Paleoclimate Data Assimilation of Monsoon Precipitation in China Over the Past 500 Years

Monsoon precipitation in China influences the livelihoods of approximately two-thirds of its population, making an understanding of its regional patterns and long-term variability essential for improving future precipitation forecasts. However, the relatively short span of instrumental records and the limited skill of climate models in simulating precipitation hinder our ability to uncover the driving mechanisms behind historical monsoon precipitation changes. To address these gaps, this study integrates multiproxy precipitation reconstructions with climate model simulations to assimilate China precipitation fields over the past 500 years. Our analysis highlights robust assimilation results in North and Southwest China, suggesting a potential teleconnection influenced by the South Asian summer monsoon. Similarly, assimilation in East China successfully captures Meiyu rainfall variations closely associated with the East Asian summer monsoon. Furthermore, our analyses indicate that precipitation in North, Southwest, and East China exhibits strong responses to interannual-scale El Niño-Southern Oscillation (ENSO) variability and decadal-scale Pacific Decadal Oscillation (PDO) fluctuations. These findings not only deepen our understanding of the mechanisms underlying China’s monsoon precipitation evolution but also provide a valuable scientific basis for refining future projections of monsoon climate in China.