Четковидные русла рек – «горячие точки» криолитозоны

Тарбеева, А.М.; Арп, К.Д.; Ефремов, В.С.; Крыленко, И.В.; Лебедева, Л.С.

Авторы: Тарбеева А.М., Арп К.Д., Ефремов В.С., Крыленко И.В., Лебедева Л.С.
Сборник: Сборник докладов международной научной конференции памяти выдающегося русского гидролога Юрия Борисовича Виноградова. ТРЕТЬИ ВИНОГРАДОВСКИЕ ЧТЕНИЯ ГРАНИ ГИДРОЛОГИИ
Год издания: 2018
Место издания: Санкт-Петербург
Первая страница: 132
Последняя страница: 138
Аннотация: Beaded streams, characterized by prominent alternation of lake-like pools connected by narrow runs, are typical first order watercourses in permafrost regions. However, their formative mechanisms are still not completely clear. Meanwhile, these streams have great ecological significance, providing feeding and overwintering habitats for many aquatic organisms in cold regions. In order to establish the processes in the beaded channels and to discover their formative mechanisms, we conducted observations of thermal regime of the channel and surrounding floodplain on the Shestakovka River in Central Yakutia in the permafrost taiga and on Blackfish Creek on the North slope of Alaska in the arctic tundra. The channel of Upper Shestakovka River in winter consist of isolated reservoirs of pressurized water (2-3 m depth), underlayed by lenses of thawed sediments (taliks) up to 4 m depth, remain in the deep reaches associated with the channel extensions. The runs are frozen to the bottom, the ice thickness in them reaches 0,5-0,6 m. The temperature of sediments under the channel bed is 14°C higher than at the same depths under the floodplain. The average annual water temperature on the channel bed in the pools was +1,9°С, the maximum reached +12°С, while the average annual air temperature was –7°С. Observations on the Blackfish Creek in Alaska have shown that the its pools are even warmer: the average annual bed temperature is + 2,9°C at lower (-10.7 °C) air temperatures. The additional heating effect on the channel on tundra rivers, is provided by snow cover, which is thicker due to wind drift accumulation in the narrow and deeply incised channels of small rivers. Positive temperatures in the beaded pools indicate the possibility of thermokarst developing. However, the Shestakovka channel is formed in low ice content sediments. This suggests that the main role in the formation of the Shestakovka pools play uneven erosion during the flood, which does not exclude the development of thermokarst in other channels in permafrost regions, in particular in Alaska.
Добавил в систему: Тарбеева Анна Михайловна

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Четковидные русла рек – «горячие точки» криолитозоныстатья Электронная публикация

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