大气新粒子生成参数化方案的测量与应用研究

Measurement and Application of Atmospheric New Particle Formation Parameterization

该研究搭建流动管反应器研究了气态硫酸-水-氨气(H2SO4-H2O-NH3)三元成核体系,实测了不同NH3浓度条件下新粒子成核速率和生长速率与前驱气体浓度、温度和湿度各影响因素之间参数化关系。依据气溶胶动态平衡方程,结合实际大气成核过程中成核速率、碰并清除速率、生长速率和新粒子浓度变化速率的定量联系,间接估算出大气新粒子碰撞捕获效率系数γ在10 nm以下平均值为0.07,在10~20 nm平均值为0.12。结合Kerminen and Kulmala公式,将实测的参数化关系式耦合到区域空气质量模型WRF-Chem中,用模式模拟了2016年杭州G20会议期间新粒子生成粒径谱、纳米级气溶胶数浓度和亚微米气溶胶数浓度,结果表明能够在一定程度上预测新粒子生成事件的发生和超细粒子的数浓度。

New particle formation from gaseous H2SO4-H2O-NH3 using a flow tube reactor was investigated.The relations between nucleation rate,growth rate and gaseous concentration,temperature and relative humidity were measured.Coagulation sticking probability of new particles onto pre-existing aerosols was estimated to be 0.07 on average for sub-10 nm new particles and 0.12 on average for 10-20 nm particles,on the basis of the quantitative relationship among nucleation rate,growth rate,coagulation rate and number concentration change rate in the atmosphere.Using Kerminen and Kulmala equation,nucleation and growth parameterizations were incorporated into WRF-Chem to simulate new particle formation events observed during 2016 G20 Summit in Hangzhou.The simulation of size spectra,number concentration of sub-100 nm particles and number concentration of 100~1000 nm particles indicated that the new parameterization can predict the occurrence and intensity of new particle formation events.