2203号台风“暹芭”近海近地层风工程参数特征分析

Wind Characteristics of Typhoon Chaba in Marine Near-ground Boundary Layer

关键词:  台风“暹芭”  风切变  阵风系数  湍流强度

Key words:  Typhoon Chaba (2203)  wind shear  gust factor  turbulence intensity

摘要:

利用2203号台风“暹芭”影响期间广东省阳江市海上漂浮式激光雷达的观测数据，将台风过境过程划分为外围大风区、眼墙区和眼区，并对各区域的垂直风切变、阵风系数和湍流强度等关键风工程参数进行统计分析，拟为海上工程抗风设计提供参考。研究表明，幂定律较好地拟合了台风影响期间200m高度内的垂直风剖面，整体风切变指数为0.114。风切变指数在眼区最小，在眼墙区较大，局部甚至出现超IEC极端风速模型推荐值的现象。阵风系数在100m以下随高度增加而减小，而在120m高度的台风眼区出现突然增大现象。各高度层的阵风系数在全风速段分布均比较集中，强风阵风系数分布集中在平均值的±10%区间，并随高度增加而呈对数函数递减趋势。湍流强度总体上随高度增加而减小，最大值出现在眼墙区和眼区，整体处在IECC类标准以下。

Abstract:

Using the observation data from an offshore floating LiDAR system in Yangjiang, Guangdong Province, during the impact of Typhoon Chaba (2203), this study divides the typhoon passage into the outer gale region, eyewall region, and eye region, and conducts a statistical analysis on key wind engineering parameters including vertical wind shear, gust factor, and turbulence intensity, aiming to provide a reference for the wind-resistant design of offshore engineering. The results show that the power law effectively fits the vertical wind profile within 200 m during the typhoon impact, with an overall wind shear exponent of 0.114. The wind shear exponent is the smallest within the eye region and larger in the eyewall region, locally even exceeding the recommended values of the IEC extreme wind speed model. The residuals of the logarithmic law fit to the wind speed are smaller than the power law, and the overall fit is closer to the observation. The gust factor decreases with increasing height below 100 m, while it may suddenly increase at a height of 120 m within the typhoon eye region. The gust factors at all height levels are highly concentrated in the whole wind speed range. Specifically, the strong wind gust factor are concentrated in the ± 10% interval of the average value and decrease with increasing height, showing a logarithmic function relationship. The turbulence intensity generally decreases with increasing height, with the maximum values occurring in the typhoon eyewall and eye regions, which remains predominantly below IEC Class C standard.