Predictions for particle deposition to vegetative canopies

Gas-particle interactions above a Dutch heathland: III. Modelling the influence of the NH<sub>3</sub>-HNO<sub>3</sub>-NH<sub>4</sub>NO<sub>3</sub> equilibrium on size-segregated particle fluxes

“…review by Gallagher et al, 1997) tending to larger values than predicted by theoretical models (Slinn, 1982) and observed during wind tunnel studies (Chamberlain, 1966). In addition, particles frequently show apparent upward fluxes (cf.…”

“…This parameterization is either taken from field measurements, which appear to be unaffected by gtpc processes (cf. Nemitz et al, 2004b) or from theoretical studies, such as Slinn (1982).…”

“…This scenario shows that if equilibrium is attained at a higher height and exceeded near the surface, gtpc will result in a decrease of the particle deposition flux with height (with the potential for apparent particle emission fluxes if determined by gradient methods), but apparent emission from the sizesegregated EC measurements will never occur, as the flux follows the parameterization of the surface deposition at the equilibrium height, which serves as a lower limit. The prediction of V ds derived for z=2 m (thin lines) resulting from three different parameterizations of V ds,inert (bold lines), according to Slinn (1982), (Nemitz et al, 2004b, Eq. 12) and V ds,inert ≡4 mm s −1 .…”

Development of an Atmosphere-Soil-Vegetation Model for Investigation of Radioactive Materials Transport in the Terrestrial Biosphere

“…(14) is an empirically determined number based on experimental measurements of filter efficiencies. Equation (14) includes both effects of convection (Re) and particle diffusion (Sc) and is physically more reasonable than the prior parameterizations using only Sc in the commonly used model such as Slinn 24) and Zhang et al 25) . When small particles perfectly follow a streamline that happens to come within one particle radius of the foliar surface, the particle hits the leaf and is captured because of its finite size (interception).…”

Dry nitrogen deposition estimates over a forest experiencing free air CO2 enrichment

“…Particulate NO 3 À and NH 4 1 deposition velocities were estimated using a version of Slinn's (1982) model, modified to account for particle speciation and surface wetness (Ruijgrok et al, 1997). Deposition rates for HNO 3 and NH 3 were calculated using the classic resistance analogy (Hicks et al, 1987) in which the deposition velocity is viewed as the reciprocal of the sum of resistances to deposition due to turbulence (R a , calculated via Garland, 1977), diffusion across the quasilaminar sublayer of air surrounding the receptor elements (R b , calculated via Meyers et al, 1989), and surface uptake processes that collectively determine the canopy resistance (R c ).…”