Precipitation variation and trend projection in the eastern monsoon region of China since 1470

Extra long-term data series for precipitation is essential to the analysis of climate change and projection of regional water security in the future. While the observation data are often limited to only a few decades, historical documents could be used to reconstruct and estimate the historical precipitation to extend the data series. Based on the 'Atlas of drought/flood in China for the last 500-year period' and the observed precipitation data from 1959, this study reconstructed the long sequence of precipitation for the monsoon region of eastern China from 1470 to 2019. This study also investigated the variation pattern of precipitation for this 500-year period, explored the impacts of human-induced climate change and natural climate variability on precipitation, and projected the change trend of precipitation for the four scenarios from CMIP6. The results show that: ① The interannual distribution of precipitation in the region wasuneven with obvious wet and dry variations, 1470-1691 was in the dry period, 1692-1924 was a wet period, and turned into another dry period since 1925 with a quasi-181-year cycle; ② The impact of human-induced climate change has become apparent since 1991, wit a significant change in the tendency rates for precipitation in the Hai River, the Lower Yellow River and Yangtze River basins and the accelerated increasing trend of precipitation in the region; ③ Under the future climate change scenarios, the multi-year average precipitation would have a significant increase comparing to the baseline period of 1961-1990, greater seasonal variations, and higher risk of regional drought and flood. However, further study is needed on the liability for the change trend and risk analyses due to the uncertainty of future climate scenarios.