关键词: 标准化降水蒸散指数（SPEI）, 年际变化, 季节变化, 干旱

Abstract: Based on the daily precipitation，temperature，relative humidity，actual vapor pressure，wind speed and sunshine duration record from 65 meteorological stations in 1961-2012，the standardized precipitation evapotranspiration indices（SPEI）were calculated and verified for assessing the droughts in Northeast China.M K method and Empirical Orthogonal Function（EOF）were also used to analyze drought characteristic in different time scale over Northeast China as well.The results showed that the SPEI could capture the evolution of droughts over the Northeast region.Annual SPEI showed an obvious fluctuation during 1961-2012，the lasting droughts in Northeast China occurred in the late 1960s，and variability of droughts was most severe in the middlewest part in late 1970s and from ending of 1990s to early 21st century.Seasonal SPEI showed different characteristics，with no obvious trend in spring before 21st century，but wetting tendency was found after 2003.Occurrence of droughts in summer and autumn tended to increase，and more sever since mid1990s in autumn in the southwest Heilongjiang province and the western Jilin province.While an obvious wetting tendency have been detected for winter season since early 21st century in the middlewest Jilin province and the north Liaoning province.

Key words: Standardized precipitation evapotranspiration index（SPEI）, Annual variation for SPEI, Seasonal variation for SPEI, Droughts