| 摘要: |
| 【目的】探究渭河流域气象干旱的时空分布特征及演变规律，为该流域社会经济的可持续发展提供支持。【方法】以渭河流域1960-2016年20个气象站逐月降水量和月平均气温数据为基础，基于标准化降水蒸散指数定量描述干旱，并运用经验函数正交分析法（EOF）对渭河流域各站点组成的历史干旱指数矩阵进行分解，分离干旱场的时空分布结构；采用具有一定物理意义的互不相关的典型分布模态代替原干旱场研究流域干旱空间分布规律，采用典型分布模态对应的时间系数研究流域干旱的时间分布规律。【结果】渭河流域气象干旱场干旱指数矩阵分解得到的前5个特征值的累积方差贡献率达到86.44%，但仅前2个特征值通过了North显著性检验，累积方差贡献率接近75%；模态一时间系数的线性趋势斜率小于0，且通过了0.01显著性水平检验；模态一时间系数于1984年、1986年、1989年发生3次突变，到1996年达到0.05显著性水平。【结论】渭河流域气象干旱场存在全流域一致型和东南 西北反位相型两种空间分布模态，两种空间分布模态对应全流域干旱少雨、湿润多雨、东南湿润西北干旱、东南干旱西北湿润4种干旱表现形式；模态一时间系数有显著减小趋势，反映流域干旱化趋势日益显著，而模态二时间系数无显著变化。 |
| 关键词: 气象干旱 干旱时空分布 经验正交函数分解法 标准化降水蒸散指数 渭河流域 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金项目（51679189）；国家重点研发计划项目（2017YFC04044-04） |
|
| Temporal and spatial distribution of drought in the Weihe River Basin based on EOF |
|
ZHOU Kai,WANG Yimin
|
| Abstract: |
| 【Objective】The temporal and spatial distribution characteristics and evolution of meteorological drought in the Weihe River Basin were explored to support sustainable socio-economic development in the basin.【Method】Based on the monthly precipitation and mean temperature at 20 meteorological stations in the Weihe River Basin from 1960 to 2016,the drought was quantitatively described based on the standardized precipitation evapotranspiration index.The empirical function orthogonal analysis (EOF) was used for decomposition of historical drought index matrix and the spatial and temporal distribution structures of the dry field were separated.The typical spatial distribution pattern with certain physical meaning was used to replace the original dry field to study the spatial distribution of the arid basin.The time coefficient corresponding to the typical distribution mode was also used to study the temporal distribution of drought.【Result】The cumulative variance contribution rate of the first five eigenvalues obtained from the drought index matrix decomposition of meteorological drought field in the Weihe River Basin reached 86.44%,but only the first two eigenvalues passed the North significance test with cumulative variance contribution rate of close to 75%.The linear trend slope of the time coefficient was less than 0 and passed the 0.01 significance level test.The first modal time coefficient had three mutations in 1984,1986,and 1989,and reached the 0.05 significance level in 1996.【Conclusion】There were two spatial distribution modes,the whole basin consistent type and the southeast-northwest anti phase type,in the meteorological drought field in the Weihe River Basin.The two spatial distribution modes corresponded to four draught forms of drought and less rain in the whole basin,wet and rainy in the whole basin,southeast humid northwest drought,and southeast dry northwest humid.The modal-time coefficient had a significant decreasing trend,reflecting the-significantly increasing trend of aridification in the basin,while the modal two time coefficient had no significant change. |
| Key words: meteorological drought time and space distribution of drought empirical orthogonal function (EOF) standardized precipitation evapotranspiration index (SPEI) Weihe River Basin |
