Evaluation of ocean-atmospheric indices as predictors for summer streamflow of the Yangtze River based on ROC analysis

He, Ran-Ran; Chen, Yuanfang; Huang, Qin; Yu, Sheng-Nan; Hou, Yong

doi:10.1007/s00477-018-1551-z

Cited by 9 publications

(7 citation statements)

References 48 publications

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“…Several studies have demonstrated that a skillful streamflow forecast can enhance the efficiency of water allocation systems to manage the trade-off between hydropower, irrigation, municipal, and environmental services [28][29][30][31]. The potential for employing seasonal forecast in the Yangtze River basin has been investigated in several research studies, mostly through statistical techniques [32][33][34]. However, the potential application of the available seasonal forecasts for reservoir impoundment operation is not well understood in the Yangtze River basin.…”

mentioning

confidence: 99%

Evaluation of GloFAS-Seasonal Forecasts for Cascade Reservoir Impoundment Operation in the Upper Yangtze River

Chen

Guo

Wang

et al. 2019

Water

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Standard impoundment operation rules (SIOR) are pre-defined guidelines for refilling reservoirs before the end of the wet season. The advancement and availability of the seasonal flow forecasts provide the opportunity for reservoir operators to use flexible and early impoundment operation rules (EIOR). These flexible impoundment rules can significantly improve water conservation, particularly during dry years. In this study, we investigate the potential application of seasonal streamflow forecasts for employing EIOR in the upper Yangtze River basin. We first define thresholds to determine the streamflow condition in September, which is an important period for decision-making in the basin, and then select the most suitable impoundment operation rules accordingly. The thresholds are used in a simulation-optimization model to evaluate different scenarios for EIOR and SIOR by multiple objectives. We measure the skill of the GloFAS-Seasonal forecast, an operational global seasonal river flow forecasting system, to predict streamflow condition according to the selected thresholds. The results show that: (1) the 20th and 30th percentiles of the historical September flow are suitable thresholds for evaluating the possibility of employing EIOR;(2) compared to climatological forecasts, GloFAS-Seasonal forecasts are skillful for predicting the streamflow condition according to the selected 20th and 30th percentile thresholds; and (3) during dry years, EIOR could improve the fullness storage rate by 5.63% and the annual average hydropower generation by 4.02%, without increasing the risk of flooding. GloFAS-Seasonal forecasts and early reservoir impoundment have the potential to enhance hydropower generation and water utilization. events [3,4]. Conventionally, during wet season, reservoir operators release water preferentially for flood control [5,6] while storing water before the end of wet season to meet the demand for hydropower generation, navigation, and water supply. For full replenishment of storage, reservoir operators and academic researchers have highlighted the importance of reservoir impoundment operation and impoundment rules in several studies [7][8][9][10].Reservoir operation rules are often used to provide guidelines for reservoir operators to determine the amount of controlled discharge. Among these rules, the reservoir impoundment rules are designed to refill the reservoir and raise the storage water level. The New York City rule [11] is among the early guidelines for reservoir impoundment and provides the probability of spills rather than the amount of spill to minimize the water shortage [12]. Since the development of the New York City rule, different types of reservoir impoundment operation rules have been developed and employed for various reservoir systems [7,[13][14][15][16][17]. In the Yangtze River, which is one of the largest rivers in the world by discharge volume with huge reservoir storage capacity, the impoundment operation is complex and challenging. Water managers and stakeholders employ prede...

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confidence: 99%

Evaluation of GloFAS-Seasonal Forecasts for Cascade Reservoir Impoundment Operation in the Upper Yangtze River

Chen

Guo

Wang

et al. 2019

Water

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“…The results of correlation analysis in our study show the robust statistical connection between ENSO and the streamflow of Zhimenda and Datong, indicating the opportunities of forecasting the lagged streamflow by ENSO indices. Recent studies suggested that the ENSO event may be an essential source forecasting the summer streamflow in YRB and the MEI is the key ocean‐atmospheric predictors in summer streamflow forecasting (He et al ., ; Ye et al ., ). However, in our study, the Yichang streamflow was demonstrated as the transition zone between the source region and mid‐lower reaches.…”

Section: Discussionmentioning

confidence: 98%

Influence of mature El Niño‐Southern Oscillation phase on seasonal precipitation and streamflow in the Yangtze River Basin, China

