基于变动范围法(RVA)的信江水文改变及生态流量研究

选择信江下游梅港站1950~2010年日径流量,根据流域大型水库界牌枢纽运行时间将梅港站径流序列分为建库前(1953~2001)和建库后(2002~2010)两个时段。采用变动范围法(Range of Variability Approach,简称:RVA)分析水库运行对下游梅港站流域生态水文指标改变度,并分析了信江下游生态流量。研究表明:33个水文指标有22个发生中高度改变,11个指标发生低度改变,其水文综合改变度为0.51,属于中度改变;梅港站生态流量值均在RVA阈值内,基本能够保持河流稳定流量,但2月、7~9月及12月河道生态流量大于RVA下限。可适量增大水库下泄水量,降低对下游河段生态系统的威胁。     

观音阁水库建设运行对太子河本溪段水文情势影响

大型水库建设往往会引起水文情势变化,为真实反映观音阁水库建立对太子河本溪段径流及生态环境的影响,选取本溪(五)水文站1951～2014年日径流量,根据观音阁水库建设时间将日径流量划分为1951～1995年和1996～2014年两个时间段,采用基于水文改变指标法(Index of Hydrologic Alteration,IHA)的变化范围法(Range of Variability Approach,RVA)分析水库运行对太子河本溪段的生态水文指标改变度。结果表明:本溪(五)水文站整体水文改变度达到71.43%,属于高度改变;月平均流量非汛期除4月外其他月份均增加,汛期有较小程度降低,低流量次数减少,低流量持续时间缩短,充分体现水库丰蓄枯补作用;极小流量增大,极大流量有所降低,可见水库的建设运行严重改变的河流原有的极值变化过程;逆转次数增加且为高度改变,可能会破坏动植物生境的稳定性,阻碍水生生物生长。     

黄河源区基流变化及影响因子分析

利用黄河源区的4个水文站及13个气象站的日系列资料,基于改进的加里宁基流分割法,分析了1956—2000年以来黄河源区基流和以水文站为节点控制的各个子流域的基流变化及其影响因素.结果表明:黄河源区基流比例较大,多年平均基流指数为0.652;黄河沿以上流域基流指数为0.556,黄河沿-吉迈区间基流指数为0.588,吉迈-玛曲区间基流指数为0.649,玛曲-唐乃亥区间基流指数高达0.704.从绝对量来看,黄河源区多年平均基流量为132.46×108m3;子流域中,玛多以上流域基流量最小,为3.92×108m3,吉迈-玛曲区间基流量最大,为68.82×108m3.对于整个研究区,年降水量决定年基流量,气温影响基流,气温升高,基流减少.不同子流域的基流对气候变化响应不同,玛曲以上各个子流域基流随气温升高而减少,而在玛曲-唐乃亥区间年气温对年基流量无明显影响.黄河源区年代尺度基流指数和降水量成反比关系.     

变化环境对NamLik1-2水库下游生态水文情势的影响研究

为探究重要国际河流湄公河支流NamLik河在NamLik1-2水库建设后下游的生态水文情势变化,基于水库下游Hinheup水文站1980—2018年日平均流量数据、流域ERA5再分析气象数据以及NamLik流域地理信息数据,采用IHA＿RVA法定量分析水库运行后河流水文情势改变;基于SWAT模型分析了气候变化和水库调度对水库下游径流年内分配变化的贡献率。结果表明：（1）NamLik1-2水库建库后下游水文情势发生较大改变,整体水文改变度达79%,属于高度改变;下游河道流量年内分配变化显著,月均流量指标的水文改变度达到70.4%。（2）基于SWAT模型对无水库情景的天然径流还原结果,计算得到水库对径流汛期减少和枯季增加的贡献率分别为142%和71%,而气候变化的相应贡献率分别为-42%和29%,水库运行是引起下游径流年内分配变化的主要原因。     

