Mountain permafrost thickness evolution under influence of long-term climate fluctuations (results of numerical simulation)

As a result of the thermal inversion, mean annual air temperatures usually decrease from the mountain slopes to the valley bottoms in East Siberia. However, the permafrost thickness below the inter-mountain depressions is typically smaller than within the rock massifs. Four major factors are responsible for permafrost thickness formation: the temperature and amplitude of long-term (100 Kyr period cycles) temperature variations at the ground surface, the relief, the geothermal heat flux variability and the vertical geocryological zonality phenomenon. A two-dimensional finite difference conductive heat transfer model with phase changes was used. The numerical modeling showed that the mountain permafrost thickness is determined by relief and also depends on climatic history. The knowledge of mountain permafrost dynamics is very important for understanding the underground water drainage and storage within the continental mountain regions.