1415号台风“海鸥”广西极端暴雨预报偏差分析及地形订正

Bias analysis and topographic correction of Guangxi extreme rainstorm forecast of Typhoon Kalmaegi

利用地面自动站降水资料、ERA5再分析资料、广西壮族自治区气象台降水落区和ECMWF模式预报数据对1415号台风"海鸥"在广西暴雨预报偏差进行了分析,并开展了地形降水订正研究。结果表明,对"海鸥"强降水落区预报准确,但大暴雨以上量级降水明显偏弱,大暴雨和特大暴雨漏报严重。降水经地形订正后,大暴雨以上降水TS(BS)评分由0.19(0.27)大幅度提升到0.35(0.53)且暴雨及以下量级降水评分无明显改变,但地形降水订正方法对特大暴雨仍无明显订正技巧;偏南风、东北风及偏东风在广西复杂地形下均会产生地形降水,实际业务预报中应加以考虑,有助于提升对强降水开始时间的预报效果。

Based on the precipitation data of ground automatic station, reanalysis data of ERA5,precipitation falling area of Guangxi Meteorological Observatory and ECMWF model prediction data, the rainstorm prediction deviation of Typhoon Kalmaegi in Guangxi was analyzed, and the topographic precipitation correction was carried out. The results show that the prediction of heavy precipitation area is accurate, but the precipitation above downpour is obviously underestimated, downpour and torrential rain are seriously underreported. After the topographic correction of precipitation, the TS(BS) score of precipitation above downpour is greatly increased from 0.19(0.27) to 0.35(0.53), and the precipitation score of rainstorm and below has no obvious change, but the topographic precipitation correction method still has no obvious correction skills for torrential rain. The southerly wind, northeast wind and easterly wind will produce topographic precipitation under the complex terrain of Guangxi. It should be considered in the actual operational prediction, which will help to improve the prediction effect of the start time of heavy precipitation.