Author
Listed:
- V. E. Romanovsky
- T. E. Osterkamp
Abstract
Precise temperature data from four Alaskan permafrost sites (Prudhoe Bay, Barrow and two sites near Fairbanks) combined with computer modelling provide quantitative measures of the existence and dynamics of unfrozen water in the active layer and permafrost. Unfrozen water contents are negligible for living and dead moss layers, small in the peat layers and larger in the silts, and show significant site‐to‐site variation. The effect of unfrozen water on the ground thermal regime is largest immediately after freeze‐up and during cooling of the active layer. It is less important during warming and thawing of the active layer and during freezing and thawing of seasonally frozen ground. The effects last less than a month in cold permafrost and throughout most of the freeze‐up period in warm permafrost. Physically, unfrozen water introduces a spatially distributed latent heat and changes thermal properties which retards the thermal response of an active layer or permafrost. Unfrozen water in the freezing and frozen active layer and near‐surface permafrost also protects the ground from rapid cooling and creates a strong thermal gradient at the ground surface that increases the heat flux out of the ground. This enlarged heat flux also enhances the insulating effect of the snow cover. There do not appear to be any inherent difficulties in using conductive heat modelling for the active layer during the period when the zero curtain exists. Copyright © 2000 John Wiley & Sons, Ltd. Des données précises de température du sol provenant de quatre sites où existe un pergélisol en Alaska (Prudhoe Bay, Barow et deux sites près de Fairbanks) sont comparées avec des modèles obtenus par ordinateur, et de cette comparaison, sont tirées des mesures quantitatives de l'existence et de la dynamique de l'eau non gelée du pergélisol et de la couche active. Les contenus en eau non gelée sont négligeables dans les couches de mousses vivantes et mortes, petites dans les couches de tourbe, et plus importantes dans les limons où lse variations sont significatives d'un endroit à l'autre. L'effet de l'eau non gelée sur le régime thermique du sol est le plus marqué immédiatement après le gel et pendant le refroidissement de la couche active. Il est moins important pendant le réchauffement et le dégel de la couche active et pendant le gel et le dégel de la couche saisonnièrement gelée. Les effets de cette eau non gelée persistent moins d'un mois dans les réegions de pergélisol ‘froid’ mais se manifestent pendant la majorité de la période de gel dans le pergélisol dit ‘chaud’. Physiquement, l'eau non gelée introduit une chaleur latente qui modifie les propriétés thermiques et retarde la variation de température de la couche active on du pergélisol. L'eau non gelée dans la couche gelant et gelée, et dans le pergélisol proche de la surface, protège le sol d'un refroidissement rapide et crée un fort gradient thermique dans le sol proche de la surface du sol, gradient qui augmente le flux de chaleur. Celui‐ci accroît aussi l'effet d'isolation de la couverture neigeuse. Aucune difficulté particulière n'apparaît dans l'emploi de la conduction thermique pour modéliser le tarnsfert de chaleur dans la couche active pendant la période zéro. Copyright © 2000 John Wiley & Sons, Ltd.
Suggested Citation
V. E. Romanovsky & T. E. Osterkamp, 2000.
"Effects of unfrozen water on heat and mass transport processes in the active layer and permafrost,"
Permafrost and Periglacial Processes, John Wiley & Sons, vol. 11(3), pages 219-239, July.
Handle:
RePEc:wly:perpro:v:11:y:2000:i:3:p:219-239
DOI: 10.1002/1099-1530(200007/09)11:33.0.CO;2-7
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Citations
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Cited by:
- Lucash, Melissa S. & Marshall, Adrienne M. & Weiss, Shelby A. & McNabb, John W. & Nicolsky, Dmitry J. & Flerchinger, Gerald N. & Link, Timothy E. & Vogel, Jason G. & Scheller, Robert M. & Abramoff, Ro, 2023.
"Burning trees in frozen soil: Simulating fire, vegetation, soil, and hydrology in the boreal forests of Alaska,"
Ecological Modelling, Elsevier, vol. 481(C).
- E. Schuur & B. Abbott & W. Bowden & V. Brovkin & P. Camill & J. Canadell & J. Chanton & F. Chapin & T. Christensen & P. Ciais & B. Crosby & C. Czimczik & G. Grosse & J. Harden & D. Hayes & G. Hugelius, 2013.
"Expert assessment of vulnerability of permafrost carbon to climate change,"
Climatic Change, Springer, vol. 119(2), pages 359-374, July.
- A. Britta K. Sannel, 2020.
"Ground temperature and snow depth variability within a subarctic peat plateau landscape,"
Permafrost and Periglacial Processes, John Wiley & Sons, vol. 31(2), pages 255-263, April.
- Aleksandr Zhirkov & Petr Permyakov & Zhi Wen & Anatolii Kirillin, 2021.
"Influence of Rainfall Changes on the Temperature Regime of Permafrost in Central Yakutia,"
Land, MDPI, vol. 10(11), pages 1-19, November.
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