature anomaly
; thermal regime
; Norway
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| 英文摘要: | 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 km2 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 km2 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 km2 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. © 2016 Author(s). |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/75132
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| Appears in Collections: | 影响、适应和脆弱性
气候变化与战略
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作者单位: | Department of Geosciences, University of Oslo, Oslo, Norway; Norwegian Water Resources and Energy Dirct., Oslo, Norway
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| Recommended Citation: | |
Gisnas K,, Westermann S,, Vikhamar Schuler T,et al. Small-scale variation of snow in a regional permafrost model[J]. Cryosphere,2016-01-01,10(3)
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