Hydrological Responses to Climate Change in Nenjiang River Basin,Northeastern China

Under the background of global climate change, hydrological responses to climate change were investigated in Northeastern China. This study analyses the trends of annual and seasonal temperature, precipitation and streamflow series in Nenjiang River Basin. Correlations between streamflow and meteorological variables were investigated, while parametric method and nonparametric tests were applied to determine the trends and correlations. Data collected from a series of monitoring stations showed significant increasing trends of annual and seasonal mean temperature versus time, whereas during the whole period the annual and seasonal precipitation in the basin did not exhibit similar trends although temporal and spatial variations were detected. Affected by the precipitation and temperature changes, significant trends of decreasing annual, spring and autumn streamflow were demonstrated; the decrease concentrating mainly on the mainstream and tributaries of the left bank. Correlation analyses revealed strong relationships between the streamflow and meteorological variables in Nenjiang River Basin, and the impacts of climate change on streamflow were complicated. Results from this study will help water resource managers for decision makings that address the consequences of climate change.     

基于滑动Copula函数的金沟河流域径流-气温关系变异诊断

为探究变化环境下金沟河流域径流和气象因素的关系变异情况,根据八家户水文站1964—2016年的水文气象数据,采用极点对称模态分解(ESMD)方法、Spearman相关分析和滑动Copula函数对流域内水文气象要素进行了分析。结果表明:金沟河流域的径流序列整体上呈微弱的减小趋势,降水和气温序列呈增加趋势,ESMD趋势项反映出金沟河流域的径流、降水和气温序列均呈非线性趋势变化;降水和气温序列的突变时间分别为1983年和1997年,径流序列的突变时间为2002年和2015年;滑动Copula函数不同窗口下的相关系数显示径流-气温关系变异时间为1997年,联合序列的最佳Copula函数由1964—1997年阶段的Gauss-Copula函数变异为1998—2016年阶段的Gumbel-Copula函数。气候变化和人类活动是造成金沟河流域径流-气温关系变异的主要原因。研究结果有助于了解金沟河流域内水文气象要素的变化特征及径流气象要素的关系变异时间,可为流域内的其他水文计算提供参考依据。     

基于MODIS的积雪时空变化与CMADS气象因子相关性研究——以塔什库尔干河流域为例

积雪是塔什库尔干河流域宝贵的资源,了解流域融雪时空变化规律及其与气象、地形因素的相关关系具有重要意义。基于不同高程带、坡度和坡向的Arc GIS解译积雪覆盖数据和CMADS数据,采用方差分析和Pearson相关性分析等方法,研究不同高程带、坡度和坡向雪盖时空变化规律及其与气象因子的相关关系。结果表明:平均气温、太阳辐射和降水是影响塔什库尔干河流域积雪的主导气象因子,同时还受地形(高程、坡度、坡向)的限制;积雪覆盖率在各地形上存在明显季节差异性及月差异性,积雪覆盖率与气象因子相关度从高到低依次排序为:平均气温太阳辐射降水风速相对湿度,积雪覆盖率与前3个因素存在显著负相关关系,风速次之,与相对湿度的相关性最小。     

松花江流域河流泥沙及其对人类活动的响应特征

对松花江流域主要水文站输沙量变化的分析表明：51年来,嫩江除1998年发生洪水外其余年份输沙量变化不大,第二松花江输沙量表现为明显的下降趋势,松花江干流输沙量也表现为下降趋势,而松花江整个流域在1979年之前为下降趋势,1979年之后为上升趋势。松花江干流区域和第二松花江为主要的泥沙来源区,分别占整个松花江流域输沙量的72.1%和16.2%。通过对单位降雨侵蚀力输沙量的分析,松花江流域输沙量负荷的变化与流域内重大历史事件、国家政策等人为活动的变化密切相关。＂大跃进＂时期嫩江流域输沙量负荷显著增大,三年自然灾害时期各区段输沙量负荷都出现峰值,＂文革＂时期各区段输沙量负荷起伏变化比较大,改革开放特别是家庭联产承包责任制实施以后,各区段输沙量负荷都呈现显著增长的趋势,90年代自然灾害频发使输沙量负荷持续出现峰值,直至1999年退耕还林后输沙量负荷才有所下降,但此后输沙量负荷又有不同程度的增长趋势。     

