云下洗脱-Eulerian模式

SCAVENGING BELOW-CLOUD——EULERIAN MODEL

在Eulerian模式中,在大气氨浓度大于硝酸的条件下,简要讨论了各种污染物对雨水组成的影响.结果表明,在本文考虑的情况下,氨对SO_2气体洗脱和SO^(2-)形成的影响最大,且能抑制雨水的酸化;过氧化氢的作用略小于氨.气溶胶对雨水SO_4^(2-)浓度的贡献小于气体.云下H_2O_2和O_3氧化能力的大小取决于雨水的pH、降落距离和各自的浓度.在雨水pH高,降落距离短和各自浓度小时,O_3的氧化能力大于H_2O_2,反之则H_2O_2大于O_3.对韶关降水酸化的模拟表明,考虑气体污染物补充机制的Eulerian模式可以较好地模拟现场降水酸化过程.

Effects of initial concentrations of atmospheric pollutants on composition of ground rainwater are discussed based on Eulerian model. A base gas scenario is designed to be with concentration of NH3 gas much greater than that of HNO3(g). The simulation results indicate that NH3 is the most important gas for SO3 gas scavenging and SO_4~2- formation among various gases below -cloud at the conditions considered in this study, and the next is H2O2. The results also show that the oxidation rate of S(Ⅳ) by H2O2 and O3 in raindrops depends on pH, fall distance below-cloud and their concentrations. At high pH value, short fall distance and low concentrations of H2O2 and O3, S(Ⅳ) oxidation by O3 is dominant, otherwise, S(Ⅳ) oxidation by H2O2 is more important than by O3. The simulation for Shaoguan precipitation acidification shows that the results obtained by Eulerian model are generally consistent with that from field observations.