基于EOF和REOF的1470—1911年黄河中下游地区旱涝空间分布特征分析

Spatial characteristics of drought/flood disasters based on EOF and REOF in the middle and lower reaches of the Yellow River from 1470 to 1911

基于通过历史文献资料重建的1470-1911年黄河中下游地区36个站点的历史旱涝等级序列和矢量化的历史地图,利用EOF、REOF方法分析旱涝灾害空间特征。EOF方法展开的结果表明:前4个模态累计方差贡献率为71.85%,主要表现为第一、二、四特征向量场呈经向带状分布,第三特征向量场呈纬向分布;第一特征向量场的空间分布均为正值,说明黄河中下游地区的旱涝变化具有一致性,但是其余各特征向量场之间特点差异明显,说明在不同背景场和影响条件下,旱涝变化还存在较多局域性特征;REOF展开的结果可将黄河中下游地区旱涝划分为5个典型的敏感气候分区,这为进一步研究该区旱涝变化的区域性特征奠定了基础。

Based on the collected and sorted records of the drought and flood in the middle and lower reaches of the Yellow River region,China from 1470 to 1911,the paper reconstructed the sequence of drought and flood of 36 stations and the history map of the study area,and analyzed the spatial characteristics using EOF and REOF.The results from the EOF analysis showed that the cumulative variance contribution rate of the first 4 models is 71.85%.The main characteristics indicated that the first,the second and the fourth models displayed a longitude distribution,while the third model was shown a latitude distribution.The spatial distribution of the first eigenvector field were all positive,which indicated that there was consistency for the changes of drought and flood in the middle and lower reaches of the Yellow River region.But there were obvious difference among the rest of the eigenvector fields,which illustrated the drought and flood change also had the local features under the different background conditions and field effects.Based on the results from the REOF analysis,there can be divided into five typical sensitive climate partitions in the middle and lower reaches of the Yellow River region.The analysis laid the foundation for the further study about drought/flood regional characteristics.