Warm Rain Processes Affected by Explosion: Insights From First 3D Large-Eddy Simulation and Implications for Weather Modification

Artilleries and rockets are used in weather modification techniques. However, the impact of the explosion generated by them on cloud microphysics and rain formation remains highly uncertain. It is challenging to isolate the effects of the explosion on cloud development from the natural evolution of the cloud based on observational data, and there is a lack of high-resolution cloud models capable of simulating these effects. This study investigates the impact of the explosion on the microphysics of a warm cumulus cloud, for the first time, by coupling an explosion model and a 3D large-eddy simulation model offline. The results show that the rain forms faster due to the explosion, but the maximum rain intensity decreases. The mechanism responsible for this is that the explosion produces negatively biased pressure bands, which ultimately enhances the convergence and collisional-coalescence process. The enhanced process increases the size and content of raindrops, triggering faster rain formation. However, faster rain formation reduces the transport of cloud droplets to higher levels and decreases the maximum rain intensity. The results provide new insights into how explosion affects cloud and rain processes, contributing to a better understanding of weather modification techniques.