Automated Time‐lapse ERT for Improved Process Analysis and Monitoring of Frozen Ground
Automated Time‐lapse ERT for Improved Process Analysis and Monitoring of Frozen Ground
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DOI：
10.1002/ppp.732
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发表时间：
2011-10
影响因子：
5
通讯作者：
C. Hilbich;C. Fuss;C. Hauck
中科院分区：
文献类型：
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作者：
C. Hilbich;C. Fuss;C. Hauck
描述了一种新的自动电阻率层析成像（A-ERT）系统，该系统允许在高山或极地地形中连续测量电阻率分布。连续电阻率监测的优点，而不是在不规则的时间间隔单次测量，说明使用永久冻土监测站在瑞士阿尔卑斯山的希尔索恩。数据处理经过调整，可对生成的大量2D电阻率剖面进行自动化、时效性处理和质量评估。来自一年数据集的结果显示，在积雪期间的时间变化较小，初夏融雪和秋季冻结期间的变化最大，这与近地表土壤湿度或次表层温度的变化同步。在融雪期，观察到空间可变的渗透过程，导致土壤水分的快速增加和相应的电阻率在几天内下降。这种渗透导致了活跃层融化的开始，早在季节性积雪消失之前。统计分析表明，在一年的过程中，空间和时间的变化是相似的，这表明了空间异质性对活动层动力学的重要性。由于其具有成本效益的能力，即使在更深的深度也能监测冻结和融化过程，因此新的A-ERT系统可以广泛应用于永久冻土地区，特别是在长期退化过程的背景下。版权所有© 2011约翰威利父子有限公司.
A new automated electrical resistivity tomography (A‐ERT) system is described that allows continuous measurements of the electrical resistivity distribution in high‐mountain or polar terrain. The advantages of continuous resistivity monitoring, as opposed to single measurements at irregular time intervals, are illustrated using the permafrost monitoring station at the Schilthorn, Swiss Alps. Data processing was adjusted to permit automated time‐effective handling and quality assessment of the large number of 2D electrical resistivity profiles generated. Results from a one‐year dataset show small temporal changes during periods with snow cover, and the largest changes during snowmelt in early summer and during freezing in autumn, which are in phase with changes in either near‐surface soil moisture or subsurface temperature. During the snowmelt period, spatially variable infiltration processes were observed, leading to a rapid increase in soil moisture and corresponding decrease in electrical resistivity over a period of a few days. This infiltration led to the onset of active‐layer thawing long before the seasonal snow cover vanished. Statistical analyses showed that both spatial and temporal variability over the course of one year are similar, indicating the significance of spatial heterogeneity regarding active‐layer dynamics. As a result of its cost‐effective ability to monitor freezing and thawing processes even at greater depths, the new A‐ERT system can be widely applied in permafrost regions, especially in the context of long‐term degradation processes. Copyright © 2011 John Wiley & Sons, Ltd.