Assessment of the transfer of the dust-sand-salt material from the dry bottom of the Aral Sea

Institute of Seismology, Academy of Sciences of the Republic of Uzbekistan, Tashkent, Uzbekistan

^* Corresponding author: uz-hydrolog@mail.ru

Abstract

The study of the Aral Sea and its impact on the natural environment of the adjacent areas is one of the long-standing problems of hydrometeorology. Around the middle of the last century, individual scientists and then individual institutions took part in these studies, but the most thorough study of the Aral Sea and its basin began in the late 1950s – early 1960s of the last century. The existence of the Aral Sea is almost entirely determined by the inflow of river water into it. A significant decrease in the volume of flow in the Amu Darya and Syr Darya basins, the waters of which are taken for irrigation of huge crop areas (about 7 million hectares), is the main reason for the steady decline in sea level. Irretrievable flow withdrawals have already completely exhausted the compensatory capacity of these rivers and led to the disruption of water and salt balances. By the beginning of 1990, the area of the Aral Sea was decreasing by 1.8 and 2.8 times compared to long-term averages, with the level dropping by 14.3 meters compared to 1961. If the rate of level fall remains the same, by 2030 the level will have fallen by about 18 metres. This rapid recession has exposed large areas of the sea floor. In 1980, the area of formed land reached about 10 thousand km², and in 1990 27 thousand km², and in 2020 56 thousand km² and the former Aral Sea bed became a source of sand, dust and salts. The open surfaces of saline soils of light mechanical composition began to undergo intensive weathering processes, which led to the development of dust-salt storms and the transport of dust and salt aerosol to the adjacent territories of the Republic of Kazakhstan and Central Asia, including irrigated farming massifs in the Amu Darya and Syr Darya deltas. Visible dust-salt plumes detected from artificial Earth satellites are several hundred kilometres long. This indicates the large-scale nature of the process of solid phase particles entering the atmosphere, as well as their prolonged transformation in the suspended state. The article considers the issues of assessment of dust-sand-salt material transport from the dried Aral Sea bed, as well as the conditions of origin and development, their dynamics, local structure, distribution areas and others.