营口地区一次暴雨过程中的预报失误分析

Analysis of an Unsuccessful Forecast for a Heavy Rainfall Event in Yingkou

[目的]分析营口地区一次暴雨过程中预报失误的原因。[方法]利用自动站降水资料和MICAPS资料,对2010年7月19~22日营口地区出现的暴雨天气过程进行了分析;并利用雷达、云图资料和数值预报产品,分析了7月21日的预报失误原因。[结果]造成7月21日暴雨预报失误的主要原因是：①此次降水过程持续时间长,降水不连续且分布不均,21日的强降水与前2个时段的强降水不同,是局部短时强降水,此类降水预报难度大;②数值预报不稳定,误差大;③20日夜间已经出现强降水,与21日傍晚出现的强降水间隔时间不长,容易使预报员疏忽,并且在此期间雷达和云图的暂时静寂也形成了一定的干扰。对于暴雨预报的着眼点应该立足于数值预报的形势预报,而不应将注意力放在要素预报上;应坚持以形势分析判断为主,要素判断为辅的原则;对于强降水的预报,数值预报往往误差较大,不能盲信,预报员应根据经验对其进行正确的订正预报。[结论]该研究为暴雨的预报分析提供参考依据。

[Objective]The reason for the unsuccessful forecast of a heavy rainfall event in Yingkou was analyzed.[Method]Based on the precipitation data observed by automatic weather stations and MICAPS data,a heavy rainfall Event was studied in Yingkou from 19 July to 21 July in 2010.Then the analysis of an unsuccessful forecasting for the heavy rainfall on 21 July was illustrated by CINRAD-SA data,satellite data and numerical forecast products.[Result]The main reason for the unsuccessful forecast was that the duration of the rainfall was long and inconsecutive.The distribution was uneven.Strong precipitation on 21st was different from the one in previous two durations.It was regional short term strong precipitation.And the forecast difficulty was large;the numerical forecast was unstable and erroneous;strong precipitation occurred in the night on 20th,which was shortly before the strong precipitation in the evening of 21st.This would easily confuse the reporter.Besides,the short term stillness of radar and cloud during this time would form certain disturbance.The focus of rainstorm forecast should based on the numerical forecast instead of element forecast;insisting on situation analysis and taking element judgment as auxiliary;as for strong precipitation forecast,there was large error in numerical forecast and can not be relied.Reporter should report the correct one based on experience.[Conclusion]The study provided reference for the forecast of rainstorm.