雷电电磁波沿地表传播的时延误差修订及其对电离层高度的反演OA

The peak time delay of ground waves,caused by propagation effects,significantly impacts the inversion results of the equivalent reflection height of the ionospheric D-layer.Previous studies primarily focused on the influence of ground factors on the peak time delay of the ground waves.The author intro-duces a novel approach that revises the peak time delay of ground waves using the equivalent propagation velocity to invert the equivalent reflection height of the ionospheric D-layer.The new method incorpo-rates the influence of the sky waves on the peak time delay of the ground waves.The impact of the sky waves on the peak time delay of the ground waves is analyzed using the Finite-Difference Time-Domain(FDTD)model.Simulation results reveal that,under typical daytime conditions,the sky waves begin to affect the ground wave at a distance of 700 km,while under typical nighttime conditions,the sky waves begin to affect the ground wave at a distance of 800 km.The revised delay results obtained by the new method are compared with the delay results simulated by the FDTD model to verify the effectiveness of the method.Finally,based on the lightning data obtained from a long-range lightning location network,the method proposed in this article,which considers both ground factors and the sky waves on the peak time delay of the ground waves,is compared with the method that only considers the influence of ground fac-tors.The results show that the inversion of the equivalent reflection height of the ionospheric D-layer obtained by the new method is less affected by distance changes and is more reasonable.