基于SPEI的1961-2012年东北地区干旱演变特征分析

Evolution Analysis on Droughts in Northeast China During 1961-2012 Based on SPEI

基于1961-2012年东北地区65个气象站逐日降水、气温、相对湿度、实际水汽压、风速和日照时数资料,计算标准化降水蒸散指数(SPEI),并对SPEI指数评价实际干旱的能力进行验证,采用M-K趋势检验和正交经验分解函数等统计方法,分析近52a东北地区年、季尺度的干旱演变特征。结果表明:SPEI指数可以表征东北地区的干旱特征;1961-2012年,全区年SPEI指数呈现明显的阶段性特征,20世纪60年代后半段、70年代后半段和90年代后半段-21世纪初的3个时段发生了连续干旱,中西部地区是干湿变化异常敏感的地区。东北地区春季干湿状况变化趋势不明显,但在2003年以后出现变湿态势,夏、秋季有不显著的干旱化态势,20世纪90年代中期以后秋季干旱化态势明显增强,黑龙江省西南部和吉林省西部地区秋旱加强态势较其它地区明显;冬季21世纪全区趋于变湿,变湿态势较明显的地区位于吉林省中西部和辽宁省北部。

Based on the daily precipitation, temperature, relative humidity, actual sunshine duration record from 65 meteorological stations in 1961 - 2012, vapor pressure, wind speed and 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 SPE1 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 21^st century. Seasonal SPEI showed different characteristics, with no obvious trend in spring before 21^st 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 21^st century in the middle-west Jilin province and the north Liaoning province.