Ground thermal conditions in a frost‐crack polygon, a palsa and a mineral palsa (lithalsa) in the discontinuous permafrost zone, northern Sweden
Abstract Ground temperature measurements were collected during 1997 to 1998 at three locations in the discontinuous permafrost zone in northern Sweden. Measurements were made in two frost‐crack polygons, two palsas and a mineral palsa (lithalsa). Important for the formation of permafrost at all loca...
| Published in: | Permafrost and Periglacial Processes |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2001
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1002/ppp.395 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.395 https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.395 |
| Summary: | Abstract Ground temperature measurements were collected during 1997 to 1998 at three locations in the discontinuous permafrost zone in northern Sweden. Measurements were made in two frost‐crack polygons, two palsas and a mineral palsa (lithalsa). Important for the formation of permafrost at all locations are (i) the absence of snow and, (ii) local soil properties. The seasonal variation in apparent thermal diffusivity—with higher diffusivities in summer than in winter in the mineral soil of the frost‐crack polygon and relatively little seasonal variation in the peat of the palsas—is the main cause for the cooler conditions in the palsas in summer. Morphology adds to the temperature fluctuations as indicated by highly fluctuating ground temperatures in the dome‐shaped mineral palsa as compared to the frost‐crack polygon. Occasional ground temperature gradients of more than −10 °C/m are probably sufficient for seasonal frost cracking. Copyright © 2001 John Wiley & Sons, Ltd. |
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