Challenges and solutions for long-term permafrost borehole temperature monitoring and data interpretation
Long-term borehole temperature monitoring in mountain permafrost environments is challenging under the hostile conditions reigning in alpine environments. On the basis of data measured in the SLF borehole network we show three situations where ground temperature data should be interpreted with cauti...
| Main Authors: | , |
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| Format: | Article |
| Language: | deu |
| Published: |
Copernicus Publications
2016-06-01
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| Series: | Geographica Helvetica |
| Online Access: | http://www.geogr-helv.net/71/121/2016/gh-71-121-2016.pdf |
| Summary: | Long-term borehole temperature monitoring in mountain permafrost
environments is challenging under the hostile conditions reigning in
alpine
environments. On the basis of data measured in the SLF borehole network we
show three situations where ground temperature data should be interpreted
with caution. (i) Thermistors have the tendency to drift, particularly if
exposed to moisture or mechanical strain. This induces apparent warming or
cooling, which can be difficult to differentiate from real ground
temperature changes. Recalibration of thermistor chains is impossible if
they cannot be extracted as a result of borehole deformation in creeping
permafrost terrain. A solution using zero-curtain-based detection of drift
and correction of data is presented. This method is however limited to the
active layer, due to the lack of a reference temperature at greater depth.
(ii) In contrast to drift-induced apparent warming, actual warming may be
induced by natural processes or by the effects of construction activity.
(iii) Control data from neighbouring boreholes are sometimes used to fill
data gaps and discern drift – however these data may only underline the
strong spatial variability of ground temperatures rather than provide
measurement redundancy. A selection of recently observed problems regarding
borehole monitoring in a hostile measurement environment are discussed, and
advantages and possible drawbacks of various solutions including measurement
redundancy or alternate instrumentation are presented. |
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| ISSN: | 0016-7312 2194-8798 |