基于北京市区实测数据的雷暴风风场时空统计特性研究

雷暴风引发的结构破坏、财产损失和人员伤害屡有发生，其风场特性的认识和研究是结构抗雷暴风设计的基础。该文基于北京市区325 m高气象塔实测数据识别的70个雷暴风事件，采用经典雷暴风模型对其平均风及脉动风时空特性等进行了统计分析，研究结果表明：雷暴风频发于夏季，其峰值风速主要出现在北京时间的下午及傍晚时分且较易发生于西北方向；在峰值风速发生时段，平均风速剖面均值呈现轻微的鼻形特征；雷暴风湍流强度和阵风因子剖面与大尺度稳态强风特性存在较大差异，且雷暴风统计结果均大于大尺度稳态强风的对应值；北京市结构抗雷暴风设计中可考虑应用Von Karman谱计算雷暴风荷载。该研究结果可为雷暴风风场统一模型的建立和结构抗雷暴风设计提供参考。

SPATIAL AND TEMPORAL STATISTICAL CHARACTERISTICS OF THE WIND FIELD OF THUNDERSTORM OUTFLOWS BASED ON MEASURED DATA IN BEIJING URBAN AREA

The structural damage, property loss and personal injury caused by thunderstorm outflows often occur, and the understanding and study of their wind field characteristics are the basis of the design of structure resistance to thunderstorm outflows. The 70 thunderstorm outflow events identified based on the measured data of 325m high meteorological towers in Beijing urban area are statistically analyzed by applying the classical signal decomposition model of thunderstorm outflows. The research results show that thunderstorms occur frequently in summer, whose peak gust speeds mainly occur in the afternoon and evening of Beijing time and are more prone to occur in the northwest. When the peak wind speed occurs, the moving average wind speed profile presents a slight nose shape. The turbulence intensity and gust factor profiles are quite different from that of synoptic winds, and the statistical results of thunderstorm outflows are larger than the corresponding values of synoptic winds. The power spectral density of thunderstorm outflows is in good agreement with Von Karman model. The results of this study can provide a basis for the establishment of a unified model of the wind field of thunderstorm outflows and the design of structure resistance to thunderstorm outflows.