1965—2015年海河流域干旱时空变化特征分析

基于海河流域1965—2015年月降水和气温数据，利用标准化降水蒸发指数（Standardized Precipitation Evapotranspiration Index, SPEI）、Mann-Kendall检验和经验正交函数(Empirical Orthogonal Function, EOF)分析等方法，分析海河流域干旱时空特征。结果表明：1）就时间变化来看，年、春、夏季SPEI序列呈干旱化趋势，秋季呈湿润化趋势，仅夏季干旱变化通过了0.05显著性检验。年、季干旱发生频率表明春旱显著，各年代干旱站次比表明近51年来干旱范围有所增加。2）就空间变化来看，中等干旱在年、夏季集中于永定河系的东部、大清河系及北三河系，春、秋季集中于滦河河系、大清河系及漳卫河系的西部；轻度干旱在年、春、夏季集中于滦河河系、北三河系、大清河系，秋季集中于永定河系、子牙河系及漳卫河系。年、春、夏季在流域范围内呈干旱化趋势，秋季在永定河系、大清河系、北三河系及滦河河系呈湿润化趋势。3）就空间模态来看，近51年来海河流域第一模态的年、季主要时空分布型为全流域一致型，第二模态的年、夏、秋季主要时空分布型为南部—北部反向分布型，春季呈西北部—东南部反向分布型。

Characteristics of spatiotemporal variation of drought in the Haihe River Basin from 1965 to 2015

Based on the data of monthly precipitation and monthly temperature from 1965 to 2015 in Haihe River Basin, the spatiotemporal characteristics of drought in the Haihe River Basin are analyzed by using the Standardized Precipitation Evapotranspiration Index (SPEI), Mann-Kendall test and Empirical Orthogonal Function (EOF) analysis. The results indicated that: 1) In terms of temporal variation, SPEI at scales of year, spring and summer showed the same trend of drought, whereas SPEI in autumn showed a trend of wetting. Only the variation of SPEI in summer showed significance at 0.05 level. The frequency of annual and seasonal drought indicated a significant drought in spring. The ratio of drought in different decades indicated that the drought range has increased in recent 51 years. 2) From the view of spatial variation, moderate drought was concentrated in the east of the Yongding River system, the Daqing River system and the Beisan River system at scales of year and summer, and occurred mainly in the Luanhe River system, the Daqing River system and west of the Zhangwei River system in spring and autumn. Mild drought was focused on the Luanhe River system, the Beisan River system and the Daqing River system at scales of year, spring and summer, and on the Yongding River system, the Ziya River system and the Zhangwei River system in autumn. The whole basin showed a trend of drought at scales of year, spring and summer. In autumn, the Yongding River system, the Daqing River system, the Beisan River system and the Luanhe River system showed a trend of wetting. 3) In terms of spatial modes, the primary spatiotemporal distribution type of the first mode at the annual and seasonal scale of the Haihe River Basin in recent 51 years is the consistent type of the whole basin; the second mode is the reverse distribution type in the south-north part at the annual scale and in summer and autumn, and the reverse distribution type in the northwest-southeast part in spring.