导　　师： 郑粉莉

学科专业： 070503

授予学位： 硕士

作　　者： ;

机构地区： 西北农林科技大学

摘　　要： 研究极端降水变化对河流水沙变化的影响将为流域洪涝灾害预警提供科学依据、为水沙治理提供重要的参考。本文基于河龙区间12个气象站点56年/(1957~2012年/)日降水数据及55年/(1957~2011年/)径流泥沙年数据，采用滑动平均、Mann-kendall非参数检验、累计距平以及空间克里金差值等分析方法，分析了河龙区间降水和极端降水的时空变化特征及长期变化趋势，研究了河龙区间径流泥沙动态变化过程及变化趋势。通过对比选择出与径流和泥沙相关性最好的降水指标和极端降水指标，以此为基础分别定量评估了降水（极端降水）变化与人类活动对河龙区间水沙变化的影响。论文主要结论如下： （1）基于河龙区间1957~2012年日降水数据，分析了区间降水的时空变化特征。河龙区间年降水量多年均值为451.5mm，汛期降水量多年均值为333.5mm，二者空间上均自西北向东南逐渐增大。降水年内分布非常集中，5~9月降水量占到年降水量的81/%以上，汛期降水量占全年的73/%以上。年降水量、汛期降水量及春夏秋三季降水量均呈不明显减少趋势，而冬季降水量呈现不明显增加趋势。 （2）选取国际通用和国内常用的7个极端降水指标/(R10、R50、R10p、R5d、SDLL、R95p、R95t），研究了河龙区间56年极端降水的时空变化特征。7个极端降水指标空间上均自北向南逐渐增大，最小值多出现在清水河站，最大值多出现在延安站。并且，7个极端降水指标均呈减少趋势，其中仅最大五日降水量R5d减少趋势显著，减少速率为0.24mm//a。 （3）基于河龙区间/(1957~2012年）和子流域皇甫川流域/(1954~2004年）日降水数据，采用修正的Richardson日降雨侵蚀力估算方法计算降雨侵蚀力，并对降雨侵蚀力时空变化特征进行了分析。河龙区间56年降雨侵蚀力均值为1329.6MJ· mm///(hm2·h·a/)，空间上以清水河站为降雨侵蚀力低值中心，自西北向东南逐渐增大。区间12个站点中清水河和五寨两站降雨侵蚀力呈不显著增大趋势，其余10个站点降雨侵蚀力均呈不显著减小趋势，整个流域降雨侵蚀力也呈现不显著减小趋势。皇甫川流域降雨侵蚀力均值为1136.1MJ· mm///(hm2·h·a/)，同样自西北向东南逐渐增大，其低值中心出现在乌兰沟，高值中心出现在长滩和沙圪堵。研究期内，皇甫川流域降雨侵蚀力呈不显著减小趋势。 （4）基于河龙区间55年/(1957~2011年/)径流和输沙数据，探究了径流和泥沙动态变化过程及变化趋势。区间径流量均值为44.58×108m3，研究期内呈极显著下降趋势，下降速率为0.96×108m3//a；输沙量均值为5.60×108t，同样呈现极显著的下降趋势，下降速率为0.19×108t//a。应用Mann-Kendall突变检验配合累计距平方法最终判定河龙区间径流量和输沙量突变年份均为1979年。 （5）以1979年作为径流和泥沙突变年，以1957~1979年作为基准期，建立基准期、检验期（1980~2011年）以及整个研究期（1957~2011年）三个时段径流和输沙与各降水指标关系式。径流和泥沙量与R95p、R和FP、R10p四个指标的线性相关性均好于其与年降水量P的相关性，在拟合径流和泥沙与降水因子线性关系时，可以选择R95p、R和FP、R10p四个指标，FP为最佳指标。 （6）选取年降水量P、汛期降水量FP两个降水指标以及极端降水量R95p和大雨雨量R10p两个极端降水指标，评估降水（极端降水）变化与人类活动对河龙区间水沙变化的影响，四个指标所评估得结果大体相同，20世纪80年代和21世纪前12年人类活动对径流和泥沙减少的贡献率较大，均大于70/%，20世纪90年代人类活动和降水变化对径流和泥沙减少的贡献率基本相等，各占50/%左右。以20世纪80年代为参考，21世纪前12年人类活动每年减少径流量14.1×108m3，每年减少输沙量2.5×108t。 The researches on impacts of extreme precipitation change on river runoff and sedimentchnage can provide scientific basis for flood warning and important reference forwater resources management. Based on the precipitation data from12meteorological stationsduring1957to2012and river runoff, sediment data during1957to2011in theHekouzhen-Longmen region, the temporal and spatial variation of the average precipitationand extreme precipitation in long-term trends were analyzed and the dynamic changes andtrends of runoff and sediment were studied, using the methods inear trend estimate,Mann-kendall non-parametric tests, cumulative anomalies and spatial kriging. The bestindicator of extreme rainfall change was selected, finally the quantitative assessment of riverrunoff and sediment variation caused by human activities and extreme precipitation changewas conducted. The main results were as follows: /(1/) Based on the precipitation data during1957to2012, the spatial and temporalvariation of precipitation were analyzed in the Hekouzhen-Longmen region. The averageannual precipitation was451.5mm, the average precipitation in flood season was333.5mm,and these two indicators were gradually increased from northwest to southeast in space. Theannual precipitation mainly concentrated in May to September which took over81/%of theannual precipitation, and the precipitation in flood season took over73/%of the annualprecipitation. The annual precipitation, the precipitation in flood season and the precipitationin spring, summer and autumn decreased non-significantly while the precipitation in winterincreased non-significantly. /(2/)7internationally