Small-scale experimental simulation of lightning using vertical wires deployed by drones in the atmosphere: on the land and sea lightning peak current asymmetry

Several works have shown a land/ocean asymmetry in the intensity of lightning. Intense lightning flashes are found to occur over the ocean. One of the factors determining this asymmetry could be the relaxation time constant of the media where lightning strikes. This work presents a novel experiment to simulate lightning through ground-isolated long vertical wires polarized by the atmospheric potential. The transient currents when the wires strike ground/seawater are measured. We found a significant reduction of the peak current when the wire strikes dry loamy soil compared to seawater. Nevertheless, the reduction is much less pronounced as long as the soil presents some moisture. A simple numerical model supports the experimental results. The sensitivity of the peak current versus the media properties might be one of the determining factors in the land/ocean asymmetry.