Moisture Source Attribution of Synchronized Extreme Precipitation Communities During the Indian Summer Monsoon

Abstract Extreme precipitation during the Indian summer monsoon often occurs in spatially and temporally synchronized clusters, greatly amplifying flood risk. However, the moisture sources feeding such synchronized extremes and their long‐term evolution remain poorly understood. This study integrates nonlinear event synchronization, complex‐network analysis, and Lagrangian moisture tracking to quantify oceanic and terrestrial moisture contributions to nine synchronized extreme precipitation communities over India and to examine their changes between 1951–1987 and 1988–2024. The results show that these communities are governed by distinct moisture‐transport pathways, ranging from land‐influenced to ocean‐dominated control. Several regions exhibit enhanced oceanic contributions and weakened terrestrial recycling in recent decades, while others show the opposite tendency. These shifts are strongly seasonally structured, with contrasting early‐ and late‐monsoon dominance emerging across regions. The findings provide a new physical framework linking synchronized extreme precipitation over India to evolving moisture transport pathways under climate and landuse change.