定量分析青狮潭水库对漓江生态环境的影响

以漓江上游现有的青狮潭大型水库为依据,采用IHA和RVA方法分析了33个水文指标的变化程度,揭示水库调节对漓江生态环境的影响。结果表明:水库调节能够明显增加枯水期12月、1月和2月的月平均流量,增加值为4.5~12.3m3/s;可使得年最小1d流量与年最大1d流量间隔时间变宽,增加45d,但对年最小连续1d、3d和7d的极端水文条件改善不明显;高流量脉冲历时有所增加,低流量脉冲历时减小,日均流量平均增加率和减少率均减小;漓江水文情势整体改变度为中度。漓江水利工程调节既要满足旅游通航需要,也应重视极端枯水期的调节。     

黄河源区气候变化的季节特征与区域差异研究

基于黄河源区有关气象台站的观测数据,对该区黄河沿水文站以上、黄河沿水文站-吉迈水文站区间、吉迈水文站-玛曲水文站区间、玛曲水文站-唐乃亥水文站区间各区域及整个黄河源区1960-2014年期间气温、降水的季节变化特征及其区域差异进行了分析。结果表明：黄河源区气温变化与全球气温变化有着较好的一致性,各区年平均气温与各季气温的年际变化均呈波动状上升态势并明显高于过去50a全球与我国气温的升幅,且各气温系列升幅差异不大;而各区年平均气温与各季气温的年代际变化的上升态势较年际变化的更为显著,但不同区域各季气温升幅差异较大。各区气温均在1996年后出现一个跃动,跃动后各气温系列均值较跃动前有较大幅度的上升。由于区域地理环境的影响,黄河源区降水量的变化比较复杂,各区各季降水量的变化具有较大的差异。近50余年来,总体上整个河源区平均降水量的年际变化呈不明显的增长态势。其中河源区的上半部分,即黄河沿以上、黄河沿-吉迈之间等海拔较高的区域年降水量增长比较显著,而源区的下半部分,即吉迈-玛曲、玛曲-唐乃亥之间的区域,年降水呈减少态势,并且对全区平均降水量与产流量贡献最大的吉迈-玛曲之间的区域,年降水量的减少非常显著。各区冬春季和夏季降水量普遍呈增长态势,秋季是河源区各季节中降水唯一减少的季节,其中吉迈-玛曲之间的区间秋季降水量的减少最为显著。各区域各季降水量的年代际变化较其年际变化差异更大,但近十余年来大部分区域各季降水普遍偏多。各区域降水系列亦有突变发生,但突变时间并不像气温系列那样一致;年降水量与夏季降水量的突变大都发生在2005年,秋季降水量突变大都发生在1986年,春季和冬季降水量突变的时间杂乱无序;突变前后系列均值有增有减,且幅度大小不等。     

概化的Tank模型及其在龙羊峡水库汛期旬平均入库流量预报中的应用

Tank模型（又称为水箱模型），是一种用于流域径流预报的确定性水文模型，根据龙羊峡水库入库主要产流区－－黄河上游唐乃亥水文站以上流域下垫面条件下产汇流特性，将其概化为以降雨量为输入，径流量为输出的单孔出流的线性水箱，工用于该水库汛期旬平均入库流量的预报，经对历史资料进行拟合和试验预报的 结果表明，该模型具有较高的预报精度，现已应用于黄河上游龙羊峡水库汛期旬平均入库来水量的中期预报中，取得了十分显著的经济效益。     

黄河源区气候变化的环境效应研究

以黄河源区气象台站的降水和气温资料以及玛多、达日、玛曲、唐乃亥和兰州水文站的径流资料为基础, 分析研究了该区降水、气温、水文变化趋势, 并对研究区的土地利用现状变化及原因进行了探讨. 结果表明: 在年代际变化趋势上, 黄河源区气温总体上呈升温态势, 降水呈减少趋势, 径流量也表现为减少趋势.土地利用现状的变化表明人类活动对研究区生态湿地的干预增强.自然因素和人类活动的综合作用, 使得黄河源区生态环境进一步恶化, 亟需进行人工干预, 保护和改善黄河源区生态湿地环境.     

