香港地区雷电风速联合分布

Joint Probability Distribution of Lightning & Wind Speed in Hong Kong

雷电数据的统计分布是指导输电线路防雷设计的重要基础。输电线路设计规程中杆塔雷电过电压下风偏设计为经验参数,缺乏对雷电风速联合分布的深入研究。利用香港地区气象数据,研究雷电风速联合分布。分析表明雷电在时域上呈高度不均匀分布,日地闪数量服从Burr分布,而雷电与风速服从Gumbel-Copula联合分布。经验分布和理论分布中,日地闪次数超1000次且风速接近和超设计风速雷暴日的地闪数占比均在20%左右。结合气象学背景的分析表明,飑线等强对流天气下并发的雷暴大风是造成强雷暴时超设计风速概率畸高的根本原因。

Probability distribution of lightning data plays a key role in lightning protection of transmission lines. The design of wind deviation under lightning overvoltage of transmission tower is an empirical parameter in transmission line design code. Meteorological data of Hong Kong are investigated to analyze joint probability distribution of lightning and wind. It is uncovered that daily cloud to ground（CG） flashes follows Burr distribution, which is highly skewed toward a few days with notable lightning. The lightning and wind follows a Gumbel-Copula joint distribution. According to empirical and theoretical distribution, there are about 20% of CG flashes occur in the days with wind around or over 15 m/s and CG flashes over 1000. In-depth investigation suggests that the severe convection with squall line contribute much to the likelihood of the days with high wind and lightning storms.