The nature and dynamics of frozen ground in alpine and subarctic periglacial environments
The nature and dynamics of frozen ground in alpine and subarctic periglacial environments
复制标题
高山和亚北极冰缘环境冻土的性质和动态
DOI：
10.1177/0959683609353432
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
C. Kneisel
中科院分区：
文献类型：
--
作者：
C. Kneisel
对高海拔高山和高纬度亚北极永久冻土环境中复杂的不连续和零星的永久冻土分布和特征进行了空间评估，采用了由传统(地貌制图)和现代技术(二维近地表地球物理、地表和地下温度监测)组成的不同方法相结合的方法。电阻率层析成像(ERT)已被证明是研究高山和亚北极山区多年冻土的一种特别合适的多功能方法。对高山和亚北极冰缘环境中冻土的性质和动态进行了天气学比较，证实了不均匀和片状的永久冻土产状，表明冻土的表面结构特征以及积雪的分布和持续时间有很大关系。关于冻土动力学，有地貌和地球物理证据表明永久冻土的堆积和退化。目前，在环境因子变化较小的调查研究区，这两个过程都是可能的。可以得出的结论是，时间尺度从几十年到几千年不等的永久冻土可以在很近的地方共存，例如，最近暴露在FOREFIELD和全新世推冰川和岩石冰川中的近现代永久冻土形成。为了解释小规模的非均匀地貌实地观测，需要地球物理测绘和多次现场测量，以了解复杂的冰缘环境，监测当代多年冻土条件，并能够区分年际波动和长期趋势。这种综合方法被认为有可能增进对复杂冰川和冰缘环境中全新世和次现代地貌演变的了解，这些环境可能表现出活跃、不活跃和残存的地貌。
A spatial assessment of the complex discontinuous and sporadic permafrost distribution and characteristics in high-altitude alpine and high-latitude subarctic permafrost environments was achieved using a combination of different methodological approaches consisting of traditional (geomorphological mapping) and modern techniques (2D near surface geophysics, surface and subsurface temperature monitoring). For the study of alpine and subarctic mountain permafrost with small-scale heterogeneity of surface and subsurface characteristics electrical resistivity tomography (ERT) has proven to be an especially well-suited and multifunctional method. Synoptic comparison of the nature and dynamics of frozen ground in alpine and subarctic periglacial environments confirmed heterogeneous and patchy permafrost occurrences showing a strong relationship to the surface textural characteristics and snow cover distribution and duration. Concerning frozen ground dynamics there is geomorphological and geophysical evidence for permafrost aggradation and degradation. At present both processes are possible in the investigated study areas with small-scale variation of the environmental factors. It can be concluded that permafrost with a timescale varying from several decades to a few thousand years can coexist in close proximity, such as, for instance, subrecent permafrost formation in a recently exposed glacier forefield and Holocene push moraines and rock glaciers. In order to account for the small-scale heterogeneity geomorphological field observations, geophysical mapping and multiple in situ measurements are required to understand complex periglacial environments, to monitor the contemporary permafrost conditions and enable a differentiation between interannual fluctuations from long-term trends. Such integrated approaches are thought to have the potential to improve the understanding of the Holocene and subrecent landscape evolution in complex glacial and periglacial environments which may exhibit active, inactive and relict landforms in close proximity.