基于VAR模型的新疆金沟河气象要素与径流关系分析

为探究气候变化下金沟河流域气象要素与径流之间的关系,根据新疆金沟河流域2006-2015年的月平均降水、积雪覆盖率、气温和径流资料,采用VAR模型方法分析了降水、积雪覆盖率、气温变化与径流变化之间的相互响应关系及响应程度。结果表明：降水、积雪覆盖率、气温与径流之间互相影响,但径流对降水、积雪覆盖率和气温的影响范围更大;径流对于降水、积雪覆盖率和气温的冲击响应方向不太一致,而降水、积雪覆盖率和气温对于径流冲击的响应均具有滞后性;通过方差分解可知,除径流自身冲击外,降水、积雪覆盖率和气温对径流变化的贡献程度依次为：气温 > 积雪覆盖率 > 降水,金沟河流域径流的主要影响因素为气温。研究结果可为流域内的各类水文计算提供参考依据。     

Use of satellite data for water resources modelling

Daily data from NOAA¹ satellites are combined with ground‐based meteorological, hydrometric, physiographic and land‐use data in a microcomputer database. A hydrologic model is applied to one basin in the Rocky Mountains and one on the prairies so that the effects of different physiographic and climatic characteristics might be investigated. Results show that using satellite data for areally distributed model inputs such as snow cover is a viable alternative to extrapolating from point measurements.     

Reconstruction of a long streamflow record using tree rings in the upper Kurshab River (Pamir-Alai Mountains) and its application to water resources management

A 294-year streamflow record of the upper Kurshab River was inferred from tree-ring width chronology of Turkestan juniper from the Pamir-Alai Mountains of Kyrgyzstan. The reconstructed streamflow variations were consistent with other hydrometeorological reconstructions of northern Pakistan and western Tien Shan on a decadal timescale, which demonstrate both increased and decreased streamflow intervals and trends. The new reconstruction and other hydrometeorological series successfully captured the recent wetting trend of Central Asia. Wavelet analysis indicates that decadal and interannual cycles exist in the reconstructed streamflow, which may be linked to solar activity and the North Atlantic Oscillation.     

黄河流域降水演变规律研究

基于黄河流域及其周边地区1000多个水文气象站近50年的月降水资料所生成的整个流域及其29个三级区的面雨量过程,采用多种时间序列分析方法,研究了黄河流域降水的随机性、趋势性和周期性。结果表明：黄河流域各三级区降水量Hurst系数的分布范围在0.449～0．644之间,说明其具有长期弱相关性;Kendall秩次相关检验结果表明黄河流域降水减少的趋势性不明显,从三级区看,大通河享堂以上等7个三级区降水有一定的减少趋势;黄河流域降水的短周期为准3年周期,中长周期一般表现为l1年和22年左右的周期。     

基于BORDA计数法的多元水文时间序列相似性分析

本文针对水文时间序列的特点和当前多元时间序列相似性分析研究的不足,提出了一种新的基于BORDA数的多元水文时间序列相似性度量计算方法。该方法首先根据多元水文时间序列数据复杂性进行主成分变换降维,然后利用线性分段斜率距离分别计算单一序列的相似性,最后采用基于BORDA计数法的投票方法获得多元水文时间序列整体相似性。为了证明提出方法的可行性和有效性,分别以太湖五站水位序列和宜丰洪水过程相似性分析为例进行了验证。分析结果表明,基于BORDA计数法的多元水文时间序列相似性度量计算方法可以满足防汛指挥中相似水文过程查找的需要。     

Variability of Water Resource in the Yellow River Basin of Past 50 Years, China

We use Mann–Kendall trend test and Lepage method to study spatial and temporal variations of the streamflow series over the past 50 years based on daily hydrologic data from six gauging stations in the Yellow River basin. Research results indicate that: (1) The streamflow of the Yellow River basin is decreasing and water resource deficit tends to be more serious from the upper to the lower Yellow River basin; (2) Zero-flow days are observed after 1970 and overwhelmingly prevail during 1990–2000. Moreover, zero-flow events are observed mainly during spring and summer; (3) Low flow events are more sensitive to climatic changes and human activities when compared to the high flow events, which is mainly reflected by larger fluctuation of timing of change points. Furthermore, the timing of change point of hydrologic events tends to be earlier from the upper to the lower Yellow River basin, indicating more intensive impacts of human activities on water resource in the lower Yellow River basin. The current research will be greatly helpful for sound and effective water resource management in the Yellow River basin, being characterized by serious water deficit.     

