考虑河床地形变化的河道水位机器学习预测模型

    Machine learning prediction model of river water level considering riverbed topographic change

    • 摘要: 为建立适用于河床地形变化较大河段的机器学习水位预测模型,通过选取2002~2012年地形变化较大的赣江南昌河段为研究对象,采用河道不同时段的过流面积表征河床地形的变化,与河道水文资料一起作为输入特征,对预见期分别为1-3d的外洲站水位进行了预测。结果表明,所建长短时记忆(LSTM)模型在预测外洲水位时具有较好的表现,预见期1-3d水位预测的NSE和R分别达到0.977和0.987以上,特别是预见期第1d的水位预测精度最高,评估指标RMSE和MAE分别为0.063 m和0.043 m,NSE和R均为0.999。与不考虑地形变化影响的模型预测结果相比,预测水位的RMSE和MAE分别降低了14.9%和10.4%。通过不同输入特征方案的对比分析,表明河床地形变化较大的河道,在模型输入中增加河道地形特征,有助于模型学习到地形变化与水位变化之间的映射关系,提高模型对水位的预测精度。

       

      Abstract: In order to establish a machine-learning water level prediction model applicable to river sections with large changes in riverbed topography, the Nanchang River section of the Ganjiang River with large topographic changes from 2002 to 2012 as the research object was selected, and adopting the overflow area of the river at different times of the day to characterize the changes of the riverbed topography, together with the hydrological data of the river as the input features, the water level of the Waizhou station with the forecast period of 1-3 days was predicted, respectively. The results showed that the proposed long short-term memory (LSTM) model had a good performance in predicting the water level at Waizhou, and the NSE and R of predicting the water level from forecast period of 1-3 days reached more than 0.977 and 0.987, respectively. Especially the highest accuracy of predicting the water level from day 1 of the forecast period, and the evaluation indexes of RMSE and MAE were 0.063 m and 0.043 m, respectively, and the NSE and R were both 0.999 with. RMSE and MAE of the predicted water level were reduced by 14.9% and 10.4%, respectively, compared with the results of the model prediction without considering the influence of topographic changes. Through the comparative analysis of different input feature schemes, it shows that for the river channel with large topographic changes, adding the topographic features of the river channel in the model input can help the model learn the mapping relationship between topographic changes and water level changes, and improve the prediction accuracy of the model for water level.

       

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