Assessing the effect of electrocollection by ice and liquid hydrometeors on the scavenging of submicron-sized aerosol particles

As hydrometeors in the upper troposphere are usually solid, especially in winter, ice crystals, snow, and graupel serve as important aerosol scavengers in the atmosphere. Electrostatic forces are highly relevant to the removal of submicron aerosol particles (APs), as they provide an additional mechanism for capturing particles that might otherwise be difficult to remove from the atmosphere. However, this type of scavenging is less well understood than scavenging by liquid hydrometeors, both theoretically and experimentally. Motivated by gaps in knowledge regarding the scavenging of APs by ice crystals, we investigated the impact of electrostatic collection of APs by solid hydrometeors on the scavenging of APs from the air. Collection kernels were calculated for discrete values of the diameters of cloud ice, snow, and graupel. These kernels were then implemented in a cloud-resolving numerical model, using a three-moment microphysical scheme with six separate hydrometeor categories, along with a two-moment aerosol scheme introduced by Vučković et al. (2022). We also considered electroscavenging processes for liquid hydrometeors, where, in addition to the point Coulomb force interaction, image charge induction was included, following previous work (Vučković et al., 2025a). This effect was not considered for solid hydrometeors. All other known collection mechanisms were also included. The aerosol particles were treated as ice-nucleating (with AgI properties) and non-nucleating in separate experiments. Our results suggest that the reduction in the total mass of aerosol particles in the air caused by electrostatic scavenging by liquid hydrometeors was greater than that caused by electrostatic scavenging by cloud ice by a factor of six after one hour of model integration. Electrostatic scavenging by solid hydrometeors increased the relative aerosol precipitation mass by less than 0.1%, while the inclusion of liquid hydrometeor electrostatic scavenging increased the aerosol precipitation mass by 24% (Vučković et al.,2025b).

Acknowledgements: 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:

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

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