高级搜索

台风“贝碧嘉”灾害性天气的多模式对比评估及维持机制分析

Multi-model comparative assessment and maintenance mechanism analysis of severe weather caused by Typhoon Bebinca

  • 摘要: 2024年9月16日,台风“贝碧嘉”以强台风级登陆上海,异常地维持强热带风暴及以上强度达18 h,引发上海市、江苏省多地大暴雨和大风灾害性天气,对电网防灾减灾与电力新能源生产调度带来严重威胁。采用地面观测、ECMWF全球模式、GFS全球模式和江苏电网高分辨率(JWRF)区域模式预报资料,从降水和风速预报技巧TS评分、空间分布和风速误差等多个维度,对比评估各模式对台风引起的风雨灾害的预报效果,并基于JWRF区域模式预报结果探讨台风登陆后的异常维持机制。结果表明:(1) 各模式对强降水的量级、大风的空间分布的预报基本准确,但存在强降水落区位置偏南、大风风速高估等共性问题。(2) 与全球模式相比,高分辨率区域模式在强降水(尤其是大暴雨)落区位置、强降水极值和大风风速预报方面表现更为出色。(3) GFS全球模式和JWRF区域模式提前24 h的降水预报将大暴雨落区北调,准确性较提前36 h的预报结果有所提升。(4) 登陆台风的异常维持主要受长三角区域平坦地形及湿润地表等陆地特征引起的“棕海效应”和东海水汽输送影响,而垂直风切变则对台风的维持起到了一定的削减作用。研究结果有助于提升长三角区域针对台风等电力气象灾害性天气的多场景预报能力。

     

    Abstract: On September 16th, 2024, Typhoon Bebinca (2413) made landfall in Shanghai at severe typhoon intensity, and maintained intensity as a severe tropical storm for 18 hours, triggering disastrous weather events like heavy rainfall and strong winds across Shanghai and Jiangsu areas. Based on land surface observations, the performances of two global models, i.e., the European Center for Medium-Range Weather Forecasts (ECMWF) model, the Global Forecast System (GFS) model, and a regional model, i.e., the Jiangsu grid operational Weather Research and Forecasting (JWRF) model, were compared in forecasting the typhoon-caused rainfall and wind by the metrics of threat score, the prediction accuracy of precipitation location, and extreme values; meanwhile, the maintaining mechanism of Bebinca was investigated based on the JWRF regional model’s forecasts. The main findings are as follows: 1) All three models accurately predicted the spatial distribution and intensity of heavy rainfall and the spatial distribution of wind speeds, but showed southward biases in their forecasts of the location of heavy rainfall and overestimation of the wind speed magnitude. 2) The JWRF model outperformed the other two global models in forecasting the location of heavy rainfall, especially torrential rainfall, maximum precipitation, and the wind speed magnitude. 3) In the 24-h lead time forecasts, the GFS and JWRF models adjusted the location of torrential rainfall northwards, reaching higher accuracy than their 36-h lead time forecasts. 4) Further diagnostic analysis identified the brown ocean effect and water vapor transport from the East China Sea as the main causes for the typhoon’s maintaining presence. The research results contribute to improving and enhancing multi-scenario forecasting capabilities for typhoons and other severe weather events.

     

/

返回文章
返回