Abstract: Extreme weather events have been paid wide attention in recent years because it is an important aspect in the field of climate change research. Influenced by human activities and environmental changes, extreme weather events have increased significantly in different degrees in global scale. Extreme precipitation has the most typical characterization of extreme weather events, both domestic and overseas scientists have focused on the change of extreme precipitation. Northeast China is very sensitive to climate change;however, research on extreme precipitation index in Northeast China still remains fragmented. Based on daily precipitation data of 84 weather stations in Northeast China from 1961 to 2013, this paper analyzed the features of six extreme precipitation indices over Northeast China by using linear regression, climate tendency, Mann-Kendall nonparametric test, Principal component analysis and Empirical Mode Decomposition (EMD) method. Results show as follows:(1) Consecutive Dry Days (CDD) exhibited significant increase trend during the recent 53 years, while the other five extreme indices showed decrease trend.(2) In 1960s and 1980s, the average of CDD was the lowest, while the Consecutive Wet Days (CWD) was the highest.(3) The variation coefficient of extreme wet day precipitation (R99) was the biggest of all the extreme indexes, while CDD and CWD were the smallest, indicating that R99 was the most unstable index and CDD and CWD were the most stable index in recent 53 years.(4) Except for CDD and CWD, other extreme precipitation indices all had good correlations with total precipitation in summer. (5) Almost all extreme precipitation indices varied with a three-year period except for very wet day precipitation (R95) and extreme wet day precipitation (R99). In addition, maximum 1-day precipitation (RX1day) and maximum 5-day precipitation (RX5day) had a period of 17 a, and CDD, R95, R99, RX5day had periods between 30 and 32 years. It is well known that Northeast China has frequent drought and flood disasters, especially the drought disasters. By comparing the spatial distribution change of CDD and CWD in Northeast China, the paper has found that the drought risk is increasing in Northeast China, which is consistent with the study results by other scholars. Though most extreme precipitation indexes have indicative function to drought and flood years, the complicated and changeable regional drought and flood problem make it more important to further get a more comprehensive understand of the regional drought and flood problem, and distinguish the human activity influence and natural variability.

Key words: extreme precipitation, spatial and temporal variability, Northeast China