集合数值预报方法在山洪预报中的初步应用

选取湖南4个典型山洪个例,分析了嵌套模式不同分辨率的预报效果,并采用多物理过程组合的集合预报方法,研究区域集合数值预报技术在山洪预报中的应用。研究指出,单一模式条件下,使用模式嵌套技术提高分辨率,并不能有效地改进对引发山洪灾害的突发强降水过程的预报能力,且这种单一的确定性预报,对暴雨等灾害性天气的预报存在不确定性。集合预报是解决单一预报不确定性提出的新方法,与单一模式提供的确定性预报结果相比,集合预报可为山洪预报提供多种定量预报产品。利用集合平均预报、极值预报,可以引导对山洪采取分类应对措施;集合预报在给出降水分布的同时,还给出伴随预报结果的可信度;概率定量降水预报(PQPF)与水文预报模型结合,可以用于概率水文预报。

The Preliminary Application of Ensemble Prediction in Flash Flood Forecasting

Four flood cases were selected to compare the effect between different model resolutions,an experiment has been implemented to study the flood prevention using ensemble forecast approach,which constructed by various physical processes of mesoscale model.The results indicate that it is not a beneficial selection under the actual operational conditions,to improve the forecast capability of heavy rain which caused mostly flash flood events only by heightening the model resolution,moreover,there are uncertainties in the results of single determinate forecasting.Thus the ensemble approach was introduced in the fields of flood prevention,compared with the single forecasting of determinate model,a series of quantitative results were offered by ensemble prediction.The different precipitation grand of ensemble average and ensemble extremum can lead to classify the measures.Additionally,the ensemble prediction can not only offer the distribution of precipitation but also offer the quantitative reliability with the result,combine the Probabilistic Quantitative Precipitation Forecasts(PQPF) with hydrological model,a probabilistic hydrological forecasting system can be built.