上海临海沿岸水域大风分布特征及分区预警效果评估

Characteristics of Gales in Shanghai Coastal Zones and Early Zonal Warning Assessment of Gales

摘要:

上海沿岸水域船舶和港口众多，灾害性天气频繁。利用2016—2022年上海沿岸水域代表站点的逐时自动站和预警相关数据，选取大风为研究对象，分析了大风时空分布特征，评估了大风分区预警预报质量及经济效益。结果表明：①距海岸线越远，大风日数越多、风速越大、持续时间越长；过程风力越大，各海区的风力差异越明显，台风引起的风力差异跨越5个风级；②相比统一预警，各海区大风分区预警漏报率明显降低，最高降幅5%，长江口区西部海区空报率降低8%以上，TS评分提高了10%以上；③大风分区预警时间提前量减少3 h以上，持续时间最长缩短16 h以上，可减少近1800万人民币的损失，大大提高了生产经营效益。

Abstract:

There are many ships and ports in Shanghai coastal zones, where disastrous weather occurs frequently. Meteorological disasters often threaten the safety of people’s lives and properties along the coast and in the ports. In the past, the meteorological warnings for Shanghai coastal zones are mainly based on those issued for Yangshan Port by Shanghai Marine Meteorological Centre (SMMC), which are called “unified warnings”. However, there are obvious differences in the time and intensity of meteorological disasters in each region, and the unified warnings cannot meet the needs of the production and operation of the shipping and ports. In 2020, Shanghai coastal zones were divided into five sub-zones, where the meteorological forecast and warnings were carried out separately from July 2020. Based on hourly observational data of the representative stations in Shanghai coastal zones and warning signal data from 2016 to 2022, the gale events are selected to analyse the statistical characteristics of temporal and spatial distribution and evaluate the forecast quality and the economic benefits of the zonal warnings. The results show that: (1) The farther away from the coastline, the more gale days, the higher the wind speed and the longer the duration; the higher the wind speed during the process, the more obvious the difference of wind scale. In particular, the wind scale caused by typhoons can range up to 5 levels. (2) Compared with the “unified warning”, the missing alarm rate (MAR) of gale warnings in each sea area has been reduced significantly, by up to 5%, the false alarm rate (FAR) for the western part of Yangtze River estuary is reduced by more than 8% and the TS score is significantly improved by more than 10%. (3) The advance time of gale warnings has been reduced by more than 3 hours, the maintaining duration has been shortened by more than 16 hours at most, which can reduce the loss of nearly 18 million RMB and improve the production efficiency of the coastal zones of Shanghai greatly. The results of this paper show that refined marine meteorological forecasts and early warnings provide a safety guarantee for marine transportation and port production operations, resulting in significant social and economic benefits and the enhancement of the comprehensive guarantee level of marine meteorological services in Shanghai. In the next step, we will continue to research and develop more refined objective forecast methods adapted to this business, then build a regional shared operational system platform and extend it to the Yangtze River Delta region, so as to promote the high-quality development of shipping meteorological integration in the Yangtze River Delta region.