ABSTRACT Graphical abstract showing significant warming, a negligible increase in precipitation, and decreased runoff in major rivers of Western Mongolia based on long-term data. As a vital ‘water tower’ in arid regions, Western Mongolia is highly sensitive to climate change, where alterations in hydrological processes profoundly impact regional ecological security and pastoralism. However, systematic analyses of long-term trends accounting for spatiotemporal and elevational differences through multi-method validation remain lacking. This study, utilizing meteorological and hydrological observation data and integrating methods including the Mann-Kendall trend test, Innovative Trend Analysis, and Sen's Slope Estimator. The results reveal a pronounced regional warming of 1.96 °C (Z = 6.36) over the 41-year period, contrasted with a minimal precipitation increase of just 6.08 mm (Z = 0.89). Critically, trends diverged by elevation: warming was more intense at lower altitude, while higher elevations experienced a decrease in precipitation. Concurrently, major rivers such as the Zavkhan (Z = −0.51) and Khovd (Z = −3.05) exhibited declining discharge trends, and these changes showed a moderate positive correlation with precipitation (r = 0.38). The combined pattern of intensifying warming and reduced highland precipitation exacerbates the risk of declining flows, particularly in glacially-fed systems. This research provides essential empirical evidence for understanding hydrological responses in endorheic basins and establishes a scientific foundation for adaptive water resource management in Western Mongolia and similar arid regions.
Dashlkham et al. (Wed,) studied this question.