基于四种方法的月径流预测研究

径流预测对于水资源的合理开发利用与统筹配置具有重要意义。根据黄土高原地区渭河支流-北洛河状头水文站和泾河张家山站的月径流资料,运用门限自回归模型、神经网络模型、方差分析外推法以及季节水平模型四种方法对其进行预测,观察模拟效果并比较各自优缺点。对于枯水期月径流,季节水平模型对于两站预测合格率均为100%;方差分析外推法对于状头站和张家山站预测合格率分别为90%,80%;门限自回归模型对于两站的预测合格率均为80%;神经网络模型预测两站汛期月径流合格率均为100%。表明季节水平模型适用于枯季月径流的预测,神经网络模型适宜于汛期月径流预测,并且精度良好。     

二滩水电站中期径流序列预测研究

分别利用门限回归模型（TR模型）和人工神经网络模型对二滩水电站的月平均径流量序列进行了预测。通过计算可知，门限回归模型和人工神经网络模型都可以很好地解决月平均径流的预测问题，相对误差总体上都比较小。但门限回归模型计算繁琐，不能及时、快速得到计算结果，而人工神经网络模型计算快速，占用内存小，还有很好的容错性，即使在数据不完全的情况下，也能及时准确地得到径流预报值。考虑到模型自身的特点和优势，在实际运行中推荐使用人工神经网络模型进行月平均流量的计算和预测。     

基于季节性自回归模型的龙溪口电站径流预报

利用岷江下游高场站1940～2004年共65 a月径流实测序列,对序列随机成分、基本特征进行分析,确定月径流序列为季节性时间序列,因此,采用季节性自回归模型进行模拟预报,确定模型为一阶季节性自回归模型。模拟预测的结果表明:10～12月预报效果较差,其它月份预报精度均较高,该模型能够用于龙溪口电站的月径流模拟预报。     

嘉陵江中游段中长期径流预报研究

通过对嘉陵江流域中游段的径流特性及变化规律进行研究,应用目前较为成熟的人工神经网络模型、最近邻抽样回归模型、自回归模型和均生函数模型,对嘉陵江流域中游段年径流进行预报。实例分析和预测结果比较表明:人工神经网络模型与最近邻抽样回归模型能更好地预测嘉陵江中游段的年径流。     

自回归模型在月径流过程概率预报中的应用

把自回归模型用于月径流过程概率预报中。首先根据历史径流的概率分布利用自回归模型预报出一个概率，再根据这个预报出的概率进行径流概率预报。并把这种方法用于三峡电站的入库径流预报中，取得了较好的效果。     

多支流河段径流预测方法比较研究

以塔里木河流域为例，建立了多支流河段多元线性回归和人工神经网络两种径流预测模型，并对预测效果进行了系统的比较。结果表明，两种方法都能以令人满意的精度进行径流过程的模拟和预测；人工神经网络比多元线性回归更适合于在多支流河段上进行径流预测。     

若尔盖湿地黑河径流分析及预测

根据若尔盖湿地若尔盖水文站逐日平均流量资料(1988～2008年),应用滑动平均法、不均匀度、变化幅度以及自相关系数分析了若尔盖湿地黑河径流年际变化以及年内分配规律,并采用门限回归模型以及最近邻抽样回归模型对日径流进行了拟合和预测。研究表明,若尔盖黑河径流量年内分配十分不均,年内变化曲线呈现双峰型;日径流短期内具有良好的相依性;且年径流量自1988年以来具有明显的减小趋势;门限回归模型、基于时间序列分析的最近邻抽样回归模型用于逐日平均流量预测,效果较好。     

ANN、ANFIS和AR模型在日径流时间序列预测中的应用比较

水文预测是水文学为经济和社会服务的重要方面。其预报结果不仅能为水库优化调度提供决策支持,而且对水电系统的经济运行、航运以及防洪等方面具有重大意义。自回归模型(AR模型)、人工神经网络(ANN)和自适应神经模糊推理系统(ANFIS)在日径流时间序列中应用广泛。将这三种模型应用于桐子林的日径流时间序列预测中,不仅采用纳什系数(NS系数)、均方根误差(RMSE)和平均相对误差(MARE)为评价指标,对三种模型的综合性能进行了比较。而且,在对三种模型预测结果的平均相对误差的阈值统计基础上,分析了三种模型的预测误差分布。同时,通过研究模型性能指标随预见期的变化过程评价了三种模型不同预见期下的预测能力。结果表明ANFIS相对于ANN和AR模型不仅具有更好的模拟能力、泛化能力,而且在相同的预见期下具有更优的模型性能,可以作为日径流时间序列预测的推荐模型。     

