基于防汛需求的降雨预报精度评估方法

针对现有研究对降雨预报精度评价大多着眼于测站或流域的总量误差,很少考虑降雨预报的空间分布、时程分配误差这一问题,提出一种综合时程、空间、总量等3个维度的降雨预报精度评价方法。在量级上,建立以相对误差为基础的量级评价指标;在空间上,引入容差区间,考虑全流域网格后得出空间分布评价指标;在时程上,采用确定性系数评价时程的匹配度,得到时程分配评价指标。选取甬江流域近年的预报和实测数据为例,采用上述方法对多种数值预报模式的进行了综合评价。结果表明:提出的评价方法能够挖掘出传统评价方法未充分关注的时程分配等要素。因此,该方法能够较好地基于防汛场景需求评价流域降雨预报精度,也可为多种预报模式的融合应用提供依据。

Rainfall forecast accuracy evaluation method for flood control demand

Using the results of numerical rainfall forecast as the input of the hydrological model can effectively prolong the flood forecast period,and strive more time for flood control.The accuracy of rainfall numerical forecast results used in flood forecast largely determines the accuracy of the hydrological model forecast.Therefore,carrying out evaluation research on the accuracy of rainfall forecast results is of great significance to flood forecasting work.Scholars at home and abroad have carried out researches on the accuracy of rainfall forecasting.However,most of the existing researches focus on the total error of rainfall forecasted by river basins and stations and have not considered the spatial distribution and time history distribution errors of rainfall forecasts.