大城市气溶胶对光化辐射通量及臭氧的影响研究(Ⅱ)——数值试验分析

Study on the Effect of Atmospheric Aerosol on Actinic Flux and Ozone in Large City PartⅡ: Numerical Test Analyses

城市化已引起大量痕量气态污染物、气溶胶以及臭氧前体物的人为排放。从而引起区域大气化学循环的扰动变化。在分析国内外研究现状与观测实例的基础上，进一步用辐射模式与化学模式研究了气溶胶对到达地面的光化辐射通量以及臭氧形成的影响，表明气溶胶可显著减小到达地面的光化学辐射通量，减缓光化学反应进程，并进一步抑制臭氧的形成：在目前广州等大城市的污染过程中，高浓度的气溶胶可造成光化学辐射通置衰减高达70％～80％，紫外线的衰减比可见光更明显，在可见光波段随波长增大衰减幅度减小，气溶胶层的存在对短波长激发-的光化学过程的影响更加显著。分析说明城市污染大气中光化学反应的生成物与反应物之间存在自抑制过程，在目前的城市群复合污染情况下，气溶胶与臭氧之间的非线性相互作用值得关注。

Urbanization has caused a large amount of emissions of trace gaseous pollutants, aerosols and ozone precursors, inducing the disturbance in regional atmospheric chemistry circulation. Based on analyses of domestic and abroad research status and observational cases, the study on the effects of aerosols on surface actinic flux and ozone formation has been made by using radiative model and chemical model. The results show that aerosols can significantly attenuate the surface actinic flux, reduce photochemical reaction process, and further inhibit the ozone formation. In the current pollution process in Guangzhou city, heavy pollution aerosol can reduce surface actinic flux up to 70% -80%, and the attenuation at ultraviolet band is more obvious than that at visible band. The attenuation tendency drops as the wave length increases at visible band. The effect of aerosols on the photochemical reaction processes driven by shorter- wave radiation is significant. The results also reveal that there exists self - restraining processes between the reactants and products of photochemical reaction in urban polluted air. It is worth paying attention to the nonlinear interactions between aerosols and ozone in current complex pollution in city cluster.