基于多模式降水与水文模型的径流预报不确定性分析

Uncertainty analysis of Streamflow forecast based on multi-model precipitation and hydrological models

  • 摘要: 为提升流域径流预报的精度与可靠性,以清江流域为例,构建了基于多模式降水(ECMWF与NCEP)与多水文模型(GR4J与XAJ)的9种径流预报方案,并引入基于天气发生器的后处理方法(GPP)校正模式降水偏差,从确定性、概率性及不确定性3方面系统评估集合径流预报性能。结果表明:GPP方法提升了模式降水质量,进而改善了径流预报精度,尤其对误差较大的NCEP预报产品,校正效果显著;优选精度更高的降水预报产品并结合多水文模型集成策略,可进一步提升集合径流预报性能;在2020年典型洪水事件检验中,各方案在1 d和3 d预见期下均能准确捕捉峰现时间,其中多水文模型集成方案的集合平均峰值流量接近于实测洪峰。

     

    Abstract: To improve the accuracy and reliability of streamflow forecasting, nine ensemble runoff prediction schemes were developed for the Qingjiang River basin by combining two precipitation forecasts (ECMWF and NCEP) with two hydrological models (GR4J and XAJ). A generator-based post-processing method (GPP) was applied to correct systematic biases in model precipitation. The performance of each scheme was comprehensively evaluated from deterministic, probabilistic, and uncertainty perspectives. Results indicate that the GPP method significantly enhanced precipitation quality, thereby improving streamflow forecasting accuracy—particularly for the NCEP product, which exhibited larger initial errors. Integrating high-accuracy precipitation forecasts with multiple hydrological models further improved the robustness and reliability of ensemble runoff predictions. During validation against a typical flood event in 2020, all schemes accurately captured the flood peak timing at 1- and 3-day lead time. Notably, the ensemble-mean peak flows from the multi hydrological model integration schemes closely matched the observed peak.

     

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