CORRELATIONS OF INTERANNUAL VARIATIONS IN AVERAGE MONTHLY LEVELS OF THE CASPIAN SEA, AS WELL AS THE TOTAL PRECIPITATION IN ITS BASIN, AND THEIR CHANGES UNDER MODERN CLIMATE WARMING

In the modern period, the level of the Caspian Sea water surface is rapidly decreasing, which creates significant problems for the population and economy of all countries of the Caspian region. Therefore, improvement of the methods for forecasting its further changes is an urgent problem of hydrology, meteorology and ecology. It is generally accepted that the main reasons for the current decline in the Caspian Sea level are the influence of anthropogenic factors and climatic changes on the dynamics of its water balance components. A significant component of the incoming part of this balance is the amount of precipitation falling in the territory of the Caspian basin. One of the methods used for forecasting the Caspian Sea level is multiple regression analysis. The validity of the forecasts obtained with its help depends on the significance of the relationships between the studied process in the future and the factors monitored in the present and in the past that are taken into account in their development. The article assesses the significance of statistical correlations between interannual variations in the average monthly background levels of the Caspian Sea and the dynamics of precipitation amounts in its basin, as well as its changes during the period of modern climate warming. The ERA 5 reanalysis information was used as factual material on precipitation. Information on the levels was obtained from literary sources. It was found that in the period of 1979-2021 the conclusion on the significance of the relationships under consideration was characterized by the reliability of at least 0.95 only if the changes in precipitation amounts corresponded to May. As the time shift between the analyzed process and this factor increases from 0 to 36 months, their correlation remains positive and significant, but slightly weakens. During the period of modern climate warming, the revealed correlation also became weaker, which allows us to doubt its significance even in the near future. There were also identified the Caspian basin areas for which, on the contrary, the considered relationship strengthened during the same period. It implies that the probability of the scenario in which they remain significant in the future is higher than that of other scenarios. Therefore, it is reasonable to take the identified relationships into account when forecasting changes in the average level of the Caspian Sea.