层状云降水中化学过程的数值模拟

对一维时变的层状云物理化学模式的化学过程作了研究，引入了较为细致的化学模式，并以类似化学反应方程式的方式处理了气液传输、碰并和云雨转化过程。在此基础上讨论了典型条件下的云雨酸化过程。模拟结果表明，高空云雨水组成随时间逐渐减小，地面雨水组成呈峰型分布。在降水后期pH值主要同O₃和SO₂有关；主要来自气溶胶，来自NH₃，气体和气溶胶对的贡献大致相当，和Ca￣(2＋)的云下清除约占60％～80％；在降水前期H₂O₂时S(Ⅳ)的氧化超过O₃，降水后期S(Ⅳ)的氧化主要通过O₃。 

Numerical Simulation of Chemical Process in Stratiform Precipitation

A more detailed chemical process involved in an one-dimensional,time-dependent,physi-cochemical model of stratiform clouds is studied.The transmission process between gaseous and aque-ous phases, he transformation of cloud water to rainwater and the collision process are deaIt with by means of chemical equations. Based on the above approach the acidification of precipitation and wet re-moval of pollutants are simulated.The numerical tests show that the concentrations of components in the upper cloud and rainwater decrease with time gradually,but to the rainwater on the ground,it has peak profiles. In later precipitation the pH of rainwater depends mainly on the concentrations of O3 and SO2. In rainwater,the majority of results from aerosols,from NH3 gas,and from gases and aerosols equally.In average,the below-cloud scavenging of ,,or has a proportion between 60%and 80%.The oxidation of S(Ⅳ)by H2O2 is more im-portant than that by O3 in initial precipitation,but less important in late precipitation.