浙江省六大水库流域面雨量模式预报效果检验

Evaluation of the prediction by area rainfall forecast model OCF for six big reservoir basins in Zhejiang province

利用OCF(Objective Consensus Forecasting)模式对2014年浙江省梅雨、8月连阴雨、午后雷阵雨和台风降水4种不同降水过程中六大水库流域面雨量进行预报,并采用综合评分法和TS评分法对预报效果进行检验。结果表明:OCF模式对2014年浙江地区锋面降水(梅雨、8月连阴雨)预报的综合模糊评分和TS评分均较好,空报率远高于漏报率,从192 h至24 h预报时效的预报效果缓慢调整,各水库之间预报效果差异较小;OCF模式对午后雷阵雨预报的综合模糊评分和TS评分较好,空报率较高的水库流域漏报率也偏高,从192 h至24 h预报时效预报效果不稳定,且存在显著的地域差异;OCF模式对台风降水预报的综合模糊评分和TS评分均偏低,空报率高于漏报率,从192 h至24 h预报时效为显著调好趋势,各水库之间预报效果差异较大。

A fuzzy comprehensive evaluation method and TS（ Threat Score） score were used to compare and analyse the forecast skills of OCF（ Objective Consensus Forecasting） model based on areal rainfall over six reservoir basins in Zhejiang province during Meiyu period,persistent rainy weather in August,afternoon thundershowers, typhoon precipitation processes in 2014. The results show that during the frontal precipitation processes（ i. e.,Meiyu rainfall and August continuous rain processes）,OCF model has better forecast skills with higher fuzzy comprehensive and TS scores,and the false alarm ratios are far higher than the miss alarm rates. Prediction skill of OCF model is gradually improved with the lead time from 192h to 24h,and the differences predicted among reservoirs are reduced. For the afternoon thundershower cases,OCF model gets a secondary performance in fuzzy comprehensive and TS scores. When these reservoir basins gets higher false alarm rates, they has higher miss alarm rates. The forecast scores of leading time from 192h to 24h show an unstable change pattern. There are significant regional differences. For typhoons of Fungwong and Matmo,OCF model exhibits a poor performance both in fuzzy comprehensive and TS scores,and the false alarm rates are higher than those of the miss alarm. The forecast skill shows a distinct improving trend from 192h to 24h in the leading time. The differences among reservoirs are obvious.