Dry deposition models and the air/sea exchange of trace elements

Abstract

Dry deposition rates of representative trace elements were calculated from measured mass‐particle size distributions and two deposition models (Slinn and Slinn, 1980; Williams, 1982). The aim of the study was to investigate how deposition rates were affected by (1) differences in transfer velocities to smooth and broken water surfaces, (2) wind speed, and (3) relative humidity. Comparisons of the dry deposition rates that were calculated for sodium and aluminum suggest that surface waves do not greatly affect the dry deposition rates of sea‐salt or mineral aerosol particles, respectively. In contrast, the deposition rate for 210Pb was as much as 5 times higher when a term was included to account for the effects of broken water surfaces. These results suggest that the air/sea exchange of a substance whose mass is predominately associated with small particles may be significantly enhanced by deposition to broken water surfaces.