Temporal variation of extreme rainfall events in China, 1961–2009

The spatial and temporal variability of the frequency of extreme precipitation events in China for 1961–2009 was examined using the high quality rainfall dataset provided by the China Meteorology Administration (CMA) for 599 stations. Extreme events were defined by duration and recurrence interval, the event durations chosen were 1, 5, 10 and 30 days and the event thresholds were those associated with recurrence intervals of 1, 5 and 10 years. The results indicated that temporal variations of extreme precipitation index (EPI) showed interannual and interdecadal variability. Time series of anomalies of the nine regional EPI indices indicated that Northeast China, North China and the Yellow River basin had experienced a decreasing trend of extreme rainfall events during the last 50 years, while other six regions, namely the Yangtze River basin, Southeast Coast, South China, the Inner Mongolia, Northwest China and Tibetan Plateau, had experienced an increasing trend of extreme rainfall events. Seasonal results indicated that 95.6% of 1-day, 1-yr recurrence interval extreme rainfall events occurred from April to September in China. The possible attributions of trend and variability of extreme rainfall events at China include, but are not limited to, El Niño – Southern Oscillation (ENSO), the magnitude of East Asian Monsoon, wind circulations, as well as global warming. Obviously these factors are not independent. For example, it has long been recognized that ENSO can exert an important impact on the East Asian monsoon.