ATMOSPHERIC AEROSOL-PARTICLES AND THEIR ROLE IN THE FORMATION OF DEW ON THE SURFACE OF PLANT-LEAVES

Measurements of the electrical conductivity along the surface of leaves or conifer needles show that the wetting of such surfaces coated with wax already starts below a relative humidity of 100%. To explain the observations, the deposition of water soluble atmospheric aerosol particles on these surfaces is taken into account. It is shown that the capillary space between particle and settling surface and, as an additional indispensable condition, the water solubility of at least some constituents of the atmospheric aerosol particle (i.e. a combined capillary solution effect), permits the formation of condensate or dew water significantly below a r.h. of 100%.