【作者】 王淑红；

【导师】 张钰；

【作者基本信息】 兰州大学 ， 水文学及水资源， 2018， 硕士

【摘要】 在全球气候变暖和人类活动影响下,地球上水循环发生了较大变化,近几年来葫芦河流域的水文循环也呈现出一定的规律性变化,其中较为明显的是20世纪90年代以来,降水量变化不大,径流量明显减少,原有的水资源供需平衡被打破,严重阻碍了流域内经济社会的可持续发展。本文利用葫芦河上游的静宁水文站和下游秦安水文站的月径流数据,首先通过不均匀系数(Cv)、完全调节系数(Cr)和集中度(RCD)、集中期(RCP)等方法分析葫芦河流域径流年内分配特征及其时空变化情况;运用距平累积、趋势系数和滑动平均法对葫芦河年径流量、年降水量和年蒸发量的年际变化特征进行分析,运用Mann-Kendall检验法对年径流量和年降水量进行突变检验,运用Morlet小波分析年径流量和年降水量周期特征;最后采用对比法和降水-径流双累积曲线分析引起葫芦河径流量变化的主要影响因素。分析结果如下:(1)葫芦河干流径流量的年内分配特征:上下游径流主要集中在6月初到9月上旬之间,静宁站和秦安站丰水期径流量分别占年径流量的65.01%和61.35%,径流量年内分配极不均匀。在空间上下游径流量的年内分配特征较为稳定,且下游径流的集中期略滞后于上游,葫芦河流域径流量年内分配特征在时间上变化不明显。(2)葫芦河干流径流量的年际变化规律:上下游年径流量丰、平、枯年份基本相对应,变化趋势相似,径流量均在90年代以后急剧减少,61年以来上下游径流量整体呈下降趋势,且下游径流量衰减速度比上游更快。下游径流小周期的转换比上游更频繁,可能与下游流域面积大,汇入支流较多,人类活动影响,下垫面条件复杂等因素有关。1988年葫芦河流域下游年径流量发生突变,而上游径流量无显著突变点。(3)葫芦河径流量和降水量的年际变化规律对比分析:流域年降水量变化趋势与径流量变化趋势基本对应,径流量与降水量均呈下降趋势,但径流减少的速率远大于降水减少速率。上下游径流量与其流域降水量变化周期的年份对应关系不好,径流变化的主周期和次周期均小于降水变化周期。下游年径流量在1988年发生了突变,而上游径流量和流域降水量均无明显的突变点,90年代之前降水是径流的主要影响因素。(4)葫芦河径流量和蒸发量年际变化规律对比分析:上下游蒸发量过程线走向不一致,从整体看不同年代静宁站和秦安站年蒸发量变化幅度均不大,年际变化趋势线均呈缓慢下降趋势,而90年代以来葫芦河流域径流量也呈明显下降的变化趋势,即蒸发量不是径流量变化的主要影响因素。(5)人类活动对葫芦河干流径流的影响:1967-1991年人类活动对上下游径流变化影响率分别为25.0%和29.7%,1992-2016年分别为50.8%和60.5%,下游人类活动影响率大于上游,说明下游人类活动对径流量变化的影响较大,1992-2016年人类活动影响率较大,印证了葫芦河流域进入90年代降水变化不大,而径流量急剧减少的分析结果。更多还原

【Abstract】 Under the background of global climate change and human activity influence,the water cycle has taken place great changes and many parts of the world have been facing various sorts of serious water resource problems.In recent years,the Hulu River’ surface water resource has been decreasing sharply,especially from the 1990 s,and the hydrologic cycle law has been changing a lot,for an example,there is little change in precipitation but runoff is decreasing obviously,which has broken the balance between supply and demand and has seriously affected the sustainable development of social economy in the Hulu River Basin.The paper studies on the annual distribution characteristics and their temporal and spatial variation characteristics of the Hulu River runoff by non-uniform coefficient(Cv),complete adjustment coefficient(Cr),concentration(RCD)and concentrated period(RCP),according average monthly runoff data of the Jingning hydrological station on the upper reaches and the Qinan hydrological stations on the downstream.Besides,the paper studies on the variation rule of the runoff,basin precipitation and evaporation,such as annual variation trend,period and mutation characters,using the method of standard departure accumulation curve method,wavelet analysis and Mann-Kendall and so on,according annual runoff data of the two main hydrological control stations,precipitation and evaporation data in the Hulu River Basin.Finally,the paper adopts double mass curve of precipitation and runoff to investigate precipitation and human activities on the Hulu River runoff change.Results show as follows:(1)The annual distribution characteristics of the Hulu River runoff: The runoff distribution mainly concentrating on the period of early June to early September and the runoff of upstream and downstream respectively making up 65.01% and 61.35% of annual runoff during the high flow period,is extremely uneven.The index of Cv,Cr,and RCD of the Jingning station runoff is greater than that of the Qinan station,which shows that the downstream runoff distribution characteristics are more stable,and the RCP of Qinan station concentration degree is slightly larger than Jingning station,which indicates that runoff concentration period of downstream is slightly behind upstream.The time variation of runoff distribution characteristics of the Hulu River Basin is not obvious.(2)The inter-annual variation law of the Hulu River runoff: The variation trend of runoff in the upstream and downstream manifests good uniformity.Both upstream and downstream runoff shows a downward trend and has declined obviously since the 1990 s.But the downstream runoff transformation is more frequent than the upstream runoff,which probably be related to larger watershed area,more tributaries,human activity influence,complex underlying surface conditions and other factors of the downstream.Finally the mutation of downstream runoff happened in 1988,but there are no obvious abrupt changes in upstream.(3)Comparison and analysis of runoff and precipitation annual variation in the Hulu River Basin: The variation trend of runoff and precipitation manifests good uniformity.Both runoff and precipitation are decreasing,however,the rate of runoff reduction is far greater than that of precipitation.From the perspective of varying period,runoff and basin precipitation change cycle year shows little corresponding relationship,and the varying cycle of runoff is longer than that of precipitation.Finally the mutation of downstream runoff happened in 1988,but there were no obvious abrupt changes in watershed precipitation.Before the 1990 s,precipitation is the main influencing factors of the Hulu River runoff.(4)Comparison and analysis of runoff and evaporation annual variation in the Hulu River Basin: The variation trend of evaporation of the upstream and downstream is different,and both the upstream and downstream evaporation declines slowly on the whole.However runoff has declined obviously since 1990 s,which shows that evaporation has little effect on runoff in the Hulu River Basin.(5)The influence of human activities on the Hulu River runoff: In 1967-1991,the rate of human activities affecting on the upstream and downstream runoff respectively accounts for 25.0% and 29.7%,and accounts for 50.8% and 60.5% in 1992-2016.The rate of human activities effect on the downstream is greater than that of the upstream,which illustrates the impact of human activities on downstream runoff is more serious.Besides,the rate of human activities effect in 1992-2016 is bigger than that in 1969-1991,which confirms that precipitation has changed little but runoff has decreased dramatically since the 1990 s in the Hulu River Basin.更多还原