为了研究不同混合方式对气溶胶粒子光学性质的影响，利用典型外混合模型和三种内混合模型，计算了黑碳与硫酸盐及有机碳组成的混合气溶胶在550 nm波长处的光学性质。结果表明，除Maxwell-Garnett模型与Bruggeman模型的差异普遍小于2%外，所有混合模型对混合粒子及粒子群的光学性质都有明显影响。相比于外混合粒子群，内混合粒子群的吸收系数增强了20%以上，散射系数则削弱了10%~15%，并导致消光系数的最大增强达到25%；内混合模型对于单次散射反照率的减弱效果最明显，尤其在黑碳体积比小于30%和相对湿度高于70%的情况下，内混合模型使粒子群的单次散射反照率降低了20%以上。此外，除不对称因子外，混合气溶胶的其他光学性质与体积混合比以及相对湿度均呈现出明显的相关性。

In order to study the impact of mixing ways of aerosols on their optical properties, one typical external mixing model plus three different internal mixing models of aerosols are introduced. The optical properties of mixed aerosol particles formed by black carbon, sulfate and organic carbon at 550 nm wavelength are calculated. The results show that there are great differences in optical properties of mixing particles and particle groups obtained by these models except Maxwell-Garnett model and Bruggeman model (difference less than 2%). Compared with externally mixed particle groups, the mass absorption factors of internally mixed particle groups are increased by about 20%, while the mass scattering factors of the particle groups are decreased by 10%~15% in most cases. The internal mixing models make a large enhancement of the mass extinction factors of mixed particle groups by 25% for maximum. Furthermore, the reduction of single scattering albedo is significant. In particular, the reduction of the scattering albedo of the mixed particle groups can be larger than 20% under circumstances that the volume ratio of black carbon is below 30% and the relative humidity is above 70%. In addition, optical properties of mixed particles, except the asymmetry parameter, are distinctly related to the change of volume ratio or relative humidity.