【作者】 孙惠子；

【导师】 粟晓玲；

【作者基本信息】 西北农林科技大学 ， 水文学及水资源， 2012， 硕士

【摘要】 水资源短缺和生态环境恶化问题，已成为制约我国西北内陆河流域经济可持续发展的关键因素。而随着社会经济的不断发展，国民经济各部门对水文预报提出的要求越来越高，不仅要求有较高精度的短期预测，而且要求有预见期更长的中长期径流预测。因此基于组合模型的中长期径流预测研究，对流域水资源有效调控和合理利用水资源具有重要意义。论文在应用单项预测方法的基础上，应用径流预测的多种组合预测方法预测石羊河流域支流枯季径流和年径流的预测，主要研究内容和取得的主要结论如下：（1）归纳总结了目前径流预测的主要方法，包括多元线性回归（MLR）、BP神经网络、支持向量机（SVM）和自回归移动平均（ARIMA）四种单项预测方法。为了提高年径流预测的准确性，介绍了简单平均方法（SA）、加权平均方法（WA）、回归方法（Regression）、误差平方和（SSE）、人工神经网络（ANN）和时变权重方法（包括时变误差平方和（TSSE）、线性时变误差平方和（LTSSE）、几何时变误差平方和（GTSSE））八种组合预测技术。通过组合单个预测模型的误差信息，得出精度更高的预测结果。（2）采用多元线性回归（MLR）、BP神经网络和自回归移动平均（ARIMA）三个单项预测方法对石羊河支流西营河枯季径流进行了预测，用相对均方根误差（R-RMSE）和相对偏差（R-Bias）检验模型的拟合精度，结果表明单项预测模型中ARIMA模型的精度最高；采用加权平均组合预测的精度要高于简单平均组合预测的精度，并且ARIMA-MLR和ARIMA-BP组合的拟合精度较好。（3）根据前期的气象资料采用多元线性回归（MLR）、BP神经网络、支持向量机（SVM）和自回归移动平均（ARIMA）四种单项预测方法预测石羊河流域八条山水河流出山口的年径流，用R-RMSE和R-Bias检验模型的拟合精度，结果表明，SVM方法的精度最高。（4）采用八种组合预测方法，组合年径流的四种单项预测模型，共有11种组合可能，并采用预测结果的相对均方根误差（R-RMSE）和相对偏差（R-Bias）比较模型的精度。在理论上说明了：①当SA和WA两个预测误差方差的比率很大，并且当一个预测相对与另一个较差时，WA要比SA表现得好。尽管SA并不总能比那些最好的单个预测模型的精度高，但却不失为一种较为有效的组合技术。②当单项预测具有非稳定性的误差时，时变权重组合方法比恒定权重的方法产生更好的结果。③当两个预测方法的结果高度相关时，组合技术不能带来显著性的改进。在这种情况下，建议应用最好的单项预测。此时，ANN组合方法比线性组合方法可以更精确的代表单个预测之间复杂的和非线性的关系，它的R-RMSE值相对其它组合方法更小。④基于Regression和ANN的组合方法可以去除组合预测中的偏差的影响，应用偏差校正技术相对其它没有偏差校正的技术可以改进组合预测结果。（5）通过对各种组合预测方法的相对均方根误差比较，获得了八条支流径流组合预测的最优组合方法。大靖河最优的组合是在ANN组合方法下的M*SA组合；古浪河最优的组合是在LTSSE和GTSSE组合方法下的M*SA组合；黄羊河最优的组合是在ANN组合方法下的MB*SA组合；杂木河最优的组合是在Regression组合方法下的M*BSA组合；金塔河最优的组合是在Regression和ANN组合方法下的MB*SA组合；西营河最优的组合是在TSSE、LTSSE和GTSSE组合方法下的M*SA组合；东大河最优的组合是在WA、Regression和ANN组合方法下的M*BS组合；西大河最优的组合方法是在WA、Regression和ANN组合方法下的M*BSA。总体上来说：ANN、Regression和WA组合方法的的效果最好，当误差序列不平稳时，TSSE、LTSSE和GTSSE组合方法可提高精度；而M*BSA组合、MB*SA组合和SA组合的精度最高。更多还原