日径流预测方法研究

运用自回归方法、多元线性回归方法和人工神经网络方法分别对汛期和非汛期的日径流量进行了预测,汛期预报因子又分别用有降水因子和无降水因子进行了预测。预测结果表明：非汛期的预测精度较高,汛期预测效果较差。另外,在汛期,有降水因子的预测结果要比没有降水因子预测效果好。     

奴各沙站径流序列统计特征分析及其随机模拟

文章通过统计参数和自相关分析,对雅鲁藏布江奴各沙站天然年、月径流序列进行了分析,得出年径流序列离散程度较大,月径流统计参数随季节而变等有价值的结果.进而本文以实测41年径流资料为基础,应用线性平稳自回归模型和季节性一阶自回归模型,分别对奴各沙站年、月径流序列进行了随机模拟.     

小波分解与变换法预测地下水位动态

通过小波分解方法将地下水位动态的非平稳时间序列分解为多个细节信号序列和逼近信号序列，然后运用时间序列自回归模型及人工神经元网络模型对各信号序列分别进行模拟预测，模拟结果比单纯用自回归法或人工神经网络模型更接近实测值，说明通过小波分解方法进行地下水位动态模拟和预测是适合的；同时用小波变换方法对地下水位动态进行了宏观分析，使隐藏的规律性显现出来，揭示出地下水位动态变化中除了具有一个水文年内的周期性变化规律外，还存在2～3年间隔的波幅强弱变化，可以推断未来短期内地下水位动态发展仍将延续当前总体下降的趋势，与小波分解方法得到的预 测结果相吻合。     

Monthly Streamflow Forecasting Using Convolutional Neural Network

Monthly streamflow forecasting is vital for managing water resources. Recently, numerous studies have explored and evidenced the potential of artificial intelligence (AI) models in hydrological forecasting. In this study, the feasibility of the convolutional neural network (CNN), a deep learning method, is explored for monthly streamflow forecasting. CNN can automatically extract critical features from numerous inputs with its convolution–pooling mechanism, which is a distinct advantage compared with other AI models. Hydrological and large-scale atmospheric circulation variables, including rainfall, streamflow, and atmospheric circulation factors are used to establish models and forecast streamflow for Huanren Reservoir and Xiangjiaba Hydropower Station, China. The artificial neural network (ANN) and extreme learning machine (ELM) with inputs identified based on cross-correlation and mutual information analyses are established for comparative analyses. The performances of these models are assessed with several statistical metrics and graphical evaluation methods. The results show that CNN outperforms ANN and ELM in all statistical measures. Moreover, CNN shows better stability in forecasting accuracy.

     

基于人工神经网络的日径流预测

给出了用人工神经网络(ANN)对 三峡宜昌站的日径流预测模型建模的过程，对ANN输入变量的选择和个数的确定以及隐藏层 、输出层单元数的确定等关键技术问题进行了探讨。所建立的基于ANN的预测模型可以进行 提前7 d的日径流预测，预测结果令人满意。     

遗传门限自回归模型的改进及其应用

 针对门限自回归模型在实际应用过程中预测效果差于拟合效果的情况,对门限自回归模型作了改进,即：在对时序x(i)拟合和预测时,AR式靠近i半个周期的观测值用门限自回归模型的拟合和预测的计算值代替;为了清晰直观地确定出延迟步数及门限区间AR模型的阶数,提出了通过绘制自相关系数图来确定。实例表明,该改进方法提高了遗传门限自回归模型的稳定性和实用性,模型在大坝安全位移监测预报中得到了成功的应用。     

