Лëд и снег (Sep 2022)
The water level regime of periglacial lakes during the growth stage (the lakes of the Tavan-Bogdo-Ola mountain massif, South-Eastern Altai)
Abstract
Assessment of the dynamics of high-altitude glacial lakes is becoming increasingly important in the context of modern climate instability. The formation of new periglacial lakes and the growth of existing lakes as a result of the reduction of glaciers are recorded almost all over the world, including Russia. A rapid increase of a periglacial lake size may lead to the formation of an outburst flood. In this context, in order to prevent outburst floods, it is necessary to investigate outburst hazard lakes at all stages of their development. The periglacial lakes of the Altai mountains have been little-studied in comparison with other mountainous areas. At the same time, they are also characterized by the formation of new lakes during the period of climate nonstationarity. It was confirmed by the identified statistically significant trends in average monthly air temperatures during the ablation period. Based on the analysis of multi-temporal satellite images, it was found that the number of new periglacial lakes in the high-altitude territories of the Altai Republic (Katunsky ridge, North-Chuya ridge, South-Chuya ridge and the Tavan-Bogdo-Ola mountain massif) is increasing exponentially. For a more detailed survey and field hydrological studies, the authors chose the recently formed periglacial Lake Barsovo and periglacial Lake Gachi-Kol. Both lakes located within the northen slope of the Tavan-Bogdo-Ola mountain massif. Field observations, which were carried out in July-August 2021, have shown that both lakes are currently at the transgressive stage of development (growth stage). The transgressive phase of the lakes development is characterized by a rapid increase in size by the end of the warm period and a complex level regime on both diurnal and annual scales, due to the fact that both lakes are adjacent to the glacier.
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