Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 11, 635-651, 2017
https://doi.org/10.5194/tc-11-635-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
28 Feb 2017
Soil moisture redistribution and its effect on inter-annual active layer temperature and thickness variations in a dry loess terrace in Adventdalen, Svalbard
Carina Schuh1, Andrew Frampton1,2, and Hanne Hvidtfeldt Christiansen3 1Department of Physical Geography, Stockholm University, Stockholm, Sweden
2Bolin Centre for Climate Change, Stockholm University, Stockholm, Sweden
3Department of Arctic Geology, The University Centre in Svalbard, Longyearbyen, Norway
Abstract. High-resolution field data for the period 2000–2014 consisting of active layer and permafrost temperature, active layer soil moisture, and thaw depth progression from the UNISCALM research site in Adventdalen, Svalbard, is combined with a physically based coupled cryotic and hydrogeological model to investigate active layer dynamics. The site is a loess-covered river terrace characterized by dry conditions with little to no summer infiltration and an unsaturated active layer. A range of soil moisture characteristic curves consistent with loess sediments is considered and their effects on ice and moisture redistribution, heat flux, energy storage through latent heat transfer, and active layer thickness is investigated and quantified based on hydro-climatic site conditions. Results show that soil moisture retention characteristics exhibit notable control on ice distribution and circulation within the active layer through cryosuction and are subject to seasonal variability and site-specific surface temperature variations. The retention characteristics also impact unfrozen water and ice content in the permafrost. Although these effects lead to differences in thaw progression rates, the resulting inter-annual variability in active layer thickness is not large. Field data analysis reveals that variations in summer degree days do not notably affect the active layer thaw depths; instead, a cumulative winter degree day index is found to more significantly control inter-annual active layer thickness variation at this site. A tendency of increasing winter temperatures is found to cause a general warming of the subsurface down to 10 m depth (0.05 to 0.26 °C yr−1, observed and modelled) including an increasing active layer thickness (0.8 cm yr−1, observed and 0.3 to 0.8 cm yr−1, modelled) during the 14-year study period.

Citation: Schuh, C., Frampton, A., and Christiansen, H. H.: Soil moisture redistribution and its effect on inter-annual active layer temperature and thickness variations in a dry loess terrace in Adventdalen, Svalbard, The Cryosphere, 11, 635-651, https://doi.org/10.5194/tc-11-635-2017, 2017.
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This study investigates how soil moisture retention characteristics impact ice and moisture redistribution, heat transport and active layer thickness under permafrost conditions. This is relevant for understanding how climate change interacts with permafrost, which is important because there is much stored carbon in permafrost, which may be released to the atmosphere as permafrost degrades and may then act to further enhance climate warming.
This study investigates how soil moisture retention characteristics impact ice and moisture...
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