Abstract: Using the daily precipitation data from 753 stations in China during 1961-2010 and reanalysis data, the changes of summer precipitation, including the changes of the summer rainfall total, the rainfall amount of extreme precipitation, and the frequency of extreme precipitation, were investigated. These changes are similar in spatial patterns, with increasing changes over the south, and decreasing changes over the north. The Poisson regression was used to investigate the change of the frequency of extreme precipitation. The frequency increased over the Yangtze River basin and South China, and decreased over the region to the north of the Huaihe River basin. It is found with a new diagnosis tool that at most stations, the change of the the summer rainfall total is dominated by the change of intensity, and the change of the rainfall amount of extreme precipitation is dominated by the change of frequency. The relative importance of the changes in moisture and air temperature in the variability of summer rainfall total was also analyzed. In most areas north to the Yellow River, the variability of the summer rainfall total is dominated by the moisture change, while over the Yangtze River basin and South China, it is dominated by the air temperature change.

Key words: summer rainfall, daily extreme precipitation, global warming, Poisson regression