Mapping of mountain permafrost using geophysical methods
Permafrost distribution in nonpolar mountain areas is strongly influenced by topo-graphical effects. Conditions therefore change within short distances and consequently the permafrost pattern is often very complex. Warm permafrost with temperatures between -2°C and 0°C is sensitive in terms of slope...
| Published in: | Progress in Physical Geography: Earth and Environment |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
SAGE Publications
2002
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1191/0309133302pp356ra http://journals.sagepub.com/doi/pdf/10.1191/0309133302pp356ra |
| Summary: | Permafrost distribution in nonpolar mountain areas is strongly influenced by topo-graphical effects. Conditions therefore change within short distances and consequently the permafrost pattern is often very complex. Warm permafrost with temperatures between -2°C and 0°C is sensitive in terms of slope failures. It is also crucial to determine the lower permafrost boundary by geophysical means in order to calibrate models. Various geophysical methods have been applied to the mapping of mountain permafrost, including bottom temperature of the snow cover (BTS), refraction seismics, DC resistivity, ground penetrating radar (GPR), electromagnetic induction and radiometry. This paper gives an overview of investigations to map mountain permafrost distribution showing the potential of the modern use of geophysical methods. The two-dimensional DC resistivity tomography makes it possible to get an impression of internal structures. Electromagnetic induction methods showed good results, in particular the EM-31 for determining the permafrost distribution and the PROTEM to assess the overall permafrost thickness. Using passive microwave (11.4 GHz), the BTS, which is used as an indicator for the presence of permafrost, was measured. After ground surveys, an airborne test measurement from a helicopter was made. Traditional BTS measurements agreed very well with the BTS determined by radiometry. |
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