Short-term changes of permafrost degradation triggered by anthropogenic impacts and climatic events in Western Siberia 2010-2013

In light of climate warming, ice-rich permafrost landscapes are amongst the most vulnerable areas in the world. In addition, many regions in the Arctic are affected by rapid industrial development as natural resources become more and more accessible through transportation networks and new engineering technologies. The aim of this study is to examine short-term anthropogenic and natural disturbances on permafrost, in particular whether there is a relation between the effects of infrastructure and the occurrence of landslides. The study investigates a region in Central Yamal, Western Siberia, which was affected by the construction of the Bovanenkovo railway line and by high Retrogressive Thaw Slumps (RTS) occurrence in consequence of the extremely warm and wet year 2012. A change detection was performed using high optical satellite images. Furthermore, a kernel density map to illustrate RTS distribution and an analysis of RTS aspects employing a digital elevation model was conducted. To gain a better understanding of climate drivers of landslide occurrence a multifaceted approach of observational climate data, reanalysis on air temperature, precipitation and wind data as well as C-band backscatter data to derive soil moisture and the freeze/thaw soil state was performed. The change detection of anthropogenic disturbance in 2013 showed a decrease of around 40 % compared to 2010: However, active landslides along the railway line can be seen despite of maintenance techniques. The occurrence of 81 RTS at lake margins are mostly located in the flat areas of the study area and are, in contrast to many other studies, less influenced by solar radiation since most of the landslide aspects are facing to the NW and N. The application of reanalysis in remote areas appears to be a beneficial tool, as it reflects the seasonal differences of continental and maritime influenced climate and shows high accuracy with backscatter soil moisture data in the study area. Thus, RTS triggering in 2012 could be attributed to a mild winter, early snow melt, high summer temperatures, and enhanced rainfall rates. Although RTS appears to be a natural phenomenon in the study area, anthropogenic impacts might contribute to the occurrence of RTS, as the biggest hotspot of RTS is observed in close proximity to the railway line