摘要
为了研究湟水流域干旱趋势变化,选取该区17个气象站的1959-2006年的日降水数据,计算得到1960-2006年的标准化降水指数,并依据干旱等级和游程理论判定出干旱事件。然后采用Mann-Kendall趋势检验法对各站各月的、干旱历时以及干旱严重程度序列进行趋势分析,最后选用Archimedean Copula函数族的3种常用函数联合干旱历时和干旱严重程度序列,优选出拟合最佳的Copula函数构造两者的联合分布,并计算中度干旱和重度干旱情境下的联合重现期。从时间尺度上分析,湟水流域年内湿润化趋势集中在6-9月,干旱化趋势集中在12月到次年3月,出现了干旱的季节更干旱,湿润的季节更湿润的两极化情况,可能会加重流域的夏旱严重程度。在空间分布上看,整体上湟水流域东南部的干旱风险要高于西北部,并且低等程度的干旱在流域东南部发生可能性增大。
This paper selects daily precipitation data from 1959 to 2006 from 17 meteorological stations in the Huangshui River Basin forstudying drought trends here. First, the standardized precipitation index （SPI） with a scale of six months is calculated. Then, the trend ofSPI, drought duration and drought severity is studied by using the Mann - Kendall Trend Test. Finally, three commonly used functions inclu-ding Archimedean Copula Function Family are adopted to join the sequence of drought duration and drought severity, and optimize the bestcopulas connect fitting function and calculate the joint return period of combined moderate drought and heavy drought. An Analysis of timescales shows wet trends are concentrated in this basin between June and September and arid trends are concentrated from December to Marchin the next year. The polarized situation of more droughts in the severe drought seasons and the wetter in wet seasons may enhance the droughtin summer in this basin. An analysis of the spatial distribution shows the drought risk in southeastern basin is higher than that inthe northwest.The possibilities of light droughts in southeast basin will be increased.
出处
《中国农村水利水电》
北大核心
2016年第12期151-155,共5页
China Rural Water and Hydropower
基金
国家高技术研究发展计划("863"计划)项目(14110209)
国家科技支撑计划项目(2011BAD29B01)
西北农林科技大学基本科研创新重点项目(Z109021202)
关键词
标准化降水指数
湟水流域
干旱
COPULA函数
联合重现期
standardized precipitation index
Huangshui River Basin
drought
copula function
joint return period
