基于SPEI的黄河流域多时间尺度干湿变化分析

黄河流域是我国重要的经济地带和生态屏障,水资源匮乏,研究流域的干湿变化对于水资源的合理管理和利用、促进流域的可持续发展具有十分重要的现实意义。运用1966—2015年3个时间尺度(年、半年、季节尺度)的SPEI数据,基于EOF,Mann-Kendall方法研究了全球变暖背景下黄河流域的干湿变化特征,并进行归因探讨。结果表明:在过去的50年中,黄河流域的SPEI有显著的年际波动,但大部分区域的SPEI未有显著的增加或降低的趋势,区域之间的干湿变化具有非同步特征; 黄河流域气温与SPEI相关性弱,SPEI与降水有更好的同步性; 黄河流域夏、秋季节的干旱较冬、春季节严重,中部黄土高原区的干旱事件频率高于黄河流域西部高原和东部平原区。研究表明黄河流域干湿状况存在区域差异,降水是决定SPEI大小的关键因子,异常气候事件—厄尔尼诺在一定程度上会影响流域的干湿状况。

Multiple Time Scales Analysis of Dryness and Wetness Changes of the Yellow River Basin in the Past 50 Years Based on SPEI Data

The Yellow River Basin where water resources are lacking is an important economic region and ecological protective screen.Therefore,it is meaningful to research the dryness and wetness changes of the Yellow River Basin for reasonable management and use of water and sustainable development of the basin.In this study,the SPEI data from 1966 to 2015 were analyzed to acquire the characteristics of the dryness and wetness changes of the Yellow River Basin in the context of global warming through EOF and Mann-Kendall methods.Furthermore,the reasons inducing SPEI change were also discussed.The results showed that in the past 50 years,SPEI had changed temporally,but there were no obvious increase or decrease trends in SPEI,and the changes of dryness and wetness among regions were nonsynchronous;the correlation coefficient between SPEI and air temperature was small,and precipitation was the main factor determining SPEI in the Yellow River Basin;there were more droughts in summer and autumn than those in winter and spring,and compared with the western plateau and eastern plain,the Loess Platea in the Yellow River Basin had more droughts.El Nino can worsen the effects of droughts in the Yellow River Basin.