黄河源唐乃亥水文站水沙序列重建与变化规律研究

选用泽库气象站(1959~2011年)的降水量、唐乃亥水文站(1956~2011年)的年径流量、年输沙量分别与相邻位置的δ18O测定序列构造相关关系,建立以10a为滑动期的降水量变化曲线、以5a和10a为滑动期的年径流量/年输沙量变化曲线(公元192~2003年),研究千年尺度的降水量和水沙变化规律。结果表明:除了以5a为滑动期的唐乃亥年输沙量率定方程外,其它拟合方程的R2均大于0.6,相关性较高。黄河源的年径流量总体呈减小的趋势,但年输沙量变化趋势大致相同,其变化主要与降水量有关。以唐乃亥水文站为代表,1800a尺度上黄河源的年径流量/年输沙量的趋势变化可分为9个阶段,且5次呈增大趋势,4次呈减少趋势,表明水沙序列的长期变化呈多阶段性特征。     

黄河上游径流量演变特征及成因研究

利用黄河上游唐乃亥水文站1956年～1994年各月平均径流量资料,对其自身的变化规律进行诊断分析。结果表明:黄河上游月平均径流量具有很好的持续性,尤其是冬半年,其显着落后自相关可达6～8个月以上,即从秋季到次年初夏,转折期在8月～9月。近40年来,黄河上游流量经历了由小-大-小的演变过程,年径流量表现出较明显的7年周期,而秋季流量呈14年振荡。就径流各级别出现的概率而言,枯水年占41%,异常年份达2/3.夏秋季高原降水量对同期及落后半年之内的径流有显着贡献。前期青藏高原热力作用及大气环流特征对夏秋流量预测具有一定的指示性。     

新疆阿尔泰山区克兰河上游水文过程对气候变暖的响应

额尔齐斯河支流克兰河上游发源于西风带水汽影响的阿尔泰山南坡,主要由融雪径流补给,年内积雪融水可占年径流量的45%.年最大月径流一般出现在6月份,融雪季节4~6月径流量占65%.流域自20世纪60年代开始明显升温,年平均温度从50年代的1.4℃上升到90年代的5.2℃;年降水总量也呈增加趋势,尤其是冬季和初春增加最多.随着气候变暖,河流年内水文过程发生了很大的变化,主要表现在最大月径流由6月提前到5月,月径流总量增加约15%,4~6月融雪径流量也由占年流量的60%增加到近70%.在多年变化趋势上,气温上升主要发生在冬季,降水也以冬季增加明显,而夏季降水呈下降趋势;水文过程主要表现在5月径流呈增加趋势,而6月径流为下降趋势;夏季径流减少而春季径流增加明显.冬春季积雪增加和气温上升,导致融雪洪水增多且洪峰流量增大,使洪水灾害破坏性加大.近些年来气候变暖引起的年内水文过程变化,已经对河流下游的城市供水和农牧业生产产生了影响.     

Assessing the effects of climate change on the hydrological regime of the Limay River basin

The electricity generation capacity in the Limay River basin is approximately 26% of the total electrical power generation in Argentina. Assessing the potential effects of climate change on the hydrological regime of this basin is an important issue for water resources management. This study explores the presence of trends in streamflow series, evaluates climate sensitivity and studies the effects on the flow regime of predicted changes in precipitation in the basin. In order to identify and quantify changes in observed streamflow series, the Mann–Kendall test, with a modification for autocorrelated data, and an estimator of the magnitude of the trend are applied. In order to evaluate the sensitivity of streamflow to changes in climate, the concept of elasticity is used. Precipitation elasticity of streamflow is used to quantify the sensitivity of streamflow to changes in precipitation and is estimated using a power law model and a linear statistical model in two sub-basins, Aluminé and Nahuel Huapi. The effects on flow regime of the predicted changes in precipitation under different scenarios are studied. Climatic results for different scenarios of growth in greenhouse gases from some General Circulation Models are used as inputs into the proposed models. The analysis identifies decreasing trends in mean and minimum annual flows and in the low flow season. The estimates of the precipitation elasticity imply that changes in precipitation produce similar changes in streamflow and the climatic results for different scenarios show that the variations are moderate.     