【Abstract】 The problems of shortage in water resources and ecological environment deteriorationhas become a key factor in restricting the sustainable development of northwest inland rivereconomic in China. With the continuous development of the socio-economic, the requirementof various departments of the national economy on the hydrological forecasting is gettinghigher and higher, not only requires short-term forecasts of higher accuracy, but requireslong-term stream-flow forecasting. Therefore, long-term stream-flow forecasting which isbased on the combination model is of great significance to the effective regulation of the riverbasin water resources and rational use of water resources. This paper based on the applicationof individual prediction methods, applied various combination forecasting methods ofstream-flow forecasting to predict the Shiyang River Basin tributaries drought periodstream-flow and the annual stream-flow, The main research contents and the main conclusionsobtained as follows:(1) Summarized the currently main methods of stream-flow forecasting, including fourindividual prediction methods: multiple linear regression (MLR), the BP neural networks,support vector machine (SVM) and autoregressive moving average (ARIMA). In order toimprove the accuracy of the forecasts of annual stream-flow, introduct eight combinationsforecasting techniques: the simple average method (SA), the weighted average method (WA)regression methods (Regression), the sum of squared errors method (SSE), artificial neuralnetwork (ANN) and time-varying weights method (including the time-varying sum of squarederror method (TSSE), linear time-varying sum of squared error (LTSSE) and geometrictime-varying sum of squared error (GTSSE)). We can obtained more accurate predictionresults through constitute the error information of single forecasting model.(2) Apply three individual prediction methods which is including Mmultiple linearregression (MLR), BP neural network and autoregressive moving average(ARIMA)forecasted the drought period stream-flow of Xiying River of the Shiyang River,Test the fitting accuracy of the models with the relative root mean square error (R-RMSE)and the relative bias (R-Bias), the results showed that the ARIMA method has the highestaccuracy among the single models; The accuracy of the weighted average combination is higher than the simple average combination, and fitting accuracy of the ARIMA-MLRcombination and ARIMA-BP combination are better.(3) Apply four individual prediction methods which is including multiple linearregression (MLR), the BP neural network, support vector machine (SVM) and theautoregressive moving average (ARIMA) to forecast annual stream-flow from eight landscaperiver of the Shiyang River Basin according to the pre-meteorological data. Test the fittingaccuracy of the models with R-RMSE and R-Bias, the results showed that the SVM methodhas the highest accuracy.(4) Apply eight combination methods, combinating four individual prediction models ofannual stream-flow, this reached a total of11possible of combinations, and compare theaccuracy of models in relative root mean square error(R-RMSE) and the relative bias(R-Bias)of the prediction results. In theory:①When the forecasting error variance ratio of SA andWA methods, and when a prediction is relative poorer than another, WA method performs wellthan SA method. Although SA does not always perform better than that of the best constituentforecast, it was always much better than that of the worst constituent forecasts.②When theerror of individual forecasting is non-stability, time-varying weights combination methodcould produce better results than the constant weight method.③One cannot expectcombining technique to yield significant improvement when two constituent forecasts arehighly correlated. In such cases, using the best constituent forecast model is recommended. Atthis point, the ANN combining method, which has a more flexible structure and can moreaccurately represent complex and nonlinear relationships between constituent forecasts thanthe linear combining approaches, its R-RMSE is lower than other combination.④Thecombining methods based on regression and ANN can remove the effects of bias in theconstituent forecasts. By applying a technique with a bias correction component, one canimprove the combined forecast over using other techniques without a bias correctioncomponent.(5) Through compare the R-RMSE of various combinations, obtained the optimalcombinations of Shiyang River eight rivers stream-flow forecasting. The optimal combinationof Dajing River is M*SA combination in ANN methods; The optimal combination of GulangRiver is M*SA combination in LTSSE and GTSSE methods; The optimal combination ofHuangyang River is MB*SA combination in ANN methods; The optimal combination ofZamu River is M*BSA combination in Regression methods; The optimal combination of JintaRiver is MB*SA combination in Regression and ANN methods; The optimal combination ofXiying River is M*SA combination in TSSE、LTSSE and GTSSE methods; The optimalcombination of Dongda River is MB*S combination in WA、Regression and ANN methods; The optimal combination of Xida River is M*BSA combination in WA、Regression and ANNmethods; On the whole: WA、Regression and ANN combination methods perform best, Whenthe error is non-stability, TSSE、LTSSE and GTSSE combination methods can improve theaccuracy; and the accuracy of M*BSA combination、MB*SAcombination and SA combinationare the highest.更多还原