近54年渭干河流域径流变化特征及影响因素分析

基于1960~2013年渭干河流域逐月径流量观测资料及逐日气象数据,采用Kruskal-Wallis阶段转换检验、R/S分析、集合模态分解分析(EEMD)等方法研究了近54年渭干河流域径流量的年内、年际变化特征及其影响因素。结果表明:(1)近54年渭干河流域Cv、Cr较大,径流量年内分配不均衡,径流量夏季秋季春季冬季,未来这种趋势会更加明显。(2)径流年际变化特征可分为三个阶段,1960~1976年的枯水期、1976~1993年的平水期和1994~2013的丰水期。(3)径流量总体呈现增加趋势,其中夏季增长最为显著,其次是春秋季,冬季径流量有轻微减少。未来近期内,渭干河径流量还会继续保持增加。(4)流域气温和降水量亦呈增加趋势,突变点在1970s末和1990s初,与径流变化特征吻合,两者呈正相关关系。其中夏季径流量变化主要受降水影响,秋冬季径流量变化主要受气温影响。

Runoff Change Characteristics of Weiganhe River in Recent 54 Years and Their Influencing Factors Analyzing

Based on the monthly runoff data and meteorological data of the Weigan River Basin during 1960 -2013, the intra - annual and inter-annual runoff change characteristics of the Weiganhe River Basin in recent 54 years were analyzed by using Kruskal-Wallis test, R/S analysis, ensemble empirical mode decomposition (EEMD). The results show that (1) In the basin in recent 54 years, there were larger Cv and Cr of runoff, uneven distribution of inter-annual runoff, the runoff in summer > that in autumn > that in spring > that in winter, and this trend would be more obvious in the future; (2) There were 3 significant stages of intraannual runoff change characteristics, i.e. wet season from 1960 to 1976, normal season from 1976 to 1993 and drought season from 1994 to 2013; (3) The runoff presented a growth trend in the whole period, especially in summer, however experienced a slight drop in winter, and the runoff would keep going up in near future; (4) The temperature and precipitation increased in the last 54 years, the fluctuation points appeared in the late 1970s and early 1990s, which are consistent with variation characteristics of runoff. The runoff is effected by precipitation in summer and by temperature in autumn and winter.