Explicit numerical simulations of convective cloud seeding for hail mitigation using two operational methodologies

Damages associated with severe convective storms are increasing worldwide, motivating the continued use of weather modification techniques such as cloud seeding for hail mitigation. Despite decades of operational application in many countries, including Serbia, the physical effectiveness of convective cloud seeding remains insufficiently quantified due to the complexity and a wide range of physical processes in clouds.

Numerical models provide a valuable tool for examining cloud processes in depth and help us understand aerosol-cloud interactions. We use a cloud-resolving numerical model with three-moment microphysics to simulate a supercell storm. This model is modified by introducing aerosols with all known scavenging mechanisms (by 5 hydrometeor categories) included (Vučković et al. 2025b). This is achieved by implementing a two-moment aerosol scheme, where aerosols are described by the gamma distribution (Vučković et al. 2022, 2023, 2025a). Furthermore, DeMott silver-iodide freezing parameterisation is implemented. This method provides a way to track number concentration and mixing ratios of aerosols explicitly in the air and in all 6 hydrometeor categories for every grid box. Simulations are performed at 500 m horizontal and 250 m vertical resolution over a 3-hour integration period.

On the other hand, two complex operational convective cloud seeding methodologies have been implemented into the model. First developed by the Republic Hydrometeorological Service of Serbia (RHSS 2023) and the other proposed by Abshaev et al. (2023). Both methodologies consider the radar reflectivity and supercooled water parameters as well as the storm's movement and life-cycle stage to determine seeding timing and location.

This framework enables a direct numerical comparison of the microphysical and dynamical impacts of operational hail suppression strategies under controlled conditions.

 

Acknowledgement: This research was supported by the Science Fund of the Republic of Serbia, No. 7389, Project Extreme weather events in Serbia - analysis, modelling and impacts” – EXTREMES

 

References:

Abshaev, M. T., Abshaev, A. M., & Malkarova, A. M. (2022, May). Results of 65-Years Project of Hail Suppression in Russian Federation. In International Scientific Conference" Problems of Atmospheric Physics, Climatology and Environmental Monitoring" (pp. 1-28). Cham: Springer International Publishing.

Republic Hydrometeorological Service of Serbia, Hail Suppression Center (2023). Instruction 5/2023: Methods for radar identification and seeding of single-cell, multicell, and supercell hail-producing storms using the OGIS automated system. Belgrade, Serbia. (in Serbian, Cyrillic)

Vučković, V., D. Vujović, and A. Jovanović, 2022: Aerosol parameterisation in a three-moment microphysical scheme: Numerical simulation of submicron-sized aerosol scavenging. Atmos Res, 273, 106148, https://doi.org/10.1016/j.atmosres.2022.106148.

Vučković, V., D. Vujović, and D. Savić, 2023: Influence of electrostatic collection on scavenging of submicron-sized aerosols by cloud droplets and raindrops. Aerosol Science and Technology, 57, https://doi.org/10.1080/02786826.2023.2251551.

Vučković, V., Vujović, D., Savić, D., & Filipović, L. (2025a). Impact of electro-collection and ice nucleation on aerosol scavenging. Aerosol Science and Technology, 59(8), 1006–1026. https://doi.org/10.1080/02786826.2024.2441289

Vučković, V., Vujović, D., Savić, D., & Filipović, L. (2025b). The Effect of Electrocollection by Ice Hydrometeors on the Scavenging of Submicron-Sized Aerosol Particles. Atmosphere, 16(11), 1265. https://doi.org/10.3390/atmos16111265