基于VIC模型的三峡库区流域小时尺度实时洪水预报

Hourly scale real-time flood forecasting in the Three Gorges Reservoir basinbased on the VIC model

VIC模型在流域面积大于3 000 km^(2)的大型流域日或月尺度洪水模拟中表现出良好的适用性,而在大型流域小时尺度实时洪水预报过程中的适用性尚未得到验证。以三峡库区大型流域为例,通过建立小时尺度VIC分布式洪水预报模型,构建三峡库区流域实时滚动洪水预报方案,将VIC分布式洪水预报模型实地化部署并应用于2022及2023年三峡库区实时洪水预报。结果表明:VIC模型应用于2014—2021年三峡库区各子流域历史洪水模拟,率定期和验证期的洪量、洪峰平均合格率均在80%以上,确定性系数均值在0.70以上,构建的VIC分布式洪水预报模型在三峡库区及其子流域洪水模拟中表现出良好的适用性;在2022及2023年三峡库区4场典型洪水的实时洪水预报中,径流深和洪峰的平均相对误差达到16.3%和5.0%,重点产流区产流量平均相对误差为7.8%,能够准确把握库区重点产流区的洪量及来水过程,因此VIC模型在大型流域小时尺度实时洪水预报中具有较大的应用潜力。

The existing basin real-time flood forecasting system is based on the lumped model.With the increasing demand for spatial and temporal refinement of flood forecasting in large-scale basin flood control,the lumped model cannot adequately consider the unevenness of rainfall and spatial and temporal distribution of subsurface,and it is difficult to apply it to the current large-scale basin real-time flood forecasting.With the wide application of remote sensing and geographic information technology in the field of hydrology,the source of rainfall and subsurface data acquisition and data accuracy has been greatly improved,so the distributed hydrological model has gradually developed into a research hotspot in the field of hydrological modeling.However,due to the limitation of the accuracy of rainfall,runoff,and subsurface data,the application of distributed hydrological models in the field of real-time flood forecasting,especially in hourly scale forecasting,is still relatively small,and the forecast accuracy needs to be improved.With the abundant and accumulated information from satellite telemetry and ground observation sites in the basin,the hydrological and subsurface information can meet the demand for hourly flood forecast modeling by distributed hydrological models.Taken the Three Gorges Reservoir basin as an example, the process of real-time flood forecasting by the VICmodel is carried out. The process of real-time rolling flood forecasting by the VIC model is divided into three parts:data access, model operation, and result output. To address the problem the original unit line routing method of theVIC model has a daily time scale and can not be used for hourly scale real-time flood forecasting. The slope routingis carried out using the slope unit line based on Gamma distribution, the river network routing is carried out usingthe IRF-UH method, and the hourly-scale VIC distributed flood forecasting model is established. The real-timerolling flood forecasting scheme is constructed, and the VIC distributed flood forecasting model is deployed, andapplied to the reservoir area in 2022 for real-time flood forecasting.The results show that the average passing rate of flood volume and flood peak in the four sub-basins of the ThreeGorges Reservoir area during the regular and validation periods is above 80%, and the average value of thecoefficient of certainty is above 0.70. The VIC model shows good applicability in hourly-scale flood forecasting. Itachieves good results in the real-time flood forecasting of four typical floods in the Three Gorges Reservoir area in2022 and 2023, and can accurately grasp the flood volume and incoming water process in the key flow-producingareas of the reservoir area. The VIC hourly scale model is therefore a useful tool in the Three Gorges Reservoir area.Therefore, the VIC hourly scale model shows good performance in real-time flood forecasting in the ThreeGorges Reservoir area and has great potential to be applied in real-time flood forecasting in large-scale basins. Sincethere are many small and medium-sized reservoirs in the Three Gorges Reservoir area, the model structure can befurther improved and enriched at a later stage to further enhance the accuracy of the real-time flood forecastingsystem by considering the influence of human activities.