数值模式降水预报OTS订正法的实现技术  

Implement Technology of Optimal Threat Score Correction Method for Numerical Model Precipitation Forecast

作　　者：刘会军 吴启树 危国飞 韩美 潘宁 LIU Huijun;WU Qishu;WEI Guofei;HAN Mei;PAN Ning(Key Laboratory of Straits Severe Weather,China Meteorological Administration,Fuzhou 350028;Fujian Key Laboratory of Severe Weather,Fuzhou 350028;Fujian Provincial Meteorological Observatory,Fuzhou 350028)

机构地区：[1]中国气象局海峡灾害天气重点开放实验室,福州350028 [2]福建省灾害天气重点实验室,福州350028 [3]福建省气象台,福州350028

出　　处：《大气科学》2024年第5期1891-1900,共10页Chinese Journal of Atmospheric Sciences

基　　金：国家重点研发计划项目2018YFC1506905;福建省自然科学基金项目2021J01457、2022J011078;福建省灾害天气重点实验室开放课题2021KFKT05。

摘　　要：本文以ECMWF模式的逐12 h累计降水预报的订正试验为例,以福建、江西、浙江和上海为研究区域,详细介绍了福建省气象台在实现最优TS评分(Optimal Threat Score,OTS)订正法时引用或首创的三项技术,并与同类技术进行对比。结果表明:(1)用3年期准对称滑动窗口取样法采集训练样本计算OTS订正阈值,其效果优于取之前3年的当季样本的取样方法。(2)OTS订正阈值F1(即消空阈值)的大小与最高2 m温度密切相关,随着温度升高,消空阈值先变大后减小。相比不分组的方案,基于最高2 m温度预报分组计算消空阈值的方案能同时降低小雨的空报率和漏报率,使ETS评分提高5.0%~8.2%。(3)先用反距离加权插值法对模式降水预报进行插值,再应用OTS订正法对降水预报进行订正,其效果优于先用最邻近点插值法对模式降水预报进行插值,再应用OTS订正法对降水预报进行订正。This study focuses on enhancing the accuracy of 12-h cumulative precipitation forecasts from the model derived from the European Centre for Medium-Range Weather Forecasts using Fujian,Jiangxi,Zhejiang,and Shanghai as the research areas.It introduces three technologies either cited or initiated by Fujian to implement the OTS(Optimal Threat Score)correction method and compares them with similar technologies.Results are summarized in the following points:(1)A 3-year quasi-symmetric sliding window sampling method was used to collect training samples for calculating the OTS correction threshold.This approach proved to be more effective than collecting samples from the same season over the previous 3 years.(2)The magnitude of the OTS correction threshold F1(i.e.,elimination threshold)is closely related to the 2-m temperature.As the temperature rises,the elimination threshold first increases and then decreases.Grouping modeling based on the maximum 2-m temperature forecast yielded an elimination threshold under different temperature conditions.This method simultaneously reduced the false alarm ratio and missing ratio for light rain,improving the equitable threat score for light rain by 5.0%–8.2%.(3)The study compared two schemes for interpolating model precipitation forecasts before applying the OTS correction method.The first scheme employed the inverse distance weighted interpolation method,which outperformed the second scheme using the nearest neighbor interpolation method.

关 键 词：模式降水 订正 OTS(Optimal Threat Score) 实现 

分 类 号：P456[天文地球—大气科学及气象学]