Fig. 2: Runoff characteristics during documented drought and flood events.

a Results of the superposed epoch analysis (SEA) of the runoff reconstruction in the Hanjiang River for 57 historical floods during 1580–1955 CE, b 54 historical droughts during 1580–1955 CE, c 13 instrumental droughts during 1955–2014 CE, and d 14 instrumental floods during 1955–2014 CE. Dashed and dotted lines mark 99% and 95% significance. e The runoff reconstruction in the Hanjiang River based on tree rings shown together with the observed Yangtze river runoff data.