The influence of snow cover on ground freeze-thaw frequency, intensity, and duration: An experimental study conducted in coastal northern Sweden

ABSTRACT

The impact of snow cover on seasonal ground frost and freeze-thaw processes is not yet fully understood. The authors therefore examined how snow cover affects seasonal ground frost in a coastal setting in northern Sweden. Air and soil temperatures were recorded in a paired-plot experiment, both with and without snow cover, during the frost season 2012–2013. The frequency, duration, and intensity of the freeze-thaw cycles during the frost season were calculated. The results showed that the freeze-thaw frequency was 57% higher at the soil surface and the intensity 10 °C colder in the spring of 2013, when the ground lacked snow cover. Furthermore, the duration of the seasonal freeze-thaw cycle was 30 days longer on average in cases where there was natural snow accumulation. The correlation between air and ground surface temperatures weakened with increased snow-cover depth. The authors conclude that continued increases in air temperature and decreases in snow in coastal northern Sweden might alter freeze-thaw cycles and thus affect natural and human systems such as geomorphology, ecology, spatial planning, transport, and forestry.

EDITORS:

• Ivar Berthling
• Catriona Turner

KEYWORDS:

• freeze-thaw
• seasonally frozen ground
• snow-cover
• soil temperature
• subarctic Sweden

Acknowledgements

The research was financed by Vetenskapsrådet and Kammarkollegiet through the research school in geography, which existed in the period 2012–2014 at Uppsala University, the municipality of Kalix, and Nordiskt Vägforum. Thanks are due to Louise Vikman, who assisted with the management of the snow stations. Guidance in the research field and use of equipment was well tutored by Professor Jan Boelhouwers, University of Uppsala, who also contributed to methodological discussions. Useful advice was received also from Dr Anders Brandt, University of Gävle, and Professor Magnus Bohlin, University of Dalarna. We thank the responsible editor, Associate Professor Ivar Berthling, and the two anonymous reviewers for their comments and suggestions, which greatly improved the manuscript.

Notes

1. The Abisko region consists of three dispersed settlements: STF Abisko Turiststation (offering accommodation for tourists), Abisko Scientific Research Station, and Abisko Östra village. However, the researched area covers more than 100 km².