These might be helpful:

Dean A. Hegg,Peter V. Hobbs,Lawrence F. Radke, 1984: Measurements of the scavenging of sulfate and nitrate in clouds. Atmos. Env., 18(9), 1939–1946.

D.M. Chate, P.S.P. Rao, M.S. Naik, G.A. Momin,P.D. Safai,K. Ali, 2003: Scavenging of aerosols and their chemical species by rain. Atmos. Env., 37(18), 2477–2484.

My PhD thesis dealed with aerosol-Stratocumulus cloud interaction: cloud formation (nucleation scavenging) and in cloud and below cloud scavenging using an idealized two-dimensional kinematic model. In the model the cloud formation on water soluble aerosol particles (ammonium-sulphate), and the interstitial and below cloud scavenging of inactive and water insoluble aerosol particles were considered. Detailed microphysical sceme was used to calculate how the different size water drops (haze, cloud water and rain water) scavenged the different size of aerosol particles. The detailed result of the model you can find in: Szabó-Takacs B., 2011: Interaction between aerosol particle and Stratocumulus Clouds. Lambert Academic Publishing, Saarbrücken, Germany, p. 82

Robert

The Hegg et al paper dealt with nucleation scavenging, thus uptake in clouds, not scavenging by precip. Also, the publication was sharply criticised in commentary a later issue of AE.

Harry

do you want to suggest any paper? I am concern about the practical approach of scavenging of chemical species. thank you all for your comments.

Harry,

Indeed. Point taken.

Here is another paper of potential interest:

Chate, D. M., and P. C. S. Devara (2005), Parametric study of scavenging of atmospheric aerosols of various chemical species during thunderstorm and nonthunderstorm rain events, J. Geophys. Res.,110, D23208, doi:10.1029/2005JD006406

And a nice presentation at:

http://www2.mmm.ucar.edu/wrf/users/workshops/WS2011/Power%20Points%202011/8A_6_Pfister_WRFWorkshop_11.pdf

Arindam

I do not completely understand your question: (The) compounds you mention are in particles of a size range. This size dependence is described in general in, for instance, Seinfeld and Pandis, BUT this size range differs from place to place. Nitrate: in areas with abundant ammonia it is present as ammonium nitrate in submicron particles. Elsewhere it might be associated with calcium in larger particles that are much easier scavenged. Sodium is in mostly hypermicron sea-salt but also in coarse resuspended road-salt and as submicron consituent in emissions of oil refineries

summary: there is not a single value for the scavenging; also the rain drop spectrum varies and thus the scavenging

Harry

I got your point. so instead of looking for scavenging of ionic species one should look for the scavenging of molecules.

Aerosol scavenging by precipitation is mostly a function of the aerosol particle size (spectrum) and the hydrometeor size (spectrum).

Using formulations such as given in Seinfedl&Pandis, but also in several other publications mostly deals with calculating the collection efficiency of a typical droplet and hydrometeor and then this formulation must be integrated over both the aerosol and the hydrometeor spectrum.

Since usually precipitation rates determine the raindrop size distribution, e.g. Marhall-Palmer distribution, the total scavenging efficiency, i.e. the collection efficiency scaled with the precipitation rate integrated over a certain time interval should give you the scavenging rate or scavenging ratio of a precipitation event.

Arindam

molecules represent gases not compounds inside particles: please use the advice of dr Tost

You can quantify the scavenging of nitrate, sulfate etc. by precipitation by measuring the rain rate and the chemical composition of the rain water, which is a core task of the EMEP programme (http://www.emep.int/).

The problem is that this will not tell you the scavenging rate (or ratio) since that would require additional knowledge about the concentration of aerosols and gases entering the precipitating cloud. Furthermore, the inorganic ions found in the precipitation may originate from either gases or aerosols, and simply measuring inorganic ions in the precipitation will not tell you the relative contributions.

Designing an experiment that provides all this information is difficult.

There have been a number of campaigns in Europe addressing this problem experimentally, including the “Mount Rigi experiments” in Switzerland in the 80s/90s (Volken and Schumann, 1993; Staehelin et al., 1993), the series of CLACE campaigns at the high altitude station Jungfraujouch focusing mostly on mixed-phase clouds (e.g. Cozic et al., 2007), or more recently the "Hill Cap Cloud Thuringia 2010" experiment HCCT-2010 (Harris et al., 2014; Henning et al. 2014).

Cozic, J., B. Verheggen, et al. (2007). Partitioning of Aerosol Particles in Mixed-phase Clouds at a High Alpine Site. Nucleation and Atmospheric Aerosols. C. O'Dowd and P. Wagner, Springer Netherlands: 565-569.

Harris, E., Sinha, B., van Pinxteren, D., Schneider, J., Poulain, L., Collett, J., D'Anna, B., Fahlbusch, B., Foley, S., Fomba, K. W., George, C., Gnauk, T., Henning, S., Lee, T., Mertes, S., Roth, A., Stratmann, F., Borrmann, S., Hoppe, P., and Herrmann, H.: In-cloud sulfate addition to single particles resolved with sulfur isotope analysis during HCCT-2010, Atmos. Chem. Phys., 14, 4219-4235, doi:10.5194/acp-14-4219-2014, 2014.

Henning, S., Dieckmann, K., Ignatius, K., Schäfer, M., Zedler, P., Harris, E., Sinha, B., van Pinxteren, D., Mertes, S., Birmili, W., Merkel, M., Wu, Z., Wiedensohler, A., Wex, H., Herrmann, H., and Stratmann, F.: Influence of cloud pro-cessing on CCN activation behaviour in the Thuringian Forest, Germany during HCCT-2010, Atmos. Chem. Phys. Discuss., 14, 1617-1645, doi:10.5194/acpd-14-1617-2014, 2014.

Staehelin, J., A. Waldvogel, et al. (1993): Scientific goals and experiments of the project “winter precipitation at Mount Rigi”: An overview. Water, Air, and Soil Pollution 68(1-2): 1-14, doi:10.1007/BF00479389.

Volken, M. and T. Schumann (1993): A Critical review of below-cloud aerosol scavenging results on Mt. Rigi. Water, Air, and Soil Pollution 68(1-2): 15-28, doi:10.1007/BF00479390.

Hi Harry

Yes i am following Dr Tost advice.

Hi Dominik

Thank you for sending me some excellent papers on this topic.

I took a go at this problem, both theoretically and experimentally. It's quite interesting. Perhaps some of this will help:

http://onlinelibrary.wiley.com/doi/10.1029/2006JD007416/full

The following paper, though focussed on modelization, has an excellent introduction which describes all the involved cases (molecules, small and large particles , in-cloud/below cloud processes....

http://www.atmos-chem-phys.net/12/3289/2012/acp-12-3289-2012.pdf