Development of a Hybrid Data Driven Model for Hydrological Estimation

High and low stremflow values forecasting is of great importance in field of water resources in order to mitigate the impacts of flood and drought. Most of water resources models deal with the problem of not being flexible for modeling maximum and minimum flows. To overcome that shortcoming, a combination of artificial neural network (ANN) models is developed in this study for monthly streamflow forecasting. A probabilistic neural network (PNN) is used to classify each of the input-output patterns and afterward, the classified data are forecasted using a modified multi-layer perceptron (MMLP). In addition, the performance of the MLP and generalized regression neural network (GRNN) in streamflow forecasting are investigated and compared to the proposed method. The findings indicate that the R² associated with the suggested model is 46 and 80% higher compared to MLP and GRNN models, respectively.     

Daily Mean Streamflow Prediction in Perennial and Non-Perennial Rivers Using Four Data Driven Techniques

This study examines and compares the performance of four new attractive artificial intelligence techniques including artificial neural network (ANN), hybrid wavelet-artificial neural network (WANN), Genetic expression programming (GEP), and hybrid wavelet-genetic expression programming (WGEP) for daily mean streamflow prediction of perennial and non-perennial rivers located in semi-arid region of Zagros mountains in Iran. For this purpose, data of daily mean streamflow of the Behesht-Abad (perennial) and Joneghan (non-perennial) rivers as well as precipitation information of 17 meteorological stations for the period 1999–2008 were used. Coefficient of determination (R²) and root mean square error (RMSE) were used for evaluating the applicability of developed models. This study showed that although the GEP model was the most accurate in predicting peak flows, but in overall among the four mentioned models in both perennial and non-perennial rivers, WANN had the best performance. Among input patterns, flow based and coupled precipitation-flow based patterns with negligible difference to each other were determined to be the best patterns. Also this study confirmed that combining wavelet method with ANN and GEP and developing WANN and WGEP methods results in improving the performance of ANN and GEP models.     

门限人工神经网络模型及其在洪水预报中的应用

结合门限自回归模型与人工神经网络模型的建模思想，首次提出这两种方法的耦合模型，即门限人工神经网络模型，新模型的实质是一种分段非线性化的处理方法，是对现有门限模型分段线性化的很好改进。实例计算结果说明，新模型在洪水的预报中是有效的，在各种非线性时序动态预测中具有普遍意义和广泛的实用价值。     

Comparison of performance of statistical models in forecasting monthly streamflow of Kizil River,China

This paper presents the application of autoregressive integrated moving average(ARIMA),seasonal ARIMA(SARIMA),and Jordan-Elman artificial neural networks(ANN)models in forecasting the monthly streamflow of the Kizil River in Xinjiang,China.Two different types of monthly streamflow data(original and deseasonalized data)were used to develop time series and Jordan-Elman ANN models using previous flow conditions as predictors.The one-month-ahead forecasting performances of all models for the testing period(1998-2005)were compared using the average monthly flow data from the Kalabeili gaging station on the Kizil River.The Jordan-Elman ANN models,using previous flow conditions as inputs,resulted in no significant improvement over time series models in one-month-ahead forecasting.The results suggest that the simple time series models(ARIMA and SARIMA)can be used in one-month-ahead streamflow forecasting at the study site with a simple and explicit model structure and a model performance similar to the Jordan-Elman ANN models.     

Artificial neural network model for synthetic streamflow generation

Time series of streamflow plays an important role in planning, design and management of water resources system. In the event of non availability of a long series of historical streamflow record, generation of the data series is of utmost importance. Although a number of models exist, they may not always produce satisfactory result in respect of statistics of the historical data. In such event, artificial neural network (ANN) model can be a potential alternative to the conventional models. Streamflow series, which is a stochastic phenomenon, can be suitably modeled by ANN for its strong capability to perform non-linear mapping. An ANN model developed for generating synthetic streamflow series of the Pagladia River, a major north bank tributary of the river Brahmaputra, is presented in this paper along with its comparison with other existing models. The comparison carried out in respect of five different statistics of the historical data and synthetically generated data has shown that among the different models, viz., autoregressive moving average (ARMA) model, Thomas-Fiering model and ANN model, the ANN based model has performed better in generating synthetic streamflow series for the Pagladia River.