Precipitation variability in the Yangtze River subbasins

Numerous dams and reservoirs in the Yangtze River basin have been constructed. Thus understanding the variability of hydroclimatological time series is important for the development of an optimal reservoir management strategy. This is crucial for life in the densely populated basin known to be highly susceptible to floods and droughts. Time series of annual precipitation totals and precipitation totals from May to September (the rainy season) for the period from 1961 to 2002 were averaged within the subbasins of the Yangtze River. The resulting time series were analyzed for similarities and differences and continuous wavelet transforms were produced to identify inherent quasi-periodicity. The western subbasins have shown a diverse pattern of periods with high and low precipitation variance. We have detected prominent periods of high precipitation variance for the central and eastern subbasins in the 1980s and 1990s, respectively.