Synchronous droughts and floods in the Southern Chinese Loess Plateau since 1646 CE in phase with decadal solar activities

Droughts and floods are two longstanding and devastating climatic threats to mankind. They are challenging to predict mainly due to the significant spatial and temporal variations of precipitation. Using historical archives back from 1646 CE, here we present a high-resolution catchment level dataset of droughts and floods in the southern Chinese Loess Plateau (hereafter, CLP) within the middle reaches of River Jing. We have analysed the occurrences of floods and droughts based a specially-developed statistics from historical archives, as well as the daily rainfall from present-day observations within the catchment. Overall, our results show that the frequency of droughts and floods in the region is synchronous on decadal timescales with solar activities and the Pacific Decadal Oscillation (hereafter, PDO) index, and they are also broadly in phase with changes in both global and regional reconstructed temperatures. At decadal to interannual timescales, PDO and El Niño and Southern Oscillation (hereafter, ENSO) drive an uneven distribution of precipitation in different seasons in the southern CLP, which could be one of the reasons for the strong association of floods and droughts with the PDO and ENSO signals in our catchment. If the global temperature continues to rise in the future, we expect that the risk of both droughts and floods in the study region will also increase.