基于西南区域模式的四川强降水开始时间订正试验

Correction Experiment of Heavy Precipitation Onset Time in Sichuan Based on Southwest Regional Model

基于2018~2019年5~9月和2020年8月四川地面观测降水数据(含区域自动站),结合同时段西南区域模式08时起报的各要素场资料,开展了模式预报短时强降水开始时间的订正方法—最小偏差和订正法的本地化研究,并运用该方法对2020年8月强降水事件的开始时间进行了订正检验。结果表明:最小偏差和的订正法可以确定强降水开始时间相关物理因子订正阈值及最优阈值百分比;从2020年8月强降水的订正效果来看,该方法对短时强降水开始时间有一定的订正能力,强降水开始时间偏差减少2~8 h。

Based on the ground observation precipitation data from May to September in 2018~2019 and August in 2020 in Sichuan province,including the automatic station data,combined with the forecast field data of each element of the model starting from 8:00 in southwest region of the same period,the localization of the minimum deviation and correction method for predicting the start time of shorttime heavy precipitation was carried out,and the method was used to correct the start time of heavy precipitation events in August 2020.The results show that the correction method of the minimum deviation sum could determine the correction threshold and the optimal threshold percentage of the physical factors related to the start time of heavy precipitation.From the correction effect of heavy pricipitation in August 2020,the method had a certain ability to correct the start time of short-time heavy precipitation,and the deviation of the start time of heavy precipitation was reduced by 2~8 hours.