基于EEMD和EOF的鄱阳湖流域近550 a来旱涝时空变化

利用鄱阳湖流域及周边地区5个站点1467~2016年旱涝灾害史料，结合《中国近五百年旱涝分布图集》数据和现代器测降水资料，基于相关系数权重法集成重建了鄱阳湖流域近550 a旱涝序列。采用集合经验模态分解和经验正交函数等手段分析了鄱阳湖流域近550 a来的旱涝时空变化特征。结果表明：（1）鄱阳湖流域旱涝序列的各IMF分量变化规律符合自然信号的非线性变化的特征，主要的高频变化周期有2~3 a、7~8 a；中低频变化周期有22 a、36 a；低频变化周期有110 a、220 a等。（2）旱涝序列空间场的EOF分解表明，前4个模态的累积方差贡献率为93.68%，收敛效果明显。第一模态为区域整体变化一致；第二、三模态分别代表南北方向和东西方向上旱涝变化不一致；第四模态代表赣南地区的极端降水类型。（3）主要空间模态的时间系数功率谱分析结果表明，旱涝空间场模态的变化周期与旱涝序列EEMD分解的结果基本一致。关键词： EEMD；EOF；旱涝变化；时空特征；鄱阳湖流域

Spatiotemporal Variation of Drought and Flood Series in the Poyang Lake Basin in Recent 550 Years Based on EEMD and EOF Analysis#br#

Using the historical materials of 5 sites on drought and flood in the region of Poyang lake basin and the surrounding area from 1467 to 2016, combined with data from China recent five hundred years of drought and flood atlas and modern precipitation data, the drought and flood series had been reconstructed based on the correlation coefficient weighted method. Spatiotemporal variation of drought and flood series in the Poyang lake basin in recent 550 years were analyzed by means of Ensemble Empirical Mode Decomposition and Empirical Orthogonal Function. The results show (1) the changes of the IMF components in the Poyang lake basin are in line with the characteristics of the nonlinear changes of natural signals, and the main high frequency change period is 2-3 a, 7-8 a; the middle and low frequency cycle is 22 a, 36 a; the low frequency cycle is 110 a, 220 a and so on. (2) The EOF decomposition of the spatial field of the drought and flood series shows that the cumulative variance contribution of the first four modes is 93.68% and the convergence effect is obvious. The first mode is the whole region has the same drought or flood state. The second and third modes represent the inconsistency of drought and flood in north south direction and east west direction. The fourth model represents the extreme precipitation type in South Jiangxi province. (3) The results of the power spectrum analysis of the time series of main spatial modes show that the change period of the spatial pattern of drought and flood is consistent with the EEMD decomposition of drought and flood series.Key words：EEMD; EOF; drought and flood variations; spatiotemporal variation; the Poyang lake basin