Frequency and intensity of extreme precipitation events in China

Using daily rainfall data at 738 stations in China from 1951 to 2004,and defining the 95th percentile as the threshold of extreme precipitation for each station,the characteristics of the spatio-temporal distribution and the linear trend of extreme precipitation events with different durations are analyzed.Results show that the frequency of extreme precipitation events is higher in the regions south of 35°N than in other parts of China,especially in the midlower reaches and the southern parts of the Yangtze River and in the southeastern part of the Tibetan Plateau with longer duration.And it happens more in summer than in other seasons.It is found that the frequency decreases rapidly whereas the mean intensity increases with the increase of duration of extreme precipitation events,especially in eastern part of China.The trend analysis shows that there is an increasing trend for regionally averaged relative frequency but a decreasing trend for the mean intensity of 1-day extreme precipitation events.They both increase significantly in the mid-lower reaches of the Yangtze River,in South China and in eastern Plateau and decrease significantly in some parts of North and Southwest China.The frequency and intensity of the extreme events lasting more than-days show a similar spatial distribution with that of 1-day events,but show no significant trends for their regionally averaged values.