摘要
利用长江流域组网雷达、国家气象信息中心格点融合实况资料和自动气象站逐小时降水观测资料,建立了基于变分光流法的长江流域雷达外推降水预报产品,并检验分析了该产品对2020年17次长江洪水天气过程的0~3 h 39分区TS评分和全流域预报偏差。结果表明:(1)变分光流法的0~3 h临近预报效果与雷达分布呈正相关,分布越密集,预报结果越好;(2)变分光流法的0~3 h临近预报能够较好的追踪降水天气系统移动演变,降水的集中区同样也是临近预报TS评分的相对高分区;(3)变分光流法临近预报效果随着预报时效的变化以指数规律递减,0~1 h预报准确率最高;(4)变分光流法0~3 h临近降水预报结果较格点实况降水,10.0 mm以下量级降水,绝对误差率在5%以内;10.0 mm以上级别的,绝对误差率为6%~11%;(5)变分光流法0~3 h临近降水预报结果应用于长江流域定量降水预报,代替目前直接使用的数值模式输出结果,对提高洪水预报精度有较强的实用意义。
By using network radar,national gridded real-time observation datasets and the hourly precipitation observation data at the auto⁃matic weather stations in the Yangtze River Basin,the radar extrapolation precipitation forecast product of the Yangtze River Basin based on the variational optical flow method is established.The results of threat score in 39 sub-basins and deviation analysis in the whole basin for 17 flood weather events in the Yangtze River Basin in 2020 were analyzed.The results show that:1)0-3 h rainfall nowcasting with the varia⁃tional optical flow method has a positive correlation with the radar distribution range.The denser the distribution is,the better the prediction result is.2)0-3 h rainfall nowcasting with the variational optical flow method can better track the movement and evolution of the weather sys⁃tem.The precipitation concentration area is also in a relatively high zone for threat score of rainfall nowcasting.3)Threat score of 0-3 h rain⁃fall nowcasting with the optical flow method is the highest in the first hour,and the prediction skill decreases exponentially with the change of prediction time.4)Comparing 0-3 h rainfall nowcasting and the gridded real-time observation datasets of precipitation,it is found that the absolute error rate of the precipitation forecast of the variational optical flow method is less than 5%when the precipitation is less than 10.0 mm.When the precipitation is over 10.0 mm,the absolute error rate is 6-11%.5)The result of 0-3 h rainfall nowcasting with the variational optical flow method is applied to the quantitative precipitation forecast of the Yangtze River Basin replacing the output results of the current direct numerical model,which has a strong practical significance to improve the accuracy of flood forecast.
作者
田刚
陈良华
魏凡
熊红梅
TIAN Gang;CHEN Lianghua;WEI Fan;XIONG Hongmei(Wuhan Center Meteorological Observatory,Wuhan 430074;Three Gorges Cascade Dispatch&Communication Center,Yichang 443000,China;Hubei Public Meteorological Service Center,Wuhan,430074)
出处
《暴雨灾害》
2021年第3期316-325,共10页
Torrential Rain and Disasters
基金
中国长江电力股份有限公司项目“长江流域降水网格预报技术研究”(2418020001)
“梯调中心气象业务系统升级改造”(2414010001)
国家自然科学基金项目(51709218)
国家重点研发计划(2018YFE0196000)
关键词
变分光流法
长江流域洪水
雷达外推降水预报
预报误差
variational optical flow method
Yangtze River flood
radar extrapolation precipitation forecast
prediction error
