| Popis: |
The subject of this research is the historical data on the origin, geographical distribution, seasonal and long-term variability of giant aufeis ice sills in the Russian Far East. Ice sills are the ice fields, the thickness and area of which reach up to 10-12 m and several tens of sq. km respectively. They are formed in severe climatic conditions as a result of layer-by-layer freezing of groundwater poured onto the surface. This is a distinct form of seasonal, and at times, long-term glaciation, which regulates the processes of water and energy exchange in low temperature cryolithozone, as well as determines the extent of permafrost intermittency and developmental challenges. Assessment is given on the role of aufeis ice sills in the formation of river and underground runoff, transformation of terrain, morphological structure of landscape, and development of dangerous cryogenic phenomena. This article is first to review the data on aufeis ice sills in the Russian Far East that have accumulated over the past two centuries. Three author highlights the three research periods: until 1900, since 1900 to 1950, after 1950. The latter period is the most effective, indicate the creation of the map and cadastre of giant aufeis, including more than 7,000 ice fields based on the data of aerial photography. The article establishes the key patterns of their distribution, factors and conditions of formation, relation to permafrost-hydrogeological structures, forms of terrain and climate; as well as determines the peculiarities of seasonal and long-term variability. |
