Research on the Characteristics of Lightning Electromagnetic Fields in Mixed Land-sea Propagation Paths

In this article, we use the Finite-Difference Time-Domain (FDTD) method to construct a computational model for simulating lightning propagation within a mixed land-sea propagation pathway and rigorously validate the model’s effectiveness. Subsequently, we employ the established model to analyze the electromagnetic field characteristics of lightning at 10m above ground level and 3m below ground level within the hybrid propagation pathway. The outcomes of this study are as follows: 1) The vertical electric field and azimuthal magnetic field at 10m above ground level exhibit minimal sensitivity to the mixed land-sea propagation pathway, whereas the horizontal electric field experiences more pronounced variations due to the mixed land-sea propagation conditions. 2) At 3m below ground level, both the vertical electric field and horizontal electric field are significantly influenced by the mixed land-sea propagation pathway, with the vertical electric field exhibiting the most prominent sensitivity, and the azimuthal magnetic field remains unaffected by the mixed land-sea propagation conditions. 3) The influence of the mixed land-sea propagation pathway gradually diminishes with increasing distance from the interface. For distances greater than or equal to 30 m from the interface, the impact of mixed land-sea propagation pathway on the lightning electromagnetic field below the ground at a depth of 3 m can be disregarded.