Analysis and projection of runoff variation in three Chinese rivers

2016 ◽  
Vol 48 (5) ◽  
pp. 1296-1310 ◽  
Author(s):  
Lingqi Li ◽  
Irina Krasovskaia ◽  
Lihua Xiong ◽  
Lei Yan
Keyword(s):  
Annual Runoff ◽  
Empirical Orthogonal Functions ◽  
Orthogonal Functions ◽  
Flow Duration ◽  
Runoff Variation ◽  
Variation Patterns ◽  
Runoff Series ◽  
Runoff Variability ◽  
Flow Duration Curves ◽  
Wei River

Runoff variability is investigated separately for the Wei, the Bei, and the Qing Rivers in China with a focus on their respective differences in monthly flow patterns and flow duration curves (FDCs) between years with and without annual runoff deficit. The number of deficit runoff years increased in the Wei River and changed slightly in the Bei and Qing Rivers, respectively. Monthly flow variation patterns and FDCs differ between deficit and non-deficit years. The deficit years generally demonstrate earlier and more dispersed flow maxima. Deficit runoff years are contingent with the negative phase of the Polar-Eurasian Oscillation and vice versa, while generally they show contingency with the positive phase of the SST (Niño 3.4) and vice versa. The correlation between the human activity factors and the weights obtained by decomposing the runoff series into empirical orthogonal functions indicated that the human impact on the runoff variation was detectable: 22–25% in the Wei River, 28% in the Bei River, and negligible in the Qing River. We projected FDCs by weighting the distinctly different FDCs for deficit/non-deficit years according to several precipitation scenarios.

scholarly journals Study on the Variation of Annual Runoff and Influencing Factors in Kuye River during the Past 60 Years

2018 ◽  
Vol 7 (2) ◽  
pp. 72
Author(s):  
Zhihua MA ◽  
Qiaoling GUO ◽  
Ning SU
Keyword(s):  
Human Activities ◽  
Large Scale ◽  
High Strength ◽  
Annual Runoff ◽  
Runoff Variation ◽  
Runoff Reduction ◽  
Filter Methods ◽  
Runoff Series ◽  
Concentration Degree ◽  
The Impact

In this study, observed runoff series from a hydro-station respectively named Wenjiachuan station in the Kuye river was manipulated for monthly annual variation analysis assisted by using nonuniformity coefficient and concentration degree(period).the cumulative filter methods was employed to detect the trend of inner-annual runoff. Based on meteorological and hydrological data of the Wenjiachuan hydrologic station from 1955 to 2015, the paper studied the variation tendency, the abrupt and periodic changes of annual runoff using the Mann-Kendall non-parametric test and accumulation anomaly curve. Double mass curve was used to estimate the impact of human activities and climate change on the runoff variation. The curve of seasonal runoff distribution for Wenjiachuan station appeared two peak patterns. The annual runoff declined markedly, the effect of climate on runoff decreased, the influence of human activities on runoff gradually increased the human activities are the primary factors leading to the reduction of annual runoff. In human activities, large-scale water and soil conservation measures and high-strength coal mining have produced significant effects on the annual runoff reduction in Kuye River.

Recent Intensified Runoff Variability in the Hailar River Basin during the Past Two Centuries

2020 ◽  
Vol 21 (10) ◽  
pp. 2257-2273
Author(s):  
Junxia Li ◽  
Xueping Bai ◽  
Yuting Jin ◽  
Fangbo Song ◽  
Zhenju Chen ◽  
...  
Keyword(s):  
River Basin ◽  
Northeast China ◽  
Southern Oscillation ◽  
Annual Runoff ◽  
The Past ◽  
Increased Risk ◽  
Runoff Series ◽  
Tree Ring Data ◽  
Natural Land ◽  
Runoff Variability

