Multiscale Variability of Historical Meteorological Droughts and Floods in the Middle Yangtze River Basin, China

This paper examines the temporal patterns of historical droughts and floods and associated natural-anthropogenic variations in the middle Yangtze River Basin. Analyses are based principally on yearly meteorological data for 14 stations since late 15th century and monthly hydrological data for 14 stations over the past 50 years. Flood and drought cyclical patterns appear for the middle Yangtze River Basin with the aid of spectral analysis. Significant centennial-decadal scale droughts and floods are considered to be a function of sunspot activities and monsoonal climate, while the interdecadal meteorological hazards should be largely triggered by El Niño-Southern Oscillation (ENSO) variations and amplified, to a certain extent, by anthropogenic behaviors. The results show that the flood intensity has changed from decadal to interdecadal cycles in the middle Yangtze River Basin, possibly due to human behaviors leading to rapid expanse of urban populations, high shrinkage of river and lake systems, and fast construction of water facilities. This study can serve as a reference for similar studies in other geographical areas. The study leads to the general conclusion that it is crucially important in the current epoch (the Anthropocene) that public policy for urban development in the middle Yangtze River Basin, China, and likely elsewhere in the world, emphasize the harmonious development of human systems with natural ones in order to mitigate risks of meteorological hazards.