Rico Empirical and theoretical studies of dry deposition to terrestrial ecosystems have primarily been limited to uncomplicated terrain with homogeneous vegetation. The few field observations in complex terrain show that dry deposition is enhanced to a considerable degree by variation in topography and canopy structure. I propose to study variations in atmospheric deposition related to topography and canopy structure in the Luquillo Mountains of Puerto Rico by use of the chloride ion. Rain fluxes of chloride will be determined by collections in clearings or above the canopy, TF fluxes under the canopy, and dry deposition by difference. Chloride fluxes are not altered in the canopy, nor microbiologically in field samples, so that samples can be collected at long intervals if required.
Analysis is by liquid chromatography.
Atmospheric deposition of ozone, or N or S containing compounds are of great interest, but present methodological problems because of canopy interactions. Fortunately, the deposition fluxes are interrelated. The difference among all these forms of dry deposition is controlled by surface resistance, because all are delivered to the boundary layer of canopy surfaces by the same turbulent mixing. The Cl deposition results can therefore be extended to other chemical species with literature values for surface resistance. Complexities arise for gases that have sources at the soil surface, but these are certainly not unique to the study proposed here.