Spatiotemporal Variation of Water Cycle Intensity in the Pamir Plateau from 1980 to 2019 and Its Climatic Drivers

Abstract A comprehensive understanding of the hydrological cycle is essential for Earth system science and climate change research. The Water Cycle Intensity (WCI) is defined as the sum of precipitation and actual evapotranspiration within a landscape unit. It is a widely used metric to quantify the impact of climate change on the global distribution of water resources. The WCI in the Pamir Plateau, located at the heart of Asian Water Towers, has received little attention. Understanding this aspect is crucial for assessing the impact of climate change on the hydrological cycle and devising strategies to adapt to these changes. Our study assessed the spatiotemporal variation in WCI on the Pamir Plateau from 1980 to 2019 using the WCI framework. Additionally, we explored the teleconnection mechanisms linking the WCI with the Indian Ocean Dipole Mode Index (DMI), canonical El Niño-Southern Oscillation (ENSO), and El Niño Modoki (EMI) using the wavelet analysis method. The findings showed that the WCI of the Pamir Plateau experienced a statistically insignificant increase from 1980 to 2019, particularly after 2003. Spatially, the eastern Pamir Plateau WCI increased significantly, whereas the western region showed a non-significant downward trend. This study found that the WCI in the Pamir Plateau is significantly influenced by atmospheric circulation patterns, and the variation in the WCI in the Pamir Plateau is mainly affected by the canonical ENSO, as well as by the coupling effect of canonical ENSO, and EMI. In addition, based on the characteristics of the regional hydrological cycle, we developed water resource management policies targeting flood risks in the northern Pamir Plateau and drought trends in the southwestern region. These insights not only deepen our understanding of changes in terrestrial hydrological cycles and their underlying mechanisms under climate change but also provide important references for water resource management in the mountainous regions of Central Asia.