Minimum Collection Efficiency Particle Diameter during Precipitation as a Function of Rain Intensity

Abstract

This study found that the minimum collection efficiency particle diameter during precipitation is a function of rain intensity. The raindrop size distribution was parameterized with a log normal size distribution as a function of rain intensity, and the minimum collection efficiency and minimum collection efficiency diameter were obtained analytically.The results show that, during precipitation, both the minimum scavenging coefficient diameter and the minimum scavenging coefficient increase along with rain intensity. A comparison of the minimum collection efficiency diameters for various falling velocities reveals that there is not much of a difference in the diameters.Both the numerical and analytical results of this study agree well, without much loss of accuracy.

Minimum Collection Efficiency Diameter during Snow Scavenging Process

“…There have been many studies that determined aerosol filtration characteristics and most penetrating (i.e., surviving) particle size (Lee 1981;Jung and Lee 2007;Jung et al 2011Jung et al , 2013. Similar approach was used in this study.…”

“…The below-cloud scavenging is quantified in terms of the scavenging coefficient K(s À1 ): the rate of loss of aerosols from the atmosphere due to their capture by larger hydrometeors per unit time. The K has been determined via laboratory experiments (Wang et al 1978;Murakami et al 1985aMurakami et al , 1985bMurakami et al , 1985cSauter and Wang 1989;Mitra et al 1990;Bell and Saunders 1995), field measurements (Sparmacher et al 1993;Laakso et al 2003;Andronache et al 2006;Kyrö et al 2009;Paramonov et al 2011), and theoretical studies (Martin et al 1980;Wang 1989, 1991;Dick 1990;Wang et al 2010Wang et al , 2011Jung et al 2013;Zhang et al 2013) with various meteorological conditions (e.g., rain and snow). The corresponding parameterizations representing the below-cloud scavenging processes in numerical models have also been developed (Gong et al 1997;Henzing et al 2006;Tost et al 2006;Feng 2007Feng , 2009Croft et al 2009).…”