摘要
利用浙江沿海观测站资料,对2015—2018年ECMWF细网格10 m风预报进行检验评估。结果表明:站点预报误差与离岸距离密切相关,离岸较远的站点预报与观测一致性更高,但风速预报偏小,风向预报有逆时针偏差,海岸线附近站点一致性较差,风速略有偏大,风向有顺时针偏差。随着预报时效延长,风速相关系数逐渐下降,风速和风向均方根误差逐渐增加,海岸线附近的站点随时效变化相对平缓,远离海岸线的站点变化幅度更大。进一步对浮标站分析表明,冬季风主导风向NW、N、NE的风速和风向预报存在明显系统性偏差,大风速时风速预报偏小,弱风速时风向预报有顺时针偏差,风速和风向预报离散度均表现为NW风>N风>NE风;夏季风主导的S和SW风,其风速和风向预报误差相对NW和N风更小。三种典型大风天气系统中,冷空气大风过程预报效果最好,12 h时效内预报准确率达97%,96 h时效内达70%以上;热带气旋大风过程预报准确率随时效下降最显著,36 h内准确率达85%以上,36 h后快速降低,96 h后不足50%;低压倒槽大风预报准确率最差,144 h时效内准确率均在60%以下,且随时效变化不大。冷空气和热带气旋过程浮标站最大风速预报与观测基本符合线性分布,冷空气过程最大风速在144 h时效内相关系数均可通过0.05显著性水平检验,热带气旋仅48 h时效内可通过0.05显著性水平检验。通过线性回归方法,对冷空气过程浮标站最大风速预报进行订正,独立样本检验表明,该方法可以有效减小预报误差。
Using the observation data from Zhejiang coastal stations,the ECMWF 10 m wind forecast from 2015 to 2018 was verified and evaluated.The results are as follows.The forecast error is closely related to the offshore distance.The farther the station is from the coastline,the higher the consistency is.For far-shore stations,the predicted wind speeds are lower than the observed values and the wind directions have counterclockwise deviations.However,for near-shore stations,the results are opposite.With forecast lead time extending,the correlation coefficient of wind speed gradually decreases,while the root-mean-square error of wind speed and wind direction gradually increases,and this change is more pronounced for far offshore stations.Further analysis on buoy stations indicates that the forecasts of NW,N and NE winds prevailing in winter have significant systematic deviations.The predicted wind speeds are weaker for strong winds,and wind directions have clockwise deviations for light winds.The forecast dispersions of wind speed and wind direction are NW>N>NE.The prediction errors of S and SW winds prevailing in summer are relatively smaller than that of the winter NW and N wind directions.Regarding the three typical gale systems,the cold air gales obtain the best forecast outcome,with the accuracy reaching 97%in 12 h lead time and over 70%in 96 h lead time.The accuracy of tropical cyclone wind forecast declines most significantly with lead time.The accuracy is 85%in 36 h lead time,but decreases sharply to less than 50%beyond 96 h.For low pressures or reverse trough systems,the forecast accuracy remains less than 60%within 144 h lead time.The maximum wind predictions and observations at buoy stations during cold air and tropical cyclone systems are basically in line with the linear distribution.The correlation coefficient for the cold air system can pass the 0.05 significance test within 144 h,while,for tropical cyclones,it can pass the 0.05 significance test only within 48 h.The linear regression method is used to correct the maximum wind speed forecast at buoy stations for cold air systems,and the independent sample tests prove that this method is effective in reducing prediction errors.
作者
申华羽
方艳莹
涂小萍
吕劲文
陆鋆
蒋璐璐
郑铮
SHEN Huayu;FANG Yanying;TU Xiaoping;LYU Jinwen;LU Yun;JIANG Lulu;ZHENG Zheng(Ningbo Meteorological Service Center of Zhejiang Province,Ningbo 315012;Ningbo Meteorological Observatory of Zhejiang Province,Ningbo 315012)
出处
《气象》
CSCD
北大核心
2020年第11期1485-1494,共10页
Meteorological Monthly
基金
宁波市科技局公益计划项目(2019C50004)
浙江省气象科技计划项目(2018YB03)
宁波市气象科技计划项目(NBQX2015006B)共同资助.
关键词
ECMWF
10
m风
预报检验
浙江沿海
ECMWF
10 m wind
forecast verification
the offshore area of Zhejiang Province