The Effect of Electrocollection by Ice Hydrometeors on the Scavenging of Submicron-Sized Aerosol Particles

Abstract

This paper investigates the collection of aerosol particles (APs), ranging from 0.002 μm to 0.2 μm in diameter, by solid hydrometeors such as cloud ice, snow, and graupel. It specifically examines electrostatic scavenging (ESS) of APs and compares it with our previously studied scavenging by cloud droplets and raindrops. ESS by solid hydrometeors is contrasted with other scavenging mechanisms. The original two-moment aerosol scheme, which includes prognostic equations for the number and mass of APs within the numerical model, is employed in this work. It is concluded that ice crystals are most effective at electrostatic scavenging of APs compared to other solid hydrometeors. The reduction in the total mass of APs in the air caused by ESS from liquid hydrometeors exceeded six times the reduction caused by ESS from cloud ice after one hour of integration. ESS by solid hydrometeors increases the relative aerosol precipitation mass (RAPM) by less than 0.1%, whereas ESS by liquid hydrometeors raises RAPM by over 24%.

Keywords: ice hydrometeors; electroscavenging; cumulonimbus; aerosols charge distribution; scavenging coefficient