【摘要】 为研究有限电导率对地闪回击辐射场上升沿时间和场强幅值的影响规律,运用Cooray-Rubinstein计算方法对湿地、干地和沙地等不同土壤类型电导率下雷电电磁场传播特征进行了数值模拟,得出随着电导率的减小,回击电磁场波形上升沿时间明显增加,因此电导率对场强峰值到达时差法的闪电定位误差影响较大;通过波前时间和观测距离拟合函数关系可以计算闪电发生的距离或传播路径的电导率,磁感应场强幅值随着电导率的减小、观测距离的增加而衰减增大。最后通过与目前常用的反演雷电流强度的公式对比提出了考虑土壤电导率情况下反演雷电流强度的修正曲线。更多还原

【Abstract】 In order to analyze the effect of finite conductivity on the rise time and field strength amplitude of radiation field of return stroke radiation field of cloud-ground flash,we calculated the propagation characteristic of lightning return stroke electromagnetic field along the different conductivity in imperfectly ground surface such as wetland,dry land and sand by using the Cooray-Rubinstein algorithm.The results show that,due to the decrease of ground surface conductivity,the observed rise time of lightning radiation field increases obviously,which will affect the error in lightning location by using the method of time lag in arriving peak time,so the relationship formula of rise time and observed distance can be used to calculate the distance of lightning detection or the ground surface conductivity of propagation path.The results also show the lighting magnetic induction intensity amplitude attenuation decays with the ground conductivity decreasing and the observation distance increasing.Lastly,the correction curve was presented for inversion of lightning current after taking ground conductivity situation into the consideration based on the formula commonly used in inverting the strength of lightning current.更多还原