Washout/rainout contribution in wet deposition estimated by 0.5 mm precipitation sampling/analysis

摘要

A precipitation dataset collected on a 0.5 mm precipitation basis was studied. The parameters analyzed in this study were the pH (i.e., H concentration), electric conductivity (EC), and SO_4~(2-) and NO_3 concentrations. The NO_3~- concentration clearly decayed with an increase of the precipitation amount, while a larger variation was observed in the SO_4~2 concentration even when the precipitation amount increased. Assuming that the decaying NO_3~- concentration (0.70 μg ml~1) was the result of the rainout process, the estimates were: annual total deposition. 3252 mg m~(-2) yr~(-1); rainout process, 1092 mg m~(-2) yr~(-1); and rainout/total, 34%. The estimates for SO_4~(2-) were: annual total deposition, 4687 mg m~(-2) yr~(-1); rainout process, 2096 mg m~(-2) yr~(-1); and rainout/ total, 45%.