Monitoring mountain permafrost evolution using electrical resistivity tomography: A 7-year study of seasonal, annual, and long-term variations at Schilthorn, Swiss Alps
Monitoring mountain permafrost evolution using electrical resistivity tomography: A 7-year study of seasonal, annual, and long-term variations at Schilthorn, Swiss Alps
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DOI：
10.1029/2007jf000799
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发表时间：
2008-01-26
影响因子：
3.9
通讯作者：
Maeusbacher, R.
中科院分区：
文献类型：
--
作者：
Hilbich, C.;Hauck, C.;Maeusbacher, R.
提出了一种改进山地多年冻土退化观测的地球物理和热监测相结合的方法。重复电阻率层析成像（ERT）测量的时间推移反演允许活动层动态和年际冻土条件被描绘。在瑞士阿尔卑斯山Schilthorn进行的一项为期7年的研究中，对一组全面的ERT监测数据进行了分析，证实了ERT监测对短期、季节性和长期冻融过程观测的适用性。长期电阻率变化的基础上进行了评估的季节性电阻率的变化，显示了一个年度周期与高的冻结和低的冻结状态下的电阻率。一个重要的结果是检测到的持续影响的异常炎热的欧洲2003年夏天的永久冻土制度，这是比以前假设的钻孔温度更严重。ERT监测和钻孔温度数据的综合分析显示，2003年夏季的结果是大量的地面冰退化，尽管地下温度条件合适，但在随后的几年中没有恢复。与长期温度演变相关的电阻率变化归因于液态水的有限可用性和/或材料特性的变化，孔隙体积由于沉降而改变）。
A combined geophysical and thermal monitoring approach for improved observation of mountain permafrost degradation is presented. Time-lapse inversion of repeated electrical resistivity tomography ERT) measurements allows both active layer dynamics and interannual permafrost conditions to be delineated. Analysis of a comprehensive ERT monitoring data set from a 7-year study at Schilthorn, Swiss Alps, confirmed the applicability of ERT monitoring to observations of freezing and thawing processes on short-term, seasonal, and long-term scales. Long-term resistivity changes were evaluated on the basis of seasonal resistivity variations showing an annual cycle with high resistivities in frozen and low resistivities in unfrozen state. One important result is the detection of a sustained impact of the extraordinarily hot European summer of 2003 on the permafrost regime, which is more severe than previously assumed from borehole temperatures. Combined analyses of ERT monitoring and borehole temperature data revealed substantial ground ice degradation as a consequence of the 2003 summer, which did not recover in the following years despite suitable subsurface temperature conditions. Resistivity changes that are nonconforming to long-term temperature evolution are attributed to the limited availability of liquid water and/or changes in material characteristics e.g., pore volume changes as a result of subsidence).