Recurrence analysis of extreme historical drought under the current defense conditions in China

Quantifying historical extreme drought is crucial to better understand and contextualize historical extreme droughts and prepare for extreme drought events that may occur in the future. However, the potential impacts of extreme droughts such as those in historical records considering modern day drought resistance and mitigation capacities remain unclear. In order to present the methods of reconstructing historical drought recurrence and conduct a historical drought recurrence scenario analysis under the current defense conditions, a modern day recurrence of the Guangxu drought during the Qing Dynasty from 1875 to 1879 was proposed using the Qing Palace Archives. In which, the historical annual precipitation in core drought areas was quantitatively reconstructed based on snow-rain records derived from the Qing Dynasty archives. And the extreme Guangxu drought was analyzed by establishing the corresponding relationship between precipitation anomaly percentage and the historical drought catalog. This allowed for the characterization of possible impacts of severe drought on water resources, water supply, food production, and economy under current defense conditions. The results showed that if the Guangxu drought occurred today under the current natural geographical conditions, core drought areas like Beijing, Tianjin, Hebei, Shanxi, Shaanxi, Henan, and Shandong would experience water shortages greater than 50% of their multi-year average water resources. In addition, we found that water transfer projects and large-medium-sized reservoirs will play central roles in drought mitigation in the event of an historical extreme drought.