AbstractUsing tree-ring data of Pinus sylvestris var. mongolica from the Hulun Buir region in northeast China, 12 annual runoff series of the Hailar River spanning the past 202–216 years were established for the first time; these included 11 branches and one for the entire basin. These reconstructions, which could explain 29.4%–52.7% of the total variance for the measured runoffs during 1956–2006, performed well in statistical verification tests. In the whole basin’s reconstruction of 212 years, 34 extreme drought years (16.0%) and 41 extreme pluvial years (19.3%) were identified; 4 of the 10 most extreme years occurred after 1980. The consistent cycle and correlation revealed that the Hailar runoff had a teleconnection with the El Niño–Southern Oscillation (ENSO). The sharply increasing variance at the end of the reconstruction, accompanied by the increasing intensity of short cycles (4–8 years), indicated that runoff variability in the Hailar River basin has enhanced in the late twentieth century. This is verified by the drastic fluctuations in water level and area of rivers and lakes, and the frequent shift of natural land cover types in the Hulun Buir area in recent decades. The intensified runoff variability can be connected with the concurrently enhanced ENSO activity. Our study is the first to identify the intensification of recent runoff variability in the semiarid to arid region in northeast China from a long-term perspective. With projected enhancement of ENSO activity, the Hailar River basin will face the increased risk of extreme hydrological events.

scholarly journals Comparison of catchment grouping methods for flow duration curve estimation at ungauged sites in France

2011 ◽  
Vol 15 (8) ◽  
pp. 2421-2435 ◽  
Author(s):  
E. Sauquet ◽  
C. Catalogne
Keyword(s):  
Regression Models ◽  
Empirical Orthogonal Functions ◽  
Parametric Models ◽  
The Other ◽  
Orthogonal Functions ◽  
Flow Duration ◽  
Ungauged Sites ◽  
Two Parameters ◽  
Homogeneous Regions ◽  
The Impact

Abstract. The study aims at estimating flow duration curves (FDC) at ungauged sites in France and quantifying the associated uncertainties using a large dataset of 1080 FDCs. The interpolation procedure focuses here on 15 percentiles standardised by the mean annual flow, which is assumed to be known at each site. In particular, this paper discusses the impact of different catchment grouping procedures on the estimation of percentiles by regional regression models. In a first step, five parsimonious FDC parametric models are tested to approximate FDCs at gauged sites. The results show that the model based on the expansion of Empirical Orthogonal Functions (EOF) outperforms the other tested models. In the EOF model, each FDC is interpreted as a linear combination of regional amplitude functions with spatially variable weighting factors corresponding to the parameters of the model. In this approach, only one amplitude function is required to obtain a satisfactory fit with most of the observed curves. Thus, the considered model requires only two parameters to be applicable at ungauged locations. Secondly, homogeneous regions are derived according to hydrological response, on the one hand, and geological, climatic and topographic characteristics on the other hand. Hydrological similarity is assessed through two simple indicators: the concavity index (IC) representing the shape of the dimensionless FDC and the seasonality ratio (SR), which is the ratio of summer and winter median flows. These variables are used as homogeneity criteria in three different methods for grouping catchments: (i) according to an a priori classification of French Hydro-EcoRegions (HERs), (ii) by applying regression tree clustering and (iii) by using neighbourhoods obtained by canonical correlation analysis. Finally, considering all the data, and subsequently for each group obtained through the tested grouping techniques, we derive regression models between physiographic and/or climatic variables and the two parameters of the EOF model. Results on percentile estimation in cross validation show that a significant benefit is obtained by defining homogeneous regions before developing regressions, particularly when grouping methods make use of hydrogeological information.

scholarly journals Comparison of catchment grouping methods for flow duration curve estimation at ungauged sites in France

2011 ◽  
Vol 8 (2) ◽  
pp. 3233-3269 ◽  
Author(s):  
E. Sauquet ◽  
C. Catalogne
Keyword(s):  
Regression Models ◽  
Regression Tree ◽  
Empirical Orthogonal Functions ◽  
Parametric Models ◽  
The Other ◽  
Orthogonal Functions ◽  
Flow Duration ◽  
Ungauged Sites ◽  
Two Parameters ◽  
Homogeneous Regions

