Variability of SO=4, Total Sulfate, NO−3, and Total Nitrate Scavenging Ratios for the Frontal Boundary Study

Abstract

Precipitation and air concentration data collected during a U.S. Department of Energy-sponsored Frontal Boundary Study (FBS) were used to calculate scavenging ratios. The precipitation data were collected on a 100 km ϫ 100 km surface grid containing 36 sampling sites, while the air concentration data were collected by aircraft. Radar and rawinsonde data were used to position the aircraft into the air mass feeding the precipitation. The coordination of the aircraft data with surface precipitation data allows the calculation of scavenging ratios. During the study, three out of seven events sampled allowed the calculation of scavenging ratios for , total ϭ SO 4 sulfate,, and total nitrate. The 36 precipitation samplers allowed calculation of multiple scavenging ratios Ϫ NO 3 to represent an event. From these scavenging ratios, both a geometric mean and a geometric standard deviation of the scavenging ratio were calculated for each event. The geometric mean (geometric standard deviation) scavenging ratio for total sulfate is 6 ϫ 10 4 (1.

Properties of aerosols and their wet deposition in the arctic spring during ASTAR2004 at Ny-Alesund, Svalbard

“…The scavenging ratios of sulphate ranged between 1.0×10 6 and 17.0×10 6 which are comparable to values as reported for other sites (KasperGiebl, 1999;Davis et al, 1997). Relatively lower k values are obtained for 142 and 144JD, when the POSS consistently reported rain as the precipitation type.…”

“…Although all the trends in aerosol particles mentioned above may be explained by the temporal meteorological conditions, it should be noted that the time period of this campaign included the period of the aerosol transition from spring-type to summer-type, as indicated by Engvall et al (2008). Therefore, it is reasonable to regard the decrease in aerosol loading in this study as being partly a reflection of the aerosol transition processes occurring in the arctic region around this time period of the year.…”

“…According to a recent study by Engvall et al (2008) the transition from "spring-type" to "summer-type" aerosol occurs almost at the same time every year within a 10-day period including Julian Day (JD) 145. They concluded that transport alone can not explain this transition and indicated the importance of nucleation potential for new particle formation mainly driven by solar radiation.…”

An intercomparison of four wet deposition schemes used in dust transport modeling

“…However, Davis et al (1997) reported that scavenging ratios obtained from surface concentration data are in a comparable range with those obtained from aircraft measurements. Scavenging ratio depends on the particle size distribution, precipitation rates and the chemical characteristics of the particle.…”

Influences of atmospheric circulation on the variability of wet sulfate deposition

“…Dorling et al, 1992;Cana-Cascalar, 2002), and spatial-pattern analyses of atmospheric circulation (Davies et al, 1991;Yarnal, 1991Yarnal, , 1993Dorling et al, 1992;Lamb, 2003, 2005). Typical studies employ the ionic concentrations, rather than the deposition flux itself, because precipitation composition is closely linked to the concentrations of precursors in air (Engelman, 1971;Davis et al, 1997;Hicks, 2005).…”