Total Deposition of Trace Elements

Abstract

In contrast to grass surfaces where the wet deposition, depending on wind conditions and hence friction velocity, contributes from one-half to two-thirds of the total deposition (Michaelis et al. 1989, 1990), the total flux into forests is predominantly determined by the dry deposition. As a consequence, in this case, rainfall studies alone do not yield representative insight into the atmospheric impact. Figure 10.1 illustrates the relative portions of the two deposition modes for the elements sulphur, arsenic, cadmium and lead plotted quarterly for several years of the investigation period. The partition differs from element to element and in part also from year to year. In each case, a distinct seasonal variation occurs due to the meteorological influence (cf. Chaps. 7 and 9).