Abstract
This study presents an analysis of the long-term dynamics of the Caspian Sea level based on satellite altimetry data for the period 1992-2025. The analysis was carried out using the DAHITI database of hydrological time series for inland waters, which is generated from multi-mission satellite altimetry observations. The results reveal a pronounced decreasing trend in the Caspian Sea level: over the study period, the sea level declined by approximately 2.56 m, corresponding to an average rate of about 8 cm per year. The sea level decline is shown to be non-uniform and characterized by alternating phases of relative stabilization and accelerated decrease, with the most pronounced negative trends observed during the last 10-15 years. A stable seasonal variability of the sea level is identified, with maxima occurring in summer and minima in winter, as well as a significant interannual variability in the amplitude of seasonal fluctuations, reaching approximately 25 cm. The results confirm the high informational value of satellite altimetry for monitoring the Caspian Sea level and demonstrate its potential for analyzing long-term climate-driven changes in the water balance, assessing environmental risks, and supporting decision-making processes in the transboundary Caspian region.