2004年汛期(5～9月)主客观降水预报检验

VERIFICATION OF SUBJECTIVE AND OBJECTIVE PRECIPITATION FORECAST IN FLOOD SEASON OF 2004

随着气象事业的发展,天气预报的质量越来越依赖于数值预报产品的性能。预报产品检验是评价预报质量和提高预报水平的有效手段。针对2004年汛期(5～9月)中央气象台预报员及T213、HLAFS25、MM5、GRAPES、日本及德国等国内外数值预报模式短期时效的降水预报做了详细的统计学检验。检验结果表明,对于汛期平均而言,各模式与预报员的小雨预报较好,随降水量级的增加TS评分迅速下降,国内外数值预报模式之间降水预报水平差别不大,预报员与模式相比水平略高;但对于过程预报而言,过程不同,各模式和预报员的表现不同,预报员和MM5对河南暴雨预报较好;GRAPES和日本模式对台风暴雨预报略好;T213对于四川东部暴雨的大量级降水预报较好;无论是预报员,还是数值预报模式,北京暴雨的预报是一个典型的失败个例。同时,我们也发现检验系统存在一些问题,有待今后逐步改进。

With the development of meteorological cause, the quality of weather forecast more and more depends on the capability of NWP products. The verification of prediction becomes a kind of efficient method of assessing forecast quality and improving the forecast. In this paper, short-term precipitation forecast by the Centre Meteorological Office＇s forecasters and domestic and overseas NWP models in the flood season of 2004 are verified and assessed in detail with statistical methods. The mean accumulated verification results of rainfall prediction in the flood season show that TS score of light rain for both models and forecasters is higher than that in other classes. TS scores decline sharply as rainfall increases. The difference of forecast accuracy between domestic and overseas NWP models is small. The forecast by forecasters is slightly better than that of NWP models. But for the scores of important weather processes, it appears that NWP models and forecaster are well different from each other because of the various processes. TS scores of forecaster and MM5 model are better than that of others for the severe rain in Henan province. GRAPES and Japanese models are slightly higher in skill than that of others for the severe rain caused by Typhoon 0414 （unnamed）. The prediction of T213 model is better than that of others for the east of Sichuan torrential rain. However, for Beijing Storm rain, it is a typical failure case that neither NWP models nor the forecaster predict correctly. Meanwhile, there are some problems in our verification system, which must be improved step by step in the future.