Dry deposition velocities and surface-to-canopy scaling factors for aerosol calcium from forest canopy throughfall

Important problems in quantifying dry deposition to plant canopies include spatial and temporal representativeness of modeled fluxes and scaling from point measurements to the landscape. Micrometeorological approaches are limited to simple terrain and short intervals and are not applicable to coarse particles. Quantifying dry deposition of aerosols in the coarse mode, such as Ca and Mg in soil dust, is necessary to predict the effects of acidic deposition on lake acidification and forest nutrition. Although inert or surrogate surfaces can be used to measure particle fluxes, they do not reproduce foliage.