东北夏季降水异常的年代际、年际构成及成因分析

Constitutes and Formation Cause of Inter-decadal and Inter-annual Variations of Summer Rainfall Anomalies in Northeast China

利用NCEP/NCAR再分析月平均海平面气压资料、中国160站月降水资料、英国气象局和英国大气资料中心月平均海表温度资料,使用周期分析、奇异值分解和旋转EOF分析方法,分析了东北夏季降水异常的年代际、年际构成及成因。结果表明: (1)东北夏季降水异常构成中年代际、年际变化相对均衡,在局地年际变率中,东、南部年代际变化略强于西、北部。(2)在年代际、年际尺度上,东亚夏季风增强(减弱),则东北降水偏多(偏少)。(3)ElNino事件与东北区夏季风异常无直接联系,故与东北夏季降水关系不密切。

Based on the NCEP/NCAR reanalyzed monthly sea surface pressure(SLP),the 160 stations monthly precipitation of China and the Met office and British atmospheric data center(BADC) monthly sea surface temperature(SST) dataset,the constitute and formation cause of the inter-decadal and inter-annual variations of summer rainfall anomalies in northeast China have been analyzed by using the periodical analysis,SVD and REOF methods.Results show that:(1)the inter-decadal and inter-annual variations of the summer rainfall anomalies in northeast China is relatively equipoise,but the local inter-annual variability in the southeast is slightly stronger than that in the northwest;(2)on the inter-decadal and inter-annual scales the strong(weak) east Asia summer monsoon corresponds to the excess(deficient) precipitation in northeast China;(3)there is no direct connection between El Nino events and the summer monsoon in northeast China,i.e. the former has no close relation with the summer rainfall in northeast China.