基于阵风系数模型的百米级阵风客观预报算法研究

An algorithm for objective forecasting of gust winds at 100 m horizontal resolution based on a gust coefficient model

  • 摘要: 京津冀地区经济和文化的快速发展对冬季地面瞬时强风预报要求越来越高。正确估计和预测冬季地面瞬时强风,尤其是复杂地形条件下的阵风高分辨率格点精准预报,对于提升重大活动服务保障、首都及周边地区城市安全运行及防灾减灾能力等方面都具有重要意义。本研究基于京津冀长时间序列的实况观测资料,建立了阵风系数与稳定风速、风向、地形高度各要素之间的关系模型,并结合客观统计分析方法、阵风观测数据融合技术、格点偏差订正技术,发展了一种既保留模式物理参数特征和阵风局地气候特征,又发挥格点偏差订正技术的阵风客观预报方法。冬季奥林匹克赛事期间批量检验和个例分析结果表明,基于阵风系数格点模型和模式后处理订正技术得到的百米级分辨率、分钟级更新的阵风客观预报产品,24 h预报时效内张家口赛区和延庆赛区考核站平均绝对误差分别在2.3 m/s和3.0 m/s以下,延庆赛区8级以上大风,阵风风速预报评分超过0.5,解决了复杂山区数值模式阵风预报误差大、几乎无法业务应用的瓶颈问题,满足冬季奥林匹克运动会现场服务要求。

     

    Abstract: The rapid development of economy and culture in Beijing-Tianjin-Hebei region has a higher requirement for instantaneous strong wind forecasts. Correctly estimating and predicting instantaneous strong winds on the ground level in winter, especially accurate high-resolution grid-point forecasting of gusts under complex terrain condition, is of great significance for improving the service for major Winter Olympics events, the safe operation in the capital and surrounding cities, and disaster prevention and mitigation capabilities. This study establishes a relationship between the gust coefficient and wind speed, wind direction and terrain height based on long-term series of observation data in Beijing-Tianjin-Hebei. Combined with objective statistical analysis method, gust observation data fusion technology and grid point deviation correction technology, an objective gust forecast method is developed, which not only retains the model physical parameters and local climate characteristics, but also utilizes the grid point deviation correction technology. The results of batch verification and case analysis during the Winter Olympics show that the average absolute errors in the Zhangjiakou competition area and the Yanqing competition area are below 2.3 m/s and 3.0 m/s, respectively. The forecast score of gust wind speed above level 8 in the Yanqing competition area is above 0.5. It solves the bottleneck problem of large gust prediction errors and meets the on-site service requirements of major Winter Olympic activities.

     

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