accepted and commonly used extreme precipitation indicators /(R10,R50, R10p, R5d, SDLL, R95p, R95t/) were selected to study the temporal and spatial variationof extreme precipitation during56years in the Hekouzhen-Longmen region. These7indicators were gradually increased from north to south in space, the maximum values weremostly occurred in Qingshuihe station and the minimum values were mostly occurred inYanan station. These7indicators were gradually decreased during the period, the R5ddecreased significantly by0.24mm//a. /(3/) Based on the daily precipitation data of the Hekouzhen-Longmen region during1957to2012and the sub-basin Huangfuchuan basin during1954to2004, the spatial andtemporal variation of rainfall erosivity was studied using the modified Richardson estimatemethod. The average rainfall erosivity in the Hekouzhen-Longmen region was1329.6MJ· mm///(hm2·h·a/) during56years, and the value was gradually increased from northwest tosoutheast in space with the lowest center in Qingshuihe station. The rainfall erosivity inQingshuihe station and Wuzhai station were increased non-significantly while the rest of thestations were decreased non-significantly. The average rainfall erosivity in Huangfuchuanbasin was1136.1MJ· mm///(hm2·h·a/), and the value was gradually increased from northwestto southeast in space with the lowest center in Wulangou station and highest center inChangtan and Shagedu. The rainfall erosivity in Huangfuchuan basin was non-significantlydecreased trend. /(4/) Based on the river runoff and sediment data in the Hekouzhen-Longmen regionduring1957to2011, the dynamic change and variation trend of river runoff and sedimentwere studied. The average runoff was44.58×108m3with a decreasing trend by0.96×108m3//a.The average sediment was5.60×108t with a decreasing trend by0.19×108t//a. The abrupt yearwas1979which was determined by the method of Mann-Kendall test and cumulativedeparture. /(5/) Took1979as abrupt year of river runoff and sediment, the relation between riverrunoff, sediment and precipitation indicators were established in3periods: reference period/(1957to1979/);the test period /(1980to2011/) and whole period /(1957to2011/). The resultshowed that the linear correlations between river runoff, sediment and R95p, R,R10p and FPwere better than that of yearly precipitation P. Moreover. the linear correlation between riverrunoff, sediment and precipitation indicators, R95p, R, R10p and FP was selectable and FPwas the best indicator. /(6/) Took P and FP as precipitation indicator, R95p and R10p as extreme precipitationindicator, river runoff and sediment variation caused by human activities and precipitationchange was estimated respectively during1957to1979, the estimated results using4indicators were similar. In1980s and12years of21st century, the influence on river runoffand sediment caused by human activities was more than precipitation change, the contributionrate were above70/%. In1990s, the influence on runoff and sediment caused by humanactivities and precipitation change were almost the same, both occupied about50/%ofreduction of river runoff and sediment Took1980s as reference period, the runoff reductioncaused by human activities was14.1×108m3//a, and the sediment reduction caused by humanactivities was2.5×108t//a.

关 键 词： 河龙区间 径流量 输沙量 极端降水 人类活动

分 类 号： [S157]

领　　域： [农业科学] [农业科学]