气象水文模型耦合在黄河三花间洪水预报中的应用

水文预报的有效预见期越长,预报精度越高,其对防洪减灾的价值就越大,而气象水文模型的耦合是延长水文预报有效预见期的一个重要研究方向。选取黄河流域三门峡水库以下、花园口水文站以上集水面积为研究区域,基于空间分辨率为90 m×90 m的数字高程模型数据构建数字流域水系,利用中尺度非静力模式MM5进行降雨预报和气温预报,并将之作为分布式时变增益水文模型降雨和蒸发计算的输入进行关键站点的水文预报,实现了分布式时变增益水文模型与大气中尺度非静力模式MM5的单向耦合及定量降水预报与洪水预报的结合,为花园口防汛工作提供了一定的参考价值。2012年与2010年的流量滚动预报结果相比,2012年预报结果的效率系数较大,径流深相对误差较小,说明2012年预报效果较好。对预报结果分析表明,实测的水情资料完整性直接影响预报结果,而滚动预报时间段的增加,水文预报的初始场对径流预报的影响逐渐减弱,水文预报的精确度逐渐提高,预报的效果变好。

Application of the Meteorological and Hydrological Models Coupling in the Flood Forecasting in Sanmenxia-Huayuankou Reach of the Yellow River

Hydrological forecast would be more valuable in basin flood control system with the longer effective forecast period and the higher forecast accuracy, and then it is an important research direction of the meteorological and hydrological models coupling to further extend the effective forecast period of hydrological forecasting. The region from the Sanmenxia reservoir to Huayuankou station in the Yellow River was selected as the target region. Based on the 90 m × 90 m resolution grid-based digital elevation model data, the digital drainage network was generated. Precipitation and temperature forecasted by MM5 are used to be the input of distributed time-variant gain hydrological model. Precipitation and evaporation calculating to forecast the flow of the key hydrological sits. It achieves the unilateral coupling of atmos- pheric mesoscale non-hydrostatic hydrological model MM5 and distributed time-variant gain hydrological model and the target of combination of quantitative precipitation forecasting and flood forecasting, which provides a certain reference value for the Huayuankou flood prevention work. Compared with the flow rolling forecast results of 2012 and 2010, efficiency coefficient of 2012 is major, runoff depth relative error is smaller, and the forecast effect is better. Results show that hydrological data integrity can affect directly the quality of flood forecasting, the impact of the initial field on the results of the rolling flood forecasting becomes smaller and the satisfying accuracy is improved gradually with the increase of the rolling flood forecasting hours.