Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes
Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but a...
Main Authors: | , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2017-12-01
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Series: | The Cryosphere |
Online Access: | https://www.the-cryosphere.net/11/2957/2017/tc-11-2957-2017.pdf |
Summary: | Geophysical methods are often used to characterize and monitor the
subsurface composition of permafrost. The resolution capacity of standard
methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement
geometry, but also on the temporal variability in the contrast of the
geophysical target variables (electrical resistivity and P-wave velocity).
Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the
context of permafrost degradation using synthetic and field data sets of
mountain permafrost terrain. In addition, we tested the resolution
capacity of a petrophysically based quantitative combination of both methods,
the so-called 4-phase model, and through this analysed the expected changes in
water and ice content upon permafrost thaw. The results from the synthetic
data experiments suggest a higher sensitivity regarding an increase in water
content compared to a decrease in ice content. A potentially larger
uncertainty originates from the individual geophysical methods than from the
combined evaluation with the 4-phase model. In the latter, a loss of ground
ice can be detected quite reliably, whereas artefacts occur in the case of
increased horizontal or vertical water flow. Analysis of field data from a
well-investigated rock glacier in the Swiss Alps successfully visualized the
seasonal ice loss in summer and the complex spatially variable ice, water
and air content changes in an interannual comparison. |
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ISSN: | 1994-0416 1994-0424 |