Jia

Wang

Shao

et al. 2019

Intl Journal of Climatology

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As one of the most influential oceanic and atmospheric oscillations in the Earth system, El Niño‐Southern Oscillation (ENSO) has modulated numerous geophysical processes. This is particularly true for the Yangtze River Basin (YRB), which is vulnerable to Asian Monsoon and faces serious hydrological hazards. In this study, the co‐variability between lag–lead precipitation and sea surface temperature anomalies was evaluated utilizing singular value decomposition (SVD) method. Moreover, certain teleconnections between ENSO and streamflow were identified by wavelet methods. In addition, the contribution of related atmospheric variables was revealed by composite analysis. Results indicate that there are strong associations in lag–lead seasons between the wet condition (dry condition) and September–November (December–February) mature ENSO phase. Significant common power and coherence signals between the ENSO indices and the streamflow occur in the 4–8, 8–16 and 16–32 seasonal scales. Meanwhile, the activity cycle of the ENSO indices ahead of streamflow increases from the mid‐lower reaches to the source region. In addition, the Western Pacific Subtropical High is strengthened during the mature ENSO phase. Anomalous sinking motions and divergent water vapour flux occupy the YRB, reducing the precipitation and leading to the dry condition in the source region until the following March–May. On the other hand, ascending movements and abundant water vapour flux coming from northern Pacific, equatorial western Pacific and the Bay of Bengal result in the wet condition in the mid‐lower reaches.

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“…The third (model C) is a multiple linear regression model where both the electrical conductivity and the chloride ion concentration are independent variables in the equation that estimates the logarithm of FCD as a response variable. Receiver operating characteristic (ROC) analysis, which is a well-known strategy for assessing the t of models to the actual measurement results, was used to evaluate these three estimation methods (He et al, 2018). The Area Under the Curve (AUC) method was used to determine the performance of the ROC curve algorithm (He et al, 2018).…”

Section: Estimation Of Fcdmentioning

confidence: 99%

“…Receiver operating characteristic (ROC) analysis, which is a well-known strategy for assessing the t of models to the actual measurement results, was used to evaluate these three estimation methods (He et al, 2018). The Area Under the Curve (AUC) method was used to determine the performance of the ROC curve algorithm (He et al, 2018).…”

Section: Estimation Of Fcdmentioning

confidence: 99%

A Simple and Rapid Method to Assess the Quality of River Water: Correlation Between Electrical Conductivity and Fecal Coliform Density in Hyogo Prefecture, Japan

Horiguchi

Shigemura

Kitagawa

et al. 2022

Preprint

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This is a report regarding the development of a simple survey method for monitoring water pollution in the Toga River in Kobe City, Japan. This river is popular with local citizens as a water park, and especially in the summer, various activities are introduced to encourage children to play in the river. However, in recent years, contamination by fecal coliforms, probably caused by the accidental influx of domestic wastewater, often limits children from playing in the water. From May to October 2019, water samples were collected from five locations in the Toga River and the concentration of fecal coliforms was measured, along with the electrical conductivity and the chloride ion concentration of the river water, to establish a method for estimating the fecal coliform density (FCD) as a quicker alternative to a culture test. By comparing these parameters with the actual density of fecal coliforms, a high correlation was found between the electrical conductivity and FCD. On the other hand, there was almost no correlation between FCD and the chloride concentration. Receiver operating characteristic (ROC) analysis was used to evaluate the method that uses the electrical conductivity as an estimating parameter. The area under the curve (AUC) was used to determine the performance of the ROC curve algorithm. The calculated AUC value stayed high, above 0.95, over a wide range of threshold values of FCD, suggesting that this rapid method is appropriate for assessing the quantity of contaminating fecal coliforms in the range of 300–2,000/100 mL.

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Evaluation of ocean-atmospheric indices as predictors for summer streamflow of the Yangtze River based on ROC analysis

Cited by 9 publications

References 48 publications

Evaluation of GloFAS-Seasonal Forecasts for Cascade Reservoir Impoundment Operation in the Upper Yangtze River

Evaluation of GloFAS-Seasonal Forecasts for Cascade Reservoir Impoundment Operation in the Upper Yangtze River

Influence of mature El Niño‐Southern Oscillation phase on seasonal precipitation and streamflow in the Yangtze River Basin, China

A Simple and Rapid Method to Assess the Quality of River Water: Correlation Between Electrical Conductivity and Fecal Coliform Density in Hyogo Prefecture, Japan

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