1954-2009年窟野河流域降水与径流变化趋势分析

通过窟野河流域温家川水文站流量实测数据及神木气象站降水观测数据,运用累计距平法、R／S法、Mann—Kendall趋势检验法分析1954—2009年间温家川水文站以上窟野河流域降水与径流的年内、年际变化特征。结果表明,窟野河流域汛期降水量和径流量分别占全年降水量和径流量的76．6％和59．19％。20世纪50年代至90年代,径流变化过程基本与降水过程一致,但到21世纪初期,径流量出现明显下降趋势,截止到2009年,径流量已减小到1．25×10^8m3。从季节分配上来看,春、夏、秋三季的降水量呈微弱的降低趋势,而冬季降水却以0．04mm／a的趋势递增。通过对1975—2009年的煤炭开采与径流量的相关关系分析表明,虽然在这期间降水量没有明显的衰减,但是窟野河年径流量从20世纪末开始就出现了明显的减少,这主要是煤炭大规模开采等人类工程活动引发的后果。     

东江径流年内分配特征及影响因素贡献分解

基于1956~2009年实测径流、天然径流和面降水的月系列,选用集中度和不均匀系数,分析东江径流年内分配特征的时空变异规律。通过对比降水和径流年内分配特征指标的阶段变化差异,量化分解气候变化、土地利用/覆被变化、水利工程水量调节和用水消耗等主要因素对东江径流年内分配特征变化的影响贡献。结果表明:东江实测径流的集中度和不均匀系数年变化过程均有显著下降趋势,且1973年为时序变点。降水及天然径流的年内集中程度阶段变化较小,但2000~2009年降水及天然径流的年内不均匀性要明显大于20世纪80年代和90年代。降水及天然径流的年内集中度和不均匀系数由上游向下游逐渐增大,显示集水面积越大降水及径流的年内集中程度和不均匀性越大。水利工程水量调节和土地利用/覆被变化降低了径流的年内集中程度和不均匀性,而用水消耗和气候变化增加了径流的年内集中程度和不均匀性。水利工程水量调节、土地利用/覆被变化、用水消耗和气候变化,对东江径流分配特征的影响贡献率分别约为-33.5%、-9.0%、4.5%和1.0%,新丰江水库、枫树坝水库和白盆珠水库的影响贡献率分别约为-21%、-10%和-2%,且近30年来土地利用/覆被变化和用水消耗的影响贡献有逐渐增加趋势。     

Trend analysis of hydroclimatological variables in Urmia lake basin using hybrid wavelet Mann–Kendall and Şen tests

This paper investigates monthly, seasonal, and annual trends in rainfall, streamflow, temperature, and humidity amounts at Urmia lake (UL) basin and analyzes the interaction between these variables and UL’s water level fluctuation during the 1971–2013 period. Two new methods including nonparametric hybrid wavelet Mann–Kendall test and ?en’s methodology have been used to determine potential trends in the variables and their dominant periods. The results showed significant decreasing trends in the water level and streamflow series, moderate decreasing trend in the rainfall and relative humidity series, and increasing trends in the observed temperature data. The 8- , 12-month, and 2-year periods were detected as the dominant periods of the variables in monthly, seasonal, and annual timescales, respectively. The results from the interaction analysis revealed that the main factor influencing the water level at UL is decreasing trend in the streamflow series. Both the monthly series of UL’s water level and the streamflow series of the stations indicated two start points of significant decreasing trend in 1973 and 1998. Furthermore, a comparative analysis among the applied methods indicated a good agreement between the results of hybrid wavelet Mann–Kendall test and ?en’s trend analyzing method.     

A 602-year Reconstruction of July-June Streamflow in the Kuqa River, China, Reveals the Changing Hydrological Signals of the Tarim Basin

