A 578-year precipitation reconstruction in the southeastern Tibetan Plateau reveals AMV modulation of regional hydroclimate

Understanding the long-term precipitation variability of the Tibetan Plateau is essential for evaluating the modulation of water supply of the Asian Water Tower by global climate variability. In this study, we developed a 578-year tree-ring width chronology derived from Picea likiangensis and Picea brachytyla in the southeastern Tibetan Plateau (SETP). This record was used to reconstruct annual precipitation from 1445 to 2023 CE, specifically covering the period from June of the previous year to May of the current year. Comparison with other proxy records indicates that Indian Summer Monsoon (ISM) variability was likely the primary mechanism driving centennial-scale precipitation variability in the SETP before 1850. During this period, solar activity and frequent intense volcanic eruptions were likely the dominant external forcing factors. Furthermore, climate simulations and observational data indicate that the Atlantic Multidecadal Variability (AMV) has been the primary internal driver of decadal to multidecadal precipitation variability since 1850. Our analysis suggests that AMV-related thermodynamic and dynamic forcing modulates the atmospheric water supply to rivers in the SETP by influencing regional water cycle characteristics.