地学前缘 ›› 2021, Vol. 28 ›› Issue (1): 428-437.DOI: 10.13745/j.esf.sf.2020.10.22

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基于EMD组合模型的径流多尺度预测

李福兴1(), 陈伏龙1,*(), 蔡文静1, 何朝飞1, 龙爱华1,2   

  1. 1. 石河子大学 水利建筑工程学院, 新疆 石河子 832000
    2. 中国水利水电科学研究院 流域水循环模拟与调控国家重点实验室, 北京 100038
  • 收稿日期:2020-07-28 修回日期:2020-10-23 出版日期:2021-01-25 发布日期:2021-01-28
  • 通讯作者: 陈伏龙
  • 作者简介:李福兴(1995—),男,硕士研究生,主要从事水文学及水资源问题研究。E-mail: 562220261@qq.com
  • 基金资助:
    国家自然科学基金项目(51769029);国家重点研发计划项目(2017YFC0404301);石河子大学高层次人才科研启动资金项目(RCZK2018C23);新疆维吾尔自治区研究生科研创新项目(XJ2019G113)

Multiscale runoff prediction based on the EMD combined model

LI Fuxing1(), CHEN Fulong1,*(), CAI Wenjing1, HE Chaofei1, LONG Aihua1,2   

  1. 1. College of Water Conservancy & Architectural Engineering, Shihezi University, Shihezi 832000, China
    2. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
  • Received:2020-07-28 Revised:2020-10-23 Online:2021-01-25 Published:2021-01-28
  • Contact: CHEN Fulong

摘要:

受全球气候变化与人类活动影响,径流序列愈发呈现出非稳态与非线性特征,为降低由此而引发的预报误差,充分发挥不同模型对提高径流预测精度的优势,针对传统径流预报模型的单一性,以干旱区典型内陆河玛纳斯河为例,采用经验模态分解(EMD)提取径流序列中具有物理含义的信号,得到不同时间尺度的多个固有模态函数(IMF)及1个趋势项,利用 ARIMA模型与GRNN模型分别对不同时间尺度的IMF分量进行模拟,分析径流未来变化趋势。运用多元线性回归法、Spearman相关系数法、平均影响值法筛选大气环流因子作为神经网络模型的输入项,根据子序列的局部频率特点构建组合模型。最后将各IMF分量的预测结果重构,得到径流的最终预测值。单一评价指标无法全面评价模型精度,本文通过构建TOPSIS评价模型对径流预测模型进行定量评估,客观评价模型优度。结果表明:EMD分解能有效提取径流序列中隐含的多时间尺度信号,由趋势项可知玛纳斯河径流量总体呈上升趋势;EMD分解可提高ARIMA模型25%的合格率,但对于高频率分量IMF1、IMF2、IMF3,ARIMA模型的相对误差达到70%以上,预测结果不理想;经过筛选预报因子可有效提高GRNN模型精度,其中MIV法筛选的预报因子最适合玛纳斯河,与EMD-ARIMA组合后的GRNN模型的合格率最高,TOPSIS模型得分也最高。预测结果可作为水资源规划与调度的科学依据,建模思路也可为优化径流预测模型提供新途径。

关键词: EMD, 径流预测, GRNN模型, 组合模型, 模型评价

Abstract:

Affected by global climate change and human activities, runoff sequences increasingly show unsteady and non-linear characteristics. In order to reduce the forecast errors caused by these runoff characteristics, we took full advantages of different models to improve the accuracy of runoff prediction traditionally done by the single model approach. Taking the Manas River, a typical inland river in the arid area as an example, we used empirical mode decomposition (EMD) to extract physically meaningful signals from the runoff sequence to obtain multiple intrinsic mode functions (IMF) at different time scales and a trend indicator. We then used the ARIMA and GRNN models to simulate the IMF components at different time scales and analyze the future runoff changing trends. Next, we used the multiple linear regression, Spearman correlation coefficient and average influence value methods to screen the atmospheric circulation factors and them used as inputs to the neural network model; we then constructed the combined model according to the local frequency characteristics of the sub-sequences. Finally, we reconstructed the prediction results of each IMF component to obtain the runoff prediction. However, a single evaluation index cannot fully evaluate the accuracy of the prediction model. In this paper, we constructed the TOPSIS evaluation model to quantitatively evaluate the runoff prediction model and objectively evaluate the model’s superiority. The results show that using EMD can effectively extract the multi-timescale signals hidden in the runoff sequence, and the trend indicator indicated that the Manas River runoff is on the rise. Using EMD could improve the passing rate of the ARIMA model by 25%; but the relative errors of high frequency components IMF1, IMF2 and IMF3 in the ARIMA model were more than 70%, indicating the prediction results are not ideal. In the GRNN model, selected predictors could effectively improve the model accuracy, and the predictors selected by the MIV method were shown to be most suitable for the Manas River. Overall, the GRNN-EMD-ARIMA combination model had the highest passing rate, and the TOPSIS model had the highest score. The prediction results can be used as a scientific basis for water resources planning and dispatching, and the modeling ideas can also provide new ways to optimize runoff prediction models.

Key words: EMD, runoff prediction, GRNN model, coupled model, model evaluation

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