A regional tree-ring width chronology of Schrenk spruce(Picea schrenkiana) was used to determine the annual(previous July to current June) streamflow of the Kuqa River in Xinjiang, China, for the period of 1414–2015. A linear transformation of the tree-ring data accounted for 63.9% of the total variance when regressed against instrumental streamflow during 1957–2006. The model was validated by comparing the regression estimates against independent data. High streamflow periods with a streamflow above the 602-year mean occurred from 1430–1442, 1466–1492, 1557–1586, 1603–1615, 1687–1717, 1748–1767, 1795–1819, 1834–1856, 1888–1910 and 1989–2015. Low streamflow periods(streamflow below the mean) occurred from 1419–1429, 1443–1465, 1493–1556, 1587–1602, 1616–1686, 1720–1747, 1768–1794, 1820–1833, 1857–1887 and 1911–1988. The reconstruction compares well with the tree-ring-based streamflow series of the Tizinafu River from the Kunlun Mountains; both show well-known severe drought events. The streamflow reconstruction also shows highly synchronous upward trends since the 1980 s, suggesting that streamflow is related to Central Asian warming and humidification. Thus, the influences of the extremes and the persistence of low streamflows on local society may be considerable. Climatic changes in the watershed may be responsible for the change in the hydrologic regime of the Tarim Basin observed during the late twentieth century.     

Impacts of climate change on flow regime and sequential threats to riverine ecosystem in the source region of the Yellow River

Climate change is expected to have substantial impacts on flow regime in the Upper Yellow River (UYR) basin that is one of the most important biodiversity hotspots in the world. These impacts will most possibly exert negative effects on the habitat availability for riverine species. Thus, it is necessary to understand the alteration of river flow regime under climate scenarios. In this paper, we use the modified hydrological model HBV in conjunction with three general circulation models under three representative concentration pathways (RCP 2.6, 4.5, and 8.5) to address changes in flow regime under climate change for the UYR basin in the mid-term (2050s) and end-term (2080s) of the twenty-first century. Flow regime is quantified using the Indicators of hydrological alteration approach. Thereafter, the potential threats to riverine ecosystem in the UYR basin are identified based on the projected alterations of various flow characteristics and their ecological influences. The results showed that the magnitude of monthly flow would increase during the dry period. The date of the annual 1-day minimum streamflow will likely shift toward earlier time under different scenarios, and significant increases in magnitude of annual minimum flow of different durations were detected under both RCP 4.5 and 8.5 scenarios in the 2080s. In addition, assessments of the modification degree of the overall flow regime revealed that climate change would remarkably modify (medium level) the overall flow regime in the UYR basin, particularly by the end of the twenty-first century or under the high emission scenarios. Besides, destruction of habitat and reduced availability of food induced by substantially increased hydrological instability in the 2080s would make two endangered fishes more vulnerable in the UYR basin. These findings provide insights into potential adaptive countermeasures for water resource management and environmental system restoration in the Upper Yellow River.     

内蒙古中北部土壤碳库构成及其影响因素

采用网格采样法荻取内蒙古中北部半干旱区土壤样品共527件,分析其碳库构成特征及其影响因素,并初步评估了未来气候变化背景下的碳库变化趋势。结果表明,研究区土壤碳库仍以有机碳为主,不同土壤类型中有机碳占总碳61％～97％,其中沼泽土有机碳密度最高,风沙土最低,盐土无机碳密度最高,暗棕壤最低;在空间分布上,土壤碳受气温和降水...     

塔里木河流域2001年四源一干河川径流运行分析

2001年塔里木河流域四条源流出山口天然径流量计266.5×10⁸m³, 比多年平均值多40.70×10⁸m³, 增加1%.源流区在进入塔里木河干流前总耗水量为220.0×10⁸m³, 与多年平均值比较多43.4×10⁸m³, 增加24.6%, 而入塔里木河水量为46.4×10⁸m³, 比多年平均4.12×10⁸m³减少1.64×10⁸m³.塔里木河干流龙头站--阿拉尔站2001年年径流量为45.72×10⁸m³, 接近多年均值46.00×10⁸m³, 属平水年.干流上游区间耗水量24.77×10⁸m³, 占阿拉尔站年径流量的54.2%; 中游区间耗水量1.94×10⁸m³, 占阿拉尔站年径流量的41.4%; 下游区间耗水2.025×10⁸m³(纯塔里木河水), 仅占阿拉尔站年径流量的4.4%. 2001年从开都河-孔雀河的博斯腾湖和塔里木河向下游绿色走廊的应急输水于11月16日水流到台特玛湖, 从而结束了塔里木河下游近30 a干涸的历史, 使下游绿色走廊恶化环境开始恢复.