淮河流域径流时空变化特征分析

基于淮河流域主要干支流26个水文站点1956-2008年的实测径流资料,针对不同时间尺度,采用Mann-Kendall、Sequential Mann-Kendall和Distribution-free CUSUM等多种非参数检验方法对径流年际变化的趋势性和突变性进行分析。结果表明:流域径流年际变化趋势存在一定空间差异,除上游区表现出不显著的上升趋势外,大部分地区呈现出下降趋势,其中淮河水系中游以北地区与沂沭泗水系表现出显著的下降趋势;淮河水系径流量在春季(尤其4-5月份)表现出最大范围的下降趋势,在夏季(尤其7-8月份)呈现出以上升趋势为主的变化趋势,径流量年内分布不均匀化将进一步加大,可能加剧地区水资源供需矛盾和旱涝灾害;沂沭泗水系径流量在夏季表现出最大范围的下降趋势,7月份径流量的趋势值中值最小,达到了95%的显著水平;受到强烈的人类活动影响,流域年径流突变年份存在一定的时空差异,总体主要发生在20世纪70、80年代。     

黄河上游径流丰枯空间分布特征及其影响因素

针对目前青藏高原背景下的区域径流丰枯空间分布特征与其影响因素之间的联系仍不清楚,以及单站点或多站点平均的丰枯指标难以反映区域径流空间分布特征的问题,采用不同时间尺度的标准径流指数,结合经验正交函数、奇异值分解等方法分析了黄河上游1969—2012年径流丰枯的空间分布特征及其与青藏高原降水、气温和积雪3种气象因子的关系。结果表明:黄河上游径流丰枯情况具有区域一致的主要空间分布模态(主要受气象因子的影响)和东北—西南反位相分布的次要空间分布模态(主要受人类活动的影响);夏、秋季比冬、春季更可能出现多年径流量偏丰或偏枯的情形;青藏高原降水、气温和积雪是影响黄河上游径流丰枯空间分布的主要气象因子,降水对径流丰枯变化起主控作用,积雪和气温的季节性影响较明显;青藏高原东北部、东部、北部是影响径流丰枯变化的关键区。     

Developing a Snowmelt Forecast Model in the Absence of Field Data

In data poor regions predicting water availability is a considerable challenge for water resource managers. In snow-dominated watersheds with minimal in situ measurements, satellite imagery can supplement sparse data networks to predict future water availability. This technical note presents the first phase of an operational forecast model in the data poor Elqui River watershed located in northern Central Chile (30°S). The approach applies remotely-sensed snow cover products from the Moderate Resolution Imaging Spectrometer (MODIS) instrument as the first order hydrologic input for a modified Snowmelt Runoff Model. In the semi-arid Elqui River, snow and glacier melt are the dominant hydrologic inputs but precipitation is limited to up to six winter events annually. Unfortunately winter access to the Andean Cordillera where snow accumulates is incredibly challenging, and thus measurements of snowpack are extremely sparse. While a high elevation snow monitoring network is under development, management decisions regarding water resources cannot wait as the region is in its eighth consecutive year of drought. Our model applies a Monte Carlo approach on monthly data to determine relationships between lagged changes in snow covered area and previous streamflow to predict subsequent streamflow. Despite the limited data inputs the model performs well with a Nash-Sutcliffe Efficiency and R² of 0.830 and 0.833 respectively. This model is not watershed specific and is applicable in other regions where snow dominates hydrologic inputs, but measurements are minimal.

     

Impact of Climate Change on Water Resources in the Tarim River Basin

The plausible association between climate change and the variability of water resources in the Tarim River basin, west China is investigated in this study. The long-term trend of the hydrological time series including temperature, precipitation, and streamflow are detected by using both parametric and nonparametric techniques. The possible association between the El Niño/Southern Oscillation (ENSO) and these three kinds of time series are tested. This study enhances the knowledge of the climate change impact on water resources in the Tarim River basin. The conclusion obtained in this investigation shows that the temperature experienced a significant monotonic increase at the 5% level of significance during the past 50 yr, and precipitation also exhibited an upward tendency during the past several decades. A significant jump is also detected for both time series around 1986. This may be resulted from the possible impact of climate change, although the interior climate mechanism needs further investigation. Although precipitation and the streamflow from the headwater of the Tarim River exhibited significant increase, decreasing trend has been detected in the streamflow along the mainstream of the river. It implies that anthropogenic activities instead of the climate change dominated the streamflow cessation and the drying-up of the river. Results also showed that no significant association exists between the ENSO and the temperature, precipitation and streamflow in the study area. This conclusion shows that the water curtailment, river desiccation, and ecosystem deterioration in the Tarim River basin may be mainly resulted from the impact of human activities.     