Abstract. The study aims at estimating flow duration curves (FDC) at ungauged sites in France and quantifying the associated uncertainties using a large dataset of 1080 FDCs. The interpolation procedure focuses here on 15 percentiles standardised by the mean annual flow, which is supposed to be known at each site. In particular, this paper discusses the relevance of different catchments grouping procedures on percentiles estimation by regional regression models. First, five parsimonious FDC parametric models were tested to approximate FDCs at gauged sites. The results show that the model based on Empirical Orthogonal Functions (EOF) expansion outperforms the other ones. In this model each FDC is interpreted as a linear combination of regional amplitude functions with weights – the parameters of the model – varying in space. Here, only one amplitude function was found sufficient to fit well most of the observed curves. Thus the considered model requires only two parameters to be estimated at ungauged locations. Second, homogeneous regions were derived according to hydrological response on one hand, and geological, climatic and topographic characteristics on the other hand. Hydrological similarity was assessed through two simple indicators: the concavity index (IC) that represents the shape of the standardized FDC and the seasonality ratio (SR) which is the ratio of summer and winter median flows. These variables were used as homogeneity criteria in three different methods for grouping catchments: (i) according to their membership in one of an a priori French classification into Hydro-Eco-Regions (HERs), (ii) by applying a regression tree clustering and (iii) by using hydrological neighbourhood obtained by canonical correlation analysis. Finally, regression models between physiographic and/or climatic variables and the two parameters of the EOF model were derived considering all the data and thereafter for each group obtained through the tested grouping techniques. Results on percentiles estimation in cross validation show a significant benefit to form homogeneous regions before developing regressions, particularly when grouping methods use hydrogeological information.

Empirical Methods in Short-Term Climate Prediction

2006 ◽  
Author(s):  
Huug van den Dool
Keyword(s):  
Climate Prediction ◽  
Empirical Orthogonal Functions ◽  
Data Sets ◽  
Seasonal Forecasts ◽  
Short Term ◽  
Orthogonal Functions ◽  
Ocean Atmosphere Interaction ◽  
Global Coverage ◽  
Atmosphere Interaction ◽  
Global Data

This clear and accessible text describes the methods underlying short-term climate prediction at time scales of 2 weeks to a year. Although a difficult range to forecast accurately, there have been several important advances in the last ten years, most notably in understanding ocean-atmosphere interaction (El Nino for example), the release of global coverage data sets, and in prediction methods themselves. With an emphasis on the empirical approach, the text covers in detail empirical wave propagation, teleconnections, empirical orthogonal functions, and constructed analogue. It also provides a detailed description of nearly all methods used operationally in long-lead seasonal forecasts, with new examples and illustrations. The challenges of making a real time forecast are discussed, including protocol, format, and perceptions about users. Based where possible on global data sets, illustrations are not limited to the Northern Hemisphere, but include several examples from the Southern Hemisphere.

scholarly journals Spatio-Temporal Patterns of Mass Changes in Himalayan Glaciated Region from EOF Analyses of GRACE Data

2021 ◽  
Vol 13 (2) ◽  
pp. 265
Author(s):  
Harika Munagapati ◽  
Virendra M. Tiwari
Keyword(s):  
Temperature Anomaly ◽  
Mass Gain ◽  
Snow Accumulation ◽  
Empirical Orthogonal Functions ◽  
Total Water ◽  
Orthogonal Functions ◽  
Grace Data ◽  
Grace Satellite ◽  
Spatio Temporal ◽  
Gravity Recovery

The nature of hydrological seasonality over the Himalayan Glaciated Region (HGR) is complex due to varied precipitation patterns. The present study attempts to exemplify the spatio-temporal variation of hydrological mass over the HGR using time-variable gravity from the Gravity Recovery and Climate Experiment (GRACE) satellite for the period of 2002–2016 on seasonal and interannual timescales. The mass signal derived from GRACE data is decomposed using empirical orthogonal functions (EOFs), allowing us to identify the three broad divisions of HGR, i.e., western, central, and eastern, based on the seasonal mass gain or loss that corresponds to prevailing climatic changes. Further, causative relationships between climatic variables and the EOF decomposed signals are explored using the Granger causality algorithm. It appears that a causal relationship exists between total precipitation and total water storage from GRACE. EOF modes also indicate certain regional anomalies such as the Karakoram mass gain, which represents ongoing snow accumulation. Our causality result suggests that the excessive snowfall in 2005–2008 has initiated this mass gain. However, as our results indicate, despite the dampening of snowfall rates after 2008, mass has been steadily increasing in the Karakorum, which is attributed to the flattening of the temperature anomaly curve and subsequent lower melting after 2008.

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