Scaling Relation of Retrogressive Thaw Slumps on the Taymyr Peninsula

Abstract:
Vast areas of the Arctic host ice-rich permafrost, which is becoming increasingly vulnerable to terrain altering thermokarst in a warming climate. Among the most rapid and dramatic changes are retrogressive thaw slumps (RTSs). These slumps evolve by a retreat of the RTS headwall during the summer months, making their change visible by comparing digital elevation models over time. In this study we use digital elevation models generated from TanDEM-X observations to derive volume and area change rates for RTSs over a 4 to 5 year time-frame. We selected three study regions on the Taymyr Peninsula in Siberia. The area-to-volume scaling could be well described using an power law (V ≈ Aalpha), with values varying between 1.06 to 1.42 between the regions. The distributions of area and volumetric change rates of thaw slumps followed a inverse γ function with a distinct peak and an exponential decrease for large slumps. Such distribution are already known to describe change rates of landslides in temperate climate zones. The individual areas showed some similarities and difference in the computed rollover, cutoff and exponential decay coefficients that are used to describe the probability density function.