塔里木河流域第七次应急输水期间径流情势及其对河流生态的影响

基于2005年塔里木河流域8个气象台站、4个探空站及4条源流出山口和干流15处控制断面2005年的水文气象监测资料,对塔河"四源一干"2005年气象和径流情势进行分析。结果表明:塔河流域山区及平原区的气温和降水量均较常年高,天然来水量较常年增加21%,干流输水总量为56.88亿m3,输水改善了河道两侧及下游的水生态环境,但其过程中耗水量仍较大。就第7次向塔里木河下游输水对水环境和生态环境的效应进行评价。     

PREDICTING THE LIKELIHOOD OF ALTERED STREAMFLOWS AT UNGAUGED RIVERS ACROSS THE CONTERMINOUS UNITED STATES

An approach is presented in this study to aid water‐resource managers in characterizing streamflow alteration at ungauged rivers. Such approaches can be used to take advantage of the substantial amounts of biological data collected at ungauged rivers to evaluate the potential ecological consequences of altered streamflows. National‐scale random forest statistical models are developed to predict the likelihood that ungauged rivers have altered streamflows (relative to expected natural condition) for five hydrologic metrics (HMs) representing different aspects of the streamflow regime. The models use human disturbance variables, such as number of dams and road density, to predict the likelihood of streamflow alteration. For each HM, separate models are derived to predict the likelihood that the observed metric is greater than (‘inflated’) or less than (‘diminished’) natural conditions. The utility of these models is demonstrated by applying them to all river segments in the South Platte River in Colorado, USA, and for all 10‐digit hydrologic units in the conterminous United States. In general, the models successfully predicted the likelihood of alteration to the five HMs at the national scale as well as in the South Platte River basin. However, the models predicting the likelihood of diminished HMs consistently outperformed models predicting inflated HMs, possibly because of fewer sites across the conterminous United States where HMs are inflated. The results of these analyses suggest that the primary predictors of altered streamflow regimes across the Nation are (i) the residence time of annual runoff held in storage in reservoirs, (ii) the degree of urbanization measured by road density and (iii) the extent of agricultural land cover in the river basin. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.     

松花江流域NPP时空演变及其对极端气候的响应机制

为探究全球气候变化条件下松花江流域陆地生态系统健康程度的变化特征,基于2000—2020年MODIS MOD17A3HGF数据集,采用趋势分析、相关性分析、M-K检验、地理探测器和相对重要性分析等方法,结合气象站点数据和土地利用数据,分析植被净初级生产力（net primary productivity,NPP）时空演变特征及其对极端气候事件的响应机制。结果表明：松花江流域年均NPP值为407.45g/m2（以C计,下同）,以年均4.82g/m2的速率显著上升（p<0.01）;极端降水事件对植被NPP空间分异性的影响强于极端气温事件,极端气候指数间交互作用的影响大于单一极端气候指数的影响,流域及农田和草地生态系统NPP主要受总降水量（PRCPTOT）与年平均最低气温（TMIN）交互作用的影响,森林、湿地和聚落生态系统NPP分别受中雨日数（R10mm）与年平均最高气温（TMAX）交互作用、强降水量（R95P）与TMIN交互作用和 R10mm与暖夜日数（TN90P）交互作用的影响;时间尺度上PRCPTOT、TMAX和TMIN是植被NPP的主要影响因素,空间尺度上PRCPTOT和TMIN是多年平均NPP的主要影响因素。研究结果可为量化气候变化背景下区域生态系统健康程度和应对极端气候事件措施的制定提供科学依据。     

基于多尺度熵理论的葛洲坝水库对长江干流径流影响研究

为研究葛洲坝水库对长江水文系统复杂性的影响,采用多尺度熵理论对长江干流宜昌、汉口、大通3个主要控制水文站的径流量序列进行分析。结果表明:长江干流径流序列复杂度从上游到下游表现为逐渐增加趋势;葛洲坝水库蓄水对长江干流径流序列结构复杂性产生了一定的影响,改变了天然条件下的系统复杂度,改变程度随距离的增大而减弱。     

Impact of Climate Change on the Hydrological Regime and Water Resources in the Basin of Siatista

This paper examines an assessment of the impact of climate change on hydrological regimes and water resources in the basin of Siatista, a sub-basin of the Aliakmon river basin, located in Northern Greece. Initially all acquired hydrometeorological data of the study area, as well as the hydrometric data at the outlet of the basin, were analyzed and processed. A monthly conceptual water balance model was then calibrated using historical hydrometeorological data for determining changes in streamflow runoff under two different equilibrium scenarios (UKHI, CCC) referring to the years 2020, 2050 and 2100. It was found that by applying the two scenarios there will be a reduction of the mean winter runoff values, a serious reduction of summer runoff, an increase of maximum annual runoff and a decrease of minimum annual runoff values, an increase of potential and actual evapotranspiration, leading to a decrease of soil moisture, a reduction of snow accumulation and melting due to temperature increases, resulting in a decrease of spring runoff values and a shifting of the wet period towards December, resulting in severe prolongation of the dry period.