Precipitation scavenging

Sinks, chemical species, or method OH, reaction with OH radical S, sedimentation P, precipitation scavenging NO, reaction with NO radical uv, photolysis by ultraviolet radiation Sr, destmction at surfaces O, adsorption or destmction at oceanic surface. 

Upward diffusion of water vapor through the cold temperatures of the tropopause is very inefficient in fact, the upper limit of cloud formation often occurs at the tropopause. Thus the stratosphere is so dry as to prevent rain formation, and particles and gases have very much longer residence times there than in the troposphere. Stratospheric removal requires diffusion back through the tropopause, which then may be followed by precipitation scavenging. 

Under some circumstances transport processes other than fluid motion and molecular diffusion are important. One important example is sedimentation due to gravity acting on particulate matter submerged in a fluid, e.g., removal of dissolved sulfur from the atmosphere by precipitation scavenging, or transport of organic carbon from the surface waters to the deep... 

The concentration of small ions in the atmosphere is determined by 1) the rate of ion-pair production by the cosmic rays and radioactive decay due to natural radioactive substances, 2) recombination with negative ions, 3) attachment to condensation nuclei, 4) precipitation scavenging, and 5) transport processes including convection, advection, eddy diffusion, sedimentation, and ion migration under the influence of electric fields. A detailed differential equation for the concentration of short-lived Rn-222 daughter ions including these terms as well as those pertaining to the rate of formation of the... 

Heavy metals are removed from the atmosphere by means of surface uptake and precipitation scavenging. The ecosystem-specific dry deposition scheme is based on the resistance analogy approach and distinguishes 16 land use types. Wet removal by precipitation considers both in-cloud and sub-cloud scavenging. 

The advection scheme of the regional model is improved to take into account the surface orography. Terrain following vertical structure of the model domain with higher resolution was incorporated. Wet removal of heavy metals from the atmosphere was enhanced by developing newparameterizations of precipitation scavenging. Both in-cloud and sub-cloud wet removal were modified on the basis of the up-to-date scientific literature data. 

Davies, T. D., and J. R. Mitchell, Dry Deposition of Sulphur Dioxide onto Grass in Rural Eastern England with Some Comparisons with Other Forms of Sulphur Deposition, in Precipitation Scavenging, Dry Deposition, and Resuspension, Vol. 2, Dry Deposition and Resuspension (H. R. Pruppacher, R. G. Semonin, and W. G. Slinn, Eds.), pp. 795-804, Elsevier, New York, 1983. 

Hales, J. M A Generalized Multidimensional Model for Precipitation Scavenging and Atmospheric Chemistry, Atmos. Environ., 23, 2017-2031 (1989). 

Atlas E, Giam CS. 1987. Ambient concentration and precipitation scavenging of atmospheric organic pollutants. Water Air Soil Pollut 38 19-36. 

Radionuclides with half-lives of minutes to hours would be useful in studying atmospheric precipitation scavenging mechanisms since their half-lives are of the same order of magnitude as the time scale on which... 

Some recent studies of the resuspension of deposited material from soil and grass. In Precipitation Scavenging, Dry Deposition and Resuspension, ed. H.R. Pruppacher, R.G. Simonin W.G.N. Slinn, pp. 1087-97. Amsterdam Elsevier. 

Murray, M.W., Andren, A.W. (1992) Precipitation scavenging of polychlorinated biphenyl congeners in the Great Lakes region. Atmos. Environ. 26A., 883-897. 

Tucker, W.A., Lyman, W.J., Preston, A.L. (1983) Estimation of the dry deposition velocity and scavenging ratio for organic chemicals. In Precipitation Scavenging, Dry Deposition, and Resuspension. Pruppacher, et al., Editors, pp. 1242-1256, Elsevier Science Publishing Co., New York. 

Transport from the atmosphere to land and water Dry deposition of particulate and gaseous pollutants Precipitation scavenging of particulate and gaseous pollutants Adsorption of gases onto particles and subsequent diy and wet deposition Transport within the atmosphere Turbulent dispersion and convection Atmospheric transformation Diffusion to the stratosphere Photochemical degradation Oxidation by free radicals and ozone Gas-to-particle conversion... 

The following arguments may indicate that precipitation scavenging of fresh EC in fumulus clouds may not be too important. 

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