Amplified summer extreme precipitation over the Tibetan Plateau in the early 21st century

The Tibetan Plateau (TP) has experienced significant intensification of extreme precipitation events in recent decades, with cascading risks to water security and fragile ecosystems. This study reveals a distinct post-2000 surge in summer extreme precipitation over the TP, predominantly driven by a sharp increase in the frequency of extreme events. The northwestern TP exhibits the most substantial amplification, representing the primary area hotspot. We attribute this extreme precipitation increase pattern to an intensified westward moisture transport from the western Pacific, dynamically modulated by an anomalous anticyclone extending from the eastern TP to the western Pacific. Mechanistically, this anticyclonic anomaly constitutes a pivotal node in an atmospheric wave train anchored by concurrent North Atlantic sea surface warming and Arctic sea ice loss. Remarkably, these two mid-to-high-latitude external forcings collectively account for more than 50% of the observed increase in extreme precipitation frequency over the TP. Our findings underscore a post-2000 increased Arctic control over Third Pole hydroclimate variability, providing new insights into how Arctic climate impacts vulnerable mountain systems.