Home – Home – Jornals – Earth’s Cryosphere 2021 number 1

An additional comprehensive study of the Peschanaya Gora (Sand Hill) outcrop and other sections of aeolian coversands in Central Yakutia has revealed that, together with loess-ice (Yedoma) covers, they were two related granulometric and mineralogical derivatives, which had formed as a result of aeolian processing of Quaternary alluvium during the second half of the Late Neopleistocene. Episodes of desertification took place 22.0-14.0, 12.8-11.8, and 0.6-0.1 ka BP. A decrease in aeolian activity and consolidation of dune massifs by a soil-vegetative cover took place in the intervals of 14.0-13.0 and 10.0-0.6 ka BP. The largest episode of desertification took place during the last global thermic minimum (MIS-2) and led to a sharp decline in the mammoth biome, the disappearance of the wooly mammoth and rhinoceros in Central Yakutia.

The simplified dependencies for estimation the fraction of the ice formed in a drop of fresh water when falling in the atmospheric air have been obtained. Based on mathematical modeling, the intensity of the freezing of salt-water droplets with various variants of salt rejection from the freezing boundary has been determined. An estimate of the increase in air temperature in a droplet plume consisting of drops of salt water has been given. The fraction of ice in a drop of salt water falling in atmospheric air and in a droplet plume has been calculated depending on the air temperature and the size of the drops.

The research deals with four different hypotheses on the development of thermokarst plains with fluvial erosion based on the mathematical modeling of their morphological pattern. The models result from the mathematical morphology of landscapes, which broadly uses the random processes. The analysis revealed that each variant of the development is characterized by a specific probabilistic distribution of sizes, areas of thermokarst lakes first of all. The empirical testing was done for 17 key sites with different environmental and permafrost conditions in Western and Eastern Siberia, and Canada. Our analysis revealed that in the majority of cases the areas of the thermokarst lakes within the homogenous sections of the thermokarst plains with fluvial erosion obey the integral exponential distribution. Hence, the model of the morphological pattern corresponding to the asynchronous start of thermokarst process is valid, and the increase in the size of the lakes is proportional to the heat loss density through the side surface. Thus, the morphological pattern of the vast areas of thermokarst plains with fluvial erosion is in a state of dynamic equilibrium, which should be taken into account when predicting its development and assessing natural risks.

2020 marked the 60th anniversary of the Melnikov Permafrost Institute SB RAS. This paper presents a brief history of its foundation and describes the major research achievements and outputs over the last decade. Promising avenues and projects for further geocryological research are outlined. In view of intensive industrial development of the permafrost regions, the authors believe that the Melnikov Permafrost Institute should be accorded a National Research Institute status with relevant government support.